c) Volatility  29   PCNB and many of its metabolites are moderately volatile. Volatilization is likely a significant route of dissipation when the pesticide is not incorporated, as when it is applied as a foliar spray ( e. g., to turf) or through overhead sprinkler irrigation; e. g., chemigation on potatoes). PCNB may volatilize more from moist or saturated soils than dry soils because it adsorbs less to wetter soils. One study reports that most of the PCNB that was lost from soil during 10 months of incubation was due to volatilization.

d) Photodegradation The primary degradation pathway for PCNB in clear and shallow surface water is through photodegradation, when the compound is present in an unsorbed state. Photodegradation of PCNB in surface water is moderately rapid, with half lives on the order of a few days or less. Photodegradation of PCNB in turbid or deeper waters may be limited by the attenuation of sunlight and adsorption of the compound to suspended particles in the water column. PCNB is stable to hydrolysis, and stable to photodegradation on soil.

e) Aerobic and Anaerobic Metabolism As seen in Table 15, PCNB biodegrades slowly in aerobic soils and more rapidly in anaerobic soils. The persistence of PCNB in aerobic soils is supported by data in the published literature, with half lives of almost 10 months reported in one citation. Guideline aquatic metabolism data for PCNB have not been submitted.

f) Mobility PCNB is immobile in most soils, but may have slight or even moderate mobility in soils low in organic matter. PCNB has a low potential for leaching to groundwater. PCA and PCTA are expected to be immobile in soil. Pentachlorobenzene is slightly mobile to immobile in soil. In terrestrial field dissipation studies, PCNB generally did not leach below the 6 to 12 inch soil depth, and PCA, PCTA and pentachlorobenzene generally remained in the 0 to 6 inch soil depth. g) Drift and Surface Water PCNB may reach surface water through drift when applied as a spray and particularly with foliar applications ( such as to turf). PCNB and its major degradates are all generally persistent under field conditions and may reach surface water bodies. The slow biodegradation of PCNB in most soils will increase opportunities for surface water contamination.

h) Bioconcentration PCNB has a very high potential to bioaccumulate in fish. Fish will metabolize PCNB, but the impact of depuration is limited by the persistence of PCNB and its metabolites in the aquatic environment, which create a regular source of exposure. Bioconcentration factors ( BCFs) are reported in other fish species at levels consistent with those reported for bluegill sunfish, i. e., up to 1100X in whole fish. Higher BCF values have been reported for aquatic plants, at up to 3100X for algae.  30   2. Impact of Fate Characteristics on Risk The Agency is particularly concerned about PCNB's environmental persistence, bioaccumulative potential, and potential for long range transport. These fate characteristics increase the extent and scope of the risks PCNB and its metabolites pose to nontarget organisms, but their effect cannot be quantified.

The relationship between PCNB's fate characteristics and ecological risk is detailed in the document " Synopsis of Pentachloronitrobenzene Environmental Loading and Ecological Risk," April 26, 2006, which is accessible through http:// www. regulations. gov/ , Docket Number OPP 2004 0202. To summarize this relationship:

The persistence of PCNB and its metabolites in the environment: ° increases opportunities for exposure because organisms are exposed to residues for a long time after application of the pesticide ( or may be continuously exposed between applications) ° limits the extent of depuration because organisms remain in contact with or may ingest food items contaminated with residues ° increases opportunities for bioaccumulation through the food chain The evidence that PCNB and is metabolites are subject to long range transport is limited but compelling, and: ° field data show significant quantities of PCNB can volatilize from the field ° exposure models do not account for long range transport and underestimate exposure; ° PCNB is not expected to degrade appreciably in the atmosphere ° atmospheric transport increases opportunities for exposure and increases the extent of risk ( exposure occurs outside areas where PCNB is applied and to species which otherwise would not be exposed)

PCNB and its metabolites partition to organic matter and sediment, and: ° effects on benthic organisms are uncertain and unaccounted for in the risk assessment ° this partitioning likely contributes to bioaccumulation and amplification of residues in the food chain The fate characteristics of PCNB and its metabolites ( including persistence and partitioning to lipids and organic matter) indicate the potential to bioaccumulate up the food chain. While bioconcentration data are limited: ° application of the Gobas food web bioaccumulation model developed by EPA's Office of Water ( http:// www. epa. gov/ glnpo/ lmmb/ foodweb. html) suggests that the aquatic food chain can serve as a mechanism for significant bioaccumulation ° the risk quotients cited in this RED do not account for exposures related to bioaccumulation, so they understate ecological risks  31   In addition, the metabolites of PCNB are not only likely to be persistent and have the potential to bioaccumulate: ° they are assumed to be toxicologically equivalent to PCNB ° and are accounted for in modeling the aquatic exposures cited in this RED, but not in the terrestrial exposures, resulting in underestimates of risk 3. Environmental Loading The combined effect of the fate characteristics on the amount of the pesticide and its metabolites entering and remaining in the environment is referred to in this document as " environmental loading." Environmental loading varies with the different use sites for a pesticide, and is a function of how much of the pesticide is introduced into the environment, as measured by usage ( pounds applied for a use site on an annual basis), percent crop treated ( what proportion of a given use site is treated in a year), application rates, and application methods ( for a volatile pesticide like PCNB, a foliar application may result in more volatilization and a greater potential for long range transport).

PCNB is a widely used pesticide with many different use sites. These use sites differ in usage, percent crop treated, application rate, and application method. The fate characteristics of PCNB and its metabolites tend to increase the amount of these compounds that remain biologically available in the environment, for long periods after application. There is a great deal of evidence to indicate that toxic residues of PCNB will persist in the environment and that the aquatic community is particularly vulnerable to this chemical. Based on the screening level assessment summarized in this RED, estimated environmental concentrations are sufficient to result in both acute and chronic effects on aquatic animals. It likely that if the full effect of the persistence, bioconcentration, and long range transport characteristics of PCNB and its metabolites associated with environmental loading could be quantified, aquatic organisms could be exposed to PCNB residues that exceed acute and chronic effect thresholds by several orders of magnitude. The fate and toxicological characteristics of PCNB and its metabolites are not fully quantified in this RED and contribute to an underestimation of risk.

4. International and Domestic Standards for Persistence, Bioaccumlation, and Long range Transport The persistence, bioaccumulative potential, potential for long range transport , and ecotoxicity of PCNB and its metabolites, when examined relative to national and international standards, suggest that PCNB has much in common with substances that have been officially identified as " persistent organic pollutants" ( POPs)" and " persistent bioaccumulative toxic substances" ( PBTs).

The 2001 Stockholm Convention establishes global controls on substances listed as POPs, defining them as organic substances that are persistent and bioaccumulate, have potential for longrange transport, and are likely to cause significant adverse human health or environmental effects. PCNB is not one of the 12 POPs listed for elimination or restriction, nor is the Agency proposing  32   that PCNB be listed as a POP, but the Agency believes that PCNB shares some characteristics with substances which may be proposed for listing.

Screening criteria have been established to identify compounds which may be added to the original POPs list. The screening criteria are described in Annex D of the Convention, which can be found at http:// www. pops. int/ documents/ convtext/ convtext_ en. pdf. The screening criteria and how PCNB relates to these criteria are described below.

a) Persistence The POPs criterion for persistence is a half life in water greater than two months, soil and sediment half lives greater than six months or, alternatively, evidence that the substance is otherwise sufficiently persistent to be of concern.

No data are available for PCNB half lives in water. The half life of PCNB alone in aerobic soil has been measured as 189 days; for the parent plus PCA half lives are 489 and 1012 days ( two studies, results supported by the open literature). The anaerobic soil half life for PCNB plus PCA is 410 days. Residues of PCNB and its metabolites remain in soil and may be taken up by plants in measurable quantities several years after PCNB was last applied. PCNB clearly meets the persistence criterion.

b) Bioaccumulation The POPs criterion for bioaccumulation is a bioaccumulation or bioconcentration factor greater than 5,000 in aquatic species; a log octanol water coefficient ( Kow) greater than 5; evidence that a chemical presents other reasons for concern, such as high bioaccumulation in other species, high toxicity or ecotoxicity; or monitoring data indicating the bioaccumulation potential of the chemical is sufficient to warrant its consideration.

Bioaccumulation is the net uptake of a chemical from the environment by all possible routes ( respiration, diet, dermal) from any source ( water, dissolved, colloidal or particular organic carbon, sediment and other organisms) ( Spacie et al. 1995). Bioconcentration is a measure of the relative amounts of residues in tissue to concentrations in water.

PCNB has a tendency to bioconcentrate in aquatic organisms. Bioconcentration factors ( BCFs) of 1100 and 1800X have been reported for whole fish and visceral tissue respectively. BCFs as high as 3100X have been observed for PCNB in aquatic plants. The log Kow for PCNB is reported as 4.22 ( Hansch et al., 1995). PCNB does not meet the bioconcentration criterion on the basis of either BCFs or log Kow.

Empirical information on bioaccumulation for PCNB is lacking, but its fate characteristics, and the fate characteristics of its metabolites, suggest a tendency to bioaccumulate up the food chain, based on their tendency to concentrate in organic matter, sediment, and lipids. In addition, the ecotoxicity and fate characteristics of PCNB contribute to opportunities for non target exposures, and potential risks of concern, in a broad range of species and both within and outside  33   areas where PCNB is applied. Although it is not clear that PCNB meets the POPs numerical criteria for bioaccumulation, its ecotoxicity and fate characteristics suggest other reasons for concern about its bioaccumulative potential.

c) Long range Transport The POPs criterion for long range environmental transport is detection of the chemical in locations distant from the source; monitoring data showing that long range transport may occur via air, water or migratory species; environmental fate properties demonstrating potential for long range transport; and, for a chemical that migrates through air, a half life in air of greater than two days Residues of PCNB have been detected in locations, e. g., Saskatchewan, Canada, where it is not used. Based on its vapor pressure, PCNB will exist almost exclusively in the vapor phase in the atmosphere. The estimated photo oxidation half life for PCNB in the vapor phase is estimated to be 2,200 days. Given that the compound is also hydrolytically stable, degradation in the atmosphere is expected to be negligible. PCNB meets the long range transport criterion.

d) Adverse Effects The POPs criterion for adverse effects is toxicity or ecotoxicity data that indicate the potential for damage to human health or to the environment.

PCNB is toxic in many test species, including those representing wildlife. PCNB is highly toxic to freshwater fish and invertebrates ( LC50s between 0.1 and 1.0 mg/ L) and very highly toxic to estuarine/ marine fish and invertebrates ( LC50 less than 0.1 mg/ L) on an acute exposure basis. PCNB is toxic on chronic basis to aquatic and terrestrial animals. PCNB meets the adverse effects criterion established by the Stockholm Convention.

A contaminant and metabolite of PCNB, pentachlorobenzene, has been nominated for addition to the Convention on Long range Transboundary Air Pollution ( LRTAP), a regional agreement on air pollutants similar to the global POPs Convention.

e) PBT Criteria and the Resource Conservation Challeng The Agency has also established criteria for identifying Persistent Bioaccumulative Toxic substances ( PBTs). Criteria are defined at two levels, the more restrictive of which calls for a ban on production while additional data are developed. The criteria can be found at: http:// www. epa. gov/ fedrgstr/ EPA TOX/ 1999/ November/ Day 04/ t28888. htm.

The more restrictive criterion for persistence is a half life in soil of 60 days or more. PCNB alone and PCNB plus its predominant metabolite, PCA, exceed this criterion. PCNB exceeds the less restrictive bioconcentration criterion of a BCF greater than 1000. According to PBT criteria, determinations of toxicity are based on best professional judgment on existing data. As noted above, PCNB is very toxic to a wide range of fauna.  34   The PBT criteria, which are the basis for regulatory action relating to pre manufacture notices for toxic substances, excluding pesticides, have also been used by the Agency to identify priority chemicals for the Resource Conservation Challenge ( RCC). Under the RCC, PCNB has been identified as one of 31 priority chemicals for which a strategy is being developed for voluntary reduction in waste streams, through a variety of programs including pollution prevention, substitution, minimization, and cradle to grave chemical management. Documentation may be found at http:// www. epa. gov/ epaoswer/ hazwaste/ minimize/ chemlist. htm and http:// www. epa. gov/ epaoswer/ osw/ conserve/ strat plan/ strat plan. htm# chemreduc.

5. Monitoring Data There are no surface water monitoring data available for PCNB or PCA in the US Geological Survey's National Water Quality ( NAWQA) database ( neither of the compounds is an analyte). According to EPA's Pesticides in Ground Water Database, A Compilation of Monitoring Studies: 1971 1991, National Summary, PCNB is not found in groundwater at significant levels or frequencies. In sampling of 1708 wells, only three detections of PCNB occurred, at a range of 0.008 to 0.275 µ g/ L. No information is available on whether the monitoring sites corresponded with PCNB use sites or times of usage.

In a groundwater monitoring study of 18 wells in three counties in California ( July 1994  1995), PCNB was not detected ( California EPA, 1995). In a review of multiple studies in which sampling was conducted in surface water and/ or groundwater at golf courses, PCNB was monitored in surface water for an unspecified number of studies, but was not detected ( Cohen et al., 1999).

A literature search was conducted to obtain published information ( generally post 1990) on the occurrence of PCNB and its degradates in the aquatic and terrestrial environments. PCNB, PCA, and PCTA have not been detected frequently in North American waters. Detections of pentachlorophenol in the environment cannot necessarily be attributed to the degradation of PCNB, as pentachlorophenol itself is extensively used as a wood preservative. Similarly, detections of pentachlorobenzene are probably most commonly the result of its formation as a byproduct in the manufacture of other compounds or as a degradate of hexachlorobenzene ( HCB), and industrial uses.

The compounds PCA, pentachlorobenzene, and PCP were monitored in studies of the Mississippi River and tributaries ( Illinois, Missouri, Ohio, Arkansas, White, and Yazoo Rivers; Rostad et al., 1993). PCA was detected in the surface waters at multiple locations, at concentrations of 0.018 to 0.055 ng/ L. Pentachlorobenzene was detected in the Mississippi River and two of its main tributaries, but was not likely a result of PCNB use. Its presence was attributed to degradation of HCB, as suggested by the concentration profiles of the two compounds. PCP was not found in any of the surface water samples.

The Agency has concluded that monitoring data on PCNB are limited and/ or incomplete information is available. As such, the data are not substantial enough to quantitatively incorporate  35   into the water assessments. Additionally, it is not clear in most cases whether the water bodies and wells sampled correspond with, or were targeted to correspond with, PCNB usage in terms of location or time. Subsequently, when the registrants submitted study specific information from a number of monitoring studies previously submitted in summary form, the Agency concluded that the data do not support the registrants' contention that a weight of evidence approach incorporating the newly submitted monitoring data would indicate that modeled values were too high. This later review, in its entirety, may be viewed the " Review of Surface Water Monitoring Data ( Summary Report and Original Monitoring Reports) Submitted to Support PCNB Reregistration, July 19, 2005," which has been posted to the PCNB docket.

6. Estimated Concentrations of PCNB and Metabolites in Water Resources a) Estimated Environmental Concentrations ( EECs) for the Ecological Risk Assessment Environmental fate parameters and use characteristics were input to PRZM/ EXAMS modeling to yield estimates of environmental concentrations for use in the PCNB ecological risk assessment. The use parameters used in the model are those associated with PCNB as currently registered. Table 16 shows input values for the five scenarios modeled in this manner. The EECs are based on data for residues of the parent, PCA, PCTA, pentachlorobenzene, pentachlorophenol, PCTASO, PCTASO2 and HCB, including volatiles.  36   Table 16. Selected input parameters for EECs of PCNB plus metabolites Parameter Value Source and/ or Comments Application Rate: lb ai/ A/ application ( turf: 2 applications/ year, 21 day interval;

others: 1 application/ year) turf: 32.67 peanuts: 10 cabbage ( cole crop): 30 potatoes: 25 cotton: 2 product labels Date of First Application turf: November 15 peanuts: April 15 cabbage: August 15 potatoes: May 20 cotton: April 20 USDA Crop Profiles: http:// www. ipmcenters. org / CropProfiles/

Application Type; Depth of Incorporation turf, foliar/ ground spray; 0 cm peanuts, band/ ground spray; 0 cm cabbage, broadcast spray; 10 cm potatoes, granular; 10 cm cotton, in furrow spray; 0 cm product labels Soil Partition Coefficient ( Kd; in mL/ g) 15.5 ( lowest non sand value) MRID 416482 01 Aerobic Soil Metabolism Half life t1/ 2 = 1124 days ( total residues; 90th percentile of upper confidence bound on mean of two values ) MRID # s 429119 02, 413845 01, 417132 02, 421128 01 Spray Drift Fraction ( ground spray) 0.01 Application Efficiency 0.99 input parameter guidance Molecular Weight 295.3 g/ mole Vapor Pressure 1.13 x 10 4 Torr Henry's Law Constant 4.42 x 10 5 atm m3 mol product chemistry data Solubility in Water at 25oC 4.4 ppm 10X solubility limit of 0.44 ppm, per input parameter guidance Aerobic Aquatic Metabolism Half life t1/ 2 = 2248 days ( total residues)* 2X aerobic soil metabolism t1/ 2 per input parameter guidance  37   Parameter Value Source and/ or Comments Anaerobic Aquatic Metabolism Half life t1/ 2 = 2004 days ( total residues)* 2X anaerobic soil metabolism t1/ 2 per input parameter guidance; data from MRID 413843 01 Hydrolysis Half life @ pH 7 stable MRID # s 408653 01, 409726 01 Aquatic Photolysis Half life 1.83 days @ pH 5 MRID # s 426062 01 and  02, 423362 01 * empirical data lacking; values derived from soil metabolism data as described in risk assessment Results of the PRZM/ EXAMS modeling for PCNB and metabolites, for selected uses as currently labeled, are found in Table 17. Peak concentrations are used to calculate acute RQs and the 1 in 10 year concentrations are used to calculate chronic RQs. A 1 in 10 year value is a value that would be equaled or exceeded once every ten years, on average. One in ten year means are estimated from running averages of 21 and 60 days.

Table 17. Surface Water Concentrations for Use in the Ecological Risk Assessment Use Site ( Rate/ Year) Peak ( Acute Assessment) 1 in 10 Year 21 day ( Fish Chronic Assessment) 1 in 10 Year 60 day ( Invertebrate Chronic)

Cabbage ( 30 lb ai/ A) 84 ppb 56 ppb 36 ppb Cotton ( 2 lb ai/ A) 28 ppb 20 ppb 14 ppb Peanuts ( 10 lb ai/ A) 97 ppb 46 ppb 25 ppb Potato ( 25 lb ai/ A) 22 ppb 11 ppb 5 ppb Turf ( 32.67 lb ai/ A, 2X) 259 ppb 187 ppb 139 ppb Detailed information on the modeling and complete results are presented in Appendix D6 of the " Environmental Fate and Ecological Risk Assessment for the Re registration of Pentachloronitrobenzene, February 15, 2005." Water concentrations used for the ecological RQs have been recalculated to reflect proposed mitigation. The revised EECs are discussed in Section IV.  38   b) Drinking Water Concentrations The water concentration used to estimate dietary risk is shown in Table 5 above. The value was derived from PRZM/ EXAMS modeling of physical chemical properties of PCNB and PCA and the high end application parameters for PCNB use on turf. Even though concentrations of PCNB in groundwater from use of PCNB on ornamental bulbs are estimated to be higher, the drinking water assessment relies on the surface water/ turf values because of the extent of turf use and the predominance of surface water as the source of drinking water. Water concentrations for the drinking water assessment have been recalculated to reflect proposed mitigation, as discussed in Section IV.

7. Estimates of Ecological Risk The Agency typically estimates ecological risk by calculating the ratio of EECs to ecotoxicity values. These risk quotients ( RQs) are then compared to LOCs used by the Agency to indicate potential risk to nontarget organisms and the need to consider regulatory action. As noted above, the fate characteristics of PCNB and its metabolites cannot be fully accounted for in developing the RQs, and so contribute to the underestimation of risks. When they are available and of good quality, the results of field studies and incident data may add to the weight ofevidence LOCs are established for duration of exposure ( acute and chronic), wildlife type ( e. g., mammals and birds, fish and aquatic invertebrates), and endangered species. The standard LOCs and the corresponding risk presumptions are presented in Table 18.

Table 18. LOCs and Risk Presumptions IF... THEN the Agency presumes...

Mammals and Birds The acute RQ > LOC of 0.5 Acute risk The acute RQ > LOC of 0.1 Acute effects may occur in Endangered Species The chronic RQ > LOC of 1 Chronic risk and Chronic effects may occur in Endangered Species Fish and Aquatic Invertebrates The acute RQ > LOC of 0.5 Acute risk The acute RQ > LOC of 0.05 Acute effects may occur in Endangered Species The chronic RQ > LOC of 1 Chronic risk and Chronic effects may occur in Endangered Species Terrestrial and Aquatic Plants The acute RQ > LOC of 1 Acute effects may occur in Endangered Species  39   The combination of uses and application methods for PCNB, and the particular fate characterstics of PCNB and its metabolites, result in many potential routes of exposure to nontarget terrestrial and aquatic organisms. For the terrestrial exposure assessment ( birds and mammals), food item exposures resulting from seed treatment and foliar applications are the major, quantifiable routes of exposure; for aquatic exposures, residues in water from soil and foliar applications are quantified.

RQs for ecological risk have been reassessed based on proposed mitigation and the use of a more refined model for terrestrial risk. These risk assessments are discussed in more detail in Section V of this RED.

a) Risk to Birds ( 1) Avian Toxicity Table 19 summarizes the avian toxicity endpoints associated with PCNB.

Table 19. PCNB Toxicity Data for Avian Species Species 5 day LC50 ( ppm) Subacute Dietary Toxicity NOEC/ LOEC ( ppm) Affected Endpoints Northern bobwhite quail > 54,000 practically non toxic 600/ 1200 Reproduction Mallard duck > 54,000 practically non toxic 600/ 1200 Growth For both test species, there was no mortality even at the highest dose tested. The Agency believes that PCNB is practically non toxic to birds on both an acute and subacute dietary basis The Agency considers measures of toxicity to birds to serve as surrogates for toxicity to reptiles and terrestrial phase amphibians, so PCNB is considered to be highly toxic to these taxa as well.

( 2) Avian Exposures Birds may ingest seed treated with PCNB, or they may be exposed when consuming other food items ( plant parts and insects) contaminated via spray or chemigation applications of PCNB. In addition to these exposures, which have been quantified for the avian risk assessment, exposure may result from incidental ingestion of contaminated soil, dermal contact with treated surfaces, preening activities, inhalation of pesticide vapor, and ingestion of contaminated drinking water.

( a) Avian Exposures from Treated Seed  40   Acute RQs were calculated in two ways for assessing risk from PCNB treated seeds. The first method assumes that a bird eats ( treated) seed only, and compares exposure from ingestion of treated seed to the acute oral toxicity endpoint ( LD50). The second method compares the LD50 to the amount of pesticide available to birds in a square foot of planted area. For chronic risks from treated seed, exposure is based on peak concentration on the seed. Exposures are shown in Table 21 below, along with corresponding RQs.

( i) Seed as Sole Food Source ( Method 1)

The first method of assessing acute risks from treated seeds is based on the exposures to the smallest seed eating birds, generally weighing about 20 g; small birds tend to eat more per unit body weight than larger birds. Exposure is estimated from the concentration of PCNB on treated seed, using daily food intake as estimated by Nagy ( 1987). Seeding rates were obtained from crop profiles ( found at http:// pestdata. ncsu. edu/ cropprofiles/ cplist. cfm? org= crop) or through discussions with registrants. LD50s were adjusted to account for the difference in body weights between the smallest seed eating birds and the ecotoxicity test species based on the formula recommended by Mineau et al. 1996.

( ii) PCNB Per Square Foot ( Method 2)

For the second method of assessing acute risk to birds from treated seed, it is assumed that 100% of the seed is available for consumption. The Agency believes this is a reasonable assumption because the seed is small and is generally not planted deeply (< 2 inches). Seed can be planted by drill or by broadcast followed by a drag chain; either method will place the seed near the surface. The amount of PCNB available for ingestion by birds is the amount present on the treated seed, expressed on a per square foot basis. The LD50 ( adjusted for different body weights) is then multiplied by the weight of the bird to yield the lethal dose of PCNB. The RQ is calculated as the ratio of the amount present on the treated seed ( on a per square foot basis) to the lethal dose.

( b) Terrestrial Exposures, Sprays and Chemigation The avian and mammalian risk assessments for spray and chemigation applications presented in this Section rely on EECs generated from a spreadsheet based model ( ELL FATE) that calculates the decay of a chemical applied to foliar surfaces for single or multiple applications. The exposure assessment also uses the methods of Hoerger and Kenaga ( 1972) as modified by Fletcher et al. ( 1994), which are based on a large set of actual field residue measurements ( including information over a hundred plant species and pesticides). Further explanation of the models used to estimate exposures presented in this Section is found in Appendix F of the " Environmental Fate and Ecological Risk Assessment for the Re registration of Pentachloronitrobenzene, February 12, 2005." More recently, the Agency has moved to an improved model for assessing terrestrial wildlife exposures and risks, called TREX, which accounts for different diets and food source preferences for different kinds of birds and mammals. Risk quotients derived from the TREX model, and taking into account risk mitigation measures proposed by the registrants, are presented in Section IV of this RED.  41   Terrestrial EECs for nongranular formulations were calculated for cole crops, cotton, peanuts, and turf, using labeled application parameters. EECs were calculated for four categories of food items potentially contaminated with residues as a result of the PCNB applications: short grass; tall grass; broadleaf plants and small insects; and fruits, pods, seeds, and large insects. EECs for PCNB are always highest on short grass and for smaller birds, and lowest on fruits, pods, seeds, and large insects and for larger birds, with concentrations on the short grass more than an order of magnitude higher. A summary of environmental exposures estimated in this way is found in Table 20.

Uncertainties in the terrestrial EECs are primarily associated with a lack of data on interception and subsequent dissipation from foliar surfaces. When such data are lacking, as in this case, EFED assumes a 35 day foliar dissipation half life, based on the work of Willis and McDowell ( 1987). The assumption is a conservative one for foliar surfaces, because even a persistent chemical like PCNB will be washed off leaves by rain or dew. Given that PCNB residues have been shown to remain in agricultural fields for several years after the last application, residues may remain in grit well beyond the 35 day half life.

Table 20. EECs on Bird/ Mammal Food Items from Spray and Chemigation Applications Use site Application rate modeled (# applications/ interval, if relevant) Maximum EECs ( ppm), for acute assessment Mean EECs ( ppm) for chronic assessment Cole crops ( Cabbage) 22.5 lbs ai/ A* ( 1 application) 338 to 5400 158 to 1913 10 lbs ai/ A ( 1 application) 150 to 2400 70 to 850 5 lbs ai/ A ( 2 applications/ 30 days) 116 to 1862 54 to 660 Peanuts 3.2 lbs ai/ A ( 3 applications/ 7 days) 128 to 2049 60 to 726 Potato 5.0 lbs ai/ A ( 4 applications/ 7 days) 247 to 3946 115 to 1397 Turf 43.56 lbs ai/ A ( 2 applications/ 7 days) 1222 to 19555 570 to 6926 * not the highest rate on current labels for this use ( 3) Avian Risk Quotients  42   ( a) From Ingestion of PCNB Treated Seed Acute and Chronic RQs associated with treated seed are shown in Table 21.

Table 21. Avian Acute and Chronic Risk Quotients for PCNB treated Seed Crop EEC mg ai/ day Acute RQ Method 1a EEC mg ai/ ft2 Acute RQ Method 2b EEC mg/ kg seed Chronic RQc Barley 296 < 0.19 1.22 < 0.04 1171 2.0d Bean 119 < 0.07 0.78 < 0.02 469 0.78 Corn 119 < 0.07 0.12 < 0.01 469 0.78 Cotton 573 < 0.36 0.43 < 0.01 2265 3.8d Oats 435 < 0.27 2.29 < 0.07 1718 2.9d Peas 237 < 0.15 1.76 < 0.06 937 1.6d Peanuts 138 < 0.09 0.77 < 0.02 547 0.91 Rice 352 < 0.22 2.32 < 0.07 1390 2.3d Sorghum 69 < 0.04 0.02 < 0.01 273 0.46 Soybeans 237 < 0.15 0.98 < 0.03 937 1.6d Sugar Beets 425 < 0.27 0.14 < 0.01 1679 2.8d a Acute RQ Method 1 = mg kg 1 day 1 / LD50 b Acute RQ Method 2 = mg ft2 / LD50 c Chronic RQ = mg kg 1 seed / NOAEC d Exceeds chronic risk level of concern, RQ > 1.0 PCNB is practically nontoxic to birds on an acute exposure basis ( no mortality was observed at the highest dose tested in birds). The Agency's concern for birds is primarily with chronic exposures. Chronic RQs exceed levels of concern for seven of the 11 seed types that were assessed. ( b) From Spray and Chemigation Applications Acute and chronic RQs associated with selected non seed treatment uses of PCNB ( as currently labeled), for a range of food items and sizes of bird, are summarized in Table 22. The use parameters used to generate these RQs are shown in Table 20.  43   Table 22. Avian Risk Quotients from Spray and Chemigation Applications Use site Range of acute RQs Range of chronic RQs Cole crops ( Cabbage) < 0.01 to< 0.10 0.56 to 9.01 Peanuts < 0.01 to< 0.04 0.19 to 4.01 Potato < 0.01 to< 0.07 0.41 to 6.61 Turf < 0.02 to < 0.36 2.01 to 331 1 exceeds chronic risk level of concern PCNB is practically nontoxic to birds on an acute exposure basis ( no mortality was observed at the highest dose tested in birds). The Agency's concern for birds is primarily with chronic exposures. For the modeled uses, as currently labeled, chronic RQs exceed LOCs ( RQ > 1) in many instances. When the impact of environmental loading is factored in, risks would be higher than those represented by risk quotients alone. Risk Quotients for birds and spray and chemigation applications of PCNB have been reassessed with the improved model TREX and based on the registrant risk mitigation proposal. This reassessment is discussed in Section IV of this RED.

b) Risk to Mammals ( 1) Mammalian Toxicity Table 23 summarizes mammalian toxicity endpoints for PCNB.

Table 23. PCNB Toxicity Data for a Representative Mammalian Species Species LD50 in ppm Acute oral toxicity ( MRID#) NOAEC in ppm ( MRID#) Chronic Endpoints Laboratory rat Rattus norvegicus > 5050 practically non toxic ( 414431 01) 200 ( 434693 03) liver, thyroid hypertrophy; thyroid follicular cell hyperplasia In the rat acute oral study, no mortality was seen even at the highest dose tested. The Agency believes that PCNB is practically nontoxic to mammals on an acute oral exposure basis. Chronic RQs are based on the NOAEC from a two generation rat reproduction study. The relationship of the endpoints in this study ( liver and thyroid effects) to more typical ecological assessment endpoints ( e. g., impaired reproduction, growth and survival) is not clear.

( 2) Mammalian EECs  44   Mammalian exposures from treated seed were calculated in the same manner as that described above for birds. Exposures are shown in Table 24 below.

Potential exposures resulting from spray and chemigation applications of PCNB were calculated for mammals in the same way as for birds, with the same use sites and application parameters. The range of potential exposures for mammals can be found in Table 20 above.

( 3) Mammalian Risk Quotients ( a) From Ingestion of PCNB Treated Seed Table 24 shows the EECs and RQs for acute and the chronic mammalian exposures from ingestion of treated seed.

Table 24. Mammalian Risk Quotients for Ingestion of Treated Seed Crop EEC mg ai/ day Acute RQ Method 1a EEC mg ai/ ft2 Acute RQ Method 2b EEC mg/ kg seed Chronic RQc Barley 172 < 0.02 1.22 < 0.01 1171 5.9d Bean 69 < 0.01 0.78 < 0.01 469 2.3d Corn 69 < 0.01 0.12 < 0.01 469 2.3d Cotton 332 < 0.04 0.43 < 0.01 2265 11d Oats 252 < 0.03 2.29 < 0.02 1718 8.6d Peas 137 < 0.02 1.76 < 0.01 937 4.7d Peanuts 80 < 0.01 0.77 < 0.01 547 2.7d Rice 204 < 0.02 2.32 < 0.01 1390 7.0d Sorghum 40 < 0.01 0.02 < 0.01 273 1.4d Soybeans 137 < 0.02 0.98 < 0.01 937 4.7d Sugar Beets 246 < 0.03 0.14 < 0.01 1679 8.4d Wheat 69 < 0.01 0.66 < 0.01 469 2.3d a Acute RQ Method 1 = mg kg 1 day 1 / LD50 b Acute RQ Method 2 = mg ft2 / LD50 c Chronic RQ = mg kg 1 seed / NOAEC d Exceeds chronic risk level of concern ( RQ > 1)  45   PCNB is practically nontoxic to mammals on an acute oral exposure basis. The Agency considers the likelihood of acute mortality to mammals to be low for the modeled uses. Chronic risk LOC ( RQ > 1) is exceeded for every type of treated seed.

( b) From Spray and Chemigation Applications RQs were calculated for mammals of three sizes. RQs are shown in Table 25; use parameters used to generate these RQs are as in Table 20.

Table 25. Acute RQs for Mammals PCNB is practically nontoxic to mammals on an acute basis. The Agency considers the likelihood of mammalian acute mortality to be low for all of the modeled uses.

Chronic risk quotients from spray and chemigation applications for mammals are based on a NOAEC of 200 ppm, but the relevance of the thyroid and liver effects from this study of laboratory rats to more relevant ecological assessment endpoints of impaired reproduction, growth and survival in wildlife is not clear. Chronic RQs were calculated for different food sources and mammals in a range of three sizes. RQs are shown in Table 26; use parameters are those shown in Table 20.

Table 26. Chronic mammalian risk quotients for selected uses of nongranular products Range of Chronic Mammalian RQs ( by animal wt.) Use Site 15 g 35 g 1000 g Cole crops ( Cabbage) 71 to 5131 51 to 3561 11 to 811 Peanuts 21 to 2281 21 to 1581 0.35 to 361 Potato 51 to 3751 41 to 2601 0.74 to 591 Turf 261 to 18581 181 to 12911 41 to 2931 1 exceeds chronic risk of concern Range of Acute Mammalian RQs ( by animal weight) Use site 15 g 35 g 1000 g Cole crops ( Cabbage) < 0.01 to < 1.0 < 0.01 to < 0.71 < 0.01 to < 0.16 Peanuts < 0.01 to < 0.45 < 0.01 to < 0.31 < 0.01 to < 0.07 Potato < 0.01 to < 0.74 < 0.01 to < 0.52 < 0.01 to < 0.12 Turf < 0.05 to < 3.7 < 0.04 to < 2.6 < 0.01 to < 0.58  46   For the majority of the selected uses sites, as currently labeled, the chronic mammalian chronic risk LOC ( RQ > 1) is exceeded for all sizes of animal and food items evaluated. When the impact of environmental loading is factored in, risks would be higher than those represented by risk quotients alone. Risk Quotients for mammals and spray and chemigation applications of PCNB have been reassessed with the improved model TREX and based on the registrant risk mitigation proposal. This reassessment is discussed in Section IV of this RED.

c) Risk to Fish and Aquatic Invertebrates Tables 27 and 28 summarize the toxicity endpoints used in the hazard assessment of aquatic species for PCNB.

( 1) Toxicity to Freshwater Species Table 27. Acute and chronic toxicity data for freshwater species Acute Toxicity Chronic Toxicity Species 96 hr LC50 ( mg/ L) Acute Toxicity NOEC/ LOEC ( mg/ L) Endpoints Freshwater fish Rainbow trout Oncorhynchus mykiss 0.32 highly toxic 0.013/ 0.032 reduced growth and reproduction Bluegill sunfish Lepomis macrochirus 0.10 highly toxic

Rainbow trout Oncorhynchus mykiss ( formulated product) 0.31 highly toxic

Bluegill sunfish Lepomis macrochirus ( formulated product) 0.24 highly toxic

Freshwater invertebrate Water flea Daphnia magna 0.77 ( 48h LC50) highly toxic 0.018/ 0.030 reduced growth and reproduction PCNB is highly toxic to freshwater fish and invertebrates on an acute exposure basis. The Agency considers measures of toxicity to freshwater fish to serve as surrogates for toxicity to aquatic phase amphibians, so PCNB is considered to be highly toxic to aquatic phase amphibians as well.  47   ( 2) Toxicity to Estuarine/ Marine Species Table 28. Acute Toxicity Data for Estuarine/ Marine Species Species 96 hr LC50 ( in mg/ L) Acute Toxicity Estuarine/ Marine Fish Sheepshead minnow ( Cyprinodon variegatus) 7.9 moderately toxic Estuarine/ Marine Invertebrates Eastern oyster ( Crassostrea virginica) 0.023 very highly toxic Mysid shrimp ( Mysidopsis bahia) 0.012 very highly toxic PCNB is moderately toxic to estuarine/ marine fish and very highly toxic to estuarine/ marine invertebrates on an acute exposure basis. Chronic data are lacking for estuarine/ marine species. Since estuarine/ marine invertebrates are more sensitive to PCNB on an acute basis than their freshwater counterparts, it is reasonable to assume that they may be more sensitive on a chronic exposure basis as well.

( 3) Exposure for Aquatic Species Surface water concentrations resulting from PCNB application to five selected crops, as currently labeled, were estimated with the Tier II model PRZM EXAMS. The results of this modeling are summarized in Table 17 above.

( 4) Risk Quotients for Aquatic Species Peak EECs as derived from the PRZM EXAMS model were compared to acute toxicity endpoints for aquatic species to derive acute risk quotients. There are no chronic toxicity data for PCNB in estuarine/ marine animals, so chronic risk quotients could not be generated for these species. The results of these assessments are summarized in Tables 29 ( freshwater animals) and 30 ( estuarine/ marine animals).  48   Table 29. Acute and chronic risk quotients for freshwater animals exposed to PCNB Acute RQs Chronic RQs Use site ( application parameters as in Table 16) Freshwater Fish Freshwater Invertebrates Freshwater Fish Freshwater Invertebrates Cole crops 0.841 0.112 4.33 3.13 Cotton 0.282 0.04 1.53 1.13 Peanuts 0.971 0.132 3.53 2.63 Potatoes 0.222 0.03 0.8 0.6 Turf 2.61 0.342 8.23 5.93 1 exceeds acute risk to nonlisted species ( RQ > 0.5) and endangered species ( RQ > 0.05) LOCs 2 exceeds acute risk to endangered species LOC ( RQ > 0.05) 3 exceeds chronic risk LOC ( RQ > 1)

Table 30. Acute risk quotients for estuarine/ marine animals exposed to PCNB Acute RQs Crop ( application parameters as in Table 16) Estuarine/ Marine Fish Estuarine/ Marine Invertebrates Cole crops 0.01 7.01 Cotton < 0.01 2.31 Peanuts 0.01 8.11 Potatoes < 0.01 1.81 Turf 0.03 221 1 exceeds acute risk to nonlisted species ( RQ > 0.5) and endangered species ( RQ > 0.05) LOCs For these uses as currently labeled, acute risk LOCs for nonlisted species are exceeded for freshwater fish following application to cole crops, peanuts, and turf; acute risk endangered species LOCs are exceeded for all sites. The chronic risk LOC is exceeded for freshwater fish and invertebrates on all sites but potatoes.

While no acute risk LOCs for estuarine/ marine fish are exceeded for any of the crops, the likelihood of adverse chronic effects is uncertain since no data are available to assess the chronic toxicity of PCNB in these species. Estuarine/ marine invertebrates appear to be much more sensitive to PCNB than their freshwater counterparts on an acute exposure basis; based on the chronic RQs for invertebrates in Table 29, it is reasonable to assume that the chronic risk LOC may be exceeded for estuarine/ marine invertebrates. Based on this uncertainty, the Agency presumes chronic risk to estuarine/ marine animals.  49   Risk quotients for aquatic species have been reassessed based on the risk mitigation proposal submitted by the registrants, as discussed in Section IV of this RED.

d) Risks to Insects PCNB is practically nontoxic to bees on an acute exposure basis ( LD50> 0.1 µ g/ bee). The Agency did not conduct a risk assessment for nontarget insects.

e) Risks to Terrestrial and Aquatic Plants No data are available on the toxicity of PCNB to terrestrial or aquatic plants. The Assessment Tools for the Evaluation of Risk ( ASTER) model, which relies on structure activity relationships, suggests that the toxicity of chlorinated benzenes like PCNB increases with the number of chlorine atoms. Further discussion of the ASTER model and its implications for PCNB can be found in the " Environmental Fate and Ecological Risk Assessment for the Reregistration of Pentachloronitrobenzene," February 15, 2005.

8. Risk to Endangered Species The risk assessment for PCNB indicates a potential for acute and chronic risks to listed species associated with the modeled use sites. These risks have been reassessed pursuant to mitigation measures proposed by the registrants, as detailed in Section IV. A full accounting of risks to listed species is made in that Section.

The Agency can not preclude the potential for indirect effects to listed species that may be dependent upon taxa that experience direct effects from the use of PCNB. These findings are based solely on EPA's screening level assessment and do not constitute " may affect" findings under the Endangered Species Act ( ESA) for any listed species.

To address concerns about risks to Federally listed endangered and threatened species from pesticide use, the Agency has developed the Endangered Species Protection Program ( ESPP). The assessments of risk for aquatic and terrestrial wildlife described in this RED serve as a screening tool to determine the need for any species specific assessments for PCNB and listed species. In accordance with the ESPP, EPA will consider ecological parameters, use information, and geographic relationships, as well as biological requirements and behavioral aspects of a particular species to develop a species specific assessment for listed species. The Agency's species specific analysis also will take into consideration any risk mitigation measures implemented as part of the RED decision for PCNB.

Following this future species specific analysis, a determination whether there is a likelihood of potential effects to a listed species may result in additional limitations on the use of PCNB, other measures to mitigate any potential effects, or consultations with the Fish and Wildlife Service and/ or the National Marine Fisheries as appropriate. If the Agency's speciesspecific assessments result in the need to modify the use of the pesticide in specific geographic  50   areas, those changes will be undertaken through the process described in the Agency Federal Register Notice ( 54 FR 27984) on implementation of the Endangered Species Protection Program.

Until a species specific analysis is completed, the ecological risk mitigation measures being implemented through the RED will reduce the likelihood that endangered and threatened species may be exposed to PCNB. Information about the Agency's assessment process for threatened and endangered species is posted at www. epa. gov/ espp.

9. Ecological Incident Reports One incident has been recorded for PCNB in the Ecological Incident Information System ( EIIS), for cotton seed which failed to germinate following an unincorporated granular application.

IV. Risk Management, Reregistration, and Tolerance Reassessment Decision A. Determination of Reregistration Eligibility Section 4( g)( 2)( A) of FIFRA calls for the Agency to determine, after submission of relevant data concerning an active ingredient, whether or not products containing the active ingredient are eligible for reregistration. The Agency has previously identified and required the submission of the generic ( i. e., active ingredient specific) data required to support reregistration of products containing PCNB as an active ingredient. The Agency has completed its review of these generic data, and has determined that the data are sufficient to formulate the reregistration eligibility decision for products containing PCNB.

The Agency has completed its assessment of the dietary, occupational, residential, environmental, and ecological risks, and the benefits associated with the use of pesticide products containing the active ingredient PCNB. Based on the assessments and on public comments on the assessments, the Agency is announcing decisions about the human health and ecological effects associated with PCNB, including tolerance reassessment decisions under FFDCA and reregistration decisions under FIFRA as amended by FQPA. The Agency has determined that PCNB containing products for some uses are eligible for reregistration provided that the risk mitigation measures outlined in this document are adopted and label amendments are made to reflect those mitigation measures. Label changes are described in Section V. Those uses of PCNB eligible for reregistration are:

° Cole crops ( products labeled for control of clubroot only) 2 ° Seed treatments ° Flowering bulbs in commercial production 2 The only products for use on cole crops which are eligible for reregistration are those which are limited to the cole crop/ clubroot combination, and no other diseases may be added to the label of a registered product either by amendment or through the notification process ( PR Notice 98 10).  51   The Agency has determined that the uses of PCNB on turf, residential ornamentals, green beans, cotton, potatoes, dry beans and peas, garlic, peanuts, tomatoes, peppers, and ornamentals in commercial production ( except for flowering bulbs) are not eligible for reregistration and must be deleted from product labels. Products labeled exclusively for one or more of these ineligible uses will not be eligible for reregistration.

Based on its evaluation, the Agency has determined that PCNB products, unless labeled solely for use on sites listed as eligible for reregistration and otherwise as specified in this document, would present risks inconsistent with FIFRA. Accordingly, should a registrant fail to implement any of the risk mitigation measures identified in this document, the Agency may take regulatory action to address the relevant risks. If all changes outlined in this document are incorporated into the product labels and/ or effected via product cancellation, then the risks associated with the use of PCNB will be adequately mitigated for the purposes of this determination.

B. Public Comments and Responses Following the release of the Agency's revised risk assessments and the solicitation of risk management options for PCNB, public comment came primarily from the registrants. These comments were mostly technical in nature and the Agency examined each comment to determine if the risk assessments should be revised to reflect the criticisms, alternative methodologies, and additional information they provided. Public comments on benefits were submitted by the Golf Course Superintendents Association of America. These comments were also examined and considered in development of the Agency's benefits assessment for PCNB. The public comments, responses from the Agency, revised risk assessments, and the PCNB benefits assessment can all be accessed through the Federal government wide electronic docket management and comment system at http:// www. regulations. gov/, in Docket Number OPP 2004 0202.

After the comment period on the risk assessments closed, the registrants raised questions about an adsorption coefficient used in the drinking water assessment for turf. These questions led to a minor modification of the water assessment. The registrants also have proposed a number of risk mitigation measures for PCNB. The Agency assessed risks as they would be if these measures were adopted, and has based its reregistration decision for PCNB on the impact of these measures on risk: where risks would be mitigated adequately by the mitigation measures, and where they would not, and what additional measures would be needed to reduce all risks below levels of concern.

C. Regulatory Position 1. Food Quality Protection Act Findings a) " Risk Cup" Determination  52   Based on available data, EPA has reassessed the tolerances associated with this pesticide. EPA has determined that risk from dietary ( food sources only) exposure to PCNB is within its own " risk cup," if the risk mitigation measures proposed by the registrants are considered. Based on the risk mitigation proposal, the chronic dietary risk associated with PCNB for food only is less than 100% of the cPAD.

An aggregate assessment was conducted for exposures through food, drinking water, and residential use, incorporating the adjustments to the drinking water assessment that would be appropriate if the registrants' risk mitigation proposal were implemented. Under these conditions, the dietary risk from food and water combined is less than 100% of the cPAD. The Agency has determined that the aggregate human health risks from exposures to PCNB are within the risk cup ( still less than 100% of the cPAD) only when the exposures associated with residential uses of PCNB are eliminated. Amvac and Chemtura have proposed to terminate the residential turf uses of PCNB. The Agency believes that the use of PCNB on residential ornamentals also contributes to potential residential risks of concern, similar to those from use on turf. Thus, this use is ineligible for reregistration. Based on the aggregate assessment, and if all residential uses of PCNB are terminated, EPA has concluded that the tolerances for PCNB meet FQPA safety standards. In reaching this determination, EPA has considered the available information on the special sensitivity of infants and children, as well as aggregate exposure from food, water, and residential uses.

b) Determination of Safety to U. S. Population The Agency has determined that the established tolerances for PCNB, with amendments and changes as specified in this document, meet the safety standards under the FQPA amendments to section 408( b)( 2)( D) of the FFDCA, and that there is a reasonable certainty no harm will result to the general population or any subgroup from the use of PCNB. In reaching this conclusion, the Agency has considered all available information on the toxicity, use practices, exposure scenarios, and environmental behavior of PCNB.

c) Determination of Safety to Infants and Children EPA has determined that the established tolerances for PCNB, with amendments and changes as specified in this document, meet the safety standards under the FQPA amendments to section 408( b)( 2)( C) of the FFDCA, that there is a reasonable certainty of no harm for infants and children. The safety determination for infants and children considers the factors noted above for the general population, but also takes into account the possibility of increased dietary exposure due to the specific consumption patterns of infants and children, as well as the possibility of increased susceptibility to the toxic effects of PCNB residues in this population subgroup.

FQPA directs EPA, in setting pesticide tolerances, to use an additional tenfold margin of safety to protect infants and children, taking into account the potential for pre and postnatal toxicity and the completeness of the toxicology and exposure databases. The statute authorizes EPA to replace this tenfold FQPA safety factor with a different FQPA factor only if reliable data demonstrate that the resulting level of exposure would be safe for infants and children. For  53   PCNB, the Agency has determined that an uncertainty factor of 10X must be retained for the dietary ( chronic), residential exposure ( incidental oral, dermal and inhalation), and aggregate risk scenarios for PCNB.

No findings of significant toxicological concern were identified in the submitted developmental or reproductive toxicity data, and no neurobehavioral alterations or evidence of neuropathological effects were observed in the available data. The Agency's retention of the 10X factor relates to potential effects on thyroid function after in utero exposure and in children that would not have been detected in studies already undertaken. There are additional uncertainties associated with the potential effects of bioaccumulation of PCNB and metabolites in human systems. The Agency's uncertainty about potential thyroid effects after in utero exposure and in children is discussed in Section III of this RED.

d) Endocrine Disruptor Effects EPA is required under the FFDCA, as amended by FQPA, to develop a screening program to determine whether certain substances ( including all pesticide active and other ingredients) " may have an effect in humans that is similar to an effect produced by a naturally occurring estrogen, or other endocrine effects as the Administrator may designate." When the appropriate screening and/ or testing protocols being considered under the Endocrine Disruptor Screening Program have been developed, PCNB may be subject to additional screening and/ or testing to better characterize effects related to endocrine disruption. e) Cumulative Risks The Food Quality Protection Act ( FQPA) requires EPA to consider " available information" concerning the cumulative effects of a particular pesticide's residues and " other substances that have a common mechanism of toxicity" when considering whether to establish, modify, or revoke a tolerance. Potential cumulative effects of chemicals with a common mechanism of toxicity are considered because low level exposures to multiple chemicals causing a common toxic effect by a common mechanism could lead to the same adverse health effect as would a higher level of exposure to any one of these individual chemicals.

PCNB is an organochlorine member of the substituted aromatics class of pesticides ( George W. Ware, The Pesticide Book, Fourth ed., 1994). A cumulative risk assessment has not been conducted for members of this class of pesticides as part of this human health risk assessment. Exposure of test animals with PCNB does not appear to result in endpoints the same as those resulting in test animals exposed to the organochlorine pesticides chlorothalonil or pentachlorophenol. The endpoints used to assess human health risks for PCNB are primarily thyroid hypertrophy and hepatocellular hypertrophy and hyperplasia. The endpoints for chlorothalonil have been identified as various kidney and forestomach effects, and the endpoints identified for pentachlorophenol are carcinogenicity ( hemangiosarcomas, hepatocellular tumors, and adrenal tumors) and developmental effects ( increased resorptions of fetuses, reduced fetal weight, skeletal malformations of fetuses). The Agency has not undertaken a comprehensive assessment of organochlorine pesticides with respect to common mechanism. For information regarding EPA's efforts to determine which chemicals have a common mechanism of toxicity and  54   to evaluate the cumulative effects of such chemicals, see the policy statements by the EPA's Office of Pesticide Programs concerning common mechanism determinations and procedures for cumulating effects from substances found to have a common mechanism on EPA's website at http:// epa. gov/ pesticides/ cumulative/ .

2. Tolerance Summary The Agency has reassessed all current tolerances for PCNB. The Agency has also determined the eligibility of reregistration for all uses of PCNB; the rationale for these determinations is described later in this Section. The Agency will give consideration to overseas use of PCNB and international trade in determining whether to propose revocation of tolerances associated with uses of PCNB that are not eligible for reregistration. In proposing a schedule for revocation, the Agency also will take into account the last legal use date, movement through the market of commodities with residues resulting from legal use, and the persistence of PCNB and its metabolites.

The Agency has also evaluated residue data associated with uses of PCNB for which tolerances have not yet been established. Some of these uses are not eligible for reregistration, and the Agency will not establish tolerances for the associated commodities.

The Agency believes that the correct tolerance expression for residues of PCNB and its metabolites is residues of PCNB, PCA, and PCTA. The current tolerance expressions for " pentachloronitrobenzene" or " pentachloronitrobenzene ( PCNB) and its metabolites pentachloroaniline ( PCA) and methyl pentachlorophenyl sulfide ( MPCPS)" should be changed to " pentachloronitrobenzene ( PCNB) and its metabolites pentachloroaniline ( PCA) and pentachlorothioanisole ( PCTA)." PCTA and MPCPS are two different names for the same compound.

a) Tolerances Currently Listed Under 40 CFR § 180.291( a)

The tolerance expression in 40 CFR § 180.291( a) for pentachloronitrobenzene will be changed to pentachloronitrobenzene ( PCNB) and its metabolites pentachloroaniline ( PCA) and pentachlorothioanisole ( PCTA).  55   Table 31. PCNB Tolerances Listed Under 40 CFR § 180.291( a)

Commodity Current Tolerance ( ppm) Tolerance Reassessment ( ppm) Comment Cottonseed 0.1 TBD* Confirmatory residue data for seed treatment use are currently in review. Conservative assumptions have been applied to ensure that dietary risks are not underestimated. * TBD = To be determined b) Tolerances Currently Listed Under 40 CFR § 180.291( b)

Tolerances listed at 40 CFR § 180.291 ( b) will be moved to 40 CFR § 180.291 ( c) to conform to the Agency standard for citing regional tolerances. 40 CFR § 180.291 ( b) will be reserved for tolerances associated with Section 18 uses. The tolerance expression in 40 CFR § 180.291( c) will be changed to pentachloronitrobenzene ( PCNB) and its metabolites pentachloroaniline ( PCA) and pentachlorothioanisole ( PCTA).  56   Table 32. Tolerances Listed Under 40 CFR § 180.291( b)

Commodity Current Tolerance ( ppm) Tolerance Reassessment ( ppm) Comments Collards 0.2 0.2 Kale 0.2 0.2 Mustard Greens 0.2 0.2 Residue data from IR 4 support the current tolerance for regional registrations.

c) Interim Tolerances Listed Under 40 CFR § 180.319 Tolerances listed under § 180.319 will be reassigned to § 180.291( a).

Table 33. Interim tolerances Listed Under 40 CFR § 180.319 Commodity Current Tolerance ( ppm) Tolerance Reassessment ( ppm) Comment/ Correct Commodity Definition Beans 0.1 TBD* Confirmatory residue data for seed treatment use are currently in review.

Broccoli Brussels Sprouts Cabbage Cauliflower 0.1 0.1 Head and Stem Brassica Vegetable Crop Subgroup Garlic 0.1 0.1 Peanuts 1 TBD* Confirmatory residue data for seed treatment use are currently in review.

Potatoes 0.1 0.1 Peppers 0.1 Tomatoes 0.1 0.1 Fruiting Vegetables ( except Cucurbits) Crop Group * TBD = To be determined. Conservative assumptions have been applied to ensure that dietary risks are not underestimated.

40 CFR § 180.291( d) will be reserved for tolerances associated with inadvertent residues.

d) Tolerances That Need to Be Proposed Under 40 CFR § 180.291( a)

For several uses of PCNB resulting in residues in associated commodities, tolerances have not been proposed previously. For commodities listed in Table 34 with residues from seed treatment use, new data may be required pending approval of the new analytical method.  57   Table 34. Tolerances That Need To Be Proposed under 40 CFR § 180.291( a)

Commodity Tolerance Assessment ( ppm) Comment Cotton gin byproducts Barley, grain, hay and straw Corn, grain, forage and fodder Oat, forage, grain, hay and straw Peas Rice, grain and straw Safflower, seed Sorghum forage, grain, and stover TBD* Confirmatory residue data for seed treatment uses are currently in review.

Soybean, forage, hay and seeds 0.02 Sugar beet, roots and tops Wheat, forage, grain, hay, and straw Confirmatory residue data for seed treatment uses are currently in review.

Milk Cattle fat, meat, and meat byproducts ( mbyp)

Goat fat, meat, and mbyp Horse fat, meat, and mbyp Sheep fat, meat, and mbyp Hog fat, meat, and mbyp Eggs Poultry, fat Poultry, mbyp TBD*

* To be determined. Conservative assumptions have been applied to ensure that dietary risks are not underestimated.

e) Codex Harmonization There are no established or proposed Codex maximum residue limits ( MRLs) for PCNB.

f) Analytical Methods and Residue Data Requirements The Agency has reassessed the current tolerances for PCNB based on the current analytical methodology. The current analytical method determines just three compounds ( parent + PCA + PCTA). The Agency has determined that a new analytical method must be developed to  58   account for all metabolites of PCNB. The Agency is requiring a new standardized analytical method for PCNB that converts all or most of the 80 plus residues of concern ( parent and metabolites) to one or a few common moieties for use in quantifying total residues in field trials. The new method is needed because all PCNB metabolites are of toxicological concern, are fairly stable in the environment, tend to accumulate in treated soil, are found in rotational crops, and occur in varying ratios. It is possible that the tolerance expression for residues associated with the use of PCNB will be revised based on this new method.

The Agency is deferring a decision about what additional data will be needed for magnitude of residues until after a new analytical method is approved. It is possible that additional residue data will be needed at that time, and that those data could result in a determination by the Agency that one or more of the tolerance level recommendations made here should be changed. Decisions about whether a new enforcement method is needed will also be deferred until a new analytical method is approved, so the requirement for developing an enforcement method is reserved. The requirement for submitting analytical reference standards is reserved on the same basis.

3. Regulatory Rationale The Agency has determined that certain uses of PCNB are eligible for reregistration provided that the risk mitigation measures outlined in this document are adopted, and label amendments are made to reflect these measures, as described in this document.

The following is a summary of the rationale for managing risks associated with the use of PCNB. Where labeling revisions are warranted, specific language is set forth in the summary tables of Section V of this document. The Agency's decisions on the reregistration of PCNB are based on the Agency's initial assessment of risks, a risk mitigation proposal submitted by the registrants, and whether additional risk mitigation is necessary to justify reregistration. The registrants' risk mitigation plan was proposed in two parts, and the Agency also made some technical refinements and an error correction to its risk assessments during the same interval. A chronology is provided below to facilitate understanding of the risks and potential risk reduction associated with the registrants' proposal and the Agency's changes. The Agency's assessments and supporting documents identified in the chronology are all available through http:// www. regulations. gov/ in Docket Number OPP 2004 0202.

a) Chronology of Assessments and Mitigation Proposals The Agency initially assessed the human health and ecological risks of PCNB as currently registered. The Agency also assessed the benefits associated with the major, currently registered uses of PCNB. The reregistration eligibility decision for PCNB is based on an evaluation of both risks and benefits. The risk assessments went through several iterations based on public comments, proposed mitigation, and the correction of an error in and refinements to the dietary assessment. A chronology of the Agency risk reassessments and registrant responses may be helpful in tracking the risk conclusions discussed in this document.  59   The Agency released risk assessments revised to address public comments ( mostly technical in nature) on March 2, 2005, and determined at that time that the dietary, residential, aggregate, ecological, and some occupational risks associated with the uses of PCNB were of concern. The risks discussed in Section III of the RED reflect the assessments made public in March 2005.

On June 10, 2005, the two registrants of technical grade PCNB, Amvac and Chemtura, proposed a risk mitigation plan focused mainly on reducing dietary and worker risk.

The Agency subsequently determined that the proposal adequately addressed most of the occupational risks, but that dietary, residential, and ecological risks would not be reduced below levels of concern.

Subsequent to the Agency's evaluation of this proposal, the registrants verbally supplemented their original mitigation plan by proposing that all turf uses of PCNB except golf course tees, greens, and fairways be terminated. At the same time, the Agency moved to correct an error in its dietary risk assessment related to how PCNB residues partition in the liquid and fat portions of milk, and to refine the dietary assessment by more accurately reflecting the composition of the diet for lactating cows and its contribution to residues in milk. In addition, the proposal to eliminate all turf uses except specific golf course sites allowed the Agency to incorporate a Golf Course Adjustment Factor ( GCAF) into the drinking water and ecological water exposure assessments to represent the smaller portion of golf course area on potentially treated with PCNB. The risks discussed in this Section of the RED primarily reflect the Agency's assessment of the registrants' complete proposal.

The Agency concluded that the registrant's complete proposal, together with the correction to and refinement of the dietary assessment, would decrease estimates of dietary and most of the occupational and residential risks below levels of concern. The dietary risk conclusions are captured in an October 20, 2005 assessment. Residential risk would be eliminated for applications to turf. Residential risks posed by the use of PCNB on ornamentals would not be mitigated by the proposal.

Although the complete proposal would also reduce wildlife risk estimates for PCNB, the Agency did not find it adequate to address ecological risk concerns. The ecological risk quotients associated with the registrants' proposal are captured in the Agency documents dated July 7 and August 9, 2005. In addition to risk quotients that exceed ecological levels of concern for most of the assessed uses, the fate and transport characteristics of PCNB and its metabolites are indicative of a potential for environmental loading that increases risks substantially, although to a degree that cannot be quantified.

The Agency also conducted a complete benefits assessment for the major uses of PCNB. The assessment, captured in a May 16, 2006 document, is described in this Section. The Agency has developed a qualitative analysis of benefits for the minor uses of PCNB. The Agency acknowledges that for these uses, more complete benefits information could result in a different assessment of potential benefits. The Agency is actively soliciting such information in an effort to  60   gain a better understanding of the relationship between risks and benefits for those uses. The minor uses for which the Agency seeks such information and the particular kinds of information that could be useful in refining the benefits analysis for these uses are detailed in this Section. It is possible that such information, provided during the comment period, could change the Agency's understanding of the risk/ benefit relationship for specific uses, and result in amendment of the reregistration eligibility decisions on the subject uses.

All of the assessment documents cited in this RED are available from the docket at http:// www. regulations. gov/ in Docket Number OPP 2004 0202.

This RED is based on the Agency's current understanding of the risks and benefits associated with PCNB use. For uses of PCNB which are not eligible for reregistration, the Agency has made a determination that risks outweigh benefits. The rationale for the determinations on the different uses of PCNB is detailed in this Section.

b) Summary of Mitigation Measures Proposed by Registrants The jointly proposed risk mitigation plan submitted by Amvac and Chemtura on June 10, 2005 focused mainly on reducing dietary and worker risk. Measures proposed by the registrants included:

° Reduction of maximum seasonal application rates Peppers ( from 20 to16.5 lb ai/ A/ season) Beans ( from 2 to 1 lb ai/ A/ season) Peanuts ( from 2 to 1 lb ai/ A/ season) Cotton ( from 2 to 1.5 lb ai/ A/ season) Cole crops ( from 30 to 22.5 lb ai/ A/ season). ° Termination of garlic use ° Restriction of golf course use to tees, greens, and fairways ° Prohibition of some application methods and formulation types, including all aerial applications and broadcast applications to ornamental bulbs ° Additional PPE for workers ( For peanuts, risk quotients were originally assessed at a rate of 10 lb ai/ A/ season. The 2 lb rate represents a recent intermediate rate reduction originating with the registrants. For the cole crops, the current labeled maximum application rate of 30 lb ai/ A/ season was the basis for estimating drinking water concentrations and the environmental concentrations for aquatic organisms in the original assessment. An application rate of 22.5 lb ai/ A/ season was modeled to calculate risk to terrestrial wildlife in the original assessment.)

The registrants later proposed to terminate all turf uses of PCNB except golf course tees, greens, and fairways. The later proposal would terminate PCNB use on residential lawns; industrial/ commercial turf; other ornamental turf including turf in school yards, parks, playing fields, and playgrounds; sod farms; and other golf course areas.  61   c) Human Health Risk Mitigation ( 1) Dietary Risk Mitigation The Agency assessed the chronic dietary risks from drinking water that would be associated with the registrants' complete mitigation proposal. In this assessment, the Agency used an alternate adsorption coefficient for the turf use than that used in the original assessment, based on a technical comment from the registrants. The proposed rate reductions and termination of most turf uses would not affect estimates of food only dietary exposure because residues estimated on food were mainly based on field trial data and cannot be reliably adjusted for different application rates, and turf uses do not result in residues on food.

The registrants' complete mitigation proposal would also allow the Agency to incorporate a Golf Course Adjustment Factor ( GCAF) into the dietary and ecological water exposure assessments to represent the smaller portion of golf course area on which PCNB could be used. In accordance with Agency policy, as captured in " Golf Course Adjustment Factors for Simulated Aquatic Exposure Concentrations," December 7, 2005, the proportion of golf course turf that is tees, greens, and fairways has been estimated at 34%. The Agency's dietary assessment based on the mitigation proposed by the registrants was also revised to reflect technical refinements needed to more accurately assess the contribution of PCNB residues in animal diets and animal commodities. The use of the GCAF and the technical refinements together resulted in decreased estimates of dietary, residential, and aggregate risk below levels of concern. ( The GCAF also contributed to the reduction of estimates of ecological risk associated with the turf use.)

Table 35 shows the modeled surface water drinking water concentrations that would be associated with the proposed mitigation, drawn from the July 7, 2005 memo entitled " Revised/ Refined Tier II Aquatic Exposure Values for the Drinking Water and Ecological Exposure Assessments of PCNB for Use During Phase 6   Risk Mitigation," for potatoes and turf only. The revised values for cole crops, peanuts, and cotton are drawn from the August 9, 2005 memo entitled " Revised Tier II Surface Water Exposure Values and Terrestrial Exposure Values for PCNB Based on Proposed Lower Application Rates ( Risk Mitigation Phase)." Both memos are posted to http:// www. regulations. gov/ in Docket Number OPP 2004 0202.

Table 35. Estimated Drinking Water Concentrations Based on Proposed Mitigation Scenario ( application rate; # of applications/ year) Source EDWCs 1 in 10 year concentrations ( used to assess chronic risk)

Turf ( 32.67 lb ai/ A; 2) 12.2 ppb Potato ( 25 lb ai/ A; 1) 1.7 ppb Cabbage ( 22.5 lb ai/ A; 1) Surface water 10.3 ppb  62   Peanuts ( 1 lb ai/ A; 1) 1.7 ppb Cotton ( 1.5 lb ai/ A; 1) 5.7 ppb Although the cabbage 1 in 10 year concentration is slightly lower than the turf value, the Agency determined that cabbage concentration was a more reasonable worst case than the concentration modeled for the use of PCNB on golf courses, because based on the registrants' proposal, PCNB use on golf course would be limited to tees, greens, and fairways. The 1 in 10 year value for cabbage, representing cole crops in general, was selected for use in the revised chronic dietary risk assessment. The values in Table 35 can be compared to the turf value in Table 5, which was used to assess dietary risk from PCNB as currently registered.

Concurrent with the assessment of the risk mitigation proposal, the Agency determined that residues of PCNB and metabolites in animal food items ( especially milk) had been overestimated in part because the theoretical diet of lactating cattle contained too high a proportion of potato culls. Lactating cattle are typically fed a higher proportion of grain, rather than potatoes, for more protein. The Agency refined the theoretical diet to more closely approximate the actual diet fed to lactating cows. In addition, the Agency looked more closely at how PCNB and its metabolites are likely to separate into aqueous and fat components of animal tissue and milk, and determined that the metabolites are not likely to appear in milk to the degree which had been assumed for the earlier dietary risk assessments. The Agency corrected this error.

Table 36 shows the revised dietary risk estimates for food alone and food plus water that would be associated with the risk mitigation proposed by the registrants and the revisions to described above. These results are discussed more thoroughly in the memo " Pentachloronitrobenzene ( PCNB). Chronic Dietary Exposure Assessments for the Reregistration Eligibility Decision ( RED)," dated October 20, 2005 and posted to http:// www. regulations. gov/ in Docket Number OPP 2004 0202.

Table 36. Chronic Dietary Risk Estimates Based on Proposed Mitigation and Technical Refinement/ Correction of the Original Assessment Population Subgroup Risk from all crops, no water, % cPAD Risk from all crops, with water, % cPAD U. S. Population 12 33.4 All infants (< 1 yr) 8 79 Children 1 2 yrs 34 66 Children 3 5 yrs 25 55 Children 6 12 yrs 16 36  63   Population Subgroup Risk from all crops, no water, % cPAD Risk from all crops, with water, % cPAD Youth 13 19 yrs 10 26 Adults 20 49 yrs 9 30 Adults 50+ yrs 10 32 Females 13 49 yrs 9 29 For the general population and all subgroups, the dietary risks that would be associated with the proposed mitigation are below 100% of the cPAD. The values in Table 36 can be compared to those in Table 4, which represent the risks based on PCNB as currently labeled, and without the correction and refinement made to the original assessment. The registrants' proposal would be adequate to reduce the dietary risk associated with the use of PCNB below levels of concern. Mitigation required by this RED will reduce overall usage of PCNB and is likely to reduce the occurrence and magnitude of inadvertent residues in crops for which PCNB is not registered.

( 2) Residential Risk Mitigation The registrants proposed to terminate all residential turf uses of PCNB, so residential handler and post application exposures associated with those uses would be eliminated. The residential risk assessment for PCNB focuses on turf, the predominant residential use site for the fungicide. While PCNB is also used on broadleaf ornamentals, treatment would occur most typically at nurseries and other production facilities, before plants are purchased for placement in lawns and gardens. Residential use on non turf ornamentals is limited, but based on the very high risks for children on treated turf and the potential for residential ornamental applications to result in similar exposures, the Agency believes that PCNB use on ornamentals in yards and gardens may pose residential post application risk. The registrants' proposal does not adequately address residential risk. The Agency has determined that the use of PCNB on residential ornamentals is not eligible for reregistration.

( 3) Golfer Post Application Risk Mitigation Risk to golfers reentering golf course areas treated with PCNB up to nine days previously has been estimated to be above levels of concern. The results of this initial assessment are found in Table 7. Since this initial assessment was made, an ARTF golf course maintenance exposure study has been submitted to the Agency, and the Agency believes it is appropriate to use data from that study to refine the PCNB post application golfer risk estimates. Review of information ( in the form of transfer coefficients and residues on turf) from that study indicates that the golfer reentry risk estimates on the day of treatment are above the target MOE of 1000 ( 3100 4100), and therefore not of concern. These results are discussed more thoroughly in the memo " PCNB: HED Revision of Golfer Risk Assessment," dated March 6, 2006 and posted to  64   http:// www. regulations. gov/ in Docket Number OPP 2004 0202. No additional risk mitigation is needed to reduce the golfer post application risk associated with the use of PCNB.

( 4) Aggregate Risk Mitigation Under the registrants' mitigation proposal, the dietary risk estimates associated with PCNB use would fall below levels of concern, and residential risk associated with use on turf would be eliminated. Residential risks of concern, and as a consequence, aggregate risks of concern, would still be associated with the use of PCNB on ornamental plants around the home. The Agency has determined that the aggregate human health risks from exposures to PCNB are within the risk cup ( still less than 100% of the cPAD) only when the exposures associated with all residential uses of PCNB are eliminated. The Agency has determined that the full complement of residential PCNB uses, including the use on ornamentals, must be terminated in order for the Agency to make a finding that tolerances associated with the use of PCNB are safe.

( 5) Occupational Handler Risk Mitigation In many cases, occupational risks of concern for PCNB would be adequately reduced by the use of PPE as proposed by the registrants; in other cases, additional PPE is needed. Several scenarios are associated with short and intermediate  term MOEs below 100 even at the highest applicable levels of protections afforded by PPE and engineering controls. These scenarios are tabulated below. Scenario numbers are provided for ease of reference to the relevant handler risk tables ( Tables 10, 11, and 13 above).

Table 37. Risks of Concern for Handlers, with Maximum PPE and Engineering Controls Exposure Scenario ( Number) Comments Mixer/ Loaders ( Non seed treatment) dry flowables/ chemigation/ sod farms ( 6) liquids/ chemigation/ sod farms ( 16) wettable powders/ chemigation/ soil banding cole crops ( 42) wettable powders/ chemigation/ sod farms ( 50) wettable powders/ groundboom/ sod farms ( 51) Even with closed systems, MOEs 20 89 Non seed Applicators ( Non seed treatment) dry flowables as spray/ high pressure handwand/ ornamentals ( 58) emulsifiable concentrates / high pressure handwand/ industrial lawn ( 65) wettable powders/ high pressure handwand/ industrial lawns ( 87) Engineering controls for applicators ( enclosed cab) not feasible for hand held equipment; even with most protective PPE ( coveralls + chemical resistant gloves + air purifying respirator), MOEs 5.9 59 Mixer/ loader/ applicators or loader/ applicators ( Non seed treatment) liquids/ handgun sprayer/ ornamentals ( 94) Enclosed cab not feasible for hand held equipment; with most protective PPE ( coveralls + chemical resistant gloves), dermal MOE is 77  65   Exposure Scenario ( Number) Comments granules/ belly grinder/ ornamentals ( 98) Enclosed cab not feasible for hand held equipment; no data available to assess risk if coveralls worn; with chemical resistant gloves, dermal MOE is 21 granules/ push type spreader/ ornamentals ( 99) Enclosed cab not feasible for hand held equipment; no data available to assess risk if respirators worn; with no respirator, inhalation MOE is 88 wettable powders/ low pressure handwand ornamentals ( 100) wettable powders/ low pressure handwand shade trees ( 101) Engineering controls for applicators ( enclosed cab, closed systems) not feasible for hand held equipment; even with most protective PPE ( coveralls + chemical resistant gloves + airpurifying respirator), dermal MOEs 3.1 18, inhalation MOEs 0.58 3.4 The registrants have proposed mitigation measures would which adequately address the risks for most of the scenarios represented in Table 37. These measures are:

° Terminate turf uses other than tees, greens, fairways ( Scenarios 6, 16, 20, 89, 65, 87) ° Prohibit cole crops chemigation ( 42) ° Prohibit sod farm chemigation ( 50) ° Prohibit ground boom application of WP formulation to sod farms ( 51) ° Prohibit foliar and WP applications to ornamentals ( 58, 94, 100, 101) ° Prohibit granular application by belly grinder to ornamentals ( 98)

If these mitigation measures were implemented, occupational risks for all the scenarios shown in Table 37 would be eliminated, except for Scenario # 99, applying granules with a pushtype spreader to ornamentals. The formulation/ application combination for this use poses risks that the Agency addresses in labeling requirements detailed in Table 47 at the end of this Section.

The registrants have not proposed measures to address risks to handlers of treated seed, but respirators are required to address risks of concern for these workers. PPE and other label requirements to address worker risks are detailed in Table 47.

( 6) Occupational Post application Risk Mitigation Occupational post application risk mitigation for PCNB use is not necessary because the associated risk estimates fall well below levels of concern even on the day of treatment ( Table 14). d) Ecological Risk Mitigation The Agency recalculated ecological risk quotients based on the full complement of mitigation measures proposed by the registrants. The revisions based on the mitigation proposal are detailed in the documents " Revised/ Refined Tier II Aquatic Exposure Values for the Drinking Water and Ecological Exposure Assessments of PCNB for Use During Phase 6   Risk  66   Mitigation," July 07, 2005 ( for turf and potatoes) and " Revised Tier II Surface Water Exposure Values and Terrestrial Exposure Values for PCNB Based on Proposed Lower Application Rates ( Risk Mitigation Phase)," August 9, 2005 ( for cabbage, peanuts, and cotton). Both documents are available at http:// www. regulations. gov/ in Docket Number OPP 2004 0202.

Environmental loading is not accounted for in the modeling of RQs for either terrestrial animals or aquatic animals, so ecological risk is underestimated.

Table 38 shows the EECs that would be associated with the proposed mitigation.

Table 38. Surface Water Concentrations Based on Proposed Mitigation Use Site ( Application Parameters) Peak ( Acute Assessment) 1 in 10 Year 21 day ( Fish Chronic Assessment) 1 in 10 Year 60 day ( Invertebrate Chronic) Cabbage ( 22.5 lb ai/ A) 36.4 ppb 15.3 ppb 9.5 ppb Cotton ( 1.5 lb ai/ A) 12.3 ppb 6.4 ppb 4.8 ppb Peanuts ( 1 lb ai/ A) 8.2 ppb 3.1 ppb 1.9 ppb Potato ( 22.5 lb ai/ A) 7.7 ppb 2.5 ppb 1.3 ppb Turf ( 32.67 lb ai/ A, 2 applications) 33.9 ppb 12.1 ppb 7.5 ppb The values in Table 38 can be compared to the values in Table 17, which were used to estimate RQs for PCNB as currently registered. The values in Table 39 represent what the RQs would be if the proposed mitigation were implemented.

( 1) Aquatic Risk Quotients Based on Proposed Mitigaiton Table 39. Risk Quotients for Aquatic Animals Based on Proposed Mitigation Use Site ( parameters as in Table 38) Freshwater Acute RQs Estuarine/ Marine Acute RQs Freshwater Chronic RQs Fish Invertebrate Fish Invertebrat e Fish Invertebrate Cabbage 0.36b 0.05 < 0.01 3.03a 0.73 0.85 Cotton 0.12b 0.02 < 0.01 1.03a 0.37 0.36  67   Use Site ( parameters as in Table 38) Freshwater Acute RQs Estuarine/ Marine Acute RQs Freshwater Chronic RQs Fish Invertebrate Fish Invertebrat e Fish Invertebrate Peanuts 0.08b 0.01 < 0.01 0.68a 0.15 0.17 Potato 0.08 b 0.01 < 0.01 0.64 a 0.1 0.14 Turf 0.34 b 0.04 < 0.01 2.8 a 0.58 0.67 a exceeds acute level of concern b exceeds acute endangered species level of concern RQs from Table 39 may be compared to the RQs in Table 28 and 29, which represent RQs for PCNB as currently registered. Although aquatic concentrations would decrease based on the proposed rate reductions, acute RQs would still exceed the acute high risk or endangered species LOCs for freshwater fish and estauarine/ marine invertebrates on all sites. Without chronic toxicity data for estuarine/ marine animals, chronic risk quotients for those species cannot be calculated. Since estuarine/ marine invertebrates are more sensitive to PCNB on an acute basis than their freshwater counterparts, it is reasonable to assume that they would be more sensitive on a chronic basis ( and that corresponding RQs would likely exceed the chronic LOC of 1.0).

( 2) Terrestrial Risk Quotients Based on Proposed Mitigation For cabbage, cotton, and peanuts, RQs for terrestrial wildlife were also recalculated based on the registrant proposal. RQs were not recalculated for potatoes and turf because the registrants did not propose rate reductions for these sites, and the GCAF is not appropriate for application to terrestrial wildlife.

The Agency based its initial assessment of concentrations of PCNB and metabolites on food sources for terrestrial wildlife on the ELL FATE model. Revisions based on the mitigation proposal ( found in the August 9, 2005 document) were estimated with an improved version of that model, called TREX, which accounts for different diets and food source preferences for different kinds of birds and mammals. The TREX results for terrestrial RQs based on the registrant proposal are shown in Tables 40 and 41. Table 40 shows dose based avian acute RQs, and Table 41 shows dietary based avian chronic RQs.  68   Table 40. Avian Acute Dose based RQs Based on Proposed Mitigation Range of Acute Avian RQs by Body weight Use Site 20 g 100 g 1000 g Cabbage < 0.02 to < 0.31 < 0.05 to < 0.88 < 0.25 to < 3.9 Cotton < 0.01 to < 0.02 < 0.01 to < 0.06 < 0.02 to < 0.26 Peanuts < 0.01 < 0.01 to < 0.04 < 0.01 to < 0.17 Table 41. Avian Chronic Dietary based RQs Based on Proposed Mitigation Use Site Range of Chronic Avian RQs Cabbage 0.56 to 9.0a Peanuts 0.03 to 0.40 Cotton 0.04 to 0.60 a exceeds chronic risk level of concern ( RQ   1.0)

The terrestrial assessment for PCNB as currently registered relied on ELL FATE and the assessment based on proposed mitigation relies on TREX, so direct comparisons between RQs are not appropriate. PCNB is practically nontoxic to birds on an acute basis, and the Agency considers the likelihood of avian acute mortality to be low for all of the modeled uses. The proposed mitigation would reduce terrestrial exposures, but some avian chronic RQs would still exceed levels of concern. When the impact of environmental loading is factored in, chronic risks would be higher than those represented by risk quotients alone.

Revised risk quotients for mammalian wildlife also are based on exposures modeled by TREX. Risk quotients are shown in Table 42.

Table 42. RQs for Mammals Based on Proposed Mitigation Range of Acute RQs by Body Wt. Range of Chronic RQs by Body Wt.

Use Site 15 g 35 g 1000 g 15 g 35 1000 g Cabbage < 0.01 to 0.46 0.02 to 0.40 0.01 to 0.21 3.3 to 234a 2.8 to 200a 1.5 to 107a Peanuts < 0.01 to 0.02 < 0.01 to 0.02 < 0.01 to 0.01 0.14 to 10a 0.12 to 8.9a 0.07 to 4.8a Cotton < 0.01 to 0.03 < 0.01 to 0.03 < 0.01 to 0.01 0.22 to 16a 0.2 to 13a 0.10 to 7.2a a exceeds chronic risk level of concern ( RQ   1.0)  69   For the modeled chronic mammalian RQs, LOCs are exceeded for all sizes and sites. PCNB is practically nontoxic to mammals on an acute basis, and the Agency considers the likelihood of mammalian acute mortality to be low for all of the modeled uses. e) Synthesis of Risk Ranking from RQs and Environmental Loading In general, the mitigation measures proposed by the registrants would be reflected in somewhat lower RQs for aquatic and terrestrial wildlife, but in many cases, those reductions would be insufficient to address concerns for non target species. In addition, the fate and transport characteristics of PCNB and its metabolites intensify the risk to non target organisms. The overall impact of the fate and transport characteristics of PCNB on the RQs cannot be quantified and thus contributes to an underestimation of ecological risk expressed only as RQs.

The combined effect of the fate characteristics on the amount of the pesticide and its metabolites entering, translocating, and remaining in the environment is referred to in this document as " environmental loading." Environmental loading varies with the different use sites for a pesticide, and is a function of how much of the pesticide is introduced into the environment and remains in the environment, as measured by:

° Usage ( pounds applied on an annual basis)  a measure of the amount of PCNB introduced into the environment as a whole and available for potential exposures to wildlife immediately after application; and the amount of parent and metabolites available for these exposures in the long term, and available for bioaccumulation in the food chain and long range transport to other ecosystems and species outside the treatment area ° Percent crop treated ( what proportion of a given use site is treated in a year)  a measure of how environmental inputs of PCNB are distributed within areas where the crop is grown, suggestive of how likely wildlife living in close association with a given crop are to be exposed to harmful levels of PCNB and its metabolites at the time of application and, through the persistent nature of PCNB and its metabolites, in the long term ° Application rates  reflect the concentration of toxic material present on individual food items and in water bodies within or in close proximity to a treated area at the time of application and during the time it takes for residues to dissipate or travel off site. Application rates are a factor in calculating RQs, unlike usage and percent crop treated, but applied material not consumed or otherwise taken up by non target organisms can persist in the environment, and is available for long range transport or other off site movement.

° Application methods for a volatile pesticide like PCNB, a foliar application may result in more volatilization and a greater potential for long range transport. In contrast, incorporated treatments, including seed treatments, may be more likely to result in persistent residues in soil or water bodies near the area of application or contiguous areas.

Usage, percent crop treated, and application rate for each use site were compared to the range of values for all the use sites, and identified as high end, midrange, or low end within the range. Distinctions between high end and midrange and between midrange and low end values  70   were based, where possible, on natural gaps within the ranges. Usage, percent crop treated, and application rates were categorized as in Tables 43 45, with use sites listed from high to low.

Table 43. Domestic Usage of PCNB Use site and Usage Category Annual Usage, lbs ai High end Turf ( tees, greens, and fairways) > 400,000 Cotton 400,000 Midrange Potato 60,000 Green beans 30,000 Cole crops 23,000 Low end Peanuts 5,000 Dry beans and peas 2,000 Peppers 2,000 Others < 500 Table 44. Domestic Percent Crop Treated for PCNB Use site and PCT Category Percent Crop Treated High end Green beans 15 20% Midrange Cotton up to 10% Cole crops up to 10% Low end Peppers up to 5% ( New Mexico chile peppers reported up to 13%) Potatoes up to 5% Peanuts < 2.5% Dry beans and peas < 2.5% Turf ( tees, greens, and fairways) NA Others NA NA = Information not available  71   Table 45. Maximum Application Rates for PCNB Use site and Application Rate Category Application Rate, lbs ai/ A High end Turf ( tees, greens, and fairways) 32.67 ( twice/ season) Cole crops 22.5 Potato 22.5 Garlic 20.0 Peppers 16.5 Ornamentals Variable but generally high Midrange Tomato 7.0 Low end Cotton 1.5 Green beans 1.0 Peanuts 1.0 Dry beans and peas 1.0 The placement of individual use sites within the ranges for usage, percent crop treated, and application rates, with consideration of the application method ( foliar, incorporated) together were used to describe the environmental loading associated with each use, as shown in Table 46.  72   Table 46. Potential Environmental Loading for PCNB Use Sites Use Site Usage Category PCT Category Application Rate Category Notes Environmental Loading Cole Crops Midrange Midrange High end Medium Tees, greens, and fairways High end NA High end Foliar application High Cotton High end Midrange Low end Medium Potatoes Midrange Low end High end Some " over the top" applications High Peanuts Low end Low end Low Seed Treatments NA NA Low end Low Green Beans Midrange High end Low end Medium Dry beans, peas Low end Low end Low end Low Garlic Low end NA High end Medium Tomatoes Low end Low end Midrange Low Peppers Chile peppers Low end Midrange High end Up to 13 PCT in NM Medium Other peppers Low end Low end High end Medium Ornamentals Bulbs Low end NA High end Medium Other Low end NA High end Medium The Agency assigned a risk ranking to each PCNB site based on the interplay of risk quotients ( where available) and environmental loading, and on the idea that risk quotients exceeding levels of concern are the starting point, and that environmental loading adds to the risk concerns suggested by the RQs. The magnitude of the risk quotients also plays a role. Where risk has not been quantitatively assessed as risk quotients, the risk ranking relies on measures of environmental loading alone. The risk rankings for PCNB use sites are shown in Table 47. Use sites represent non seed treatment uses unless otherwise noted.  73   Table 47. Use specific risk characterization RQs and environmental loading 1,2 Use site Aquatic Risk Quotients exceeding LOCs Terrestrial Risk Quotients exceeding LOCs Environmental loading Risk Ranking Uses for which RQs have been calculated Cole crops Acute RQs: FW fish, ES 0.36 FW invertebrate, ES 0.05 EM invertebrate 3.0 Chronic RQs: Avian up to 9.0 Mammalian up to 234 Medium High Golf course tees, greens, and fairways Acute RQs: FW fish, ES 0.34 EM invertebrate 2.8 Chronic RQs: Avian up to 33 Mammalian up to 1858 High High Cotton Acute RQs: FW fish, ES 0.12 EM invertebrate 1.0 Chronic RQs: Mammalian RQs up to 16 Medium Medium Potatoes Acute RQs: FW fish, ES 0.08 EM invertebrate 0.64 Chronic RQs: Avian up to 6.6 Mammalian up to 375 High High Peanuts Acute RQs: FW fish, ES 0.08 EM invertebrate 0.68 Chronic RQs: Mammalian RQs up to 10 Low Medium Seed treatments Chronic LOCs exceeded for all seed types; Cotton ( highest RQ) 11; assumes diet of seeds only Low Low Uses for which RQs have not been calculated Green beans Medium Medium Dry beans, peas Low Low Garlic Medium Medium Tomatoes Low Low Peppers Medium Medium Ornamentals ( commercial) Medium Medium The Agency undertook an analysis of the benefits of PCNB use in order to examine the relationship between ecological risks and benefits, on a use by use basis.

f) Benefits of PCNB Use 1 The turf and potato RQs for terrestrial wildlife based on ELL FATE Version 1.4a; all others based on T REX Version 1.22 2 FW = freshwater; E/ M = estuarine/ marine; ES = endangered species  74   The May 22, 2006 document, " Benefits and Cost Analysis of PCNB and Alternatives for Use on Golf Course Turf ( Tees, Greens, Fairways), Cotton, Potatoes, Green Beans, and Cole Crops ( Cabbage, Brussels Sprouts, Cauliflower), the Agency examined the major uses of PCNB not proposed for termination by the registrants. This document has been posted on the PCNB docket and may be accessed at http:// www. regulations. gov/ in Docket Number OPP 2004 0202. From this examination, the Agency concluded that, with the exception of the use of PCNB on cole crops for clubroot, all the major uses of PCNB are associated with minimal benefits, because the target pests could be managed with comparable efficacy by alternative pesticides, at no or minimally greater cost.

The Agency has not quantitatively assessed benefits for the minor uses of PCNB. For these uses, the Agency made assumptions about benefits based on the qualitative assessment of public comment, comments solicited by USDA through the Regional IPM Centers, Crop Profiles posted at http:// www. ipmcenters. org/ Crop Profiles/, anecdotal information about how users value PCNB, and usage and percent crop treated information as indicators of benefits. In an effort to better understand the relationship between the risks and benefits of these minor uses, the Agency is at this time actively soliciting comments relating to benefits,. The sites for which the Agency is soliciting benefits information are: dry beans and peas, peanuts, tomatoes, peppers ( all types), and ornamentals in commercial production ( all types except for flowering bulbs).

Types of information which would be useful in this regard include data from comparative efficacy trials for different pesticides used to control diseases on these sites, information about the relative costs of using PCNB and potential alternatives, production cost data, information on why registered alternatives are not appropriate for specific diseases in a particular State or under particular climatic conditions, and documentation of the lack of alternatives for controlling a particular disease.

The Agency ranked the benefits ( assessed or assumed) of the PCNB uses as either high or low, to represent the two ends of a spectrum. These rankings are shown in Table 48. Use sites represent non seed treatment uses unless otherwise noted. " Uses not quantitatively assessed for benefits" do not include turf other than tees, greens, and fairways, or garlic, because the registrants have proposed to terminate those uses. The risk/ benefit balance for uses not quantitatively assessed for benefits could be reconsidered if substantive benefits information is made available during the comment period after release of this RED. It is possible that a change in the risk/ benefit balance for any of these uses could result in amendment of the RED.  75   Table 48. Benefits characterization of uses of PCNB Use site Usage, percent crop treated Other benefits information Benefits ranking Uses quantitatively assessed for benefits ( as per May 16, 2006 document)

Green beans 30,000 lbs ai/ yr, 15 20% crop treated Numerous effective and economical alternatives for both target diseases Low Cole crops 23,000 lbs ai/ yr, up to 10% crop treated Several effective and economical alternatives for control of wirestem For wirestem, Low Lack of feasible alternatives for control of clubroot For control of clubroot: High Golf course turf ( tees, greens, and fairways) 400,000+ lbs ai/ yr Numerous highly effective, economically feasible alternatives with lesser risk of phytotoxicity Low Cotton 400,000 lbs ai/ yr, up to 10% crop treated Several alternatives of comparable efficacy and cost Low Potatoes 60,000 lbs ai/ yr, up to 5% crop treated. Several equally effective alternatives of comparable cost Low Uses not quantitatively assessed for benefits; benefits information being solicited Turf other than tees, greens, fairways 100,000 lbs ai/ yr ( approximate) Benefits for tees, greens, and benefits represent conservative estimate of benefits for other turf, since the tolerance for disease damage on tees, greens, and fairways is very low relative to other turf sites ( registrants have proposed to terminate) Low Dry beans and peas 2,000 lbs ai/ yr, < 2.5% crop treated Assumed to be Low benefit, based on limited use. No USDA respondents cited use as critical. Low Peanuts 5,000 lbs ai/ yr, < 2.5% crop treated Assumed to be Low benefit, based on limited usage. USDA respondent in TX cited extensive use, mainly in tank mixes; respondent in OK cited declining use Low  76   Use site Usage, percent crop treated Other benefits information Benefits ranking Garlic Limited usage Assumed to be Low benefit, based on limited usage ( registrants have proposed to terminate) Low Tomatoes Limited usage Assumed to be Low benefit because no USDA respondents cited use as critical. Low Peppers 2,000 lbs ai/ yr, up to 5% crop treated EPA seeks specific information on benefits to all types of peppers NM Crop Profile says PCNB used on 13% chile pepper acreage Low Other peppers: Only USDA respondent to mention peppers says use is important in DE Low Ornamentals in commercial production Limited usage EPA seeks specific information on benefits to all types of ornamentals in commercial production. Anecdotal information suggests PCNB is important in production of flowering bulbs. High CA Crop Profile indicates 29% of containerized nurseries use PCNB as a soil drench, numerous alternatives are cited Low Seed treatments ( Application rates much lower than rates for corresponding soil applications, typically < 10%) Assumed to be High benefit, based on input of USDA; use on rice and safflower seed may be less critical High 4. Determination of Eligibility for Reregistration Based on the assessment of human health risks associated with the PCNB uses, the Agency has determined that post application risks associated with residential and related uses are unacceptable. These uses are not eligible for reregistration because the Agency cannot make a determination that the tolerance reassessment for PCNB meets the FQPA safety finding based on the contribution of these uses to the aggregate risks for PCNB. In addition, the registrants have proposed to terminate the turf uses of PCNB other than golf course tees, greens, and fairways. The following uses are not eligible for reregistration:  77   The Agency has evaluated the relationship of risks and benefits for all PCNB uses on a use by use basis. The uses of PCNB which do not demonstrate a favorable risk/ benefit relationship are not eligible for reregistration. For most of the minor uses of PCNB, where benefits could not be quantified, the Agency believes that there may be publicly held information on benefits that could affect our understanding of this relationship, and the reregistration eligibility decisions for these uses. The Agency has solicited information that could better inform the decisions on these uses.

The risk/ benefit comparisons and the reregistration eligibility decisions for all the uses of PCNB for which these comparisons have been made are shown in Table 49. Decisions which could potentially be affected by the submission of benefits information during the comment period following the release of the RED are shown in italics.

Table 49. Determinations of Reregistration Eligibility for PCNB uses Use Site Risk/ Benefit Eligibility Green beans Medium/ Low Not eligible Cole crops ( PCNB is used to control two different diseases of cole crops)

For treatment of wirestem High/ Low Not eligible For treatment of clubroot High/ High Eligible Tees, greens, fairways High/ Low Not eligible Cotton Medium/ Low Not eligible Potatoes High/ Low Not eligible Turf other than tees, greens, fairways* High / Low Not eligible Dry beans/ peas Low/ Low Not eligible Garlic Low/ Low Not eligible Peanuts Medium/ Low Not eligible Tomatoes Low/ Low Not eligible Peppers Chile peppers Medium/ Low Not eligible Other peppers Medium/ Low Not eligible Production ornamentals Flowering bulbs Medium/ High Eligible Other ornamentals Medium/ Low Not eligible Seed treatments Low/ High Eligible * Residential turf and ornamentals, and turf on school grounds, and in parks, playgrounds  78   The uses of PCNB with risks rated higher than benefits are not eligible for reregistration. Uses with benefits ranked higher than risks are eligible for reregistration.

One use of PCNB appears in Table 49 with both high risks and high benefits. Because the use of PCNB to control clubroot on cole crops is a subset of the overall use of PCNB on cole crops, the usage and percent crop treated figures cited here may be overstated. The Agency believes that the environmental loading associated with the clubroot use is probably lower than that associated with overall use. In addition, the use of PCNB on cole crops when applied via chemigation poses occupational risks that cannot be adequately mitigated with PPE or engineering controls. The Agency has determined that the use of PCNB on cole crops, if labeled for control of clubroot only, and to prohibit applicaton via chemigation, is eligible for reregistration.

Several uses of PCNB have both low risks and low benefits. Because the ecological risks for PCNB are assumed to be underestimated, due to the significant but unquantified impact of environmental loading, and because the Agency is willing to consider the reregistration decision in light of information which supports greater benefits for these uses, they are not eligible for reregistration, pending consideration of such information submitted during the comment period after release of the RED.

Based on the risk benefit comparisons, and the other considerations discussed above, the Agency has determined that the following uses of PCNB are not eligible for reregistration:

° green beans ° cole crops ( if not labeled for control of clubroot only and to prohibit application via chemigation) ° turf ° cotton ° potatoes ° dry beans and peas ° garlic ° peanuts ° tomatoes ° peppers ° ornamentals in commercial production ( except for flowering bulbs) ° The Agency has determined that the following uses of PCNB are eligible for reregistration:

° cole crops ( labeled for control of clubroot only and to prohibit application via chemigation) ° flowering bulbs ( labeled for commercial use only) ° seed treatments  79   5. Labeling Requirements In order to be eligible for reregistration, all products containing PCNB must bear specific use and safety information on their labeling. In addition, certain generic and product specific data will be required for PCNB products. The specific label statements and a list of outstanding data requirements are found in Section V of this RED document.

6. Endangered Species Considerations Risk Quotients for PCNB, reflecting mitigation measures proposed by the registrants, indicate a potential for acute and chronic risks to listed species associated with the modeled use sites, as noted below:

Terrestrial organisms Mammals ° Chronic RQs exceed LOCs for cole crops, peanuts, cotton, and potatoes for all mammals feeding on short grass, tall grass, and broadleaf plants and insects ° Chronic RQS exceed LOCs for turf for all mammals feeding on all forage items Birds ( reptiles, terrestrial phase amphibians) ° Chronic RQs exceed LOCs for cole crops and potatoes for birds feeding on short grass, tall grass, and broadleaf plants and insects ° Chronic RQs exceed LOCs for turf for birds feeding on all forage items ° Chronic RQs exceed LOCs for seed eating birds for all modeled seed treatments Seed treatments ° Chronic RQs exceed LOCs for treated seeds of barley, cotton, oats, peas, rice, soybean, and sugar beet for seed eating birds ° Chronic RQs exceed LOCs for treated seeds of all types for seed eating mammals Aquatic organisms Freshwater fish ( aquatic phase amphibians) ° Acute RQs exceed LOCs for all sites Freshwater invertebrates ° Acute RQs exceed LOCs for cole crops Estuarine/ marine invertebrates ° Acute RQs exceed LOCs for all sites Although the reregistration decisions for PCNB uses will eliminate or reduce exposures in many instances, endangered species LOCs associated with the remaining uses of PCNB may still be exceeded for aquatic and terrestrial species.  80   To address concerns about risks to endangered species from pesticide use, the Agency has developed the Endangered Species Protection Program ( ESPP). The assessments of risk for aquatic and terrestrial wildlife described in this RED serve as a screening tool to determine the need for any species specific assessments for listed species, in accordance with the ESPP. Such assessments would refine the screening level assessment by taking into account such factors as the geographic areas of pesticide use in relation to the listed species and the habits and habitat requirements of the listed species. If the Agency's species specific assessments result in the need to modify the use of the pesticide in specific geographic areas, those changes will be undertaken through the process described in the Agency Federal Register Notice ( 54 FR 27984) on implementation of the ESPP.

7. Spray Drift Management The Agency has been working closely with stakeholders to develop improved approaches for mitigating risks to human health and the environment from pesticide spray and dust drift. As part of the reregistration process, we will continue to work with all interested parties on this important issue. From its assessment of PCNB, as summarized in this document, the Agency concludes that certain drift mitigation measures are needed to address the risks from off target drift for PCNB. Label statements implementing these measures are listed in Section V of this document.

V. What Registrants Need to Do The Agency has determined that certain uses of PCNB are eligible for reregistration provided that the risk mitigation measures outlined in this document are adopted, and label amendments are made to reflect those measures. To implement the risk mitigation measures, the registrants must amend their product labeling to incorporate the label statements set forth in the Label Summary Table in Section D below. The additional data requirements that the Agency intends to obtain will include, among other things, submission of the following:

A. Submissions for Technical Grade Active Ingredient Products 1. Within 90 Days of Receipt of the Generic DCI For each PCNB technical grade active ingredient product, the registrant needs to submit the following items within 90 days of receiving the Generic DCI:

° completed response forms to the generic DCI ( i. e., DCI response form and requirements status and registrant's response form); ° submit any time extension and/ or waiver requests with a full written justification); and ° compositional analysis of registered PCNB technical materials, accounting for PCNB and all contaminants present in those materials. Materials of the same composition must be used to develop the toxicity data required by the DCI.

2. Within Generic DCI Deadlines  81   Within the time limit specified in the generic DCI, the registrant must cite any existing generic data which address data requirements or submit new generic data responding to the DCI. Please contact Jill Bloom at ( 703) 308 8019 with questions regarding generic reregistration.

By US mail: By express or courier service: Document Processing Desk ( DCI/ SRRD) Document Processing Desk ( DCI/ SRRD) Jill Bloom Jill Bloom US EPA ( 7508P) Office of Pesticide Programs ( 7508P) 1200 Pennsylvania Ave., NW 4th Floor, One Potomac Yard Washington, DC 20460 2777 S. Crystal Dr. Arlington, VA 22202 B. Submissions for End Use Products Containing PCNB 1. Within 90 Days Within 90 days from the receipt of the product specific data call in ( PDCI), the registrant must submit, for each product:

° completed response forms to the PDCI ( i. e., PDCI response form and requirements status and registrant's response form); and ° any time extension or waiver requests with a full written justification.

2. Within Product DCI Deadlines Within eight months from the receipt of the PDCI, the registrant must submit:

° two copies of the confidential statement of formula ( EPA Form 8570 4); ° a completed original application for reregistration ( EPA Form 8570 1). Indicate on the form that it is an " application for reregistration"; ° five copies of the draft label incorporating all label amendments outlined in Table 47 of this document; ° a completed form certifying compliance with data compensation requirements ( EPA Form 8570 34); and ° if applicable, a completed form certifying compliance with cost share offer requirements ( EPA Form 8570 32); and ° the product specific data responding to the PDCI.

Please contact Bonnie Adler at ( 703) 308 8523 with questions regarding product reregistration and/ or the PDCI. All materials submitted in response to the PDCI should be addressed as follows:

By US mail: By express or courier service: Document Processing Desk ( PDCI/ PRB) Document Processing Desk ( PDCI/ PRB) Bonnie Adler Bonnie Adler  82   US EPA ( 7508P) Office of Pesticide Programs ( 7508P) 1200 Pennsylvania Ave., NW 4th Floor, One Potomac Yard. Washington, DC 20460 2777 S. Crystal Drive Arlington, VA 22202 C. Manufacturing Use Products  Data Requirements and Labeling 1. Generic Data Requirements Fulfillment of the data requirements identified in the risk assessments and listed below is necessary to confirm the reregistration eligibility decision documented in this RED. The Agency will consider waiving or modifying some of these data requirements in light of this RED, which designates most uses of PCNB as ineligible for reregistration.

Table 50. Generic Data Requirements for the Reregistration Eligibility Decision on PCNB Guideline or Special Study Name or Description OPPTS Guideline No.

Direct Photolysis Rate of Parent and Degradates in Water 1 835.2240 Aerobic Aquatic Metabolism Study2 835.4300 Anaerobic Aquatic Metabolism Study2 835.4400 Invertebrate Acute Toxicity Test, Freshwater Daphnids1 850.1010 Gammarid Acute Toxicity Test1 850.1020 Estuarine/ marine Mollusk ( Oyster) Acute Toxicity Test ( Shell Deposition) 1 850.1025 Estuarine/ marine Mysid ( Shrimp) Acute Toxicity Test1 Special Study ( old guideline 72 3F)

Penaeid Acute Toxicity Test1 850.1045 Bivalve Acute Toxicity Test ( Embryo Larval) 1 850.1055 Fish Acute Toxicity Test, Freshwater ( Bluegill Sunfish) 1 850.1075 Fish Acute Toxicity Test, Rainbow Trout 1 850.1075 Daphnid Chronic Toxicity Test ( early life stage in fish) 1 850.1300 Mysid ( Shrimp) Chronic Toxicity Test ( life cycle in aquatic invertebrates  estuarine/ marine species) ( parent plus PCA) 850.1350 Early life Stage Estuarine Fish ( parent plus PCA) 850.1450 Terrestrial Plant Toxicity, Tier 1 ( Seedling Emergence) 850.4100  83   Guideline or Special Study Name or Description OPPTS Guideline No.

Terrestrial Plant Toxicity, Tier 1 ( Vegetative Vigor) 850.4150 Aquatic Plant Toxicity Test Using Lemma spp. 850.4400 Semi aquatic Plant Toxicity Test Special Study Foliar Dissipation  for use in determining potential exposures to terrestrial wildlife ( not dislodgeable residues) Special Study Radiolabeled common moiety analytical method for plants and animal commodities, as discussed in Section IV of this RED 860.1340 Enforcement analytical method  reserved pending approval of analytical method Special Study Magnitude of Residues in Meat, Milk, Poultry and Eggs reserved pending approval of analytical method 860.1480 Crop Field Trials ( Magnitude of Residues in Plants)  reserved pending approval of analytical method 860.1500 Analytical Reference Standards  reserved pending approval of analytical method 860.1650 90 day Subchronic Inhalation Toxicity Test, Rat 3, 4 870.3465 Dermal Absorption ( Dermal Penetration), Rat 3, 5 870.7600 Iodide Uptake, Rat Special Study, protocol to be proposed by registrants Comparative Thyroid Test 3, 6 Special Study Bioaccumulation of PCNB and metabolites; determination of biological half life 3, 7 Special Study Data on toxicological significance of consistent, dose related decreases in AST/ ALT in PCNB toxicity tests 3, 8 Special Study 1 Test material is PCA. 2 Soil metabolism studies must be conducted to determine conditions which favor the formation of pentachlorophenol from PCNB and to track the production/ further metabolism/ degradation of pentachlorophenol over time. 3 Since small differences in impurities may result in differences in the toxicity of test materials, these studies must be conducted with materials identical to marketed technicals. The compositional analysis of test materials for each study must be verified and the Agency will compare this documentation to the compositional analyses of each technical product required to be submitted for within 90 days of receipt of the DCI, as noted above. 4 In addition to guideline requirements, interim thyroid hormone analyses required at 7, 14, 30, and 90 days. Histopathology assessment to include thyroid analysis. 5 Conditionally required; in absence of data, Agency will continue to assume 33% dermal absorption by default.  84   6 Registrants must submit a protocol for Agency approval. A draft protocol has been developed by the Agency for another pesticide, and it may be useful as a basis for this study. Registrants must assess thyroid toxicity in adults vs. offspring. For already submitted thyroid metabolism studies ( MRIDs 440966 01 and 440966 02), deficiencies have been noted in reviews and must be addressed. For MRID 440966 02, raw data for the study were reported as missing by the testing facility and information on the purity and lots of the labeled thyroxine was not provided. For MRID 440966 01, registrant must submit ( 1) data on the fate of individual animals and verification of the number of treated animals that died prior to assignment to the experimental groups, ( 2) clarification of the different compound consumption values given in the study report, and ( 3) verification that the test diets were prepared and used within the time of demonstrated stability, 7 Submission must include required guideline items of the metabolism/ kinetics study. The tier II level study must be performed. Registrant must report circulating blood levels of key metabolites and PCNB that relate to key end points of toxicity and dose levels in other studies; dosing regimen based on thyroid study ( may be combined with comparative thyroid study if based on accepted protocol). 8 Registrant may propose to submit study to assess toxicological significance of these findings, or may propose to address data requirement with narrative explanation. The AST/ ALT finding in question are reported in MRIDs 43015801 ( rat), and 41718600 and 41718601 ( dogs).

2. Labeling for Manufacturing Use Products To ensure compliance with FIFRA, manufacturing use product ( MUP) labeling should be revised to comply with all current EPA regulations, PR Notices, and applicable policies. The MUP labeling should bear the labeling contained in Table 47.

D. End Use Products  Data Requirements and Labeling 1. Product Specific Data Requirements Section 4( g)( 2)( B) of FIFRA calls for the Agency to obtain any needed product specific data regarding the pesticide after a determination of eligibility has been made. The Registrant must review previous data submissions to ensure that they meet current EPA acceptance criteria and if not, commit to conduct new studies. If a registrant believes that previously submitted data meet current testing standards, then the study MRID numbers should be cited according to the instructions in the Requirement Status and Registrants Response Form provided for each product. A product specific data call in, outlining specific data requirements, will be issued separately from this document.

2. Labeling for End Use Products In order to be eligible for reregistration, all product labels must be amended to incorporate the risk mitigation measures outlined in Section IV. Table 47 describes how language on the labels of end use products should be amended.  85   E. Existing Stocks Generally, conditions for the distribution and sale of products bearing old labels/ labeling will be established when the label changes are approved. Specific existing stocks time frames will be established case by case, depending on the number of products involved, the number of label changes, and other factors.

F. Required Labeling Changes In order to be eligible for reregistration, all product labels must be amended to incorporate the risk mitigation measures outlined in Section IV. Table 51 details how language on the labels should be amended.  86

Table 51. Labeling Changes for Products Containing PCNB Description Amended Labeling Language Placement on Label Manufacturing Use Products For All Manufacturing Use Products " This product may be formulated into a fungicide for the following use( s) only:

soildirected applications for treatment of clubroot on cole crops; soil directed or bulb soak applications for commercial production of flowering bulb plants and bulbs; and treatments to seeds of barley, beans, corn, cotton, oats, peas, peanut, rice, safflower,

sorghum, soybeans, sugar beets, and wheat."

" This product may not be formulated into end use products labeled for use on cole crops ( unless labeled solely for treatment of clubroot), turf ( including lawns), green beans ( unless labeled solely for treatments to seeds), cotton ( unless labeled solely for treatments to seeds), potatoes, dry beans and peas ( unless labeled solely for treatments to seeds), garlic, peanuts ( unless labeled solely for treatments to seeds), tomatoes, peppers,

or ornamentals ( except commercial production of flowering bulb plants and bulbs)."

" This product may not be formulated into end use products, unless the end use products are labeled to prohibit aerial applications."

" This product may not be formulated into end use products with directions for use on cole crops, unless the end use products are labeled to prohibit chemigation applications on cole crops."

" This product may not be formulated into end use products with directions for use for commercial production of flowering bulb plants or bulbs, unless the end use products are labeled to prohibit applications directed at foliage or flowers and to prohibit broadcast applications."

" This product may be formulated into wettable powders only if packaged in water soluble packaging."

" This product may not be formulated into granular products, unless these products are labeled to prohibit application with a chest mounted rotary spreader ( belly grinder)." Directions for Use  87

Description Amended Labeling Language Placement on Label " This product may be formulated into dust products only for seed treatment applications."

" This product may not be formulated into end use products labeled for seed treatment uses, unless seed treatments are the sole use on the end use product labels."

" This product may not be formulated into end use products labeled for seed treatment uses, unless the end use products are labeled to incorporate the following language:"

" Seeds that have been treated with this product that are then packaged and offered for sale or distribution must contain the following labeling:"