UNITED STATES ENVIRONMENTAL PROTECTION AGENCY

WASHINGTON, D.C.  20460

	OFFICE OF PREVENTION, PESTICIDE

	AND TOXIC SUBSTANCES

  SEQ CHAPTER \h \r 1 MEMORANDUM

Date:  22 October 2009

SUBJECT:	Endothall; Petition for Tolerances on Irrigated Crops.  Summary of Analytical Chemistry and Residue Data.

PC Codes:  038901, 038904 and 038905	DP Barcode:  356315

Decision No.:  399181	Registration Nos.:  70506-175 and 70506-176

Petition No.:  8E7419	Regulatory Action:  Section 3

Risk Assessment Type:  NA	Case No.:  2245

TXR No.:  NA	CAS Nos.:  145-73-3; 2164-07-0; 66330-88-9

MRID No.:  See MRID Summary Table	40 CFR:  180.293

		              									Ver.Apr.08

FROM:	David Soderberg, Chemist  SEQ CHAPTER \h \r 1

		HED, RAB V (7509P)

THROUGH:	Jack Arthur, Chief

		HED, RAB V (7509P)

TO:		Sidney Jackson, Product Manager  SEQ CHAPTER \h \r 1   SEQ CHAPTER \h \r 1

		Barbara Madden, Team Leader

RD, Risk Integration, Minor Use and Emergency Response Branch,

Minor Use Team (7505P)

MRID Summary Table

MRID No.	Study Type	Comments

47520701	860.1400 Irrigated Crops (Root & Tuber Vegetables)	New DERs, 47520701.de1 (sugar beet, carrot and potato field trials) and  47520701.de2 (sugar beet processing study)

47520702	860.1400 Irrigated Crops (Bulb Vegetables)	New DERs, 47520702.de1 (onion field trials)

47520703	860.1400 Irrigated Crops (Leafy Vegetables)	New DER, 47520703.der (lettuce field trials)

47520704	860.1400 Irrigated Crops (Brassica Leafy Vegetables)	New DER, 47520704.der (cabbage field trials)

47520705	860.1400 Irrigated Crops (Legume Vegetables)	New DER, 47520705.de1 (pea, bean and soybean field trials) and 47520705.de2 (soybean processing study)

47520706	860.1400 Irrigated Crops (Fruiting Vegetables)	New DERs, 47520706.de1 (tomato field trials) and 47520706.de2 (tomato processing study)

47520707	860.1400 Irrigated Crops (Cucurbit Vegetables)	New DER, 47520707.der (cucumber field trials)

47520708	860.1400 Irrigated Crops (Citrus Fruits)	New DER, 47520708.de1 (orange field trials) and 47520708.de2 (orange processing study)

47520709	860.1400 Irrigated Crops (Pome Fruit)	New DERs, 47520709.der (apple field trials) and 47520709.de2 (apple processing study)

47520710	860.1400 Irrigated Crops (Stone Fruit)	New DER, 47520710.der (peach field trials)

47520711	860.1400 Irrigated Crops (Berry Group)	New DER, 47520711.der (blueberry and blackberry field trials)

47520712	860.1400 Irrigated Crops (Tree Nut Group)	New DER, 47520712.der (almond and pecan field trials)

47520713	860.1400 Irrigated Crops (Cereal Grain)	New DER, 47520713.de1 (corn, sorghum and wheat field trials) and 47520713.de2 (corn, sorghum and wheat processing studies)

47520714	860.1400 Irrigated Crops (Grass)	New DER, 47520714.der (grass field trials)

47520715	860.1400 Irrigated Crops (Nongrass animal feeds)	New DER, 47520715.der (alfalfa field trials)

47520716	860.1400 Irrigated Crops (Grapes)	New DER, 47520716.de1 (grape field trials) and 47520716.de2 (grape processing study)

47520717	860.1400 Irrigated Crops (Mint)	New DER, 47520717.de1 (mint field trials) and 47520707.de2 (mint processing study)

47520718	860.1400 Irrigated Crops (Rice)	New DER, 47520718.de1 (rice field trials) and 47520718.de2 (rice processing study)

47520719	860.1380 Storage Stability (Various Crops)	New DER, 47520719.der (plant storage stability data)

  SEQ CHAPTER \h \r 1 This document was originally prepared under contract by Dynamac Corporation (1910 Sedwick Road, Building 100, Suite B; Durham, NC 27713).  The document has been reviewed by the Health Effects Division (HED) and revised as needed for clarity, correctness, and to reflect current Office of Pesticide Programs (OPP) policies.

Executive Summary

  SEQ CHAPTER \h \r 1 Endothall is a selective contact herbicide, defoliant, desiccant, and aquatic algaecide belonging to the dicarboxylic acid chemical class.  The free acid of endothall and its dipotassium and mono-N,N-dimethylalkyl-amine salts (monoalkylamine) are registered in the United States primarily as aquatic herbicides for the control of a variety of plants in water bodies.  This includes irrigation canals, but only with a 7 day holding period.  Endothall is also registered for desiccation/de-foliation of alfalfa/clover (grown for seed only), cotton, and potatoes prior to harvest, and for reduction of sucker branch growth in hops.  Permanent tolerances have been established for the combined residues of endothall and its monomethyl ester at 0.1 ppm in/on cotton seeds, fish, dried hops and potatoes, and at 0.05 ppm in/on rice grain and straw [40 CFR §180.293(a)(1)].  An interim tolerance of 0.2 ppm has also been established for endothall, per se, in potable water resulting from the use of the monoalkylamine or dipotassium salts of endothall for control of aquatic plants in canals, lakes, ponds and other potential water sources.  An interim tolerance has also been established for endothall on sugar beet at 0.2 ppm [40 CFR §180.319].

There are currently three endothall end-use products registered to United Phosphorus, Inc. (UPI) for control of algae and aquatic weeds in drainage and irrigation canals, including two monoalkylamine salt formulations and a dipotassium salt formulation.  The monoalkylamine salt of endothall is formulated as either a 2 lb ae/gal SC/L formulation (EPA Reg. No. 70506-175) or an 11% granular (G) formulation (EPA Reg. No. 70506-174), containing 5% ae.  The dipotassium salt is formulated as a 4.23 lb ai/gal SC/L (EPA Reg. No. 70506-176), which is equivalent to 3.0 lb ae/gal SC/L.  [In order to avoid the complications of different molecular weights for different salts, endothall concentrations are expressed as the free acid equivalents (ae).]  Labels for these products allow for repeated broadcast applications to irrigation canals at rates yielding endothall concentrations of up to 5 ppm ae for the monoalkylamine salt and 3.5 ppm ae for the dipotassium salt.  The labels do not currently specify a maximum number of applications per season or a maximum seasonal use rate.  Depending on the concentration in the treated water, the use directions specify minimum holding times of 7 days (0.3 ppm rate) to 25 days (5 ppm rate) prior to using the treated water for irrigation of crops.

Interregional Research Project No. 4 (IR-4) has proposed amending the use directions for the 2 lb ae/gal SC/L monoalkylamine salt and the 3 lb ae/gal dipotassium salt of endothall to remove the holding times after water is treated with endothall before it can be used to irrigate crops, which would enable use of endothall on moving water in canals etc, and would effectively create a zero day PHI.  The amended uses specify minimum retreatment interval (RTI) of 7 days for irrigation canals and a maximum seasonal use rate of 30 ppm ae per season (6 applications at up to 5 ppm ae/application). In conjunction with the proposed amendments, IR-4 has proposed the following tolerances for indirect or inadvertent residues of endothall on irrigated crops:

Vegetable, root and tuber, group 1	2 ppm

Vegetable, leaves of root and tuber, group 2	3.5 ppm

Vegetable, bulb, group 3-07	2 ppm

Vegetable, leafy, except Brassica, group 4	3.5 ppm

Vegetable, Brassica, leafy, group 5	0.1 ppm

Vegetable, legume, group 6	3 ppm

Vegetable, fruiting, group 8	0.05 ppm

Vegetable, cucurbit, group 9	1.1 ppm

Fruit, citrus, group 10	0.05 ppm

Fruit, pome, group 11	0.05 ppm

Fruit, stone, group 12	0.25 ppm

Berry and small fruit, group 13-07	0.6 ppm

Nut, tree, group 14	0.05 ppm

Almond, hulls	10 ppm

Grain, cereal, group 15	2.5 ppm

Grain, cereal, forage, fodder and hay, group 16, forage	3.5 ppm

Grain, cereal, forage, fodder and hay, group 16, hay	5 ppm

Grain, cereal, forage, fodder and hay, group 16, stover	11 ppm

Grain, cereal, forage, fodder and hay, group 16, straw	6 ppm

Grain, aspirated fractions	24 ppm

Grass, forage fodder, and hay, group 17, forage	3 ppm

Grass, forage fodder, and hay, group 17, hay	19 ppm

Nongrass animal feed, group 18, forage 	3.5 ppm

Nongrass animal feed, group 18, hay	8 ppm

Grape	0.9 ppm

Peppermint tops	7 ppm

Spearmint tops	7 ppm

Rice, grain	1.7 ppm

Rice, straw	4.5 ppm

The qualitative nature of endothall residues in plants is adequately understood based upon the metabolism studies on alfalfa, cotton and sugar beets.  The qualitative nature of endothall residues in livestock is also understood based upon the adequate goat and poultry metabolism studies.  The Agency has concluded that endothall and its monomethyl ester are the residues of concern in both plant and animal commodities for purposes of the tolerance expression and risk assessment.    SEQ CHAPTER \h \r 1 The residue of concern in water is only endothall.

  SEQ CHAPTER \h \r 1 A GC method with microcoulometric nitrogen detection is listed as Method I in the Pesticide Analytical Manual (PAM, Volume II) for determining endothall residues in/on crop commodities, and a confirmatory HPLC/MSD method (Method No. KP218R0) is also available for determining residues of endothall and its monomethyl ester in fish and residues of endothall in plant commodities.  For the irrigated crop field trails and processing studies submitted with the current petition, endothall residues in/on plant commodities were determined using an adequate LC/MS/MS method (Method No. KP-242R1).  For this method, residues are extracted with water and then derivatized with heptafluoro-p-tolylhydrazine (HFTH) in 50% H3PO4.  The derivatized residues are cleaned up by solvent partitioning and elution through a solid phase extraction (SPE) cartridge.  Residues are then analyzed by LC/MS/MS using external standards for quantitation.  Residues are expressed in endothall acid equivalents, and the validated limit of quantitation (LOQ) for endothall is 0.05 ppm for plant commodities.

  SEQ CHAPTER \h \r 1 Adequate storage stability data are available supporting the sample storage conditions and durations for the irrigated crop field trials and processing studies.  The newly submitted storage stability data indicate that endothall is stable for up to 15 months in frozen tomatoes, lettuce, sugar beet roots, and corn grain and for up to 10 months in soybean seeds and oil.

The submitted field trial data on irrigated crops were conducted according to the previously submitted protocol.  Two to four field trials were conducted on each of the following crops in their major growing regions: potato, carrot, sugar beet, green and bulb onions, leaf and head lettuce, cabbage, succulent podded peas and beans, dry beans, soybean, tomato, cucumber, orange, apple, peach, blueberry, blackberry, grape, pecan, almond, field and sweet corn, sorghum, wheat, rice, alfalfa, grasses and mint.  These crops were selected to represent the major crop groups.  In each field trial, the monoalkylamine salt of endothall (2 lb ae/gal SC/L) was used to treat the irrigation water at a rate of ~5 ppm ae, and the treated water was then applied via overhead sprinklers as six broadcast foliar applications at RTIs of 5-10 days.  [The target application volume in each trial was equivalent to ~1 acre inch of water (27,154 gal/A).  Based on the concentration of the endothall in the irrigation water and the amount of water applied, the application rates for endothall were equivalent to 1.10-1.25 lb ae/A/application, for totals of 5.64-7.17 lb ae/A/season.]   We note that each field trial comprised only a single plot that was then sampled twice to provide two results.

With only a few exceptions, samples of the regulated raw agricultural commodities (RACs) from each crop were harvested on the day of the sixth application (0 days after treatment, DAT).  The 0 DAT exceptions comprise soybean seed harvested from one plot at 1 DAT, wheat grain and straw (and also the source of the aspirated grain fraction result) harvested from one plot at 1 DAT, rice grain and straw harvested from one plot at 1 DAT, some of the grass samples harvested at 1 – 2 DAT.  (Interestingly, much higher results were found for the single soybean seed and single wheat grain samples harvested at 1 DAT than for the other soybean samples and wheat grain samples harvested at 0 DAT.  This was not true for rice.)   In addition, in the field corn, sorghum and wheat field trials, samples of forage and hay (wheat only) were collected at 0 DAT, but following only 2 or 3 applications of endothall treated water.

Side-by-side tests were also conducted on some of these crops (sugar beets, lettuce, cucumber, and peaches) comparing application of the dipotassium salt of endothall (3 lb ae/gal SC/L) with the monoalkylamine salt.  Although the dipotassium salt was applied to the irrigation water following the label directions for that salt, the resulting concentration of endothall in the water was 3.5 ppm ae (0.7x rate).  [The application rates for the dipotassium salt were equivalent to 0.74-091 lb ae/A/application, for totals of 4.67-5.07 lb ae/A/season.]

Several deficiencies were noted in the field trials (see below), but the submitted field trial data can generally be considered adequate for assessing inadvertent residues of endothall on irrigated crops.  Results should be very conservative.

The residues determined in the 0 DAT samples should represent an over-estimate of residues for many of the crops tested because irrigation on the day of harvest would be highly unlikely to occur in commercial harvesting procedures.  Crops and commodities which would be unlikely to be irrigated just prior to harvest include: sugar beets, carrots, potatoes, dry bulb onions, dried peas and beans, soybeans, tree nuts, field corn grain and stover, sorghum grain and stover, wheat grain and straw, and rice grain and straw.

Also, all crops were overhead irrigated.  For grapes at least, according to BEAD, the vines may be overhead irrigated when not in fruit, as in these trials, but are usually only irrigated by drip irrigation once in fruit, to reduce the growth of mold on the grape.  In addition, HED notes that phytotoxicity was reported on a number of the crops tested, including legume vegetables, cucumbers, apple trees, peach trees, grape vines, mint and grass.  The phytotoxicity generally appeared beginning after the second application and consisted of leaf chlorosis and necrosis, with some crops also having reduced growth and stunting.  The occurrence of phytotoxicity on a wide range of crops suggests that repeated irrigation with water containing high levels (5 ppm) endothall is unlikely to occur undetected under normal agricultural conditions.  Finally, of course, the application rate used was, appropriately, at the maximum permitted rate, and the number of applications at the high end of the number of treatments expected in a season.  As always, it is expected that the maximum rate and maximum number of treatments will not be often used.

Adequate processing studies were submitted for all possible irrigated crops, with the exception of oil seed crops and processing of grapes to grape juice.  Although no processing data were submitted for any crops in the “Oilseeds Crop Group”, the available soybean processing study can serve that purpose in this case and indicates that endothall residues are unlikely to concentrate in either oilseed meal or refined oil.  Because there were problems in study for processing grapes into grape juice, a maximum theoretical processing factor of 1.2x has been used in place of the study data.  Grape juice can therefore take the same tolerance as grapes.

Based on the highest average field trial (HAFT) residues for the various irrigated crops and the observed processing factors, separate tolerances are required for the following processed commodities at the recommended levels:  apple wet pomace (0.15 ppm), raisins (3 ppm), dried citrus pulp (0.1 ppm), rice hulls (5 ppm), soybean hulls (0.3 ppm), sugar beet molasses (1.2 ppm), tomato paste (0.1 ppm), and wheat milled byproducts (5 ppm).  The wheat grain processing study also indicates that endothall residues can concentrate in aspirated grain fractions (AGF) by 15x.  Based on the HAFT residues for wheat grain, which were the highest for all grains, an appropriate tolerance for AGF would be 30 ppm.

No cattle and poultry feeding studies have been submitted for endothall.  Considering the exposure of livestock to endothall residues through both the consumption of feedstuffs from irrigated crops and from the drinking of endothall treated water treated at 5 ppm endothall ae, the calculated maximum dietary exposure of livestock to endothall is 27.7 ppm for beef cattle, 35.8 ppm for dairy cattle, 16.8 ppm for poultry, and 19.7 ppm for swine.

Proposed tolerances in meat tissues have therefore been based upon these dietary burdens and upon the TRR developed in the meat tissues when goats and chickens were fed radiolabeled endothall for the metabolism studies.  Approval will require confirmatory submission of the required feeding studies.

The Agency has concluded that the only residues of significance in rotated crops are endothall and its monomethyl and dimethyl esters.  Although data from limited field rotational crop trials have been previously required, the inadvertent exposure of crops to endothall via the use of treated irrigation water will exceed the potential exposure of crops from being planted in rotation with endothall treated primary crops.  Therefore, the establishment of tolerances for indirect/inadvertent residues of endothall on the proposed irrigated crops precludes any further need for limited field rotational trial data or for rotational crop tolerances.

  SEQ CHAPTER \h \r 1 Regulatory Recommendations and Residue Chemistry Deficiencies

Several deficiencies were noted in the subject petition, but none of these would preclude establishing permanent tolerances for inadvertent endothall residues in/on irrigated crop commodities.  Although the following deficiencies were noted in the irrigate crop field trials, no action is required to resolve these deficiencies.

	•	The bridging studies comparing the use of the monoalkylamine and dipotassium salts of endothall were of limited use as the two formulations were applied at different rates.  In terms of acid equivalents, the monoalkylamine salt was applied at a concentration of 5 ppm and the dipotassium salt was applied at a concentration of 3.5 ppm, which is the maximum allowed use rate of the dipotassium salt (0.7x rate for the monoalkylamine salt).  For each of the crops tested with both salt formulations, endothall residues were 0.6-0.9x lower for the dipotassium salt than for the monoalkylamine salt, which is consistent with the lower use rate for the dipotassium salt.  Although the bridging studies do not allow for direct comparison of the two salts, the data do indicate that endothall residues resulting from application of the dipotassium salt to irrigation canals would generally be expected to be lower than from the monoalkylamine salt, when both are applied according to current label directions.

	•	Spinach should have been used as the representative leafy vegetable crop, as foliar applications generally result in higher residues on spinach than on lettuce (leaf and head) or celery.

	•	Mustard greens should have been used as the representative Brassica vegetable crop, as foliar applications generally result in higher residues on mustard greens than on broccoli, cauliflower or cabbage.

	•	Field corn forage, sorghum forage and wheat forage and hay only received 2-3 applications prior to harvest.  For these crops, separate plots should have been established for collection of forage and hay samples so that all six applications could have made prior to harvest of forage and hay.

	•	No field trials were conducted on an oil seed crop such as, canola, flax, safflower, or sunflower.

	•	No field trials were conducted on peanuts, which is a major field crop.

The following additional deficiencies were also noted in the submitted petition; however, these deficiencies must be resolved as a condition of registration.

	•	Data are required indicating whether or not the submitted LC/MS/MS method is capable of extracting and recovering the monomethyl ester of endothall.

	•	Dairy cattle and laying hen feeding studies are required to support immediate application of endothall-treated irrigation water to crops.

	•	A revised Section F is required including the recommended tolerances on RACs and processed commodities from irrigated crops.

HED recommends for establishing permanent tolerances for indirect or inadvertent residues of endothall on irrigated crops.  The recommended tolerances for the various crops and crop groups and their associated processed commodities are listed in Table 10.  The tolerances for irrigated crops should be established under 40 CFR §180.293(d).   A human health risk assessment for endothall is forthcoming.

Background

  SEQ CHAPTER \h \r 1 Endothall is a dicarboxylic acid that is a selective contact herbicide, defoliant, desiccant, and aquatic algaecide.  The free acid of endothall (PC Code 038901) and its dipotassium (PC Code 038904) and monoalkylamine (PC Code 038905) salts are registered primarily as aquatic herbicides for the control of a variety of plants in water bodies, including irrigation canals.  However, these uses require a minimum 7 day holding period before the water can be used on crops.  They are also registered for desiccation/ defoliation of alfalfa/clover (grown for seed only), cotton, and potatoes prior to harvest, and for reduction of sucker branch growth in hops.  The Reregistration Eligibility Decision (RED) for endothall was issued September 2005.

Permanent tolerances are established for the combined residues of endothall and its monomethyl ester at 0.1 ppm in/on cotton seeds, dried hops and potatoes, and at 0.05 ppm in/on rice grain and rice straw [40 CFR §180.293(a)(1)]; and an interim tolerance has also been established for endothall on sugar beet at 0.2 ppm [40 CFR §180.319].  These tolerances are intended to cover intended direct use of endothall on these crops.  Permanent tolerances are also established for fish at 0.1 ppm straw [40 CFR §180.293(a)(1)].

Residue data supporting irrigation of crops with endothall treated water were previously submitted using cabbage, celery, grapefruit, peppers and turnips as representative crops.  However, these studies were deemed inadequate to support the establishment of crop group tolerances.  Additional data were required for other representative crop group commodities and the irrigated crop studies were conducted using endothall in the water at 3 ppm, which is 0.6x the maximum application rate of 5 ppm for aquatic sites.  The Endothall RED reiterated the need for extensive crop field trials to support the use of treated irrigation water on crops.  The application rate in these tests needed to reflect the maximum aquatic use rate of endothall (5 ppm) and the maximum possible number of applications per season.

In response to the above requirements, IR-4 has proposed amendments to the use directions for endothall on irrigation canals and has submitted extensive crop field trials to support tolerances on irrigated crops (PP#8E7419) when endothall is used with a zero day holding period.  The chemical structure and nomenclature of endothall and its salts are listed in Table 1.  The physicochemical properties of technical grade endothall and its salts are listed in Table 2.

  SEQ CHAPTER \h \r 1

Table 1.  Structure and Nomenclature of Endothall and its Salts.

Chemical Structure

Common name	Endothall

Molecular Formula	C8H10O5

Molecular Weight	186.16

IUPAC name	7-oxabicyclo[2.2.1]heptane-2,3-dicarboxylic acid

CAS name	7-oxabicyclo[2.2.1]heptane-2,3-dicarboxylic acid

CAS #	145-73-3

PC Code	038901

Current Food/Feed Site Registration	Cotton, hops, potato, alfalfa grown for seed

Chemical Structure

Common name	Endothall, dipotassium salt

Molecular Formula	C8H8K2O5

Molecular Weight	262.33

IUPAC name	Not available

CAS name	Not available

CAS #	2164-07-0

PC Code	038904

Current Food/Feed Site Registration	Cotton, hops, potato, alfalfa grown for seed, aquatic uses

Chemical Structure

Common name	Endothall, mono-N,N-dimethylalkyl amine salt

Molecular Formula	Not available

Molecular Weight	Average:  422

IUPAC name	7-oxabicyclo[2.2.1]heptane-2,3-dicarboxylic acid, compound with N,N-dimethylcocoamine

CAS name	Not available

CAS #	66330-88-9

PC Code	038905

Current Food/Feed Site Registration	Cotton, hops, potato, alfalfa grown for seed, aquatic uses

Table 2.  Physicochemical Properties of Endothall and its Salts.

Parameter	Value	Reference

Endothall (acid)

Melting point	108-110 ̊C	DP# 304026, D. Soderberg, 6/10/2004

pH	2.7 at 25 ̊C (1% solution)

	Density, bulk density, or specific gravity	0.481 g/cm3 (bulk) at 25 ̊C

	Water solubility at 25 ̊C	109.8 g/L

13.1 g/100 mL in water, pH 5

12.7 g/100 mL in water, pH 7

12.5 g/100 mL in water, pH 9

	Solvent solubility at 25 ̊C	3.4 g/100 mL in acetonitrile

2.4 g/100 mL in n-octanol

16.0 g/100 mL in tetrahydrofuran

	Vapor pressure	3.92 x 10-5 mm Hg at 24.3 ̊C

	Dissociation constant, pKa	4.32 for Step 1 and 6.22 for Step 2 at 20 ̊C (0.2% solution in 20% basic ethanol); dissociation rate 1.8-2.3 x 103 µmho within 3-5 minutes at ∼25 ̊C, by conductivity meter

	Octanol/water partition coefficient	Not applicable to endothall acid

	UV/visible absorption spectrum	Not available

	Endothall, dipotassium salt

Melting point	>360 ̊C	DP# 304026, D. Soderberg, 6/10/2004

pH	9.1 at 25 ̊C (1% solution)

	Density, bulk density, or specific gravity	0.766 g/cm3 (bulk) at 25 ̊C

	Water solubility	>65 g/100 mL in water, pH 5, pH 7, and pH 9

	Solvent solubility	<0.001 g/100 mL in acetonitrile, n-octanol, and tetrahydrofuran

	Vapor pressure	Not applicable.  An organic acid K salt is anticipated to have an insignificant vapor pressure.

	Dissociation constant, pKa	4.16 for Step 1 and 6.14 for Step 2 at 20 ̊C in water; dissociation complete at 5 mins (13.6 x 103 µmho)

	Octanol/water partition coefficient	KOW <0.02 and <0.3 at concentrations of 9 x 10-3 M and 9 x 10-4 M, respectively, at 25 ̊C

	UV/visible absorption spectrum	Not available

	Endothall, mono-N,N-dimethylalkyl amine salt

Boiling point	Not available	DP# 304026, D. Soderberg, 6/10/2004

pH	5.2 at 25 ̊C (1% solution)

	Density, bulk density, or specific gravity	1.028 g/mL at 25 ̊C

	Water solubility at 25 ̊C	≥49.2 g/100mL in water, pH 5

≥51.6 g/100 mL in water, pH 7

≥49.8 g/100 mL in water, pH 9

	Solvent solubility at 25 ̊C	≥102.5 g/100mL in acetonitrile

≥95.4 g/100 mL in n-octanol

≥104.3 g/100 mL in tetrahydrofuran

	Vapor pressure	2.09 x 10-5 mm Hg at 25 ̊C (calculated; mixed mono- and dialkylamine (C8-C20))

	Dissociation constant, pKa	4.24 for Step 1 and 6.07 for Step 2 at 20 ̊C for mixed mono- and dialkylamine (C8-C20) in acidified ethanol/water; dissociation complete ∼17 minutes (1.7 x 103 µmho) at 25 ̊C

	Octanol/water partition coefficient	KOW 2.097 at concentrations of 8.9 x 10-3 M and 8.9 x 10-4 M, at 25 ̊C

	UV/visible absorption spectrum	Not available

860.1200  Directions for Use

There are currently three endothall end-use products registered to UPI for control of algae and aquatic weeds in drainage and irrigation canals, including two monoalkylamine salt formulations and a dipotassium salt formulation.  The monoalkylamine salt of endothall is formulated as either a 2 lb ae/gal SC/L formulation (Hydrothol 191; EPA Reg. No. 70506-175) or an 11% G formulation (Hydrothol Granular; EPA Reg. No. 70506-174), which contains 5% acid equivalent of endothall.  The dipotassium salt is formulated as a 4.23 lb ai/gal SC/L (Aquathol® K; EPA Reg. No. 70506-176), which is equivalent to 3.0 lb ae/gal SC/L.

The current labels for these products allow for repeated broadcast applications to irrigation canals at rates yielding endothall concentrations of up to 5 ppm ae for the monoalkylamine salts and 3.5 ppm ae for the dipotassium salt.  (HED notes that the label directions for the dipotassium salt are expressed in lb ai rather than lb ae; therefore the use rates for the dipotassium salt are ~0.7x the use rates for the monoalkylamine salt.)  The labels do not currently specify a maximum number of applications per season or a maximum seasonal use rate.  Depending on the concentration in the treated water, the use directions specify minimum holding times of 7 days (0.3 ppm rate) to 25 days (5 ppm rate) prior to using the treated water for irrigation of crops.

IR-4 is supporting an amendment to the use directions for the 2 lb ae/gal SC/L monoalkylamine salt and the 3 lb ae/gal SC/L dipotassium salt of endothall to remove the holding time restriction for using endothall-treated water from irrigation canals for the irrigation of crops.  The amended uses also specify a minimum RTI of 7 days and a maximum seasonal use rate of 30 ppm ae per season.  Example labels containing the proposed use directions were provided and are summarized below in Table 3.

Table 3.	Summary of Proposed Use Directions for Endothall Salts on Irrigation and Drainage Canals.

Applic. Timing, Type, and Equip.	Formulation 1

[EPA Reg. No.]	Applic. Rate 2	Maximum Seasonal Rate 2	PHI (days)	Use Directions and Limitations

Endothall Monoalkylamine Salt (PC Code 038905)

Broadcast surface application to water; ground equipment	2.0 lb ae/gal SC/L

[70506-175]	5.0 ppm	30 ppm	0 3	A minimum 7-day RTI is specified.

Do not use treated water for domestic purposes or animal consumption within the following period:  0.3 ppm - 7 DAT; 3.0 ppm - 14 DAT; and 5.0 ppm - 25 DAT.

Endothall dipotassium salt  (PC Code 038904)

Broadcast surface application to water; ground equipment	3.0 lb ae/gal SC/L

[70506-176]	3.5 ppm	21 ppm	0 3	A minimum 7-day RTI is specified.

Do not use treated water for domestic purposes or animal consumption within the following period:  0.3 ppm - 7 DAT; 3.0 ppm - 14 DAT; and 5.0 ppm - 25 DAT.

1	The formulations are expressed in lb endothall ae/gal.

2	The maximum single and seasonal application rates are expressed in concentration of the endothall acid.  The 30 ppm seasonal maximum rate is equivalent to 6 applications at the maximum single use rate.

3	No holding time is required prior to use of treated water for irrigation of crops.

NS = not specified.

Conclusions.  The submitted labels are adequate to evaluate the residue data relative to the proposed use of endothall on irrigation canals.

 860.1300:  Nature of the Residue - Plants

DP# D321179, D. Soderberg, 8/30/2005

The nature of endothall residues in plants is adequately understood based on the acceptable alfalfa, cotton, and sugar beet metabolism studies reflecting use of the dipotassium salt of [14C]endothall.  An adequate cotton metabolism study is also available reflecting use of the mono-N,N-dimethylalkylamine salt of [14C]endothall.  HED has concluded that the metabolism studies using the dipotassium salt will also fulfill metabolism data requirements for the monoalkylamine salt as the two salts would be expected to behave similarly in plants.  The HED Metabolism Committee (S. Funk, 11/8/96) has also concluded that the residues of concern for both risk assessment and tolerance enforcement in plant commodities include parent endothall and its monomethyl ester.

860.1300:  Nature of the Residue - Livestock

DP# D321179, D. Soderberg, 8/30/2005

The qualitative nature of the endothall residues in livestock is adequately understood based on the acceptable poultry and goat metabolism studies.  The HED Metabolism Committee has concluded that the residues of concern in animal commodities consist of parent endothall and its monomethyl ester.

860.1340 Residue Analytical Methods

DP# D321179, D. Soderberg, 8/30/2005

Enforcement Methods

  SEQ CHAPTER \h \r 1 An enforcement method (GC with microcoulometric nitrogen detection) is listed as Method I in the Pesticide Analytical Manual (PAM, Volume II) for the determination of endothall in plant commodities.  Using this method, residues in crop commodities are extracted using acetone acidified with HCl.  The extract is concentrated, and the oil and oil-soluble materials are removed by partitioning solvents.  The endothall containing oil-free fraction is concentrated by boiling with acetic acid.  Any endothall present is converted to the N-methoxyimide derivative by reaction with methoxyamine hydrochloride.  The imide is partitioned into chloroform, concentrated and analyzed by GC using a nitrogen specific detector.  The method LOQ is 0.1 ppm.

A confirmatory HPLC/MSD method (Method No. KP218R0) is also available for determining residues of endothall and its monomethyl ester in fish and residues of endothall in plant commodities.  For this method, residues are extracted with water, acidified and, if necessary, purified using a C18 SPE column.  Residues are then derivatized with heptafluoro-p-tolylhydrazine (HFTH) and partitioned into dichloromethane (DCM).  Derivatized residue are concentrated, redissolved in toluene, and cleaned up using a silica gel cartridge.  Residues are determined by HPLC/MSD using the 397 amu ion for detection and quantitation.  The validated LOQ is 0.05 ppm for fish (endothall and endothall monomethyl ester), and the LOQs for plant commodities range from 0.01-0.10 ppm, with the initial C18 SPE cleanup step.  This method has undergone a successful independent laboratory validation using fish samples.

Data Collection Methods

m/z 397→166 ion transition was used for quantifying residues.  Residues are expressed in endothall acid equivalents.  The validated LOQ is 0.05 ppm for plant commodities.

In conjunction with the irrigated crop field trials, the above method was adequately validated on all plant matrices tested.

Conclusions.  Adequate methods are available for enforcing the proposed tolerances, and the residue data from the field trials and processing studies were collected using an adequate LC/MS/MS method.  The conditions for the derivatization step used in Method No. KP-242R1 should hydrolyze the monomethyl ester to the free acid.  However, no data were provided as to whether or not the LC/MS/MS method can recover residues of the methyl ester of endothall, which are also residues of concern.

860.1360 Multiresidue Methods

DP# D321179, D. Soderberg, 8/30/2005

Adequate data are available evaluating the recovery of endothall using the FDA multiresidue methods   SEQ CHAPTER \h \r 1 published in the FDA Pesticide Analytical Manual, Volume I (PAM Vol. I). The available data indicate that endothall is not recovered through the FDA multiresidue methods.

860.1380 Storage Stability

DP# D321179, D. Soderberg, 8/30/2005

47520719.der.doc

Adequate storage stability data are available indicating that endothall is stable under frozen storage conditions for up to 5.5 years in rice, broccoli, oranges and tomatoes; 15 months in sugar beet tops and roots; 12 months in potatoes and cottonseed; and 9 months in alfalfa seed.

≤-8°C.  Stored samples of frozen tomatoes, lettuce, sugar beet roots and corn grain were analyzed after 0, 1, 10 and 15 months of storage and the frozen soybean seed and oil samples were analyzed after 0, 1, 5 and 10 months of storage.  Endothall residues were completely stable for up to 15 months in frozen tomatoes, lettuce, sugar beet roots, and corn grain and for up to 10 months in soybean seeds and oil.  The tests on soybean seeds and oil are on-going.

The storage durations and conditions of samples from the irrigated crop field trials submitted to support this petition are presented in Table 4.

Table 4.	Summary of Storage Conditions and Durations of Samples from Irrigated Crop Field Trial and Processing Studies.

Matrix 	Storage Temperature  (°C)	Actual Storage Duration (days) Interval of Demonstrated Storage Stability (days)

Field Trials

Carrot	≤-18	33-272	469

Potato

41-58

	Sugar beet tops and roots

47-64

	Onions, green and bulb	≤-18	63- 143	469

Lettuce	≤-18	34-92	469

Cabbage	≤-18	61-118	469

Lima beans, succulent podded	 ≤-10	93-431	315-469

Dried beans

63-76

	Garden peas, succulent podded

113-127

	Soybean seed

39-385

	Tomatoes	 ≤-11	77-106	~2000

Cucumbers	 ≤-10	478	~2000

Oranges	 ≤-18	105-107	~2000

Apples	 ≤-18	230	~2000

Peaches	 ≤-10	154	~2000

Blueberries and blackberries	≤-18	85-98	~2000

Pecan nutmeat	≤-18	203	315-469

Almond nutmeats and hulls

90-96

	Corn, K+CWHR, forage, grain, and stover	≤-10	42-238	466-469

Sorghum forage, grain and stover	≤-10	51-83	466-469

Wheat forage, grain, hay and straw	≤-10	42-113	466-469

Grass forage and hay	≤-10	404-440	469

Alfalfa Forage and hay	≤-18	66-83	469

Grapes	 ≤-10	88-379	467

Mint tops	≤-18	22-336	469

Rice grain and straw	≤-10	64-99	466-469

Processing Studies

Sugar beet roots, dried pulp, molasses and refined sugar	≤-18	19-64 465

Soybean seed, hulls, meal and refined oil	≤-10	17-78	306-315

Tomato fruit, paste and puree	≤-5	77-80	~2000

Orange fruit, dried pulp, juice and oil	≤-18	109-121	~2000

306 (oil)

Apple fruit, juice and wet pomace	≤-18	231-286	~2000

Sorghum grain and flour	≤-10	26	~2000

Wheat grain, middlings, bran, flour, shouts and germ	≤-10	34-79	~2000

Corn grain, grits, meal, flour, starch, and oil 	≤-10	22-37	~2000

306 (oil)

Grape fruit, juice and raisins	 ≤-10	377-379	~2000

Mint Tops	≤-17	22-336	467

Mint Oil

241	306

Rice grain, hulls, bran and polished rice	≤-10	39-48	~2000

Conclusions.  The available storage stability data are adequate and support the sample storage conditions and durations from the irrigated crop field trials.

  SEQ CHAPTER \h \r 1 860.1400 Water, Fish, and Irrigated Crops

Fish.

DP# D307060 D. Soderberg 8/23/2004

Residue data were submitted (MRIDs 44820102, 43315801 and 42644001) showing metabolism of endothall in fish, bioconcentration of endothall residues in fish, and magnitude of the residue data in fish.  Most of the endothall radioactive residue was incorporated into natural components of the fish.  No endothall, per se, or either of its methyl esters were identified in the metabolism study, but one could infer from the combination of studies and other correlate information, that the residues of interest would be endothall and its monomethyl and dimethyl esters.

A magnitude of the residue study was performed using bluegill, catfish, crayfish, and freshwater clams in seven treated fresh water tanks and one control tank.  Using a method with an LOQ of 0.02 ppm, residues of endothall, per se, were not detected in catfish, were up to 0.026 ppm in bluegills, up to 0.23 ppm in crayfish and in freshwater clams were up to 0.96 ppm.  There was no measurable contribution to the residue from either of the methyl esters, however recovery of the methyl esters was not good.

Consistent with the  registrant’s proposal for tolerance, HED agreed that these data could support tolerances at 0.1 ppm for fish, 1 ppm for crustaceans, and 4 ppm for mussels - pending submission of either a revised metabolism study or a radio-validation study more clearly showing the importance of the methyl esters in the total residue, or revised residue data using a method showing better recovery of the two methyl esters.  A tolerance of 0.1 ppm has since been published for fish.

Irrigated Crops.

DP# D321179, D. Soderberg, 8/30/2005

47520701.de1.doc	(Sugar beet, carrot, potato)	47520702.der.doc	(Green and dry bulb onions)

47520703.der.doc	(Cabbage)	47520704.der.doc	(Leaf and head lettuce)

47520705.de1.doc	(Legume vegetables)	47520706.de1.doc	(Tomato)

47520707.der.doc	(Cucumber)	47520708.de1.doc	(Orange)

47520709.de1.doc	(Apple)	47520710.def.doc	(Peach)

47520711.der.doc	(Blueberry and blackberry)	47520712.der.doc	(Pecan and Almond)

47520713.de1.doc	(Corn, sorghum and wheat)	47520714.der.doc	(Grass)

47520715.der.doc	(Alfalfa)	47520716.de1.doc	(Grape)

47520717.de1.doc	(Mint)	47520718.de1.doc	(Rice)

Residue data supporting the use of endothall-treated water for irrigation of crops were previously submitted on cabbage, celery, grapefruits, peppers, and turnips as representative crops (DP# D321179, D. Soderberg, 8/30/2005).  In these earlier tests, the SC/L or G formulations of the monoalkylamine or dipotassium salts for endothall were applied to the above crops at a concentration of ~3 ppm using overhead or furrow irrigation, with each crop receiving 5-7 applications.  HED concluded that these data were not adequate because endothall was not applied at the maximum use rate allowed for irrigation canals (5 ppm) and because the data were insufficient to cover all irrigation crops.

In response, IR-4 submitted a protocol for conducting limited field trials on representative irrigated crops.  This protocol was discussed with ChemSAC, which provided only minor comments (ChemSAC minutes for 5/12/06 meeting).  Subsequently, IR-4 has submitted limited field trial data covering a wide variety of crops and crop groups that could be irrigated with endothall-treated water, including:  carrots, potatoes and sugar beets (groups 1 and 2); green and dry bulb onions (group 3); leaf and head lettuce (group 4); cabbage (group 5); dried and succulent (podded) peas and beans (group 6); tomatoes (group 8), cucumbers (group 9); oranges (group 10), apples (group 11), peaches (group 12), blueberries and blackberries (group 13); almonds and pecans (group 14); corn, sorghum, wheat and rice (groups 15 and 16); grass (group 17); alfalfa (group 18); and mint.  Although the field trials cover a wide variety of crops, the number of field trials conducted on any given crops was limited, ranging from 2 to 4 tests per crop.

In each field trial, the monoalkylamine salt of endothall (2 lb ae/gal SC/L) was used to treat the irrigation water at a rate of ~5 ppm ae (ae), and the treated water was then applied via overhead sprinklers as six broadcast foliar applications at RTIs of ~7 days.  The target application volume in each trial was equivalent to ~1 acre inch of water (27,154 gal/A).  Based on the concentration of the endothall in the irrigation water and the amount of water applied, the target application rate for endothall was equivalent to 1.13 lb ae/A/application, for a total of 6.79 lb ae/A/season.  Side-by-side tests were also conducted on selected crop (sugar beets, lettuce, cucumber, and peaches) comparing application of the dipotassium salt of endothall (3 lb ae/gal SC/L) with the monoalkylamine salt.  However, although the dipotassium salt was applied to the irrigation water according to the label directions for that salt, the resulting concentration of endothall in the water was 3.5 ppm ae.  [Unlike the label directions for the alkylamine salt, the label directions for the potassium salt assume that it is applied at 5 ppm as the salt, not as the acid equivalent, that is to say, the potassium salt labeled instructions describe application at 5 ppm ai, not 5 ppm ae.]

In each field trial, the endothall residues were determined using an adequate LC/MS/MS method (Method No. KP-242R1), which is described in the above Residue Analytical Methods Section.  The method was validated in conjunction with each trial, and the validated LOQ for endothall is 0.05 ppm in each commodity.  The sample storage conditions and durations for the various crop commodities from each of the field trials are supported by the available storage stability data.  The details for each of the submitted field trials are discussed below, and the endothall residues in the commodities are summarized in Table 5.

TABLE 5.	Summary of Residue Data from Field Trials with Endothall.

Commodity	Formulation type	Total Applic. Rate 1	PHI (days)	Residue Levels (ppm) 2

n	Min.	Max.	HAFT 3	Median

(STMdR)	Mean

(STMR)	Std. Dev.

Root and Tuber Vegetables

Sugar beet, tops	Monoamine salt (SC/L)	5 ppm

(6.77-6.79)	0	2	1.32	1.36	1.36	1.34	1.34	0.033

	Dipotassium salt (SC/L)	3.5 ppm

(4.80-4.88)	0	2	0.527	1.114	1.114	0.820	0.820	0..415

Sugar beet, roots	Monoamine salt (SC/L)	5 ppm

(6.77-6.79)	0	2	0.165	0.493	0.493	0.330	0.330	0.230

	Dipotassium salt (SC/L)	3.5 ppm

(4.80-4.88)	0	2	0.118	0.330	0.331	0.224	0.224	0.151

Carrot	Monoamine salt (SC/L)	5 ppm

(6.77-6.79)	0	2	0.0685	0.088	0.088	0.078	0.078	0.014

Potato	Monoamine salt (SC/L)	5 ppm

(6.77-6.83)	0	2	0.0725	0.875	0.0875	0.080	0.080	0.011

Bulb Vegetables

Green Onion	5.0 ppm

(6.75)	0	1	0.259	0.259	0.259	0.259	0.259	NA

Dry Bulb onion	5.0

(6.76)	0	1	<0.05	<0.05	<0.05	<0.05	<0.05	NA

Leafy Green Vegetables – Lettuce

Leaf lettuce	Monoamine salt (SC/L)	5 ppm

(6.73-6.76)	0	2	0.436	.9915	0.9915	0.714	0.714	0.393

	Dipotassium salt (SC/L)	3.5 ppm

(4.67-4.81)	0	2	0.248	0.7975	0.7975	0.523	0.523	0.363

Head lettuce	Monoamine salt (SC/L)	5 ppm

(6.76-7.17)	0	2	0.0865	0.5475	0.5475	0.292	0.317	0.270

	Dipotassium salt (SC/L)	3.5 ppm

(4.81-5.07)	0	2	0.066	0.509	0.509	0.2875	0.2875	0.3132

Brassica - Cabbage

Cabbage, head with wrapper leaves	5 ppm

(5.64-7.00)	0	2	0.0615	0.0625	0.0625	0.062	0.062	0.0007

Legume Vegetables

Succulent podded beans	5 ppm

(6.75, 9.02) 4	0	2	0.3075	0.4675	0.4675	0.3875	0.3875	0.113

Succulent podded peas	5 ppm

(6.74)	0	2	0.5295	0.939	0.939	0.734	0.734	0.290

Dried Beans	5 ppm

(6.77)	0	2	0.102	0.116	0.116	0.109	0.109	0.010

Soybean, dried seed	5 ppm

(6.75-6.77)	0-1	4	<0.050	0.07	0.07	0.034	0.034	0.025

Fruiting Vegetables – Tomatoes

Tomato	5 ppm

(6.74-6.77)	0	2	<0.05	<0.05	<0.05	0.05	0.05	N/A

Cucurbits - Cucumbers

Fruit 	Monoamine salt (SC/L)	5 ppm

(6.75-6.77)	0	2	0.259	0.738	0.738	0.499	0.499	0.339

Fruit	Dipotassium salt (SC/L)	3.5 ppm

(4.80-4.81)	0	2	0.324	0.433	0.433	0.522	0.522	0.389

Citrus - Orange

Orange	5 ppm

(6.63-6.78)	0	2	0.0215	0.026	0.026	0.024	0.024	0.0032

Pome Fruit – Apple

Apple	5 ppm

(6.64-6.79)	0	2	0.039	0.043	0.043	0.041	0.041	0.0028

Stone Fruits – Peach

Fruit 	Monoamine salt (SC/L)	5 ppm

(6.78-7.08)	0	2	0.044	0.152	0.152	0.098	0.098	0.076

Fruit	Dipotassium salt (SC/L)	3.5 ppm

(4.82-5.05)	0	2	0.045	0.127	0.127	0.086	0.086	0.058

Berries

Blueberry	5.0 ppm

(6.77)	0	1	0.177	0.177	0.177	0.177	0.177	N/A

Blackberry	5.0 ppm

(6.73)	0	1	0.328	0.328	0.328	0.328	0.328	N/A

Tree Nuts

Pecan, nutmeat	5 ppm

(7.01)	0	1	0.24	024	0.024	0.024	0.024	N/A

Almond, nutmeat	5 ppm

(6.80)	0	1	0.037	0.037	<0.037	0.037	0.037	N/A

Almond, hulls

0	1	7.56	7.56	7.56	7.56	7.56	N/A

Cereals, except Rice

Sweet Corn

K+CWHR	5 ppm

(6.75-6.91)

	0	2	0.05	0.17	0.17	0.11	0.11	0.085

Forage w/o ears

0	2	0.585	1.23	1.23	0.908	0.908	0.456

Forage  w/ears

0	2	0.445	0.97	0.97	0.708	0.708	0.371

Stover w/ears

0	2	0.635	4.88	4.88	2.758	2.758	3.002

Field Corn

Forage	5 ppm

(2.26-3.38) 5	0	4	0.285	0.385	0.385	0.334	0.334	0.041

Grain	5 ppm

(6.75-7.10)	0	4	0.04	0.05	0.05	0.05	0.05	0.005

Stover

0	4	1.44	3.19	3.19	2.08	2.08	0.82

Sorghum

Forage	5 ppm

(2.26-3.38) 5	0	3	0.35	2.67	2.67	1.262	1.262	1.237

Grain	5 ppm

(6.77)	0	3	0.645	1.21	1.21	1.00	1.00	0.311

Stover

0	3	0.96	4.90	4.90	2.91	2.91	1.97

Wheat

Forage	5 ppm

(2.19-3.39) 5	0	4	0.685	2.13	2.13	1.15	1.15	0.662

Hay

0	4	1.055	3.09	3.09	1.94	1.94	0.89

Grain	5 ppm

(6.58-6.77)	0-1	4	0.32	1.91	1.91	0.71	0.71	0.800

Straw

0-1	4	1.07	2.74	2.74	1.83	1.83	0.74

AGF

	1	20.3	20.3	20.3	20.3	20.3	N/A

Grasses

Forage	5 ppm

(6.64-7.02)	0-2	6	1.94	2.73	2.73	2.21	2.21	0.32

Hay

0-2	6	5.87	13.65	13.65	8.77	8.77	3.00

Alfalfa

Forage	5 ppm

(5.94-6.58)	0	2	1.77	2.12	2.12	1.95	1.95	0.25

Hay

0	2	4.93	5.20	5.20	5.07	5.07	0.19

Grapes

Grape	5.0 ppm

(6.64-6.76)	0	3	0.405	0.642	0.642	0.522	0.522	0.119

Mint

Mint	5 ppm

(6.64-6.77)	0	2	1.49	2.80	2.80	2.14	2.14	0.923

Rice

Rice grain	5 ppm

(6.75-6.77)	0-1	4	0.756	1.18	1.18	1.05	1.05	0.200

Rice Straw

0-1	4	1.02	2.6	2.6	1.90	1.90	0.66

1	The endothall concentrations are expressed in acid equivalents, and the values in parentheses are the total application rates in terms of lb ae/A.

2	Residues are expressed in terms of the free acid.  The LOQ is 0.05 ppm.  The LOQ was used for all values reported as ≤LOQ.

3	HAFT = Highest Average Field Trial.

4	One of the succulent podded bean field trials used 8 applications rather than 6 applications due to slow plant growth and maturation.

5	Field corn forage, sorghum forage, and wheat forage and hay were harvested after only two or three applications.

Root and Tuber Vegetables (Group 1).

Two field trials each were conducted on sugar beets, carrots, and potatoes in Zones 5, 10 and 11 during 2006-2007.  In each test, the monoalkylamine salt formulation of endothall (2 lb ae/gal SC/L) was used to treat the irrigation water at a rate of 5 ppm ae.  In addition, in the two sugar beet field trials, side-by-side test were also conducted using the dipotassium salt of endothall applied to the irrigation water at a concentration of 3.5 ppm ae.  The treated water was applied during vegetative development as six broadcast foliar applications using overhead sprinklers, at RTIs of 6-8 days.  Based on the concentration of the endothall and the amount of water applied, the application rates for the monoalkylamine salt of endothall were equivalent to 1.13-1.14 lb ae/A/application, for a total of 6.77-6.83 lb ae/A/season.  The application rates for the dipotassium salt were equivalent to 0.80-0.81 lb ae/A/application, for a total of 4.80-4.88 lb ae/A/season.  Single control and duplicate treated samples of sugar beet roots and tops, carrot roots and potato tubers were harvested from the respective tests on the day of the final application (0 DAT).

Following six endothall (monoalkylamine salt) applications totaling 6.77-6.83 lb ae/A/season, endothall residues at 0 DAT were 1.11-1.62 ppm in/on 4 samples of sugar beet tops from 2 plots, 0.136-0.591 ppm in/on 4 samples of sugar beet roots from 2 plots, 0.062-0.088 ppm in/on 4 samples of carrot roots from 2 plots , and 0.067-0.103 ppm in/on 4 samples of potato tubers from 2 plots.  Average endothall residues were 1.34 ppm for sugar beet tops, 0.330 ppm for sugar beet roots, 0.078 ppm for carrot roots, and 0.080 ppm for potato tubers.  The HAFT residues were 1.36 ppm for sugar beet tops, 0.493 ppm for sugar beet roots and 0.088 ppm for both carrot roots and potato tubers.  No residue decline data were provided.  No phytotoxicity was reported in any of the tests.

Following six endothall (dipotassium salt) applications totaling 4.80-4.88 lb ae/A/season, endothall residues at 0 DAT were 0.523-1.28 ppm in/on 4 samples of sugar beet tops from 2 plots and 0.115-0.345 ppm in/on 4 samples of sugar beet roots from 2 plots.  Average endothall residues were 0.821 ppm in/on sugar beet tops and 0.224 ppm in/on sugar beet roots, and HAFT residues in/on sugar beet tops and roots were 1.11 and 0.331 ppm, respectively.  Average endothall residues in/on sugar beet tops and roots were 0.6x-0.7x lower for the dipotassium salt formulation than for the monoalkylamine salt formulation.  The lower level of endothall residues for the dipotassium salt correlated closely with the lower use rate (0.7x) for the dipotassium salt.

Bulb Vegetables (Group 3).

In one green onion and one dry bulb onion field trial conducted during 2007 in Zones 6 and 10, respectively, the monoalkylamine salt formulation of endothall (2 lb ae/gal SC/L) was used to treat the irrigation water at a rate of 5 ppm ae.  The treated water was applied to onions during vegetative development as six broadcast foliar applications using overhead sprinklers, at RTIs of 7-8 days.  Based on the concentration of the endothall and the amount of water applied, the application rates for endothall were equivalent to 1.12-1.13 lb ae/A/application, for a total of 6.75-6.76 lb ae/A/season.  Single control and duplicate treated samples of green onions and dry bulb onions were harvested from the respective tests on the day of the final application (0 DAT).  Endothall residues at 0 DAT were 0.234 and 0.284 ppm in/on 2 samples from one plot of green onions and <0.05 ppm in/on 2 samples from one plot of dry bulb onions.  The average residues were 0.259 ppm for green onions and <0.05 ppm for dry bulb onions.  No residue decline data was provided, and no phytotoxicity was reported on the treated onion crops.

Leafy Vegetables, except Brassica (Group 4).

Two leaf lettuce field trials and two head lettuce field trials were conducted in Zones 1 and 10 during 2006-2007.  Side-by-side tests were conducted in each field trial using irrigation water treated with either the monoalkylamine salt of endothall (2 lb ae/gal SC/L) at a concentration of 5 ppm ae, or the dipotassium salt of endothall (3.0 lb ae/gal SC/L) at a concentration of 3.5 ppm ae.  The treated water was applied in each test during vegetative development as six broadcast foliar applications using overhead sprinklers, at RTIs of 6-8 days.  Based on the endothall concentrations and the amount of water applied, the application rates for the monoalkylamine salt of endothall were equivalent to 1.12-1.20 lb ae/A/application, for a total of 6.73-7.17 lb ae/A/season.  The application rates for the dipotassium salt were equivalent to 0.78-0.84 lb ae/A/application, for a total of 4.67-5.07 lb ae/A/season.  Single control and duplicate treated samples of leaf lettuce and head lettuce (with wrapper leaves) were harvested from the respective tests on the day of the final application (0 DAT).

Following applications of the monoalkylamine salt at level equivalent to 6.73-7.17 lb ae/A/season, endothall residues at 0 DAT were 0.410-1.24 ppm in/on 4 samples of leaf lettuce from 2 plots and 0.081-0.604 ppm in/on 4 samples of head lettuce from 2 plots.  Average endothall residues were 0.714 ppm for leaf lettuce and 0.317 ppm for head lettuce.  The HAFT residues in/on leaf and head lettuce were 0.992 and 0.548 ppm, respectively.  No phytotoxicity was reported on the treated lettuce.

Following six applications of the dipotassium salt at levels equivalent to 4.67-5.07 lb ae/A/season, endothall residues at 0 DAT were 0.241-1.01 ppm in/on 4 samples of leaf lettuce from 2 plots and <0.05-0.582 ppm in/on 4 samples of head lettuce from 2 plots.  Average endothall residues were 0.523 ppm in/on leaf lettuce and 0.288 ppm in/on head lettuce, and HAFT residues in/on leaf and head lettuce were 0.798 and 0.509 ppm, respectively.  Average endothall residues were lower (0.7x-0.9x) for the dipotassium salt than the monoalkylamine salt, which is comparable to the lower use rate for the dipotassium salt (0.7x).

Brassica Vegetables (Group 5).

In two cabbage field trials conducted during 2006 in Zone 1, the monoalkylamine salt formulation of endothall (2 lb ae/gal SC/L) was used to treat the irrigation water at a rate of 5 ppm ae.  The treated water was applied to cabbage during vegetative development as six broadcast foliar applications using overhead sprinklers, at RTIs of 6-9 days.  Based on the concentration of the endothall and the actual amount of water applied, the application rates for endothall were equivalent to 0.94 or 1.17 lb ae/A/application, for a total of 5.64 or 7.00 lb ae/A/season.  Single control and duplicate treated samples of cabbages (with wrapper leaves) were harvested from each test on the day of the final application (0 DAT).  Endothall residues at 0 DAT were <0.05-0.075 ppm in/on 4 samples of cabbage from 2 plots.  The average residues were 0.062 ppm and the HAFT residues were 0.063 ppm.  No residue decline data were provided, and no phytotoxicity was noted on the treated cabbage.

Legume Vegetables (Group 6).

A total of 10 tests were conducted on legume vegetables in Zones 1, 4, 5, 10 and 12 during 2006-2007, including 2 tests on succulent podded beans, 2 tests on dry beans, 2 tests on succulent podded peas, and 4 tests on soybeans.  In each test, a monoalkylamine salt formulation of endothall (2 lb ae/gal SC/L) was used to treat the irrigation water at a rate of 5 ppm ae.  The treated water was applied during flowering through pod and seed development as broadcast foliar applications using overhead sprinklers, at RTIs of 6-9 days.  A total of six applications were made in each test, except in one of the succulent bean tests, which used eight applications.  Based on the concentration of the endothall and the amount of water applied, the application rates for endothall were equivalent to 1.12-1.13 lb ae/A/application, for a total of 6.74-6.77 lb ae/A for the six applications or 9.02 lb ai/A for the eight applications.  Single control and duplicate treated samples of legume pods with seeds were harvested from the succulent bean and pea field trials and samples of dried seeds were harvested from the dry bean and soybean field trials.

Endothall residues were 0.291-0.521 ppm in/on 4 samples of succulent podded beans from 2 plots, 0.522-1.00 ppm in/on 4 samples of succulent podded peas from 2 plots, 0.070-0.134 ppm in/on 4 samples of dried beans from 2 plots, and <0.05-0.072 ppm in/on 8 samples of soybeans from 4 plots harvested at 0-1 DAT.  Average endothall residues were 0.388 ppm for succulent podded beans, 0.734 ppm for succulent podded peas, 0.109 ppm for dry beans, and 0.055 ppm for soybeans.  The HAFT residues were 0.468 ppm for succulent podded beans, 0.939 ppm for succulent podded peas, 0.116 ppm for dry beans, and 0.070 ppm for soybeans.  No residue decline data was provided.  Phytotoxicity was reported on plants at two field site, and consisted of chlorosis and necrosis of leaves.

Fruiting Vegetables, except cucurbits (Group 8).

In two tomato field trials conducted during 2006 in Zones 3 and 10, a monoalkylamine salt formulation of endothall (2 lb ae/gal SC/L) was used to treat the irrigation water at a rate of 5 ppm ae.  The treated water was applied to tomatoes during flowering and fruit development as six broadcast foliar applications using overhead sprinklers, at RTIs of 6-8 days.  Based on the concentration of the endothall and the amount of water applied, the application rates for endothall were equivalent to 1.12-1.13 lb ae/A/application, for a total of 6.74-6.77 lb ae/A/season.  Single control and duplicate treated samples of tomatoes were harvested from each test on the day of the final application (0 DAT).  Endothall residues at 0 DAT were <0.05 ppm in/on 4 samples of tomatoes from 2 plots.  No residue decline data were provided, and no phytotoxicity was reported on the treated tomato crops.

Cucurbit Vegetables (Group 9).

Two cucumber field trials were conducted in Zones 1 and 5 during 2006-2007.  In each trial, side-by-side tests were conducted using irrigation water treated with either the monoalkylamine salt of endothall (2 lb ae/gal SC/L) at a concentration of 5 ppm ae, or the dipotassium salt of endothall (3 lb ae/gal SC/L) at a concentration of 3.5 ppm ae.  The treated water was applied in each test during flowering and fruit development as six broadcast foliar applications using overhead sprinklers, at RTIs of 6-8 days.  Based on the endothall concentration and the amount of water applied, the application rate for the monoalkylamine salt of endothall was equivalent to 1.13 lb ae/A/application, for a total of 6.75-6.77 lb ae/A/season.  The application rate for the dipotassium salt was equivalent to 0.80 lb ae/A/application, for a total of 4.80-4.81 lb ae/A/season.  Single control and duplicate treated samples of cucumber were harvested from each test on the day of the final application (0 DAT).

Endothall residues were 0.234-0.738 ppm in/on 4 cucumber samples from 2 plots harvested at 0 DAT following irrigation applications of the monoalkylamine salt of endothall at 5 ppm ae, and were 0.310-0.459 ppm in/on 4 cucumber samples from 2 plots harvested at 0 DAT following six irrigation applications of the dipotassium salt of endothall at 3.5 ppm.  Average endothall residues in/on cucumbers were 0.499 and 0.522 ppm for the monoalkylamine and dipotassium salt formulations, respectively.  The HAFT residues were 0.738 and 0.433 ppm for the monoalkylamine and dipotassium salt formulations, respectively.  Average endothall residues were lower (0.8x) for the dipotassium salt than the monoalkylamine salt, which was comparable to the lower use rate for the dipotassium salt (0.7x).

Phytotoxicity was reported in one of the tests, and consisted of the loss of older leaves, stunting of growing tips, cupping of young leaves, chlorosis, and cessation of flowering.  However, fruit set and growth were not effected.

Citrus Fruits (Group 10).

In two orange field trials conducted during 2006 in Zones 3 and 10, a monoalkylamine salt formulation of endothall (2 lb ae/gal SC/L) was used to treat the irrigation water at a rate of 5 ppm ae.  The treated water was applied to the orange trees during fruit development as six broadcast foliar applications using overhead sprinklers, at RTIs of 5-8 days.  Based on the concentration of the endothall and the amount of water applied, the application rates for endothall were equivalent to 1.10-1.13 lb ae/A/application, for a total of 6.63-6.78 lb ae/A/season.  Single control and duplicate treated samples of oranges were harvested from each test on the day of the final application (0 DAT).  Endothall residues were <LLMV in/on 4 orange samples from 2 plots at 0 DAT, with residues above the LOD on all four samples at 0.021-0.028 ppm.  The average and HAFT residues were 0.024 ppm and 0.026 ppm, respectively, in/on oranges.  No phytotoxicity was reported on the treated trees.

Pome Fruits (Group 11).

In two apple field trials conducted during 2006 in Zones 1 and 11, a monoalkylamine salt formulation of endothall (2 lb ae/gal SC/L) was used to treat the irrigation water at a rate of 5 ppm ae.  The treated water was applied to the apple trees during fruit development as six broadcast foliar applications using overhead sprinklers, at RTIs of 7 days.  Based on the concentration of the endothall and the amount of water applied, the application rates for endothall were equivalent to 1.11-1.13 lb ae/A/application, for a total of 6.64-6.79 lb ae/A/season.  Single control and duplicate treated samples of apples were harvested from each test on the day of the final application (0 DAT).  Endothall residues at 0 DAT were <LLMV in/on 4 samples of apples from 2 plots, but were greater than the LOD, at 0.031-0.047 ppm, in 3 of the 4 samples.  The average and HAFT residues were 0.041 ppm and 0.043 in/on apples.  Phytotoxicity was noted on the treated trees (necrotic spots on leaves), but no damage was noted on the fruits.

Stone Fruits (Group 12).

Two peach field trials were conducted in Zones 2 and 10 during 2007.  In each trial, side-by-side tests were conducted using irrigation water treated with either the monoalkylamine salt of endothall (2 lb ae/gal SC/L) at a concentration of 5 ppm ae, or the dipotassium salt of endothall (3 lb ae/gal SC/L) at a concentration of 3.5 ppm ae.  The treated water was applied in each test during fruit development as six broadcast foliar applications using overhead sprinklers, at RTIs of 6-8 days.  Based on the endothall concentration and the amount of water applied, the application rate for the monoalkylamine salt of endothall was equivalent to 1.13-1.25 lb ae/A/application, for a total of 6.78-7.08 lb ae/A/season.  The application rate for the dipotassium salt was equivalent to 0.79-0.91 lb ae/A/application, for a total of 4.82-5.05 lb ae/A/season.  Single control and duplicate treated samples of peaches were harvested from each test on the day of the final application (0 DAT).

Endothall residues at 0 DAT in/on peaches were <0.05-0.160 ppm in/on 4 samples from 2 plots treated with the monoalkylamine salt and <0.05-0.136 ppm in/on the 4 samples from 2 plots treated with dipotassium salt.  Average endothall residues in/on peaches were 0.098 and 0.086 ppm for the monoalkylamine and dipotassium salt formulations, respectively.  The HAFT residues were 0.152 and 0.127 ppm for the monoalkylamine and dipotassium salt formulations, respectively.  Average endothall residues were lower (0.9x) for the dipotassium salt than the monoalkylamine salt, which is comparable to the lower use rate for the dipotassium salt (0.7x).  Phytotoxicity was reported on the treated peach trees.

Berries (Group 13).

In one blueberry and one blackberry field trial conducted during 2007 in Zones 5 and 11, respectively, a monoalkylamine salt formulation of endothall (2 lb ae/gal SC/L) was used to treat the irrigation water at a rate of 5 ppm ae.  The treated water was applied to the berry crops during fruit development and maturation as six broadcast foliar applications using overhead sprinklers, at RTIs of 6-8 days.  Based on the concentration of the endothall and the amount of water applied, the application rates for endothall were equivalent to 1.12-1.13 lb ae/A/application, for a total of 6.73-6.77 lb ae/A/season.  Single control and duplicate treated samples of blueberries and blackberries were harvested from the respective tests on the day of the final application (0 DAT).  Endothall residues at 0 DAT were 0.158 and 0.197 ppm in/on 2 samples of blueberry from 1 plot and 0.311 and 0.346 ppm in/on 2 samples of blackberry from 1 plot.  The average residues were 0.177 and 0.328 ppm for blueberries and blackberries, respectively.  No residue decline data was provided, and no phytotoxicity was reported on the treated crops.

Grapes.

In three grape field trials conducted in Zones 1, 10 and 11 during 2006 and 2007, a monoalkylamine salt of endothall (2 lb ae/gal SC/L) was used to treat the irrigation water at a rate of 5 ppm ae. The treated water was then applied using overhead sprinklers to the grapes as six broadcast foliar applications during fruit development at RTIs of 6-8 days.  Based on the concentration of the endothall and the amount of water applied, the application rates for endothall were equivalent to 1.11-1.13 lb ae/A/application, for a total of 6.64-6.76 lb ae/A/season.  Single control and duplicate treated samples of grapes were harvested on the day of the final application (0 DAT).  Endothall residues in/on grapes harvested at 0 DAT were 0.376-0.696 ppm.  The average residues were 0.522 ppm and the HAFT residues were 0.642 ppm.  No residue decline data was provided.  At two of the three field sites, phytotoxicity was noted beginning with the second application and increased in severity with subsequent applications.  The leaves initially showed signs of chlorosis and browning, with leaf necrosis occurring at later applications.

Tree Nuts (Group 14).

In a pecan and almond field trial conducted during 2006-2007 in Zones 2 and 10, respectively, a monoalkylamine salt formulation of endothall (2 lb ae/gal SC/L) was used to treat the irrigation water at a rate of 5 ppm ae.  The treated water was applied to the tree nut crops during nut development and maturation as six broadcast foliar applications using overhead sprinklers, at RTIs of 7-8 days.  Based on the concentration of the endothall and the amount of water applied, the application rates for endothall were equivalent to 1.13-1.17 lb ae/A/application, for a total of 6.80-7.01 lb ae/A/season.  Single control and duplicate treated samples of pecan and almond nutmeats and almond hulls were harvested from the respective tests on the day of the final application (0 DAT).  No phytotoxicity was reported on the treated nut crops.

Endothall residues at 0 DAT were <LOQ in/on two samples each from 1 plot each of pecan and almond nutmeats.  However, residues were detectable at 0.024 ppm in one of the pecan nutmeat samples and at 0.036 and 0.037 ppm in the two almond nutmeat samples.  Residues in/on the two almond hull samples were 6.91 and 8.20 ppm.  Average endothall residues and the HAFT residues were both 0.05 ppm for nutmeats and 7.56 ppm for almond hulls.

Cereal Grains (Except Rice).

A total of 13 field trials were conducted during 2006 and 2007 in Zones 1, 2, 5, 6, 7, and 11, including two trials on sweet corn, four trials on field corn, three trials on sorghum, and four trials on wheat (3 winter wheat and 1 spring wheat).  In each test, the monoalkylamine salt formulation of endothall (2 lb ae/gal SC/L) was used to treat the irrigation water at a rate of 5 ppm ae.  The treated water was applied to each crop during seed head formation and development as six broadcast foliar applications using overhead sprinklers, at RTIs of 6-9 days.  Based on the concentration of the endothall in the irrigation water and the amount of water applied, the overall application rates for endothall were equivalent to 1.10-1.25 lb ae/A/application, for a total of 6.58-7.10 lb ae/A/season.  Because samples of field corn forage, sorghum forage, and wheat forage and hay were harvested after only 2 or 3 applications, the total application rates for these commodities was 2.19-3.39 lb ae/A.

Duplicate control and treated samples of each commodity were harvested from the respective tests.  Samples of field corn forage, sorghum forage and wheat forage and hay were harvested 0 days after the second or third application (0 DAT).  Samples of sweet corn forage, kennels plus cob with husks removed (K+CWHR) and stover, field corn grain and stover, sorghum grain and stover, and wheat grain and straw were harvested following the sixth application at 0 DAT (or at 1 DAT in one wheat test).

In the sweet corn field trials, endothall residues at 0 DAT were <0.05-0.17 ppm in/on 4 samples of  K+CWHR, 0.52-1.28 ppm in/on 4 samples of forage without ears, 0.40-1.06 ppm in/on 4 samples of forage with ears, and 0.58-5.06 ppm in/on 4 samples of stover with ears.  Average endothall residues were 0.11 ppm for K+CWHR, 0.91 ppm for forage without ears, 0.71 ppm for forage with ears, and 2.76 ppm for stover with ears.  The HAFT residues were 0.17 ppm in/on K+CWHR, 1.23 ppm in/on forage without ears, 0.97 ppm in/on forage with ears, and 4.88 ppm in/on stover with ears.

In the field corn field trials, endothall residues at 0 DAT were 0.21-0.42 ppm in/on 8 samples of  forage harvested after only 2 or 3 applications (2.26-3.38 lb ae/A).  Following all six applications (6.75-7.10 lb ae/A), endothall residues at 0 DAT were <0.05 ppm in/on 8 samples of grain and 1.07-3.48 ppm in/on 8 samples of stover from 4 plots each.  Average endothall residues were 0.33 ppm for forage, <0.05 ppm for grain, and 2.08 ppm for stover.  The HAFT residues were 0.385 ppm in/on forage, <0.05 ppm in/on grain, and 3.19 ppm in/on stover.

In the sorghum field trials, endothall residues at 0 DAT were 0.29-3.05 ppm in/on 6 samples of  forage harvested from 3 plots after only 2 or 3 applications (2.26-3.38 lb ae/A).  Following all six applications (6.77 lb ae/A), endothall residues at 0 DAT were 0.49-1.41 ppm in/on 6 samples of grain and 0.81-7.19 ppm in/on 6 samples of stover.  Average endothall residues were 1.26 ppm for forage, 1.00 ppm for grain, and 2.91 ppm for stover.  The HAFT residues were 2.67 ppm in/on forage, 1.21 ppm in/on grain, and 4.90 ppm in/on stover.

In the wheat field trials, endothall residues at 0 DAT were 0.63-2.27 ppm in/on 8 samples of  forage and 1.00-3.09 ppm in/on 8 samples of hay harvested from 4 plots after only 2 or 3 applications (2.19-3.39 lb ae/A).  Following all six applications (6.58-6.77 lb ae/A), endothall residues at 0 or 1 DAT were 0.20-2.01 ppm in/on 8 samples of grain and 0.61-2.76 ppm in/on 8 samples of straw from 4 plots each.  Average endothall residues were 1.15 ppm for forage, 1.94 ppm for hay, 0.71 ppm for grain, and 1.83 ppm for straw.  The HAFT residues were 2.13 ppm in/on forage, 3.09 ppm in/on hay, 1.91 ppm in/on grain, and 2.74 ppm in/on straw.  Residue decline data were not provided in any field trials, and no phytotoxicity was reported for any of the treated cereal grain crops.

Rice.

In four rice field trials conducted during 2007 in Zones 4, 6 and 10, a monoalkylamine salt formulation of endothall (2 lb ae/gal SC/L) was used to treat the irrigation water at a rate of 5 ppm ae.  The treated water was applied to the rice during grain development and maturation as six broadcast foliar applications using overhead sprinklers, at RTIs of 6-8 days.  Based on the concentration of the endothall and the amount of water applied, the application rates for endothall were equivalent to 1.13 lb ae/A/application, for a total of 6.75-6.77 lb ae/A/season.  Single control and duplicate treated samples of rice grain and straw were harvested from each test on the day of the final application or one day later (0-1 DAT).  Endothall residues were 0.69-1.22 ppm in/on 4 samples of rice grain and 0.94-2.61 ppm in/on 4 samples of rice straw harvested from 2 plots each at 0-1 DAT.  Average endothall residues were 1.01 ppm for grain and 1.90 ppm for straw, and the HAFT residues were 1.18 ppm for grain and 2.60 ppm for straw.  No residue decline data was provided, and no phytotoxicity was reported on the treated rice.

Grass forage and hay (Group 17).

A total of six grass field trials were conducted in Zones 4, 6, 11 and 12 during 2006 and 2007, including 2 field trials each on bluegrass, Bermuda grass, and fescue grass.  In each test, the monoalkylamine salt formulation of endothall (2 lb ae/gal SC/L) was used to treat the irrigation water at a rate of 5 ppm ae.  The treated water was applied to the grass during vegetative development as six broadcast foliar applications using overhead sprinklers, at RTIs of 6-10 days.  Based on the concentration of the endothall in the irrigation water and the amount of water applied, the application rates for endothall were equivalent to 1.11-1.17 lb ae/A/application, for a total of 6.64-7.02 lb ae/A/season.  Duplicate control and treated samples of grass forage and hay were harvested on either the day of the final application (0 DAT) in the fescue tests, at 1 DAT in the Bermuda grass tests, or at 1-2 DAT in the bluegrass tests.  The forage samples were collected immediately after harvest, and the hay samples were field-dried for 2-6 days prior to collection.

Endothall residues were 1.70-2.86 ppm in/on 12 forage samples and 5.34-14.2 ppm in/on 12 hay samples harvested from 6 plots each at 0-2 DAT.  Average endothall residues were 2.21 ppm for forage and 8.77 ppm for hay, and the HAFT residues were 2.73 ppm for forage and 13.65 ppm for hay.  No residue decline data were provided.  Phytotoxicity was reported on the treated bluegrass at one field site, and consisted of stunting and slight chlorosis

Nongrass Animal Feeds (Forage, Fodder and Hay) (Group 18).

In two alfalfa field trials conducted during 2007 in Zones 5 and 7, a monoalkylamine salt formulation of endothall (2 lb ae/gal SC/L) was used to treat the irrigation water at a rate of 5 ppm ae.  The treated water was applied to the alfalfa during vegetative development as six broadcast foliar applications using overhead sprinklers, at RTIs of 6-8 days.  Based on the concentration of the endothall in the irrigation water and the amount of water applied, the application rates for endothall were equivalent to 0.99-1.10 lb ae/A/application, for a total of 5.94-6.58 lb ae/A/season.  Duplicate control and treated samples of alfalfa forage and hay were harvested from each test on the day of the final application (0 DAT), and the hay samples were field-dried for 1-5 days prior to collection.

Endothall residues were 1.41-2.24 ppm in/on 4 forage samples and 3.09-5.31 ppm in/on 4 hay samples harvested from 2 plots at 0 DAT.  Average endothall residues were 1.95 ppm for forage and 5.07 ppm for hay, and the HAFT residues were 2.12 ppm for forage and 5.20 ppm for hay.  No residue decline data were provided.  No phytotoxicity on the treated alfalfa was reported at either test site.

Mint.

In two mint field trials conducted during 2006 and 2007 in Zones 5 and 11, a monoalkylamine salt formulation of endothall (2 lb ae/gal SC/L) was used to treat the irrigation water at a rate of 5 ppm ae.  The treated water was applied to the mint during vegetative development as six broadcast foliar applications using overhead sprinklers, at RTIs of 6-7 days.  Based on the concentration of the endothall and the amount of water applied, the application rates for endothall were equivalent to 1.11-1.13 lb ae/A/application, for a total of 6.64-6.77 lb ae/A/season.  Single control and duplicate treated samples of mint tops were harvested from each test on the day of the final application (0 DAT).  Endothall residues were 1.31-2.89 ppm in/on 4 samples of mint tops harvested from 2 plots at 0 DAT.  Average endothall residues were 2.14 ppm, and the HAFT residues were 2.80 ppm.  No residue decline data was provided.  At one of the field sites, the treated mint exhibited signs of phytotoxicity, which consisted of reduced development and stunting of the crop.

Conclusions.  Issues pertaining to residues in potable water and fish have been resolved and are discussed in the Residue Chemistry Chapter of the Endothall RED (DP# D321179, D. Soderberg, 8/30/2005).

The submitted field trial data on irrigated crops were conducted according the previously submitted protocol.  Two to four field trials were conducted for each representative crop in the major growing regions for the respective crops.  With only a couple of exceptions, sample of regulated commodities were harvested at 0 DAT from each field trial.  Samples were analyzed for residues of endothall using an adequate LC/MS/MS method, and the sample storage durations and conditions are supported by the available storage stability data.

The submitted data are generally adequate for assessing inadvertent residues of endothall on irrigated crops.  In addition, the residues determined in the 0 DAT samples will represent an over-estimate of residues for many of the crops tested, because, because application is at the maximum rate, is all applied by overhead irrigation,  and irrigation on the day of harvest would be highly unlikely to occur due to commercial harvesting procedures.  Crops and commodities which would be unlikely to be irrigated prior to harvest include: sugar beets, carrots, potatoes, dry bulb onions, dried peas and beans, soybeans, tree nuts, field corn grain and stover, sorghum grain and stover, wheat grain and straw, and rice grain and straw.

In addition, HED notes that phytotoxicity was reported on a number of the crops tested, including legume vegetables, cucumbers, apple trees, peach trees, grape vines, mint and grass.  The phytotoxicity generally appeared beginning after the second application and consisted of leaf chlorosis and necrosis, with some crops also having reduced growth and stunting.  The occurrence of phytotoxicity on a wide range of crops suggests that repeated irrigation with water containing high levels (5 ppm) endothall is unlikely to occur under normal agricultural condition.

Although the submitted data are deemed adequate for assessing tolerances for inadvertent residues on irrigated crops, the following deficiencies were noted in the submitted field trial data.

	●	The bridging studies comparing the use of the monoalkylamine and dipotassium salts of endothall were of limited use as the two formulations were applied at different rates.  In terms of acid equivalents, the monoalkylamine salt was applied at a concentration of 5 ppm and the dipotassium salt was applied at a concentration of 3.5 ppm, which is the maximum allowed use rate of the dipotassium salt (0.7x rate for the monoalkylamine salt).  For each of the crops tested with both salt formulations, endothall residues were 0.6-0.9x lower for the dipotassium salt than for the monoalkylamine salt, which is consistent with the lower use rate for the dipotassium salt.  Although the bridging studies do not allow for direct comparison of the two salts, the data do indicate that endothall residues 敲畳瑬湩牦浯愠灰楬慣楴湯漠桴楤潰慴獳畩慳 瑬琠物楲慧楴湯挠湡污⁳楷汬戠潬敷⁲桴湡映潲 桴潭潮污祫慬業敮猠污ⱴ眠敨潢桴愠敲愠灰楬摥愠 捣牯楤杮琠畣牲湥⁴慬敢楤敲瑣潩獮ഠ

	●	Spinach should have been used as the representative leafy vegetable crop, as foliar applications generally result in higher residues on spinach than on lettuce (leaf and head) or celery.

	●	Mustard greens should have been used as the representative Brassica vegetable crop, as foliar applications generally result in higher residues on mustard greens than on broccoli, cauliflower or cabbage.

	●	Field corn forage, sorghum forage and wheat forage and hay only received 2-3 applications prior to harvest.  For these crops, separate plots should have been established for collection of forage and hay samples so that all six applications could have made prior to harvest of forage and hay.

	●	No field trials were conducted on an oil seed crop such as, canola, flax, safflower, or sunflower.

	●	No field trials were conducted on peanuts, which is a major field crop.

The levels of inadvertent residues for endothall supported by the available field trial data are listed in Table 10 and discussed below in the Proposed Tolerances Section.

860.1460 Food Handling

There are no registered uses that are relevant to this guideline topic.

860.1480 Meat, Milk, Poultry, and Eggs

DP# D321179, D. Soderberg, 8/30/2005

No cattle or poultry feeding studies are currently available for endothall, and the Endothall RED noted that these studies are required.  Because IR-4 is proposing tolerances on a wide variety of livestock feedstuffs, the dietary burdens of livestock for endothall residues were recalculated for this petition based on the maximum reasonably balanced diets (MRBD).  Using the proposed and recommended tolerances and the recent changes in calculating residues in MRBDs (Revisions of Table 1 Feedstuffs, June 2008), the MRBDs for livestock to endothall residues were calculated to be 8.97 ppm for beef cattle, 7.65 ppm for dairy cattle, 3.30 ppm for poultry and 3.58 ppm for swine (Table 6) based upon residues in the feeds.

In addition to the dietary exposure of livestock through the consumption of feedstuffs, the Endothall RED noted that livestock may also be exposed to endothall residues through the consumption of endothall-treated water.  For purposes of setting tolerances it must be considered that livestock may be exposed to water at the maximum labeled value of 5 ppm.  The potential contribution of endothall residues in water to the dietary exposure of livestock was calculated following the procedures described in PP#1F3991/1F3935 (G. Okatie, 9/4/92), based on the concentration of endothall in the drinking water, the daily water consumption, and the daily feed intake.  The estimated values for daily water consumption and food intake (dry wt. basis) are presented in Table 7, along with the calculated contribution of the treated water to the dietary burden.  When expressed on the basis of the dry feed intake, the contribution of endothall-treated water to the dietary burden would be 19.2 ppm for beef cattle, 45.4 ppm for dairy cattle, 13.5 ppm for poultry, and 16.1 ppm for swine.  When combined with the exposure to endothall residues in feedstuffs, the total dietary exposure of livestock to endothall residues would be 27.7 ppm for beef cattle, 35.8 ppm for dairy cattle, 16.8 ppm for poultry, and 19.7 ppm for swine (as shown in Table 8.

Using the TRR estimated in the relevant livestock tissues after dosing in the metabolism it is possible to make some estimate of the maximum residues expected in the livestock tissues.  In this way, residues in the tissues are estimated as shown in Table 9.  However, given the levels of dietary exposure of livestock to endothall residues in both their feedstuffs and drinking water, cattle and poultry feeding studies are required and registration must be contingent upon submission of these studies.

Table 6.   Calculation of Dietary Burdens of Endothall Residues in Livestock.

Feedstuff	Type1	% Dry Matter2	% Diet2	Recommended Tolerance (ppm) Dietary Contribution (ppm)3

Beef Cattle R: 15%; CC: 80%; PC: 5%

Grass, hay	R	88	15	18	3.07

Grain, aspirated fractions	CC	85	5	35	2.06

Wheat, milled byproducts	CC	88	40	5.0	2.28

Grain, cereal, group 15	CC	88	30	4.0	1.37

Sugar, beet, molasses	CC	75	5	1.5	0.1

Soybean, meal	PC	92	5	0.24	0.01

	TOTAL BURDEN

	100

8.9

Dairy Cattle R: 45%; CC: 45%; PC: 10%

Grass, hay	R	88	20	18	4.09

Almond, hulls	R	90	5	15	0.83

Animal feed, Nongrass, group 18, forage	R	35	20	4.0	2.29

Wheat, milled byproducts	CC	88	30	5.0	1.70

Grain, cereal, group 15	CC	88	10	4.0	0.46

Sugar, beet, molasses	CC	75	5	1.5	0.1

Soybean, meal	PC	92	10	0.24	0.02

	TOTAL BURDEN

	100

9.5

Poultry  CC: 75%; PC:  25%

Grain, cereal, group 15	CC	88	75	4.0	3.0

Alfalfa , meal, (Animal feed, Nongrass, group 18, hay) 	PC	89	5	10.0	0.5

Soybean, meal	PC	92	20	0.24	0.04

	TOTAL BURDEN	--	--	100	--	3.6

Swine  CC: 85 %;  PC:  15%

Grain, cereal, group 15	CC	88	85	4.0	3.4

Alfalfa , meal, (Animal feed, Nongrass, group 18, hay) 	PC	89	5	10.0	0.5

Soybean, meal	PC	92	10	0.24	0.02

	TOTAL BURDEN	--	--	100	--	4.0

1  R:  Roughage; CC:  Carbohydrate concentrate; PC:  Protein concentrate.

2  OPPTS 860.1000 Table 1 Feedstuffs (June 2008).

3  Contribution = ([tolerance /% DM] X % diet) for beef and dairy cattle; contribution = ([tolerance] X % diet) for poultry and swine.

4 The tolerance for soybean seeds was used for soybean meal.

Table 7.	Calculation of Dietary Burdens of Endothall Residues to Livestock from Consumption of Treated Water.

Feedstuff	Endothall concentration in water (ppm)	Water  consumption (kg/day)	Feed consumption (kg dry wt./day) 1	Dietary Contribution from water (ppm) 2

Beef cattle (feedlot cattle)	5.0	35	9.1	19.2

Dairy cattle (lactating cows)	5.0	218	24	45.4

Poultry (laying hens)	5.0	0.14	0.052	13.5

Swine (finishing hogs)	5.0	10	3.1	16.1

1	Feed consumption from ChemSAC Memo, 6/30/2008.

2	 Contribution = (endothall concentration X water consumption/day) ÷ feed consumption/day.

Table 8.	Calculation of Total (Feed Plus Water) Dietary Burdens of Endothall Residues to Livestock

Feedstuff	Feed	Water	Total

Beef cattle (feedlot cattle)	8.9	19.2	28.1

Dairy cattle (lactating cows)	9.5	45.4	54.9

Poultry (laying hens)	3.6	13.5	17.1

Swine (finishing hogs)	4.0	16.1	20.1

Table 9.  Calculation of estimated Residues in Livestock Tissues Based upon the TRR in the Metabolism Studies.

Residues of Endothall in Dairy Cattle Tissues Based upon the Goat Metabolism Study

Tissue

Total Radioactive Residues (ppm) after Feeding at 12.0 ppm

Anticipated Residues (ppm) after Feeding at 54.9 ppm

Milk.

0.006	0.028

Kidney

0.046	0.21

Liver

0.020	0.092

Muscle

0.005	0.023

Fat

0.002	0.009

Residues of Endothall in Beef Cattle Tissues, Sheep, Goats Based upon the Goat Metabolism Study

Tissue

Total Radioactive Residues (ppm) after Feeding at 12.0 ppm

Anticipated Residues (ppm) after Feeding at 28.1

Kidney

0.046	0.108

Liver

0.020	0.047

Muscle

0.005	0.012

Fat

0.002	0.005

Residues of Endothall in Swine Tissues Based upon the Goat Metabolism Study

Tissue

Total Radioactive Residues (ppm) after Feeding at 12.0 ppm

Anticipated Residues (ppm) after Feeding at 20.1 ppm

Kidney

0.046	0.077

Liver

0.020	0.034

Muscle

0.005	0.008

Fat

0.002	0.003

Residues of Endothall in Poultry Tissues Based upon the Chicken Metabolism Study

Tissue

Total Radioactive Residues (ppm) after feeding at 9.7 ppm

Anticipated Residues (ppm) after feeding at 17.1 ppm

Eggs

0.024	0.042

    Yolk

0.024	0.042

    White

0.002	0.004

Kidney and Other Meat Byproducts

0.088	0.16

Liver

0.021	0.037

Muscle

0.008	0.014

Fat

0.007	0.012

860.1500 Crop Field Trials

No new direct uses on crops are being proposed in the current petition; therefore, data requirements for crop field trials are not relevant to this petition.  In addition, because of the high application rates the current data are expected to yield higher residues than would occur in crops rotated after a terrestrial use.  Thus, these tolerances preempt the need for additional rotational crop studies.

860.1520 Processed Food and Feed

DP# D321179, D. Soderberg, 8/30/2005

47520701.de2.doc	(Sugar beet)	47520705.de2.doc	(Soybean)

47520706.de2.doc	(Tomato)	47520708.de2.doc	(Orange)

47520709.de2.doc	(Apple)	47520713.de2.doc	(Field corn, sorghum and wheat)

47520716.de2.doc	(Grape)	47520717.de2.doc	(Mint)

47520718.de2.doc	(Rice)

Adequate cotton and potato processing studies are available supporting the direct use of endothall on these two crops as a defoliate/desiccant (DP# D321179, D. Soderberg, 8/30/2005).   In the acceptable cotton processing study, cotton plants were treated with endothall as two broadcast foliar applications at rates totaling 3.2 lb ae/A (25-32x rate), with the second application being made 3 days prior to harvest.  Endothall residues were 1.49 ppm in/on the undelinted cottonseed (RAC), which was then processed into hulls, meal and crude and refined oils.  Endothall residues did not concentrate in hulls (0.36x), meal (0.22x), or refined oil (0.03x).

In the acceptable potato processing study, mature potato plants were treated with endothall (2 lb ae/gal) as two broadcast foliar applications at 5.0 lb ae/A, at RTI of 5 days, for a total of 10 lb ae/A (10x rate).  Mature tubers harvested 7 days after the second application and processed into flakes, chips and wet peel.  Endothall residues were 0.084 ppm in/on mature tubers, 0.088 ppm in flakes, 0.045 ppm in chips and 0.024 ppm in wet peel.  These data indicate that endothall residues concentrated only slightly in flakes (1.04x) and were reduced in chips (0.54x) and wet peel (0.28x) fractions.

ple, residue values ≥LOD were used to calculated processing factors whenever possible.

The sample storage conditions and durations for the various RACs and processed fractions from each of the studies are supported by the available storage stability data.  The details for each of the submitted processing studies are discussed below, and the resulting processing factors from each study are summarized in Table 10.

Table 10.	Summary of Processing Factors for Endothall from Crops Irrigated with Endothall-treated water.

RAC	Processed Commodity	Application Rate 1	PHI

(days)	Processing Factor

ppm	lb ae/A

Apple 2	Juice	5.0	6.79	0	1.2x

	Wet pomace

2.8x

Field Corn	Grits	5.0	6.77	0	NC 3

	Meal

NC 3

	Flour

NC 3

	Refined oil (dry milling)

NC 3

	Starch

NC 3

	Refined oil (wet milling)

NC 3

Grape	Juice	5.0	6.73	0	1.2x5

	Raisins

4.4x

Mint	Oil	5.0	6.64	0	<0.001x

Orange 2	Dried pulp	5.0	6.63	0	2.2x

	Juice

0.7x

	Oil

<0.2x

Rice	Hulls	5.0	6.75	1	3.9x

	Bran

2.3x

	Polished rice

0.07x

Sorghum	Flour	5.0	6.77	0	0.7x

Soybean 2	Hulls	5.0	6.77	0	3.9x

	Meal

0.8x

	Refined oil

<0.005x

Sugar beet	Dried pulp	5.0	6.79	0	1.1x

	Molasses

2.4x

	Refine sugar

<0.1x

Tomato 2	Puree	5.0	6.77	0	2.1x4

	Paste

3.3x4

Wheat	Aspirated grain fractions (AGF)	5.0	6.71	0	15x

	Germ

2.6x

	Bran

2.3x

	Middlings

0.9x

	Flour

0.6x

	Shorts

1.4x

1	The rate is expressed both in terms of the concentration in the irrigation water (ppm) and the total amount (lb ae/A) applied.

 but ≥LOD were used for calculating processing factors.

3	Residues were <LLMV and <LOD in/on field corn grain and each processed fraction.  NC = not calculated.

4	Residues were below the LLMV (<0.05 ppm) in both fruit and puree samples, but were well above the LOD at 0.002 ppm)

5  1.2x is the Maximum Theoretical Processing Factor for grape juice

Apple.  In a field trial conducted in NY (Zone 1) during 2006, a monoalkylamine salt formulation of endothall (2.0 lb ae/gal SC/L) was used to treat the irrigation water at a rate of 5 ppm ae.  The treated water was then applied using overhead sprinklers to the apple trees as six broadcast foliar applications during fruit development at a RTI of 7 days.  A volume equivalent to 1 acre inch of water (~27,154 gal/A) was applied for each application.  Based on the concentration of the endothall and the amount of water applied, the application rate for endothall was equivalent to 1.13 lb ae/A/application, for a total of 6.79 lb ae/A/season.  Single bulk control and treated samples of apples were harvested at normal crop maturity, immediately following the last irrigation (0 DAT).  The fruit was processed into juice and wet pomace using simulated commercial procedures.

Although endothall residues were <LOQ (<0.05 ppm) in/on whole fruits and juice, residues in these fractions were still above the estimated LOD (0.0025 ppm).  Therefore, residue values >LOD were used to calculate the processing factors.  Residues of endothall averaged 0.033 ppm in/on whole fruit (<LOQ) and were 0.041 ppm in juice and 0.091 ppm in wet pomace.  The calculated processing factors were 1.2x for juice and 2.8x for wet pomace.

Based on HAFT residues of 0.039 ppm for apples, the maximum expected residues would be 0.047 ppm in juice and 0.109 ppm in wet pomace.  As the recommended tolerance for pome fruits is 0.05 ppm, a separate tolerance for apple juice is not required, but a tolerance of 0.15 ppm is required for wet apple pomace.

Field corn.  In a field trial conducted in IL (Zone 5) during the 2007, a monoalkylamine salt formulation of endothall (2 lb ae/gal SC/L) was used to treat the irrigation water at a rate of 5 ppm ae.  The treated water was then applied using overhead sprinklers to field corn as six broadcast foliar applications during grain development and maturation at RTIs of 6-8 days.  A volume equivalent to 1 acre inch of water (~27,154 gal/A) was applied for each application.  Based on the concentration of the endothall in the irrigation water and the amount of water applied, the application rate for endothall was equivalent to 1.12-1.13 lb ae/A/application, for a total of 6.77 lb ae/A/season.  Single bulk control and treated samples of mature corn grain was harvested on the day of the last irrigation (0 DAT), and the corn grain was processed into grits, meal, flour and oil by dry-milling and into starch and oil by wet-milling.

Following applications totaling 6.77 lb ae/A, endothall residues were <0.05 ppm (<LOQ) in/on the corn grain (RAC) and all its processed fractions.  Although processing factors could not be determined for any processed corn fractions, there was no indication of endothall residues concentrating in processed corn commodities.  Therefore, endothall are unlikely to occur in processed commodities derived from irrigated field corn.

Grape.  In a field trial conducted in NY (Zones 1) during 2006, a monoalkylamine salt formulation of endothall (2 lb ae/gal SC/L) was used to treat the irrigation water at a rate of 5 ppm ae.  The treated water was then applied using overhead sprinklers to the grapes as six broadcast foliar applications during fruit development at RTIs of 7 days.  A total of ~1 acre inch of water (27,154 gal/A) was applied for each application.  Based on the concentration of the endothall and the amount of water applied, the application rates for endothall were equivalent to 1.12 lb ae/A/application, for a total of 6.73 lb ae/A/season.  Single bulk control and treated samples of grapes were harvested at normal crop maturity, immediately following the last irrigation (0 DAT), and the grapes were processed into juice and raisins using simulated commercial procedures.

Residues of endothall averaged 0.28 ppm in/on whole grapes (RAC) were 1.24 ppm in juice and 1.21 ppm in raisins.  Thus, the processing factors calculated from these data for juice and raisins were 4.3x and 4.4x, respectively.  However, the theoretical concentration factors for juice and raisins are 1.2x and 4.7x, respectively.  Although the processing factor for raisins was in line with the theoretical value, the processing factor for juice was impossibly higher than the theoretical value.  Therefore, the 1.2x factor will be used for assessing the need for grape juice tolerance (and in the dietary exposure assessment).

Based on HAFT residues of 0.642 ppm for grapes, the maximum expected residues would be 0.77 ppm in juice and 2.8 ppm in raisins.  As the recommended tolerance for grapes is 0.9 ppm, a separate tolerance for grape juice is not required, but a tolerance of 3.0 ppm is required for raisins.

Mint.  In a field trial conducted in WA (Zone 11) during 2006, a monoalkylamine salt formulation of endothall (2 lb ae/gal SC/L) was used to treat the irrigation water at a rate of 5 ppm ae.  The treated water was then applied using overhead sprinklers to mint as six broadcast foliar applications during vegetative development at RTIs of 7 days.  A volume equivalent to 1 acre inch of water (~27,154 gal/A) was applied for each application.  Based on the concentration of the endothall in the irrigation water and the amount of water applied, the application rate for endothall was equivalent to 1.11 lb ae/A/application, for a total of 6.64 lb ae/A/season.  Single bulk control and treated samples of mint tops were harvested at normal crop maturity, immediately following the last irrigation (0 DAT) and were processed into oil using simulated commercial procedures.

Following six overhead sprinkler applications of endothall to mint at rates totaling 6.64 lb ae/A, residues were 3.96 ppm in mint tops (RAC) and nondetectable (<0.0001 ppm) in mint oil, indicating that the processing factor of endothall in mint oil is <0.001x.  As residues are reduced in mint oil, a separate tolerance for mint oil is not required.

Orange.  In a field trial conducted in FL (Zone 3) during 2006, a monoalkylamine salt formulation of endothall (2 lb ae/gal SC/L) was used to treat the irrigation water at a rate of 5 ppm ae.  The treated water was then applied using overhead sprinklers to the orange trees as six broadcast foliar applications during fruit development at RTIs of 5-6 days.  A volume equivalent to 1 acre inch of water (~27,154 gal/A) was applied for each application.  Based on the concentration of the endothall and the amount of water applied, the application rate for endothall was equivalent to 1.10 lb ae/A/application, for a total of 6.63 lb ae/A/season.  Single bulk control and treated samples of oranges were harvested at normal crop maturity, immediately following the last irrigation (0 DAT).  The fruit was processed into juice, oil and dried pulp using simulated commercial procedures.

Although endothall residues were <LOQ (<0.05 ppm) in/on whole orange fruits and in each processed fraction, residues above the estimated LOD (0.0025 ppm) were detected in each fraction except oil.  Residues were detected at 0.019 ppm in/on whole fruit and at 0.014 ppm in juice, 0.041 ppm in dried pulp.  Residues in oil were <LOD.  Based on these residue values the processing factors were 0.7x for juice, 2.2x for dried pulp, and <0.2x for oil.  The theoretical processing factors for citrus juice and oil are 2x and 1000x, respectively.

Based on HAFT residues of 0.026 ppm for oranges, the maximum expected residues would be 0.057 ppm dried pulp.  As the recommended tolerance for citrus fruits is 0.05 ppm, a separate tolerance of 0.1 ppm is required for dried citrus pulp.  Separate tolerances are not required for citrus juice and oil.

Rice.  In a field trial conducted in TX (Zone 6) during 2007, a monoalkylamine salt formulation of endothall (2 lb ae/gal SC/L) was used to treat the irrigation water at a rate of 5 ppm ae.  The treated water was then applied using overhead sprinklers to rice as six broadcast foliar applications during grain development and maturation at RTIs of 6-7 days.  A volume equivalent to 1 acre inch of water (~27,154 gal/A) was applied for each application.  Based on the concentration of the endothall in the irrigation water and the amount of water applied, the application rate for endothall was equivalent to 1.13 lb ae/A/application, for a total of 6.75 lb ae/A/season.  Single bulk control and treated samples of rice grain were harvested at normal crop maturity, one day after the last irrigation (1 DAT), and processed into hulls, bran and polished rice using simulated commercial procedures.

Following six sprinkler applications of endothall at rates totaling 6.75 lb ae/A, residues in whole grain (RAC) were 0.872 ppm at 1 DAT, and the residues in the processed fractions were 0.60 ppm for polished rice, 3.44 ppm for hulls and 2.03 ppm for bran.  The resulting processing factors were 0.07x for polished rice, 3.9x for hulls and 2.3x for bran.  The theoretical processing factors for rice are 5x for hulls and 7.7x for bran.

Based on HAFT residues of 1.18 ppm for rice grain, the maximum expected residues would be 4.6 ppm for hulls and 1.48 ppm for bran.  As the recommended tolerance for cereal grains is 3.0 ppm, a separate tolerance for rice bran is not required, but a tolerance of 5.0 ppm is required for rice hulls.

Sorghum.  In a field trial conducted in KS (Zone 7) during 2007, a monoalkylamine salt formulation of endothall (2 lb ae/gal SC/L) was used to treat the irrigation water at a rate of 5 ppm ae.  The treated water was then applied using overhead sprinklers to the sorghum crop as six broadcast foliar applications during grain development and maturation at RTIs of 6-8 days.  A volume equivalent to 1 acre inch of water (~27,154 gal/A) was applied for each application.  Based on the concentration of the endothall in the irrigation water and the amount of water applied, the application rate for endothall was equivalent to 1.12-1.13 lb ae/A/application, for a total of 6.77 lb ae/A/season  Single bulk control and treated samples of mature sorghum grain were harvested on the day of the last irrigation (0 DAT), and the grain samples processed into flour using simulated commercial procedures.

Endothall residues were 1.49 ppm in/on sorghum grain (RAC) and 1.09 ppm in sorghum flour, indicating that residues were reduced in flour by 0.7x.  Therefore, separate tolerance is not required for sorghum flour.

Soybean.  In a field trial conducted in IA (Zone 5) during 2007, a monoalkylamine salt formulation of endothall (2 lb ae/gal SC/L) was used to treat the irrigation water at a rate of 5 ppm ae.  The treated water was then applied using overhead sprinklers to soybeans as six broadcast foliar applications during seed and pod development at RTIs of 6-8 days.  A volume equivalent to 1 acre inch of water (~27,154 gal/A) was applied for each application.  Based on the concentration of the endothall in the irrigation water and the amount of water applied, the application rate for endothall was equivalent to 1.13 lb ae/A/application, for a total of 6.77 lb ae/A/season.  Single bulk control and treated samples of soybeans were harvested at normal crop maturity, immediately following the last irrigation (0 DAT).  The soybeans were processed into hulls, meal and refined oil using simulated commercial procedures.

Following six overhead sprinkler applications of endothall (monoalkylamine salt) to soybeans at rates totaling 6.77 lb ae/A, endothall residues were 0.021 ppm (<LOQ) in/on whole seeds, 0.083 ppm in/on hulls, 0.017 ppm in meal, and nondetectable (<0.0001 ppm) in refined oil.  The processing factors were 3.9x for hulls, 0.8x for meal, and <0.005x for oil.  The theoretical processing factors for soybean commodities are 11.3x for hulls, 2.2x for meal, and 12x for oil.

Based on HAFT residues of 0.07 ppm for soybeans, the maximum expected residues would be 0.273 ppm for hulls.  As the recommended tolerance for soybean seeds is 0.2 ppm, a separate tolerance of 0.3 ppm is required for soybean hulls.

Sugar beet.  In a field trial conducted in CA (Zones 10) during 2007, a monoalkylamine salt formulation of endothall (2 lb ae/gal SC/L) was used to treat the irrigation water at a rate of 5 ppm ae.  The treated water was then applied using overhead sprinklers to the sugar beets as six broadcast foliar applications during vegetative development at RTIs of 7-8 days.  A volume equivalent to 1 acre inch of water (~27,154 gal/A) was applied for each application.  Based on the concentration of the endothall and the amount of water applied, the application rate for endothall was equivalent to 1.13 lb ae/A/application, for a total of 6.79 lb ae/A/season.  Single bulk control and treated samples of sugar beet roots were harvested at normal crop maturity, immediately following the last irrigation (0 DAT).  The roots were washed and processed into dried pulp, molasses, and refined sugar using simulated commercial procedures.

Residues of endothall averaged 0.493 ppm in/on whole unwashed roots (RAC) and were 0.554 ppm in dried pulp, 1.203 in molasses, and <0.05 ppm in refined sugar.  The processing factors were 1.1x for dried pulp, 2.4x for molasses, and <0.1x for refined sugar.  The theoretical concentration factor for refined sugar is 12.5x.

Based on HAFT residues of 0.493 ppm for sugar beet roots, the maximum expected residues would be 0.542 ppm for dried pulp and 1.18 ppm in molasses.  As the recommended tolerance for root and tuber vegetables is 1.0 ppm, a separate tolerance is not required for dried pulp, but a tolerance of 1.2 ppm is required for sugar beet molasses.

Tomato.  In a field trial conducted in FL (Zone 3) during 2006, a monoalkylamine salt formulation of endothall (2 lb ae/gal SC/L) was used to treat the irrigation water at a rate of 5 ppm ae.  The treated water was then applied using overhead sprinklers to tomatoes as six broadcast foliar applications during fruit development at RTIs of 8 days.  A volume equivalent to 1 acre inch of water (~27,154 gal/A) was applied for each application.  Based on the concentration of the endothall in the irrigation water and the actual amount of water applied, the application rate for endothall was equivalent to 1.13 lb ae/A/application, for a total of 6.77 lb ae/A/season.  Single bulk control and treated samples of tomatoes were harvested at normal crop maturity, immediately following the last irrigation (0 DAT).  The tomatoes were processed into puree and paste using simulated commercial procedures.

Residues of endothall were formally reported to be <0.05 ppm in/on whole fruits and puree and 0.069 ppm in tomato paste.  However, page 81 of the report indicated that detectable residues (≥0.002 ppm) were present in whole fruit at 0.021 ppm, 0.044 ppm in the puree, and 0.069 in the paste.  Since the residues in the puree seemed no less likely to be reasonable estimates than those on the raw fruit or in the puree (all are below the LLMV, but above the LOD. We have used these numbers to estimate factors of 2.1x for puree and 3.3x for the paste.  These numbers make reasonable sense when compared to the mass balance calculations.  EPA’s published theoretical processing factors for tomato puree and paste are 1.4 and 5.5x, respectively.

Both processing factors lead to values above the recommended tolerance.  Therefore, a separate tolerance of 0.1 ppm is required for both tomato puree and tomato paste.

Wheat.  In a field trial conducted in TX (Zone 6) during 2007, a monoalkylamine salt formulation of endothall (2 lb ae/gal SC/L) was used to treat the irrigation water at a rate of 5 ppm ae.  The treated water was then applied using overhead sprinklers to the wheat crop as six broadcast foliar applications during grain development and maturation at RTIs of 6-8 days.  A volume equivalent to 1 acre inch of water (~27,154 gal/A) was applied for each application.  Based on the concentration of the endothall in the irrigation water and the amount of water applied, the application rate for endothall was equivalent to 1.12-1.13 lb ae/A/application, for a total of 6.71 lb ae/A/season.  Single bulk control and treated samples of mature wheat grain were harvested at normal maturity, on the day of the last irrigation (0 DAT).  The wheat grain was initially cleaned to generate AGF and was then milled using simulated commercial procedures into germ, bran, middlings, shorts and flour.

Endothall residues were 1.34 ppm in/on the bulk sample of wheat grain and 20.3 ppm in/on the composited AGF sample, for a concentration factor of 15x for wheat AGF.  Following processing, endothall residues were 3.44 ppm in germ, 3.10 ppm in bran, 1.14 ppm in middlings, 0.75 ppm in flour, and 1.81 ppm in shorts.  The resulting processing factors were 2.6x for germ, 2.3x for bran, 0.9x for middlings, 0.6x for flour, and 1.4x for shorts.

Based on HAFT residues of 1.91 ppm for wheat grain, the maximum expected residues would be 28.7 ppm for AGF, 4.97 ppm for germ, 4.39 ppm for bran and 2.67 ppm for shorts.  Because residues in shorts are below the recommended 3 ppm tolerance for cereal grains, a separate tolerance in not required for shorts.  However, a tolerance of 5.0 ppm in required on wheat milled byproducts to cover residues in wheat germ and bran.  In addition, a 30 ppm tolerance is required for grain AGF.

Conclusions.  The submitted processing studies for irrigated crops are adequate, and cover all the crops requested in the Endothall RED.  The appropriate processed fractions were generated in each study, and endothall residues in each RAC and processed commodity were determined using an adequate LC/MS/MS method.  The sample storage conditions and durations are also supported by the available storage stability data.  With the exception of field corn grain, detectable residues of endothall were found in all RAC samples.  HED notes that although residues were reported to be <0.05 ppm (<LOQ) in the apple, orange, soybean and tomato samples used for processing, endothall residues were detectable in each of these RACs at 0.019-0.033 ppm.  Therefore, these detectable residues were used for calculating processing factors for these crops.

Endothall residues were shown to concentrate in the following processed fractions:  apple juice (1.2x) and wet pomace (2.8x), grape raisins (4.4x), dried citrus pulp (2.2x), rice hulls (3.9x) and bran (2.3x), soybean hulls (3.9x), sugar beet molasses (2.4x) and dried pulp (1.1x), tomato paste (3.3x), and wheat germ (2.6x), bran (2.3x) and shorts (1.4x).  (Although grape juice had an apparent concentration factor of 4.3x, HED used the maximum theoretical processing factor for grape juice (1.2x) to assess the need for a separate grape juice tolerance.)

Based on the above processing factors and the HAFT residues for the various RACs, the maximum expected residues in various processed commodities exceeded the tolerance recommended for the associated RAC.  Therefore, separate tolerances are required for the following processed commodities at the recommended levels:  apple wet pomace (0.15 ppm), raisins (3 ppm), dried citrus pulp (0.1 ppm), rice hulls (5 ppm), soybean hulls (0.3 ppm), sugar beet molasses (1.2 ppm), tomato paste (0.1 ppm), and wheat milled byproducts (5 ppm).

Although no processing studies are available for oilseed crops (canola, flax, safflower, and sunflower), the available soybean processing study is adequate for assessing the potential for concentration of endothall in oil seed meal and refined oil for purposes of this petition.  The soybean processing data indicate that endothall residues are unlikely to concentrate in meal and oil fractions from other oil seed crops.

In addition, wheat processing study showed that residues concentrated in AGF by 15x indicating that a separate tolerance will be required for AGF.  Because endothall residues were higher in wheat grain than in the other major grains (field corn, soybean and sorghum), the HAFT for wheat grain (1.91 ppm) was used to calculate the maximum expected residues for AGF (28.7 ppm).  These data indicate that a tolerance of 30 ppm would be appropriate for AGF.

  SEQ CHAPTER \h \r 1 860.1650 Submittal of Analytical Reference Standards

An analytical standard for endothall is currently available in the EPA National Pesticide Standards Repository (personal communication with Dallas Wright, ACB, 10/23/08), with an expiration date of 12/28/2012.  Analytical reference standards must be replenished as requested by the Repository.

Analytical standards of the monomethyl and dimethyl esters are required to be submitted.  The reference standards should be sent to the Analytical Chemistry Lab, which is located at Fort Meade, to the attention of either Theresa Cole or Thuy Nguyen at the following address:

	USEPA

	National Pesticide Standards Repository/Analytical Chemistry Branch/OPP

	701 Mapes Road

	Fort George G. Meade, MD  20755-5350

860.1850/1900 Confined and Field Accumulation in Rotational Crops

DP# D321179, D. Soderberg, 8/30/2005

Although the available confined rotational crop study was deemed inadequate, HED has concluded that  based upon the results of the plant metabolism data and of soil and water metabolism data, it is possible to infer that the only possible residues of significance in rotated crops are endothall and its mono methyl and dimethyl esters.  Therefore, a new confined rotational crop study is no longer required so long as limited field trials are performed that measure all three of endothall, and the monomethyl- and dimethyl- esters of endothall.

Although the Endothall RED required data from limited field rotational crop trials, the inadvertent exposure of crops to endothall via the use of treated irrigation water will clearly exceed the potential secondary exposure of crops planted in rotation with endothall treated crops such as cotton and potatoes.  Therefore, the establishment of tolerances for indirect/inadvertent residues of endothall on the proposed irrigated crops supersedes the need for limited field rotational trial data or the need for rotational crop tolerances.

860.1550 Proposed Tolerances

The residues of concern for endothall for purposes of both risk assessment and tolerance enforcement in plant and animal commodities include parent endothall and its monomethyl ester.  Permanent tolerances are currently established for the combined residues of endothall and its monomethyl ester at 0.1 ppm in/on cotton seeds, fish, dried hops and potatoes, and at 0.05 ppm in/on rice grain and straw [40 CFR §180.293(a)(1)].  An interim tolerance of 0.2 ppm has also been established for endothall acid in potable water resulting from the use of the monoalkylamine or dipotassium salts of endothall for control of aquatic plants in canals, lakes, ponds and other potential water sources.  An interim tolerance has also been established for endothall on sugar beet at 0.2 ppm [40 CFR §180.319].

The available field trial data are adequate for purposes of assessing inadvertent residues of endothall on irrigated crops.  Although the residue data available on any given crop is limited, the field trials are likely to represent a very conservative estimate of endothall residues on irrigated crops.  This is not only because crops are (properly) treated at the maximum use rate and the maximum number of times per season, but also because overhead irrigation was used and because a short PHI (0-DAT) used in each field trial.  The occurrence of phytotoxicity on a number of the crops tested also make it unlikely that repeated irrigation with water containing high levels of endothall (5 ppm) will go unrecognized and be allowed to occur under normal agricultural conditions.

In calculating recommended tolerances for irrigated crops, HED has not utilized the NAFTA MRL Calculator (or Tolerance Harmonization Spreadsheet) except for grass commodities, corn grain and soybeans.  The residues are already expected to be very conservative.  In addition, only a very limited number of field trials were performed for any crop/crop group, and there was only one plot for each field trial.  Thus, in some cases there was only a single plot tested for a crop/crop group.  Correct use of the NAFTA MRL Calculator given these limited data would add an unrealistically large additional conservative factor onto these already conservative results, and results would have less reliability given the limited number of values use for each distribution.  In addition, several tolerances are based upon residues detected below the LOQ of the method, but above the LOD.  These residues cannot be considered to be non-detectable, but the precision of determination of residues in this range is larger than normally attributed to the method, and results are usually biased high due to undue influence of background contribution to the responses. Given all of this, given that these tolerances are for inadvertent residues and therefore in many cases are based upon very broad translations of data, sometimes even across crop groups, HED has concluded that it makes better sense to estimate tolerances using a more practical, common sense approach.  In most cases these tolerances are approximately twice the highest results from the highest residues/plot tested.

The proposed tolerances for irrigated crops are listed in Table 10, along with the Agency’s recommended tolerances.  As the tolerances on irrigated crops are for inadvertent residues, they should be established under 40 CFR §180.293(d).  Substantial changes in the proposed tolerances are noted below.

IR-4 provided residue data on cabbage to support the tolerance on Brassica leafy vegetables.  However, because mustard greens typically have higher residues than cabbage, the leaf lettuce field trial data were used to assess the tolerance on Brassica leafy vegetables.

For legume vegetables, the available field trial data indicated that a single crop group tolerance is not appropriate.  Therefore, HED is recommending that separate tolerances be established for the three legume vegetable subgroups (6A, 6B and 6C), along with a tolerance on soybean seeds.  In addition, IR-4 did not propose a tolerance for the foliage of legumes (group 7).  HED is recommending a tolerance for legume foliage based on the alfalfa field trial data.

Tolerances for okra, pistachios and herbs (subgroup 19A) are being recommended based on the respective field trial data for tomatoes, tree nuts and mint.

For cereal grains, IR-4 proposed tolerances for cereal grains (except rice); however, the available residue data indicate that residues for rice grain are similar to wheat and sorghum grain, while residues in/on corn (field and sweet) are substantially lower.  Therefore, HED is recommending a crop group tolerance for cereal grain, except corn, and establishing separate tolerances for field and pop corn grain and sweet corn K+CWHR.

Although IR-4 did not propose tolerances on any processed crop fractions, the available field trial and processing data indicate that separate tolerances are required for the following processed commodities at the recommended levels:  apple wet pomace (0.15 ppm), raisins (3 ppm), dried citrus pulp (0.1 ppm), rice hulls (5 ppm), soybean hulls (0.3 ppm), sugar beet molasses (1.2 ppm), tomato paste (0.1 ppm), and wheat milled byproducts (5 ppm).  A separate tolerance is also AGF at 30 ppm.

There are currently no established Codex, Canadian, or Mexican maximum residue limits (MRLs) for endothall on plant or animal commodities.  Therefore, there are no issues related to harmonization with international MRLs.

Table 11. 	Tolerance Summary for Endothall.

Commodity	Proposed Tolerance (ppm)	Recommended Tolerance (ppm)	Comments;

Correct Commodity Definition

40 CFR §180.293(d)

Vegetable, root and tuber, group 1	2	1.0	Based on maximum residues in sugar beets (0.493 ppm), carrots (0.088 ppm) and potatoes (0.103 ppm)

Beet, sugar, molasses	None	1.5	Maximum expected residues are 1.18 ppm in molasses based on HAFT residues of 0.493 ppm in sugar beet roots and a 2.4x processing factor.

Vegetable, leaves of root and tuber, group 2	3.5	3.0	Based on maximum residues in sugar beet tops (1.62 ppm)

Vegetable, bulb, group 3	2	0.5	Based on maximum residues in green onions (0.26 ppm) and dry bulb onions (<0.05 ppm)

Vegetable, leafy, except brassica, group 4   	3.5	2.0	Based on maximum independent plot residues in leaf lettuce (0.99 ppm) and head lettuce (0.60 ppm)

Vegetable, brassica, group 5	0.1	None	Based upon Cabbage HAFT of 0.063 ppm)

Vegetable, brassica, head and stem subgroup 5A	None	0.1	Based upon Cabbage HAFT of 0.063 ppm)

Vegetable, brassica, leafy, group 5B	None	2	Based upon maximum residues in leaf lettuce, which better represents residues on leafy Brassica than does cabbage.

Vegetable, legume, group 6	3	None	Separate tolerances should be established for soybeans and the various legume subgroups based on the maximum residues in succulent beans (0.47 ppm) and succulent peas (0.94 ppm), and those in dried beans (0.12 ppm), and on soybeans (0.07 ppm).  Soybean seed tolerance (4 trials) is based upon tolerance spreadsheet.

Vegetable, legume, edible podded, subgroup 6A and

Pea and bean, succulent shelled, subgroup 6B

	None

	2.0

	Pea and bean, dried shelled, subgroup 6C	None	0.2

	Soybean seed	None	0.2

	Soybean, hulls 	None	0.5	Maximum expected residues are 0.27 ppm in hulls based on HAFT residues of 0.07 ppm in soybeans and a 3.9x processing factor.

Vegetable, foliage of legume, group 7	None	4	Based on maximum residues in alfalfa forage

Vegetable, fruiting, group 8	0.05	0.05	Based on maximum residues in tomatoes (<0.05 ppm).

Okra	None	0.05

	Tomato, paste

	None	0.1	Maximum expected residues are 0.069 ppm in paste based on HAFT residues of 0.021 ppm in tomatoes and a 3.3x processing factor for paste.

Tomato, puree	None	0.1	Maximum expected residues are 0.044 ppm in paste based on HAFT residues of 0.021 ppm in tomatoes and a 2.1x processing factor for puree.

Vegetable, cucurbit, group 9	1.1	1.5	Based on maximum residues in cucumbers (0.74 ppm).

Fruit, citrus, group 10	0.05	0.05	Based on maximum residues in oranges (<0.05 ppm).

Citrus, dried pulp	None	0.1	Maximum expected residues are 0.057 ppm in dried pulp based on HAFT residues of 0.026 ppm in oranges and a 2.2x processing factor.

Fruit, pome, group 11	0.05	0.05	Based on maximum residues in apples (<0.05 ppm).

Apple, wet pomace	None	0.15	Maximum expected residues are 0.109 ppm in wet pomace based on HAFT residues of 0.039 ppm in apples and a 2.8x processing factor.

Fruit, stone, group 12	0.25	0.3	Based on maximum residues in peaches (0.15 ppm).

Canebery subgroup 13-07A

and bushberry subgroup 13-07B 	0.6	0.6	Based on maximum residues in blueberries (0.18 ppm) and blackberries (0.33 ppm).

Grape	0.9	1.0	Based upon maximum residues on grapes ( 0.64 ppm).

Grape, raisin	None	5.0	Maximum expected residues are 2.8 ppm in raisins based on HAFT residues of 0.64 ppm in grapes and a 4.4x processing factor.

Nut, tree, group 14	0.05	0.05	Based on maximum residues in almond and pecan nutmeats (<0.05 ppm).

Pistachio	None	0.05

	Almond, hulls	10	15	Based on maximum residues in hulls (8.2 ppm).

Grain, cereal, group 15, except corn	1.9	4	The available data support a crop group tolerance, except for corn

Corn, sweet, kernel plus cob with husks removed	None	0.3	Tolerance based on maximum residues in sweet corn K+CWHR (0.17 ppm)

Corn, field, grain	None	0.07	Tolerance based on tolerance spreadsheet for corn grain

Corn, pop, grain	None	0.07

	Cereal, forage, fodder and straw, group 16, hay 	5.0	None	Combined into Forage, Hay and Straw

Cereal, forage, fodder and straw, group 16, straw	6	None	Combined into Forage, Hay and Straw

Cereal, forage, fodder and straw, group 16, forage	3.5	None	Combined into Forage, Hay and Straw

Cereal, forage, fodder and straw, Group 16, except stover

 	3.5	6	Based on maximum residues on various forages (2.7) and wheat hay and straw.  Note that field corn, sorghum and wheat forages received only 2-3 applications prior to harvest (0.3-0.5x rate).

Cereal, forage, fodder and hay, group 16, stover	11	10	Based on adequate data from field corn and sorghum stover (max 5.0 ppm).

Grain, aspirated fractions	24	35	Maximum expected residues in AGF are 29 ppm based on HAFT residues of 1.9 ppm for wheat grain and a concentration factor of 15x for AGF.

Grass, forage, fodder, and hay, group 17, forage	3	3.5	Based upon tolerance spreadsheet (6 trials)

Grass, forage, fodder, and hay, group 17, hay	19	18	Based upon tolerance spreadsheet (6 trials)

Animal feed, Nongrass, group 18, forage	3.5	4.0	Based on maximum residues in alfalfa forage (2.1 ppm) and hay (4.9 ppm)

Animal feed, Nongrass, group 18, hay	8	10

	Peppermint, tops	7	5	Based on maximum residues in mint tops (2.8 ppm).

Spearmint, tops	7	5

	Herb and spice, group 19	None	5

	Rice, grain	1.7	None	Separate tolerances are not required for rice grain and straw as these commodities are covered by the tolerances on cereal grains and cereal grain straw.

Rice, straw	4.5	None

	Rice, hulls	None	8	Based on HAFT residues of 1.0 ppm for rice grain and a processing factor of 3.9x for hulls, the maximum expected residues in rice hulls is 4.0 ppm.

Wheat, milled byproducts	None	5	Based on HAFT residues of 1.9 ppm for wheat grain and processing factors of 2.6x for germ, and 2.3x for bran, and 1.4x for shorts, the maximum expected residues in milled byproducts is 5.0 ppm.

Food commodities	None	5	Inadvertent residues on any food crop/commodity not included within the assigned crop groups and miscellaneous tolerances.  Based upon Mint.

Feed commodities	None	10	Inadvertent residues on any feed crop/commodity not included within the assigned crop groups and miscellaneous tolerances.  Based upon Cereal Grains.

Cattle, muscle	None	0.03	Based upon calculations for Dairy Cattle using metabolism data.

Cattle, kidney	None	0.20	Based upon calculations for Dairy Cattle using metabolism data.

Cattle, liver	None	0.10	Based upon calculations for Dairy Cattle using metabolism data.

Cattle, fat	None	0.01	Based upon calculations for Dairy Cattle using metabolism data.

Milk	None	0.03	Based upon calculations for Dairy Cattle using metabolism data.

Sheep, muscle	None	0.015	Based upon calculations for Beef Cattle using metabolism data.

Sheep, kidney	None	0.15	Based upon calculations for Beef Cattle using metabolism data.

Sheep, liver	None	0.05	Based upon calculations for Beef Cattle using metabolism data.

Sheep, fat	None	0.005	Based upon calculations for Beef Cattle using metabolism data.

Goat, muscle	None	0.015	Based upon calculations for Beef Cattle using metabolism data.

Goat, kidney	None	0.15	Based upon calculations for Beef Cattle using metabolism data.

Goat, liver	None	0.05	Based upon calculations for Beef Cattle using metabolism data.

Goat, fat	None	0.005	Based upon calculations for Beef Cattle using metabolism data.

Hog, muscle	None	0.01	Based upon calculations using metabolism data.

Hog, kidney	None	0.10	Based upon calculations using metabolism data.

Hog, liver	None	0.05	Based upon calculations using metabolism data.

Hog, fat	None	0.005	Based upon calculations using metabolism data.

Poultry, muscle	None	0.015	Based upon calculations using metabolism data.

Poultry, liver	None	0.05	Based upon calculations using metabolism data.

Poultry, fat	None	0.015	Based upon calculations using metabolism data.

Poultry, meat byproducts	None	0.20	Based upon calculations using metabolism data.

Egg	None	0.05	Based upon calculations using metabolism data.

References

DP Number:	D321179

Subject:	Endothall and its Salts.  Residue Chemistry Considerations for Reregistration Eligibility Decision.  Revised per Registrant Comments.

From:	D. Soderberg

To:	R. Zendzian

Dated:	8/30/2005

MRID(s):	None

  SEQ CHAPTER \h \r 1 Attachments:

Attachment 1.  Table of Individual Residue Values Found for Each Different Commodity Attachment 2:	 Tolerance Spreadsheet analyses for Commodities with Four or More Field Trials

Residue Data for Endothall