Page 1 of 48 UNITED STATES ENVIRONMENTAL PROTECTION AGENCY WASHINGTON, D. C. 20460 OFFICE OF PREVENTION, PESTICIDES AND TOXIC SUBSTANCES August 24, 2004 MEMORANDUM FROM: Kathryn Boyle, Inerts Team Minor Use, Inerts, and Emergency Response Branch Registration Division TO: Dan Rosenblatt, Chief Minor Use, Inerts, and Emergency Response Branch Registration Division SUBJECT: Science Assessment for ATBC and TEC The attached science assessment discusses the toxicity of acetyl tributyl citrate and triethyl citrate. The Lower Toxicity Pesticide Chemical Focus Group reviewed several draft assessments of this document. The Inerts Team coordinated the review process and prepared the science assessment.

The information used to perform this assessment are information from the internet on ( 1) World Health Organization ( WHO) evaluations, ( 2) British Industrial Biological Research Association ( BIBRA) abstracts, and ( 3) the Opinion of the European Commission, Health and Consumer Protection Directorate General ( CSTEE), and ( 4) structure activity relationship ( SAR) assessments performed on surrogate chemicals as prepared by the Agency's Office of Pollution Prevention and Toxics..

The Agency is performing a qualitative risk assessment. Given that the oral NOAELs/ NOEL is 1000 mg/ kg/ day in several studies, a quantitative approach is not needed for this risk assessment. However, to better understand the potential exposure patterns, the Agency is bracketing some of the potential residential exposures for ATBC and TEC. Page 2 of 48 Science Assessment for Acetyl Tributyl Citrate ( ATBC) and Triethyl Citrate ( TEC)

1. Purpose of Assessment This review serves two purposes. First, in Pesticide Petitions 8E4966 and 8E4967, the petitioner Morflex requested that the Agency establish four new tolerance exemptions for the use of acetyl tributyl citrate ( ATBC) ( citric acid, 2( acetyloxy), tributyl ester) ( CAS Reg. No. 77 90 7) and triethyl citrate ( TEC) ( citric acid, triethyl ester)( CAS Reg. No. 77 93 0) when used as solvents ( inert ingredients) under 40 CFR 180. 910 and 180.930 [ formerly 180.1001 ( c) and ( e)]. Second, there is an existing tolerance exemption for acetyl tributyl citrate used in animal ear tags that is subject to tolerance reassessment in 40 CFR 180.930 [ formerly 180.1001( e)].

2. Executive Summary The petitioner, Morflex, submitted a toxicity database that includes several studies, including a 2 generation reproductive study, and articles from open literature. Other reliable sources of information used to perform this assessment are information from the internet on ( 1) World Health Organization ( WHO) evaluations, ( 2) British Industrial Biological Research Association ( BIBRA) abstracts, and ( 3) the Opinion of the European Commission, Health and Consumer Protection Directorate General ( CSTEE), and ( 4) structure activity relationship ( SAR) assessments performed on surrogate chemicals as prepared by the Agency's Office of Pollution Prevention and Toxics..

The Agency is performing a qualitative risk assessment. Given that the oral NOAELs/ NOEL is 1000 mg/ kg/ day in several studies, a quantitative approach is not needed for this risk assessment. However, to better understand the potential exposure patterns, the Agency is bracketing some of the potential residential exposures for ATBC and TEC.

3. Use Patterns Use Pattern ( Non Pesticidal)

ATBC is used as a plasticizer in food grade plastic wrap: it is added during the manufacturing process of these plastic wraps to increase flexibility and reduce brittleness. Both ATBC and TEC are used in coatings for pharmaceutical tablets and in plastic tubings for administration of drug and blood products. ATBC is also used as a plasticizer in children's toys.

FDA Uses:

TEC is affirmed GRAS ( generally recognized as safe) under 21 CFR 184.1911 when used as a flavoring agent, a solvent and vehicle, and a surface active agent. There are also other FDAapproved uses: component of resinous and polymeric coatings, component of paper and paperboard, and under 21 CFR 181.27 as a prior sanctioned plasticizer. Page 3 of 48 ATBC is approved as a synthetic flavoring substance under 21 CFR 172.515. It is also approved as a component of resinous and polymeric coatings, a component of paper and paperboard, and under 21 CFR 181.27 as a prior sanctioned plasticizer.

4. Description of Chemicals Table 1: Description of Chemicals Parameter Acetyl Tributyl Citrate ( ATBC) Triethyl Citrate ( TEC)

manufacture prepared by esterification of butyl alcohol with citric acid, followed by acetylation prepared by esterification of ethyl alcohol with citric acid physical form practically colorless, oily liquid essentially odorless, practically colorless, oily liquid molecular formula C 20 H 34 O 8 C 12 H 20 O 7 molecular weight 402.5 276.3 vapor pressure ( mm Hg @ 20 oC) 5.2 x 10 2 6.4 x 10 3 5. Toxicity Profile: Studies Submitted by the Petitioner The petitioner, Morflex, submitted studies that were conducted using either ATBC or TEC. The ATBC database is the more extensive of the two and includes a 2 generation reproductive study and metabolism studies. The results of the Agency's 2002 review and evaluation in robust summary format are in Appendix 2. In 2004, the 2 generation reproductive study was re evaluated to consider why there was such variation in the results of the rat 90 day, 2 year, and reproduction oral studies. The results of this re evaluation are in Appendix 3. The Table below summarizes the NOAELs ( no observed adverse effects level), LOAELs ( lowestobserved adverse effects level), NOEL ( no observed effect level), and LOEL ( lowest observedeffect level).

Table 2: ATBC Toxicity Information Study Result or NOAELs/ LOAELs acute oral toxicity ( rat) LD 50 > 30 g/ kg ( Toxicity Category IV)

primary eye irritation ( rabbit) not a severe ocular irritant ( Toxicity Category III)

primary dermal irritation ( rabbit) did not induce irritation ( Toxicity Category IV)

primary dermal sensitization ( guinea pig) not a dermal sensitizer repeated insult patch test ( human) not a dermal sensitizer Page 4 of 48 90 day oral ( rat) ( in the diet)

dose levels: ( 0, 100, 300, 1000 mg/ kg/ day) NOAEL is equal to or greater than 1000 mg/ kg/ day, the highest dose tested ( HDT) LOAEL was not determined, but would be greater than 1000 mg/ kg/ day 2 year oral ( rat) ( in the diet)

dose levels: ( 0, 200, 2000, 200,000 ppm) NOAEL is equal to or greater than 20,000 ppm or 1000 mg/ kg/ day, the highest dose tested ( HDT) LOAEL was not determined, but would be greater than 1000 mg/ kg/ day 2 year dog dose levels: ( 0, 140 mg/ kg/ day) NOAEL is equal to or greater than 140 mg/ kg/ day, the highest dose tested ( HDT) LOAEL was not determined, but would be greater than 140 mg/ kg/ day 2 generation reproductive ( rat) ( in the diet)

dose levels: ( 0, 100, 300, 1000 mg/ kg/ day) Parental NOEL is equal to or greater than 1000 mg/ kg/ day, the highest dose tested ( HDT) LOEL not determined, but would be greater than 1000 mg/ kg/ day Reproductive NOAEL is equal to or greater than 1000 mg/ kg/ day, the highest dose tested ( HDT) LOAEL not determined, but would be greater than 1000 mg/ kg/ day Offspring NOEL is equal to or greater than 1000 mg/ kg/ day, the highest dose tested ( HDT) LOEL not determined, but would be greater than 1000 mg/ kg/ day In vitro Cytotoxicity at 1 mg% for 4 hours was not cytotoxic to mammalian cells Gene Mutation not mutagenic Cytogenetics did not induce chromosomal aberrations Metabolism ( rat) ATBC readily absorbed and rapidly excreted in urine and feces within 48 hours Metabolism ( human serum and rat liver homogenates) human serum and rat liver homogenates are capable of metabolizing ATBC resulting in n butanol and tributyl citrate as intermediate products Table 3: TEC Toxicity Information Study Result or NOAELs/ LOAELs Page 5 of 48 acute oral toxicity ( rat) LD 50 = 7 mL/ kg ( Toxicity Category IV)

primary eye irritation ( rabbit) not a severe ocular irritant ( Toxicity Category IV)

primary dermal irritation ( rabbit) did not induce dermal irritation ( Toxicity Category IV)

dermal sensitization ( guinea pig) TEC is a strong dermal sensitizer repeated insult patch test ( human) not a dermal sensitizer 2 year oral ( rat) ( in the diet)

dose levels: ( 0, 30, 200, 600 mg/ kg/ day) inconclusive; effects noted at 600 mg/ kg/ day two range finding ( dog) studies dose levels: ( 0, 0.05, 0.25 mL/ kg) with increase to 2.5 to 3.5 mL/ kg for 7 to 12 weeks when considered together NOAEL = 250 mg/ kg LOAEL = approximately 2.5 to 3.5 g/ kg gene mutation results varied: not mutagenic in S typhimurium or in Saccaromyces cerevisiae mouse fibroblasts 72 hour cultures: ID 50 is 6mM ID 100 is 12mM another mouse fibroblast study was inconclusive 6. SAR Assessment Performed by OPPT SAR ( structure activity relationship) assessments have not been performed for ATBC and TEC. However, SAR assessments of three structurally similar chemicals were performed on December 11, 1996, by the Office of Pollution Prevention and Toxics ( OPPT). The results of these three assessments acetyl triethyl citrate, tributyl citrate, and trimethyl citrate are discussed below:

For all three chemicals, absorption would be expected to be good for all routes of exposure. The esters were expected to hydrolyze. No significant adverse effects were expected; therefore, all three chemicals were judged to be of low toxicity.

7. Toxicity Profiles Prepared by the British Industrial Biological Research Association ( BIBRA)

ATBC The BIBRA ATBC profile was prepared in 1989. In preparing this profile, BIBRA reviewed the available acute, subchronic, chronic, and reproductive toxicity studies, and Page 6 of 48 metabolism and mutagenicity studies. ( Some of these were the same studies evaluated by the Agency.) The summary of the BIBRA dossier ( submitted by the petitioner) indicated that while " the studies of reproduction and carcinogenicity are to a standard of reporting that is less than adequate by current standards, it is considered that they do provide an indication of the general lack of adverse effect of chronic exposure to this substance."

An abstract of the BIBRA profile was located on the internet ( Toxnet, SISa). It reads as follows:

" Acetyl tributyl citrate exhibited a low acute oral toxicity in laboratory animals. Limited studies in rats involving repeated administration in the diet failed to identify any particular target organs. However, injection studies highlighted the central nervous system and blood as the site of toxic attack in various species of laboratory animals. Acetyl tributyl citrate was not mutagenic in an Ames bacterial assay."

It should be noted that the reproductive study submitted to the Agency was conducted in 1994 and was therefore not available for inclusion in the BIBRA profile.

TEC This BIBRA profile was prepared in 1998. The abstract was obtained from the internet ( Toxnet, SISb)

" Triethyl citrate was not an irritant to the skin of humans and laboratory animals. In dilute form, it showed no sensitizing potential in humans. Acute toxicity was low by the oral, dermal and inhalation routes in laboratory animals. Single oral treatment caused kidney damage in rats, and central nervous system ( CNS) effects were seen following oral or injection administration to various species of laboratory animal. In limited studies, repeated oral doses were tolerated by rats but caused liver damage in dogs and CNS effects in cats. Rats exposed repeatedly to the vapor showed lung damage. Triethyl citrate was non carcinogenic when given orally to rats in a limited study and was non mutagenic in an Ames bacterial test and in yeast. Its hydrolysis products are citric acid and ethanol."

8. Evaluations by the World Health Organization ( WHO)

TEC was evaluated by WHO in 1966, 1977, 1981, 1984, 1999, and 2000.

The following conclusions were extracted from Food Additive Series 14 available on the internet at www. inchem. org/ documents/ jecfa/ jecmono/ v14je21. htm. No absorption or metabolism were available at the time of this review. However, "[ i] t is likely that triethyl citrate will be hydrolyzed to its component parts, citrate and ethanol in vivo. Data from two year feeding studies suggest that rats can tolerate up to 2.0 g/ kg. Dogs toleranted up to 0.25 ml/ kg bw for six months without effects. Triethyl citrate was not mutagenic in several microbiological assays."

Based on the two year rat study, WHO estimated a temporary acceptable daily intake ( ADI) for man of 1  10 mg/ kg/ bw. WHO also stipulated that " repeat metabolic studies in several species, preferably including man" be submitted by 1981. Page 7 of 48 Once this information were available, TEC was reviewed in Food Additive Series 19. ( See www. inchem. org/ documents/ jecfa/ jecmono/ v19je12. htm). An ADI of 0  20 mg/ kg bw for TEC was established ( based on the same rat study as the previous temporary ADI) in which there were no toxicological effects when rats were fed a diet which was 4% ( 40,000 ppm or 2 g/ kg body weight) TEC.

The ADI was reviewed again in 1999 and was maintained. It was stated that there was "[ n] o safety concern at current levels of intake when used as a flavouring agent."

In 2000 ( see www. inchem. org/ documents/ jecfa/ jecmono/ v44je10. htm, Food Additive Series 44), the use of both TEC and ATBC as flavoring agents was evaluated by WHO. The intake for ATBC was determined to be less than 1800 ug/ person/ day. The intake for TEC was determined to be 3400 ug/ person/ day in Europe and 2400 ug/ person/ day in the United States. No concerns were identified for either chemical based on the level of intake ( which is less than the ADI), and on an understanding of the fate of the chemicals in the body after hydrolysis occurs.

9. Scientific Committee on Toxicity, Ecotoxicity and the Environment ( CSTEE)

The following is extracted from the January 8, 2004, " Opinion on the Risk Assessment for Acetyl Tributyl Citrate ( ATBC) Plasticizer Used in Children's Toys" performed by CSTEE of the European Commission, Health and Consumer Protection Directorate General.

In 1999, CSTEE had indicated that a risk assessment on use of citrates as a plasticizer in children's toys could not be performed due to a lack of exposure data.

" Therefore, a study examining the extraction of ATBC from PVC disks cut from a custom molded ball and two commercially available toys [ was] performed with human volunteers ( 5 males and 5 females, 18 to 30 years old).... Volunteers were instructed to move the disks in their mouths, draw upon, apply pressure with the tongue or lightly chew the disks for four consecutive 15 minute intervals. All saliva was collect for subsequent analysis of ATBC content. The mean rates for ATBC migration rates were 1.53, 1.75 and 2.19

g/ min" and " the highest migration rate was found to be 10.1

g ATBC/ min".

" Using the highest ATBC migration rate of 10.1

g/ min at a maximum mouthing duration of 180 min for a child weighing 8.0 kg and assuming that all the extracted ATBC is swallowed, an estimated daily intake via oral exposure becomes 227

g per kg bodyweight. This is clearly a worst case situation since the maximal extraction rate from a large, male adult and a mouthing duration of 180 minutes were used in the calculation."

10. Human Health Hazard Characterization The toxicological databases for these chemicals are a mixture of guideline studies performed in the last 15 years and older studies from the 1970s and 1950s. These older studies are more difficult to evaluate given the different standards of reporting that existed some years ago.

Both ATBC and TEC have low acute oral toxicity ( Toxicity Category IV). Ocular irritation is moderate. Both are Toxicity Category IV for dermal irritation. Neither are human Page 8 of 48 sensitizers.

Both chemicals have been reviewed by other entities. None of these organizations indicated any specific concerns for ATBC or TEC.

In a rat metabolism study, ATBC was readily absorbed and rapidly excreted in urine and feces within 48 hours. The following metabolites were detected in the urine: acetyl citrate, monobutyl citrate, acetyl monobutyl citrate, dibutyl citrate, and acetyl dibutyl citrate. ATBC was hydrolyzed in both human and rat liver homogenates resulting in n butanol and tributyl citrate ( TBC). However, in human serum the half life was 7 hours versus 30 minutes in the rat. These in vivo and in vitro studies indicate that ATBC is hydrolysed.

No metabolism studies were reviewed for TEC. However, it is expected that all citrate esters would undergo hydrolysis to citric acid and the corresponding alcohol. For TEC, this would be ethanol. The human body is able to effectively metabolize both ethanol and citric acid. Thus, the human body has known pathways to metabolize TEC hydrolysis metabolites.

Based on the submitted studies, neither ATBC or TEC is mutagenic.

The ATBC two generation reproductive toxicity study was recently re evaluated by the Agency. No adverse reproductive performance was observed at any dose. The reproductive toxicity NOAEL was 1000 mg/ kg/ day, the highest dose tested. A LOAEL was not observed. The parental NOEL and the offspring NOEL is 1000 mg/ kg/ day. The parental LOEL and the offspring LOEL was not observed.

The available information consists of the FDA affirmed GRAS status of TEC, the abstracts of the BIBRA toxicity profiles, several evaluations by the World Health Organization, the SAR assessments of the structurally related chemicals, the CSTEE Opinion, and the toxicity studies submitted by the petitioner. Taken together the weight of evidence of the available information indicate a chemical of lower toxicity.

11. Type of Assessment The Agency is performing a qualitative risk assessment. Given that the oral NOAELs/ NOEL is 1000 mg/ kg/ day in several studies, a quantitative approach is not needed for this risk assessment. However, to better understand the potential exposure patterns, the Agency will bracket some of the potential residential exposures for acetyl tributyl citrate and triethyl citrate.

12. Additional Safety Factor for the Protection of Infants and Children The toxicity database for ATBC includes a rat oral reproductive toxicity study in which NOELs of 1000 mg/ kg/ day were identified. There are also the SARs on structurally related citrate esters which did not indicate any concerns for developmental or reproductive toxicity.

ATBC, given the additional acetylation step, is the more complex, larger molecule. The acetylation step also increases the number of possible metabolites as evidenced by the results of the ATBC rat metabolism study. ATBC data can be used as surrogate data for TEC. TEC cannot be used as surrogate data for ATBC. ATBC is the more toxic of the two chemicals and has the larger available database. Page 9 of 48 There is sufficient information for the Agency to judge the potential for developmental and reproductive effects of ATBC and TEC. No additional data are needed to assess the toxicity of ATBC and TEC. There is no reason to expect that the reasonably, foreseeable uses of ATBC and TEC will constitute any significant hazard. EPA has not used a safety factor analysis to assess the risk. For the same reasons the additional tenfold safety factor is unnecessary.

13. Screening level Exposure and Risk Assessment Various publicly available screening level models were used to estimate some of the existing levels of exposure that could occur in and around the home. To assure protectiveness, these models create estimates that are deliberately intended to over estimate exposure. See Appendix 1 for the models and assumptions used. All modeling ( with the exception of the CSTEE plastic toy scenario) was performed by EPA.

Table 4: Screening Level ATBC Exposure Estimates Conducted through Modeling Type of Exposure Population Subgroup Potential Exposure Level Dietary  Food ( as a result of application to crops) US General 0.12 Females ( 13 49 years old) 0.087 Children ( 1 2 years old) 0.422 Dietary  Drinking Water US General 0.0018 Females ( 13 49 years old) 0.002 Children ( 1 2 years old) 0.0064 Dietary  Food ( As a result of use in plastic wrap) US General 0.021 Females ( 13 49 years old) 0.025 Children ( 1 2 years old) 0.15 Dietary  Food ( As a result of use as a flavoring) US General 0.26 Females ( 13 49 years old) 0.03 Children ( 1 2 years old) 0.18 Residential ( laundry detergent) ( combined dermal and inhalation) Adult 0.04326 Residential ( cleaning product)( combined dermal and inhalation) Adult 0.2021 Children's Plastic Toy Children ( 1 2 years old) 0.227 Page 10 of 48 Table 5: Screening Level TEC Exposure Estimates Conducted through Modeling Type of Exposure Population Subgroup Potential Exposure Level Dietary  Food ( as a result of application to crops) US General 0.120 Females ( 13 49 years old) 0.087 Children ( 1 2 years old) 0.422 Dietary  Drinking Water US General 0.011 Females ( 13 49 years old) 0.013 Children ( 1 2 years old) 0.04 Dietary  Food ( As a result of use as a flavoring) US General 0.034 Females ( 13 49 years old) 0.04 Children ( 1 2 years old) 0.24 Residential ( laundry detergent)( combined dermal and inhalation) adult 0.00523 Residential ( cleaning product)( combined dermal and inhalation) adult 0.1621 All screening level exposures are much less than any of the NOAELs/ NOELs from the repeated dose oral toxicity studies.

14. Risk Characterization The Agency believes that ATBC and TEC are of low toxicity. Of highest consideration in this judgement is the body's ability to effectively metabolize both ATBC and TEC to citric acid and the corresponding alcohols. The metabolism studies provided by the petitioner were helpful in reaching this determination.

Both of these chemicals are well studied. FDA, WHO, and CSTEE have all conducted assessments on the uses of these chemicals. No toxicological concerns were specified in any of the reviews and evaluations.

The Agency has used various screening level models to estimate some of the existing levels of exposure to ATBC and TEC. To assure protectiveness, these estimates are deliberately intended to over estimate exposure. Page 11 of 48 Given the information on the metabolism of the chemicals, the consistent pattern of NOAELs/ NOELs of 1000 mg/ kg/ day, an understanding of the metabolism of ATBC and TEC, and very over estimated exposure numbers, there is no need to pursue further numerical refinements to the estimated exposures. No further refinement or information are needed to assess ATBC or TEC. There is a sufficient order of magnitude difference between the NOAELs/ NOELs and the screening level exposure estimates.

15. Ecotoxicity Assessment ( performed by OPP):

Aquatic Organisms Estimated environmental concentrations ( EECs) are used to predict exposure to aquatic organisms. Surface water concentrations were estimated using the GENEEC ( GENeric Estimated Environment Concentration Version 2.0) model based on a maximum application rate of 1 lb/ acre. Results are reported in Table 4.

Table 6: Tier I upper tenth percentile EECs ( ppm) in surface water ( GENEEC 2.0) for TEC and ATBC Method of Application Application Rate ( lbs/ acre) TEC ATBC Maximum 60 day average Maximum 60 day average Aerial 1 0.058 0.053 0.0038 0.00036 OPP used the ECOSAR ( Ecological Structure Activity Relationship) software program to estimate the toxicity of ATBC and TEC to aquatic organisms. Risk is estimated as a function of the modeled EECs and the predicted toxicity.

ATBC is practically non toxic to aquatic organisms ( fish and daphnia). The risk quotients ( RQ) ( see Tables below) indicate that exposure to ATBC at 1 lb/ acre does not exceed the LOC ( level of concern) for risk to fish, invertebrates, and aquatic plants. Acute risk to fish and invertebrates is not expected at application rates less than or equal to 47 pounds per acre and 34 pounds per acre, respectively. Chronic risk to fish is not expected at application rates less than 828 lb/ acre. Toxicity data are not available to assess chronic risk to invertebrates. Currently, EPA does not assess chronic risks to plants.

TEC is practically non toxic to aquatic organisms ( fish and daphnia). The risk quotients indicate that exposure to triethyl citrate at 1 lb/ acre does not exceed the LOC for risk to fish, invertebrates, and plants ( see Tables below). Acute risk to fish and invertebrates is not expected at application rates less than 28 and 6260 pounds per acre, respectively. The RQ for fish indicates that the LOC is not exceeded for chronic toxicity at an application rate of 1 pounds per acre. Chronic risk to fish is not expected at application rates less than 7320 pounds per acre. Toxicity data are not available to assess chronic risk to invertebrates. Page 12 of 48 Table 7: Acute Toxicity of TEC and ATBC to Aquatic Organisms ( based on application rate of 1 lb/ acre)

Organism Toxicity ( ppm) EEC2 ( ppm) Risk Quotient ( EEC/ Toxicity)

ATBC Fish 96 hr LC 50= 3.6 0.0038 < 0.05 Invertebrates ( daphnia) 48 hr LC 50= 2.6 0.0038 < 0.05 Plants ( green algae) 96 hr EC 50= 0.31 0.0038 < 1 TEC Fish 96 hr LC 50= 327 0.058 < 0.05 Invertebrates ( daphnia) 48 hr LC 50= 7262 0.058 < 0.05 Plants ( green algae) 96 hr EC 50= 24.5 0.058 < 1 Table 8: Chronic Toxicity of TEC and ATBC to Aquatic Organisms ( based on application rate of 1 lb/ acre)

Organism Toxicity ( ppm) EEC2 ( ppm) Risk Quotient ( EEC/ Toxicity)

ATBC Fish 0.298 0.00036 < 1 TEC Fish 388 0.053 < 1 Terrestrial Organisms The limited acute toxicity data indicate that ATBC and TEC are practically non toxic to mammals. The Agency does not expect risk to mammals on an acute basis from the use of ATBC and TEC when applied at equal to or less than 6 and 16 pounds per acre, respectively.

When applied at 1 pound per acre, ATBC is not expected to cause chronic risks to mammals. For TEC, chronic risks to terrestrial organisms could not be determined because toxicity data are not available. Page 13 of 48 Data on the toxicity of TEC and ATBC to avian species are not available. Therefore, it is assumed that birds have the same sensitivity to TEC and ATBC as mammals.

16. Cumulative Exposure Section 408( b)( 2)( D)( v) of the FFDCA requires that, when considering whether to establish, modify, or revoke a tolerance, the Agency consider " available information" concerning the cumulative effects of a particular pesticide's residues and " other substances that have a common mechanism of toxicity."

Unlike other pesticides for which EPA has followed a cumulative risk approach based on a common mechanism of toxicity, EPA has not made a common mechanism of toxicity finding as to acetyl tributyl citrate, triethyl citrate or any citrate esters. These esters do not appear to produce a toxic metabolite produced by other substances. These are lower toxicity chemicals; therefore, the resultant risks separately and/ or combined should also be low. For the purposes of this action, therefore, EPA has not assumed that acetyl tributyl citrate or triethyl citrate have a common mechanism of toxicity with other substances. For information regarding EPA's efforts to determine which chemicals have a common mechanism of toxicity and to evaluate the cumulative effects of such chemicals, see the policy statements released by 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:// www. epa. gov/ pesticides/ cumulative/.

17. Conclusions Based on the review and evaluation of the information discussed in this assessment, the Agency finds that exempting acetyl tributyl citrate ( ATBC) ( citric acid, 2( acetyloxy), tributyl ester) ( CAS Reg. No. 77 90 7) and triethyl citrate ( TEC) ( citric acid, triethyl ester)( CAS Reg. No. 77 93 0) from the requirement of a tolerance will be safe.

Based on the NOAELs of 1000 mg/ kg/ day in several studies and on their acute toxicity profiles, both ATBC and TEC are classified as List 4A.

18. References EPA/ OPPa. Amendment to EFED Assessment: Review of the Inert Ingredients Triethyl Citrate and Acetyl Tributyl Citrate ( Mahoney, August 12, 2002, D284809))

EPA/ OPPb. EFED Assessment: Review of the Inert Ingredients Triethyl Citrate and Acetyl Tributyl Citrate ( Mahoney and Abdel Saheb, May 29, 2002, D281963, D270599, D272539)

EPA/ OPPT. OPPT Structure Activity Team Review of Seven Esters ( Rebecca Jones, January 9, 1997)

Toxnet SISa. Specialized Information Service. On line Scientific Search Engine, National Library of Medicine, National Institute of Health. Http:// www. toxnet. nlm. nih. gov. Search term: acetyl tributyl citrate; Abstract of BIBRA toxicity profile ( data entered 1990); accessed 2004.

Toxnet SISb. Specialized Information Service. On line Scientific Search Engine, National Page 14 of 48 Library of Medicine, National Institute of Health. Http:// www. toxnet. nlm. nih. gov. Search term: triethyl citrate; Abstract of BIBRA toxicity profile ( data entered 1998); accessed 2004. Page 15 of 48 Appendix 1: Screening Level Exposure Assessments for Acetyl Tributyl Citrate ( CAS Reg. No. 77 90 7) and Triethyl Citrate ( CAS Reg. No. 77 93 0)

Dietary ( Food) Exposure DEEM Model Assumptions  Actual crop specific residue data for active ingredients can be utilized as surrogate data for inert ingredient residue levels ( including secondary residues in meat, milk, poultry and eggs)  Inert ingredients are used on all crops and 100% of all crops are " treated" with inert ingredients  No adjustment made for % of inert in formulation, application rate, or multiple applications of different active ingredient formulations  Considers only preharvest applications Dietary modeling was performed utilizing the highest established tolerance level residue for each commodity.

Table 1. Estimated Chronic Dietary Exposure1 for a Generic Inert Ingredient Population Subgroup2 Estimated Exposure, mg/ kg/ day U. S. Population ( total) 0.120 All infants (< 1 year) 0.245 Children ( 1 2 years) 0.422 Children ( 3 5 years) 0.310 Children ( 6 12 years) 0.174 Youth ( 13 19 years) 0.100 Adults ( 20 49 years) 0.087 Adults ( 50+ years) 0.086 Females ( 13 49 years) 0.087 1Exposure estimates are based on highest tolerance level residues of high use active ingredients for all food forms, including meat, milk, poultry, and eggs. 2Only representative population subgroups are shown. Page 16 of 48 Dietary Exposure as a Result of Use in an Ear Tag The use of ATBC in cattle ear tags, was not considered in the above dietary estimates. ATBC can be used as the plasticizer for the ear tags. Ear tags ( generally no more than 30 grams total weight) would be applied to the animal once a year, and then used for 5 to 6 months. It is first of all highly unlikely that all of the plasticizer component of the ear tag would migrate into the animal during the 5 to 6 months. Any ATBC that did migrate into the cattle, would very likely be metabolized, and then excreted. Therefore, the use of such ear tags should not contribute significantly to secondary residues in livestock. Page 17 of 48 Dietary Exposure as a Result of Use as a Flavoring Triethyl citrate was determined to be used at a level of 2400 ug/ person/ day in the United States. ATBC was determined to be used at a level of less than 1800 ug/ person/ day. These exposures can be translated to mg/ kg/ day using standardized body weight assumptions.

Dietary Exposure from Use of TEC and ATBC as a Flavoring Population SubGroup Body Weight Dietary Exposure mg/ kg/ day TEC U. S. General Population 70 kg 0.034 Females ( 13 49 years old) 60 kg 0.04 Children ( 1 2 years old) 10 kg 0.24 ATBC U. S. General Population 70 kg 0.026 Females ( 13 49 years old) 60 kg 0.03 Children ( 1 2 years old) 10 kg 0.18 Page 18 of 48 Dietary Exposure as a Result of Use in Plastic Wraps An article in open literature suggested a daily intake of 1.5 mg ATBC as a result of use in microwaves and wrapping of food items such as cheese. This exposure can also be translated to mg/ kg/ day using standardized body weight assumptions.

Dietary Exposure from Use of ATBC in Plastic Wrap Population SubGroup Body Weight mg/ kg/ day U. S. General Population 70 kg 0.021 Children ( 1 2 years old) 10 kg 0.15 Females ( 13 49 years old) 60 kg 0.025 Page 19 of 48 CEM Inputs ID Number: Unknown Product: ATBC Chemical Name: ATBC Scenario: Laundry Detergent Population: Adult Molecular Weight ( g/ mole): 402.5 Vapor Pressure ( torr): 0.052 Weight Fraction  Median ( unitless): 0.05 Weight Fraction  90% ( unitless): 0.19 Inhalation Inputs Frequency of Use ( events/ yr): 312 Years of Use: 57 Mass of Product Used per Event  Median ( g): 200 Mass of Product Used per Event  90% ( g): 400 Inhalation Rate During Use ( m3/ hr): 0.55 Duration of Use  Median ( hours/ event): 0.333 Inhalation Rate After Use ( m3/ hr): 0.55 Duration of Use  90% ( hours/ event): 0.667 Zone 1 Volume ( m3): 20 Whole House Volume ( m3): 369 Air Exchange Rate ( air exchanges/ hr): 0.45 Body Weight ( kg): 71.8 Activity Patterns User: 1111111235542467422744411 Start Time: 9 Non User: 1111111132442477422744411 Room of Use: 5. Utility Room Hour: 0 6 12 18 Dermal Inputs Frequency of Use  Body ( events/ yr): 52 SA/ BW  Body ( cm2/ kg): 15.6 Amount Retained / Absorbed to Skin ( g/ cm2 event): 1.13e 05 Avg. Time, LADDpot, LADCpot ( days): 2.74e+ 04 Avg. Time, ADDpot, ADCpot ( days): 2.08e+ 04 Avg. Time, ADRpot, Cppot ( days): 1.00e+ 00 Page 20 of 48 CEM Inhalation Exposure Estimates ID Number: Unknown Scenario: Laundry Detergent Population: Adult Inhalation Rate ( m3/ day): 0.55 Years of Use ( years): 57 Body Weight ( kg): 71.8 Frequency of Use ( events/ year): 312 Exposure Units Result AT ( days)

Chronic Cancer LADDpot ( mg/ kg day) 3.19e 02 2.74e+ 04 LADCpot ( mg/ m3) 1.74e 01 2.74e+ 04 Chronic Non Cancer ADDpot ( mg/ kg day) 4.20e 02 2.08e+ 04 ADCpot ( mg/ m3) 2.29e 01 2.08e+ 04 Acute ADRpot ( mg/ kg day) 7.57e 01 1.00e+ 00 Cppot ( mg/ m3) 1.06e+ 02 1.00e+ 00 LADD  Lifetime Average Daily Dose ( mg/ kg day) LADC  Lifetime Average Daily Concentration ( mg/ m3)

ADD  Average Daily Dose ( mg/ kg day) ADC  Average Daily Concentration ( mug/ m3)

ADR  Acute Dose Rate ( mg/ kg day) Cp  Peak Concentration ( mg/ m3)

Note: 75 years = 2.738e+ 04 days pot  potential dose Note: The general Agency guidance for assessing short term, infrequent events ( for most chemicals, an exposure of less than 24 hours that occurs no more frequently than monthly) is to treat such events as independent, acute exposures rather than as chronic exposure. Thus, estimates of long term average exposure like ADD or ADC may not be appropriate for use in assessing risks associated with this type of exposure pattern. ( Methods for Exposure Response Analysis for Acute Inhalation Exposure to Chemicals ( External Review Draft). EPA/ 600/ R 98/ 051. April 1998 Page 21 of 48 CEM Dermal Exposure Estimates ID Number: Unknown Scenario: Laundry Detergent Population: Adult Years of Use ( years): 57 SA/ BW Body ( cm2/ kg): 15.6 Frequency of Use ( events/ year): 52 Exposure Units Result AT ( days)

Chronic Cancer LADDpot ( mg/ kg day) 9.54e 04 2.74e+ 04 Chronic Non Cancer ADDpot ( mg/ kg day) 1.26e 03 2.08e+ 04 Acute ADRpot ( mg/ kg day) 3.35e 02 1.00e+ 00 LADD  Lifetime Average Daily Dose ( mg/ kg day)

ADD  Average Daily Dose ( mg/ kg day)

ADR  Acute Dose Rate ( mg/ kg day)

Note: 75 years = 2.738e+ 04 days pot  potential dose Note: The general Agency guidance for assessing short term, infrequent events ( for most chemicals, an exposure of less than 24 hours that occurs no more frequently than monthly) is to treat such events as independent, acute exposures rather than as chronic exposure. Thus, estimates of long term average exposure like ADD or ADC may not be appropriate for use in assessing risks associated with this type of exposure pattern. ( Methods for Exposure Response Analysis for Acute Inhalation Exposure to Chemicals ( External Review Draft). EPA/ 600/ R 98/ 051. April 1998 Page 22 of 48 CEM Inputs ID Number: Unknown Product: TEC Chemical Name: TEC Scenario: Laundry Detergent Population: Adult Molecular Weight ( g/ mole): 276.3 Vapor Pressure ( torr): 0.0064 Weight Fraction  Median ( unitless): 0.05 Weight Fraction  90% ( unitless): 0.19 Inhalation Inputs Frequency of Use ( events/ yr): 312 Years of Use: 57 Mass of Product Used per Event  Median ( g): 200 Mass of Product Used per Event  90% ( g): 400 Inhalation Rate During Use ( m3/ hr): 0.55 Duration of Use  Median ( hours/ event): 0.333 Inhalation Rate After Use ( m3/ hr): 0.55 Duration of Use  90% ( hours/ event): 0.667 Zone 1 Volume ( m3): 20 Whole House Volume ( m3): 369 Air Exchange Rate ( air exchanges/ hr): 0.45 Body Weight ( kg): 71.8 Activity Patterns User: 1111111235542467422744411 Start Time: 9 Non User: Room of Use: 5. Utility Room Hour: 0 6 12 18 Dermal Inputs Frequency of Use  Body ( events/ yr): 52 SA/ BW  Body ( cm2/ kg): 15.6 Amount Retained / Absorbed to Skin ( g/ cm2 event): 1.13e 05 Avg. Time, LADDpot, LADCpot ( days): 2.74e+ 04 Avg. Time, ADDpot, ADCpot ( days): 2.08e+ 04 Avg. Time, ADRpot, Cppot ( days): 1.00e+ 00 Page 23 of 48 CEM Inhalation Exposure Estimates ID Number: Unknown Scenario: Laundry Detergent Population: Adult Inhalation Rate ( m3/ day): 0.55 Years of Use ( years): 57 Body Weight ( kg): 71.8 Frequency of Use ( events/ year): 312 Exposure Units Result AT ( days)

Chronic Cancer LADDpot ( mg/ kg day) 3.02e 03 2.74e+ 04 LADCpot ( mg/ m3) 1.64e 02 2.74e+ 04 Chronic Non Cancer ADDpot ( mg/ kg day) 3.97e 03 2.08e+ 04 ADCpot ( mg/ m3) 2.16e 02 2.08e+ 04 Acute ADRpot ( mg/ kg day) 7.15e 02 1.00e+ 00 Cppot ( mg/ m3) 9.99e+ 00 1.00e+ 00 LADD  Lifetime Average Daily Dose ( mg/ kg day) LADC  Lifetime Average Daily Concentration ( mg/ m3)

ADD  Average Daily Dose ( mg/ kg day) ADC  Average Daily Concentration ( mug/ m3)

ADR  Acute Dose Rate ( mg/ kg day) Cp  Peak Concentration ( mg/ m3)

Note: 75 years = 2.738e+ 04 days pot  potential dose Note: The general Agency guidance for assessing short term, infrequent events ( for most chemicals, an exposure of less than 24 hours that occurs no more frequently than monthly) is to treat such events as independent, acute exposures rather than as chronic exposure. Thus, estimates of long term average exposure like ADD or ADC may not be appropriate for use in assessing risks associated with this type of exposure pattern. ( Methods for Exposure Response Analysis for Acute Inhalation Exposure to Chemicals ( External Review Draft). EPA/ 600/ R 98/ 051. April 1998 Page 24 of 48 CEM Dermal Exposure Estimates ID Number: Unknown Scenario: Laundry Detergent Population: Adult Years of Use ( years): 57 SA/ BW Body ( cm2/ kg): 15.6 Frequency of Use ( events/ year): 52 Exposure Units Result AT ( days)

Chronic Cancer LADDpot ( mg/ kg day) 9.54e 04 2.74e+ 04 Chronic Non Cancer ADDpot ( mg/ kg day) 1.26e 03 2.08e+ 04 Acute ADRpot ( mg/ kg day) 3.35e 02 1.00e+ 00 LADD  Lifetime Average Daily Dose ( mg/ kg day)

ADD  Average Daily Dose ( mg/ kg day)

ADR  Acute Dose Rate ( mg/ kg day)

Note: 75 years = 2.738e+ 04 days pot  potential dose Note: The general Agency guidance for assessing short term, infrequent events ( for most chemicals, an exposure of less than 24 hours that occurs no more frequently than monthly) is to treat such events as independent, acute exposures rather than as chronic exposure. Thus, estimates of long term average exposure like ADD or ADC may not be appropriate for use in assessing risks associated with this type of exposure pattern. ( Methods for Exposure Response Analysis for Acute Inhalation Exposure to Chemicals ( External Review Draft). EPA/ 600/ R 98/ 051. April 1998 Page 25 of 48 CEM Inputs ID Number: Unknown Product: ATBC Chemical Name: ATBC Scenario: General Purpose Cleaner Population: Adult Molecular Weight ( g/ mole): 402.5 Vapor Pressure ( torr): 0.052 Weight Fraction  Median ( unitless): 0.05 Weight Fraction  90% ( unitless): 0.19 Inhalation Inputs Frequency of Use ( events/ yr): 300 Years of Use: 57 Mass of Product Used per Event  Median ( g): 61.5 Mass of Product Used per Event  90% ( g): 123 Inhalation Rate During Use ( m3/ hr): 0.55 Duration of Use  Median ( hours/ event): 0.667 Inhalation Rate After Use ( m3/ hr): 0.55 Duration of Use  90% ( hours/ event): 1.42 Zone 1 Volume ( m3): 20 Whole House Volume ( m3): 369 Air Exchange Rate ( air exchanges/ hr): 0.45 Body Weight ( kg): 71.8 Activity Patterns User: 1111111221542467422744411 Start Time: 7 Non User: 1111111132442477422744411 Room of Use: 2. Kitchen Hour: 0 6 12 18 Dermal Inputs Frequency of Use  Body ( events/ yr): 300 SA/ BW  Body ( cm2/ kg): 15.6 Amount Retained / Absorbed to Skin ( g/ cm2 event): 3.6e 05 Avg. Time, LADDpot, LADCpot ( days): 2.74e+ 04 Avg. Time, ADDpot, ADCpot ( days): 2.08e+ 04 Avg. Time, ADRpot, Cppot ( days): 1.00e+ 00 Page 26 of 48 CEM Inhalation Exposure Estimates ID Number: Unknown Scenario: General Purpose Cleaner Population: Adult Inhalation Rate ( m3/ day): 0.55 Years of Use ( years): 57 Body Weight ( kg): 71.8 Frequency of Use ( events/ year): 300 Exposure Units Result AT ( days)

Chronic Cancer LADDpot ( mg/ kg day) 1.36e 01 2.74e+ 04 LADCpot ( mg/ m3) 7.40e 01 2.74e+ 04 Chronic Non Cancer ADDpot ( mg/ kg day) 1.79e 01 2.08e+ 04 ADCpot ( mg/ m3) 9.74e 01 2.08e+ 04 Acute ADRpot ( mg/ kg day) 1.51e+ 00 1.00e+ 00 Cppot ( mg/ m3) 6.35e+ 01 1.00e+ 00 LADD  Lifetime Average Daily Dose ( mg/ kg day) LADC  Lifetime Average Daily Concentration ( mg/ m3)

ADD  Average Daily Dose ( mg/ kg day) ADC  Average Daily Concentration ( mug/ m3)

ADR  Acute Dose Rate ( mg/ kg day) Cp  Peak Concentration ( mg/ m3)

Note: 75 years = 2.738e+ 04 days pot  potential dose Note: The general Agency guidance for assessing short term, infrequent events ( for most chemicals, an exposure of less than 24 hours that occurs no more frequently than monthly) is to treat such events as independent, acute exposures rather than as chronic exposure. Thus, estimates of long term average exposure like ADD or ADC may not be appropriate for use in assessing risks associated with this type of exposure pattern. ( Methods for Exposure Response Analysis for Acute Inhalation Exposure to Chemicals ( External Review Draft). EPA/ 600/ R 98/ 051. April 1998 Page 27 of 48 CEM Dermal Exposure Estimates ID Number: Unknown Scenario: General Purpose Cleaner Population: Adult Years of Use ( years): 57 SA/ BW Body ( cm2/ kg): 15.6 Frequency of Use ( events/ year): 300 Exposure Units Result AT ( days)

Chronic Cancer LADDpot ( mg/ kg day) 1.75e 02 2.74e+ 04 Chronic Non Cancer ADDpot ( mg/ kg day) 2.31e 02 2.08e+ 04 Acute ADRpot ( mg/ kg day) 1.07e 01 1.00e+ 00 LADD  Lifetime Average Daily Dose ( mg/ kg day)

ADD  Average Daily Dose ( mg/ kg day)

ADR  Acute Dose Rate ( mg/ kg day)

Note: 75 years = 2.738e+ 04 days pot  potential dose Note: The general Agency guidance for assessing short term, infrequent events ( for most chemicals, an exposure of less than 24 hours that occurs no more frequently than monthly) is to treat such events as independent, acute exposures rather than as chronic exposure. Thus, estimates of long term average exposure like ADD or ADC may not be appropriate for use in assessing risks associated with this type of exposure pattern. ( Methods for Exposure Response Analysis for Acute Inhalation Exposure to Chemicals ( External Review Draft). EPA/ 600/ R 98/ 051. April 1998 Page 28 of 48 CEM Inputs ID Number: Unknown Product: TEC Chemical Name: TEC Scenario: General Purpose Cleaner Population: Adult Molecular Weight ( g/ mole): 276.3 Vapor Pressure ( torr): 0.0064 Weight Fraction  Median ( unitless): 0.05 Weight Fraction  90% ( unitless): 0.19 Inhalation Inputs Frequency of Use ( events/ yr): 300 Years of Use: 57 Mass of Product Used per Event  Median ( g): 61.5 Mass of Product Used per Event  90% ( g): 123 Inhalation Rate During Use ( m3/ hr): 0.55 Duration of Use  Median ( hours/ event): 0.667 Inhalation Rate After Use ( m3/ hr): 0.55 Duration of Use  90% ( hours/ event): 1.42 Zone 1 Volume ( m3): 20 Whole House Volume ( m3): 369 Air Exchange Rate ( air exchanges/ hr): 0.45 Body Weight ( kg): 71.8 Activity Patterns User: 1111111221542467422744411 Start Time: 7 Non User: Room of Use: 2. Kitchen Hour: 0 6 12 18 Dermal Inputs Frequency of Use  Body ( events/ yr): 300 SA/ BW  Body ( cm2/ kg): 15.6 Amount Retained / Absorbed to Skin ( g/ cm2 event): 3.6e 05 Avg. Time, LADDpot, LADCpot ( days): 2.74e+ 04 Avg. Time, ADDpot, ADCpot ( days): 2.08e+ 04 Avg. Time, ADRpot, Cppot ( days): 1.00e+ 00 Page 29 of 48 CEM Inhalation Exposure Estimates ID Number: Unknown Scenario: General Purpose Cleaner Population: Adult Inhalation Rate ( m3/ day): 0.55 Years of Use ( years): 57 Body Weight ( kg): 71.8 Frequency of Use ( events/ year): 300 Exposure Units Result AT ( days)

Chronic Cancer LADDpot ( mg/ kg day) 1.06e 01 2.74e+ 04 LADCpot ( mg/ m3) 5.76e 01 2.74e+ 04 Chronic Non Cancer ADDpot ( mg/ kg day) 1.39e 01 2.08e+ 04 ADCpot ( mg/ m3) 7.58e 01 2.08e+ 04 Acute ADRpot ( mg/ kg day) 5.43e 01 1.00e+ 00 Cppot ( mg/ m3) 8.71e+ 00 1.00e+ 00 LADD  Lifetime Average Daily Dose ( mg/ kg day) LADC  Lifetime Average Daily Concentration ( mg/ m3)

ADD  Average Daily Dose ( mg/ kg day) ADC  Average Daily Concentration ( mug/ m3)

ADR  Acute Dose Rate ( mg/ kg day) Cp  Peak Concentration ( mg/ m3)

Note: 75 years = 2.738e+ 04 days pot  potential dose Note: The general Agency guidance for assessing short term, infrequent events ( for most chemicals, an exposure of less than 24 hours that occurs no more frequently than monthly) is to treat such events as independent, acute exposures rather than as chronic exposure. Thus, estimates of long term average exposure like ADD or ADC may not be appropriate for use in assessing risks associated with this type of exposure pattern. ( Methods for Exposure Response Analysis for Acute Inhalation Exposure to Chemicals ( External Review Draft). EPA/ 600/ R 98/ 051. April 1998 Page 30 of 48 CEM Dermal Exposure Estimates ID Number: Unknown Scenario: General Purpose Cleaner Population: Adult Years of Use ( years): 57 SA/ BW Body ( cm2/ kg): 15.6 Frequency of Use ( events/ year): 300 Exposure Units Result AT ( days)

Chronic Cancer LADDpot ( mg/ kg day) 1.75e 02 2.74e+ 04 Chronic Non Cancer ADDpot ( mg/ kg day) 2.31e 02 2.08e+ 04 Acute ADRpot ( mg/ kg day) 1.07e 01 1.00e+ 00 LADD  Lifetime Average Daily Dose ( mg/ kg day)

ADD  Average Daily Dose ( mg/ kg day)

ADR  Acute Dose Rate ( mg/ kg day)

Note: 75 years = 2.738e+ 04 days pot  potential dose Note: The general Agency guidance for assessing short term, infrequent events ( for most chemicals, an exposure of less than 24 hours that occurs no more frequently than monthly) is to treat such events as independent, acute exposures rather than as chronic exposure. Thus, estimates of long term average exposure like ADD or ADC may not be appropriate for use in assessing risks associated with this type of exposure pattern. ( Methods for Exposure Response Analysis for Acute Inhalation Exposure to Chemicals ( External Review Draft). EPA/ 600/ R 98/ 051. April 1998 Page 31 of 48 Drinking Water Exposure ( see http:// www. epa. gov/ oppefed1/ models/ water/ index. htm)

Surface and groundwater drinking water concentrations were based on modeling using a single application of 1 lb/ acre. Surface water concentrations were modeled using FIRST. Groundwater concentrations were modeled using SCI GROW. Concentrations are linearly scalable based on application rate.  The surface water chronic concentration for ATBC is 0.44 ppb.  The groundwater concentration for either ATBC or TEC is 4.28 ppb.  The surface water chronic concentration for TEC is 26.8 ppb.

The TEC 26.8 ppb and the ATBC 4.28 ppb concentrations in drinking water were converted to mg/ kg/ day using standard Agency assumptions: ( 1) consumption of 1 liter of water per day for infants and children and 2 liters of water per day for adults, and ( 2) body weights of 10 kg for children 1 2 years, and 70 kilograms for the US general population.

TEC Generic Screening Drinking Water Exposure Estimates  Chronic Population Subgroup Exposure ( mg/ kg/ day)

1 lb/ acre application rate 5 lb/ acre application rate 15 lb/ acre application rate US General 0.00076 0.0038 0.011 Females ( 13 49 years old) 0.00089 0.00447 0.013 Children ( 1 2 years old) 0.0027 0.013 0.040 Page 32 of 48 ATBC Generic Screening Drinking Water Exposure Estimates  Chronic Population Subgroup Exposure ( mg/ kg/ day)

1 lb/ acre application rate 5 lb/ acre application rate 15 lb/ acre application rate US General 0.00012 0.00061 0.0018 Females ( 13 49 years old) 0.00014 0.00071 0.0021 Children ( 1 2 years old) 0.00043 0.0021 0.0064 Page 33 of 48 Appendix 2: Robust Summaries Prepared by EPA ( D270588, D281694)

8. Acute Oral Toxicity of Acetyl Tributyl Citrate and Triethyl Citrate The objective of the various studies considered was to determine the toxicity of triethyl citrate and acetyl tributyl citrate. Acute toxicity studies were performed on both cats and Wistar rats. The reported studies were performed by either gavage or in the diet. Some studies were a single dose and in others dosing occurred for periods of 2 months.

The effects of both chemicals were the same. Clinical signs including nausea, vomiting , ataxia, weakness, muscle twitching, tremors, reflex hyperexcitability, depression of body temperature, gasping and shallow respiration, prostration, convulsions, respiratory failure, ( central origin), circulatory depression, and death were manifested within a few minutes after administration. Death occurred in 2 hours to about 2 days or recovery in 4 hours to 3 days. There was no macroscopic or microscopic damage observed to thoracic and abdominal organs. These experiments also suggested that more than 4 hours are required to clear 25% of the chemical from the body.

The ATBC rat acute oral LD 50 > 30 g/ kg: Toxicity Category IV. The TEC rat acute oral LD 50 = 7 mL/ kg, Toxicity Category IV.

Reference: MRID 45221221. Gold, H. et al. ( 1959) On the Pharmacology of Triethyl, Acetyl Triethyl, Tributyl, and Acetyl Tributyl Citrates by Oral Administration in Rats and Cats: Lab Project Number: ATBC/ TEC 51147 26. Unpublished study prepared by Cornell University Medical College. 34 p. Reliability: Provides sufficient information for regulatory purposes.

9. Toxicity of Acetyl Tributyl Citrate Primary Eye Irritation Species/ Strain: Rabbits/ Albino Conclusions: ATBC induced ocular irritation, characterized by moderate erythema in one animal for up to 24 hours and irritation subsided by 48 hours postinstillation Not a severe ocular irritant: Toxicity Category III. Method: 0.1 ml ATBC ( purity unknown) was instilled in the left conjunctival sac of 3 male albino rabbits and observed for 72 hours post dosing for eye irritation. GLP: Yes Test Substance: ATBC, purity unknown Results: Moderate erythema was observed in 1/ 3 rabbits for up to 24 hours and was cleared by 48 hours. Reference: MRID 45221213. Chas. Pfizer ( 1975) Eye and Dermal Irritation of Citroflex A2 ( Triethylcitrate) and Citroflex A4: Lab Project Number: ATBC/ TEC 51147 15. Unpublished study. 5 p. Reliability: Provides sufficient information for regulatory purposes.

Primary Dermal Irritation Species/ Strain: Rabbits/ Albino Conclusions: ATBC did not induce irritation. Toxicity Category IV. Page 34 of 48 Method: 1 ml ATBC ( purity unknown) was applied to abdominal skin, daily, for 4 days. Animals were observed for dermal irritation for 36 hours post last application. In addition, two 3 week dermal studies in rabbits, one with intact skin and another with abraded skin were also performed. GLP: Yes Test Substance: ATBC, purity unknown Results: No dermal irritation.. Reference: MRID 45221213. Chas. Pfizer ( 1975) Eye and Dermal Irritation of Citroflex A2 ( Triethylcitrate) and Citroflex A4: Lab Project Number: ATBC/ TEC 51147 15. Unpublished study. 5 p. Reliability: Provides sufficient information for regulatory purposes.

Dermal Sensitization Species/ Strain: Guinea Pig Conclusions: ATBC is not a dermal sensitizer in guinea pigs Method: Maximization method was employed to evaluate the sensitization potential of ATBC. GLP: Yes Test Substance: ATBC, purity unknown Results: No animal showed positive signs of sensitization during the first, second, or third challenges at either the 24 or 48 hour observations. Barely perceptible erythema was observed during the first challenge phase in the untreated controls ( 1/ 4) at 48 hours. Reference: MRID 45221220 Philp, J. ( 1976) Sensitization Potential of Citroflex A2, Citroflex A4 and Citroflex 2 in Guinea Pigs: Lab Project Number: ATBC/ TEC 51147 25. Unpublished study prepared by Unilever Research Laboratory. 40 p. Reliability: High  Guideline method was used.

Human Sensitization Species: Human volunteers Conclusions: ATBC is not a dermal sensitizer to humans Methods: Human volunteers were applied with Webril patch moistened with 0.4 mL of test substance to the upper arm for 24 hours followed by a 24 or 48 hour recovery period according to the method of Draize. Nine induction treatments followed by single challenge treatment were performed. Test sites were observed for dermal irritation immediately prior to patch application at the second through ninth visits and following the tenth visit. GLP: Yes Test Substance: ATBC, unknown purity Results: No evidence of dermal irritation was observed following any induction treatment or the challenge treatment. Reference: MRID 45221201 Guillaume, R. ( 1978) Repeated Insult Patch Test: Acetyl Tributyl Citrate ( in Humans): Lab Project Number: ATBC/ TEC 51147 1. Unpublished study prepared by Hill Top Research. 24 p. Reliability: High. Tested in the population of concern. It satisfies the purpose for which it was intended: to evaluate the irritative properties of ATBC and to determine if hyperactivity to ATBC would occur following repeated application in humans. Page 35 of 48 Subchronic Oral Toxicity Species/ Strain: Rat/ Sprague Dawley Conclusion: Not toxic up to 1,000 mg/ kg/ day ( HDT) Method: Groups of 20 rats/ sex/ dose received in the diet dose levels of 0, 100, 300, or 1000 mg/ kg/ day for 90 days. All rats were checked once daily for clinical signs of toxicity. Body weights and food consumption were measured weekly. Hematology and clinical chemistry were analyzed. Water consumption was measured daily. All animals were subjected to a detailed evaluation of clinical signs of neurotoxicity and functional deficits. A gross necropsy was performed and tissues from the controls and 1000 mg/ kg/ day were examined histopathologically. GLP: Yes Test Substance: Acetyl tributyl citrate, purity > 98% Results: No systemic toxicity was noted up to 1,000 mg/ kg/ day. There were transient decreases in food consumption, decreases in body weights, and slight increases in absolute and relative weights observed in high dose males and females; however, there was no corroborative evidence of liver toxicity histologically. Hematology and clinical chemistries were not affected. There were no treatment related neurological findings in males and females. References: MRID 45257701. Jonker, D. ( 1991) Subchronic ( 90 Day) Dietary Toxicity Study with Acetyl Tributyl Citrate in Rats: Lab Project Number: ATBC/ TEC 51147 10. Unpublished study prepared by TNO Nutrition and Food Research. 352 p.

MRID 45221211. Jonker, I. ( 1991) Range Finding Study ( 14 Day) Dietary with Acetyl Tributyl Citrate in Rats: Lab Project Number: ATBC/ TEC 51147 12. Unpublished study prepared by TNO Nutrition and Food Research. 78 p. Reliability: High. Guideline method was used.

Chronic Oral Toxicity  Rat Species/ Strain: Rat/ Sherman Conclusion: NOAEL  20,000 ppm ( 1000 mg/ kg/ day). LOAEL was not established. Method: Acetyl tributyl citrate ( 99.4% pure) was administered to 20 rats/ sex/ dose at concentrations of 0, 200, 2000 or 20,000 ppm for two years. Body weights and clinical signs were recorded but frequency was not given. There was slight decrease in body weights during 5 to 15 weeks in all groups, however, the decreases were equivocal. GLP: Yes Test Substance: Acetyl tributyl citrate Results: No systemic toxicity was observed up to 20,000 ppm ( 1000 mg/ kg/ day). ( HDT) Reference : MRID 45259501. Soeler, A. et al. ( 2000) Experiments on the Chronic Toxicity of Acetyl Tributyl Citrate: Lab Project Number: ACTB/ TEC 51147 16. Unpublished study prepared by Harvard School of Public Health and Medical School. 19 p. Reliability: University conducted study provides sufficient information when considered with other information. Page 36 of 48 Chronic Oral Toxicity  Dog Species/ Strain: Dog/ Mongrel Conclusion: NOAEL  140 mg/ kg/ day. LOAEL was not established. Method: Acetyl tributyl citrate ( 99.4% pure) was administered in gelatin capsule orally to 2 dogs at a dosages of 0 or 140 mg/ kg/ day for two years. Dogs were examined for clinical signs toxicity daily and body weights weekly. Hematological parameters ( hematocrit, hemoglobin, sedimentation rate, red and white cell counts, and differential white cell counts) were determined at 6, 11, 17, 20 and 24 months. Urinalyses was performed for protein, sugar, and sediment. Treatment with acetyl tributyl citrate at 140 mg/ kg/ day did not elicit any adverse effects on clinical signs, body weights, hematology and urinalyses parameters. GLP: Yes Test Substance: Acetyl tributyl citrate Results: No systemic toxicity was observed up to 140 mg/ kg/ day. Reference: MRID 45259501. Soeler, A. et al. ( 2000) Experiments on the Chronic Toxicity of Acetyl Tributyl Citrate: Lab Project Number: ACTB/ TEC 51147 16. Unpublished study prepared by Harvard School of Public Health and Medical School. 19 p. Reliability: University conducted study provides sufficient information when considered with other information Reproductive Toxicity Species/ Strain: Rat/ Sprague Dawley Endpoint: NOAEL ( parental): 100 mg/ kg/ day LOAEL ( parental): 300 mg/ kg/ day, based on decreased body weights and water consumption NOAEL ( reproductive): 1,000 mg/ kg/ day LOAEL ( reproductive): not observed NOAEL ( offspring): 100 mg/ kg/ day LOAEL ( offspring): 300 mg/ kg/ day, based on increased pup mortality and decreased pup weights Method: Acetyl tributyl citrate ( purity not provided) was administered in diet to 30 rats/ sex/ dose at nominal dose levels of 0, 100, 300 or 1,000 mg/ kg/ day. The P ( parental) animals were given test diet for 3 ( females) or 11 ( males) weeks prior to mating to produce the F1 ( first generation) litters. After weaning, the selected F1 animals were given the same concentration test diet as P dams, for 10 weeks prior to mating, which produced the F2 ( second generation) generation progeny. The animals were checked for clinical signs of toxicity and mortality daily and detailed clinical examinations weekly. All P males were weighed pre treatment, 3 days following initiation of treatment and weekly thereafter until necropsy. All P females were weighed pretreatment, 3 days following treatment initiation, weekly throughout premating and mating, daily during gestation and weekly during lactation. All F1 males were weighed weekly from weaning until termination. All F1 females were weighed weekly from weaning to mating, daily during gestation, on LDs 4, 7, and 14, and weekly thereafter until termination. Food and water consumption were measured between weighing intervals excepting during mating. Litters were examined for survival and abnormalities ( external malformations) on LDs Page 37 of 48 1, 4, 7, 10, 14, 17 and 21. Pups were weighed on PNDs 1, 4, 7, 14, and 21. At sacrifice, gross examinations of the abdominal cavities were conducted, multiple organs were preserved in buffered formalin and examined microscopically. The following indices were calculated:  fertility index  offspring viability index at days 4 and 21  sex ratio  mortality GLP: Unknown Test Substance: Acetyl tributyl citrate, purity not known Results: When compared to concurrent controls, no treatment related changes were observed in the following parameters: mortality, clinical signs, food consumption, and gross pathology in the P or F1 adults; litter size, number of live pups, sex ratios, clinical signs, gross pathology, and histopathology in the F1 and F2 offspring. Reproductive function and organ weights were not evaluated in the parental animals. Developmental landmarks and organ weights were not evaluated in the F1 or F2 offspring. Systemic toxicity was observed at 300 mg/ kg/ day characterized by decreased body weights and water consumption. The parental toxicity LOAEL was 300 mg/ kg/ day and the NOAEL was 100 mg/ kg/ day. No adverse reproductive performance was observed at any dose. Based on the available observations, the reproductive toxicity NOAEL was 1000 mg/ kg/ day, LOAEL was not observed. Dose related increased pup mortality was observed in the F2 generation; 6, 4, 13, and 19 in the control, 100, 300, and 1,000 mg/ kg/ day dose groups, respectively. Mortality significantly increased ( 250%) in high dose F2 pups during days 7  21. Pup weights significantly decreased ( 7%) in F2 generation on PND 21. Pup body weights decreased significantly in the 1000 mg/ kg/ day F1 pups on PND 1 ( 9%), 4 ( 7%), and 21 ( 5%), and in F2 pups on PND 1 ( 9%), 4 ( 9%), 14 ( 10%), and 21 ( 12%). The offspring NOAEL is 100 mg/ kg/ day. The offspring toxicity LOAEL is 300 mg/ kg/ day based on increased pup mortality and decreased pup weight. Reference: MRID 45257702. Robbins, M. ( 1994) A Two Generation Reproduction Study with Acetyl Tributyl Citrate in Rats: Lab Project Number: ATBE/ TEC 51147 13. Unpublished study prepared by BIBRA Toxicology International. 384 p. Reliability: High. Guideline method was used; study less than 10 years old; however, lacked the purity information. It is noted that several critical evaluations were not made.

In vitro Cytotoxicity Species/ Strain: Rat/ Sprague Dawley Conclusion: ATBC at 1 mg% for 4 hours was not cytotoxic to mammalian cells. Method: Primary rat hepatocytes were exposed to ATBC ( purity unknown), in DMSO, at concentrations of 0.01, 0.05, 0.1, or 1 mg% for 4 hours. Cell cultures were also exposed to ATBC metabolite tributyl citrate ( 0.01, 0.05, 0.1 or 1 mg%) and n butanol ( 100, 200, or 400 mg%). GLP: Unknown Test Substance: ATBC, purity unknown Results: Toxicity, as indicated by elavated lactate dehydrogenase activities was not observed. Significant toxicity was observed with tributyl citrate. Page 38 of 48 Reference: MRID 45221203. Acosta, D. ( 1991) In Vitro Cytotoxicity of n Butanol, Acetyl Tributyl Citrate, and Tributyl Citrate in Primary Cultures of Rat Hepatocytes: Lab Project Number: ATBC/ TEC 51147 3. Unpublished study prepared by The University of Texas. 17 p. Reliability: University conducted study provides sufficient information when considered with other information Gene Mutation Species/ Strain: Bacteria/ Salmonella typhimurium  reverse mutation Conclusions: Not mutagenic Method: Histadine requiring mutagenic strains of salmonella typhimurium strains were exposed to ATBC in dimethylsulfoxide at concentrations of 50, 158, 500, 1580 or 5000

g/ plate and reverse mutations were determined after 48 hours incubation at 37  C, both in the presence and absence of S9 derived from Aroclor 124 induced rat and/ or hamster induced livers. GLP: Yes Test Substance: Acetyl tributyl citrate, 98.55% pure Results: No evidence of mutagenicity ( reverse mutation) was observed in strains TA98, TA100, TA1537, and TA1538. Slight precipitation was observed at doses  1000

g/ plate both in the presence and absence of S9 metabolic activation. Positive controls exhibited appropriate response. Reference: MRID 45221207. Bollapudi, B.; Linscombe, V. ( 1988) Evaluation of Acetyl Tributyl Citrate in the Ames Salmonella/ Microsome Bacterial Mutagenicity Assay: Lab Project Number: ATBC/ TEC 511147 7. Unpublished study prepared by The Dow Chemical Company. 29 p. Reliability: High. Guideline method was used.

Species/ Strain: Bacteria/ Salmonella typhimurium  reverse mutation Conclusions: Not mutagenic Method: In a plate incorporation assay, histadine requiring mutagenic salmonella typhimurium strains TA98, TA100, TA1537, and TA1538 were exposed to ATBC in dimethylsulfoxide at concentrations of 333, 1000, 3333, 6667, or 10,000

g/ plate and reverse mutations were determined after 48 hours incubation at 37  C, both in the presence and absence of S9 derived from Aroclor 124 induced rat and/ or hamster induced livers. Results: No evidence of mutagenicity ( reverse mutation) was observed in strains TA98, TA100, TA1537, and TA1538. There was slight precipitation was observed at doses  3333

g/ plate both in the presence and absence of S9 metabolic activation. Positive controls exhibited appropriate response. Reference: MRID 45221208. San, R.; Wagner, V. ( 1991) Salmonella/ Mammalian Microsome Plate Incorporation Mutagenicity Assay ( Ames Test): Lab Project Number: ATBC/ TEC 51147 8. Unpublished study prepared by Microbiological Associates, Inc. 47 p. Reliability: High. Guideline method was used; however, lacked the purity information.

Species/ Strain: Mammalian/ Chinese Hamster Ovary ( CHO) Conclusions: Did not induce mutant colonies. Method: In this forward mutation assay, CHO were exposed to ATBC in DMSO at concentrations of 25, 50, 100, 200, or 400

g/ mL with and without S9 activation for 4 hours and forward mutations were evaluated following Page 39 of 48 incubation in the medium containing the selective agent, 6 thioguanine. GLP: Yes Test Substance: Acetyl tributyl citrate, 99.02% pure. Results: Cytotoxicity was observed in the absence of S9 at  50

g/ mL in the concurrent toxicity plates; however, in the mutagenicity plates  50% of the cells survived. There were no treatment related increases in mutant frequency observed at any dose. The positive controls produced appropriate response. Reference: MRID 45221210. Dow Chemical Company ( 1991) Evaluation of Acetyl Tributyl Citrate in the Chinese Hamster Ovary Cell/ Hypoxanthine Guanine Phosphoribosyl Transferase ( CHO/ HGPRT) Forward Mutation Assay: Lab Project Number: ATBC/ TEC 51147 11. Unpublished study. 31 p. Reliability: High. Guideline method was used.

Species/ Strain: Mammalian/ mouse lymphoma Conclusions: No evidence forward mutations over background in the presence or absence of S9 activation. Method: In this in vitro assay, mouse lymphoma cells ( L5178Y TK +/ locus) were exposed to ATBC in DMSO at concentrations of 10, 70, 150, 230, or 310

g/ mL without S9 activation and 200, 270, 340, 410, 480, or 550

g/ mL with S9 activation ( duration of exposure not provided). GLP: Yes Test Substance: ATBC, purity not specified. Results: Cytotoxicity was observed at 230

g/ mL  S9 and 480

g/ mL + S9 activation. No marked increase in the mutant frequencies were observed with or without S9 activation over background. Positive controls produced appropriate response. Reference: MRID 45221209. Bigger, C.; Harbell, J. ( 1991) Mouse Lymphoma Assay ( L5178YTK+/) Acetyl Tributyl Citrate: Lab Project Number: ATBC/ TEC 51147 9. Unpublished study prepared by Microbiological Associates, Inc. 22 p. Reliability: High. Guideline method was used; however, lacked the purity information.

Cytogenetics Species/ Strain: Rat/ Lymphocytes Conclusions: Did not induce chromosomal aberrations Method: In this in vitro cytogenetics assay, rat lymphocytes were exposed to ATBC in DMSO at concentrations of 0, 40, 133, or 400

g/ mL with or without S9 activation for 4 hours. GLP: Yes Test Substance: ATBC, 99.02% pure Results: ATBC was tested up to the limit of solubility, a slight precipitate was observed at  133 ( S9) and 400 (+ S9)

g/ mL. At 400

g/ mL mitotic indices were reduced 66% at 24 hours or 74% at 48 hours ( S9) and 0% at 24 hours or 100% at 48 hours (+ S9). No statistically significant increases in aberration frequency were observed at any dose at 24 or 48 hours with or without S9 activation. Positive controls induced appropriate response. Reference: MRID 45221206. Dow Chemical Company ( 1991) Evaluation of Acetyl Tributyl Citrate in an In Vitro Chromosomal Aberration Assay Utilizing Page 40 of 48 Rat Lymphocytes: Lab Project Number: ATBC/ TEC 51147 6. Unpublished study. 26 p. Reliability: High. Guideline method was used.

Species/ Strain: Rat/ Sprague Dawley Conclusions: Not cytotoxic to mammalian cells. Method: Primary rat hepatocytes from 8 10 day old rats were exposed ATBC in DMSO at concentrations of 0.01, 0.05, 0.1, or 1 mg% for 4 hours. In addition, the ATBC metabolites, tributyl citrate ( TBC) and n butanol were tested at concentrations of 0.01, 0.05, 0.1, or 1 mg% and 100, 200, or 400 mg%, respectively. GLP: No Test Substance: ATBC, purity not provided. Results: No significant cytotoxicity, as indicated by elevated lactate dehydrogenase activities in the culture medium was observed at any dose levels tested for ATBC or its principal metabolites ( TBC and n butanol). Reference: MRID 45221203. Acosta, D. ( 1991) In Vitro Cytotoxicity of n Butanol, Acetyl Tributyl Citrate, and Tributyl Citrate in Primary Cultures of Rat Hepatocytes: Lab Project Number: ATBC/ TEC 51147 3. Unpublished study prepared by The University of Texas. 17 p. Reliability: University conducted study provides sufficient information when considered with other information Metabolism Species/ Strain: Rat/ Sprague Dawley Conclusions: ATBC was readily absorbed and rapidly excreted in urine and feces within 48 hours. Method: 4  5 male rats were dosed with a single oral of 70 mg/ kg ( 14C) ATBC ( 100% radiochemical purity) and mass balance, metabolic profile, and blood kinetics were evaluated. GLP: Yes Test Substance: ATBC, 100% radiochemical purity Results: The total recovery of radioactivity was 99.94%. Elimination of radioactivity occurred mostly within 24 hours of dosing ( 89.2% dose) and was essentially complete within 48 hours ( 99.26% dose). Elimination occurred predominantly in the urine, but a substantial amount was also excreted in the feces ( 32%). Very little radiation was expired as CO 2 ( 2.2%), and none was expired as volatile organics. The half times were as follows: KA = 1.0 hour,   = 3.4 hours, and   = 39 hours. Tissue distribution was only quantified at 48 hours post dose by which time excretion was essentially complete. Concentrations (% dose/ g) of radioactivity were as follows: the GI tract ( with contents; 0.008), the liver and perirenal fat ( 0.005 each), kidney ( 0.003), skin ( 0.002), and blood and carcass ( 0.001 each). Quantitative RP HPLC analyses isolated 9 metabolites in the urine of which 2 were identified. The primary metabolite was monobutyl citrate ( 29.44% dose). The other identified metabolite was dibutyl citrate ( 0.36% dose). Parent was not detected in the urine, and all metabolites were more polar than the parent. The seven unknown urinary metabolites each accounted for 0.7 10.6% of the dose with three unknowns accounting for 5.0, 7.0, and 10.6% of the dose. GC/ MS Page 41 of 48 analysis also detected the presence of the following metabolites: acetyl citrate, monobutyl citrate, acetyl monobutyl citrate, dibutyl citrate, and acetyl dibutyl citrate. However, no quantitative data were provided from GC/ MS. Acid hydrolysis resulted in the same qualitative peak profile, but most of the radioactivity ( 59%) was eluted in a broad peak occurring at 4.5 8 minutes. Base hydrolysis eliminated peak separation, and the majority of the radioactivity ( 94%) eluted in a broad peak occurring at 4.5 8 minutes. Quantitative RP HPLC analyses isolated 3 metabolites in the ethyl acetate extract of feces and up to 2 more metabolites in the acidic ethyl acetate extract of feces. None of the metabolites were identified. The parent was isolated in the feces ( 5.17% dose). Unanalyzed fractions of urine, feces, and CO 2 contained less than 5% dose, each. A figure of the proposed metabolic pathway was not presented. Reference: MRID 45221205. Dow Chemical Company ( 1992) Metabolism and Disposition of Acetyl Tributyl Citrate in Male Sprague Dawley Rats: Lab Project Number: ATBC/ TEC 51147 5. Unpublished study. 62 p. Reliability: Good. Guideline method was not used; however, study provides useful information Species/ Strain: Human serum and rat liver homogenates Conclusion: ATBC was hydrolyzed in both human and rat liver homogenates resulting in n butanol and tributyl citrate ( TBC), however, in human serum the halflife was 7 hours vs 30 minutes in rat. Method: ATBC ( 10.9 µ M) in dimethylsulphoxide was diluted with serum to 155 nmole/ mL and liver homogenate to 132 nmole/ ml. Samples containing 1 butanol ( 150 nmole/ ml) in serum and liver homogenate were also prepared. The samples were incubated at 37oC with magnetic stirring and duplicate 1 ml samples were collected at 3, 15, and 30 minutes, and 1, 2, 4, 6, 24, and 46 hours. The samples were acidified within 1 minute to inhibit the hydrolysis of ATBC. One of the duplicate samples and the samples fortified with n butanol were analyzed by head space capillary gas chromatography. The other duplicate samples were analyzed by capillary gas chromatography. GLP: Yes Test Substance: ATBC, purity not reported Results: In human serum, an initial half life of ATBC was approximately 7 hours. TBC was detected after one hour. Hydrolysis of ATBC resulted in the formation of n butanol and was essentially complete after 24 hours. In serum, n butanol was essentially stable (  29% after 46 hours). In rat liver homogenate, ATBC half life was less than 30 minutes. TBC was detected after 3 minutes of incubation, but not in longer incubations suggesting that ATBC is quickly hydrolyzed. Hydrolysis of ATBC resulted in the formation of n butanol and was essentially complete in 1 hour. Reference: MRID 45221202. Edlund, P.; Ostelius, J. ( 1991) In Vitro Hydrolysis of Acetyl Tributyl Citrate in Human Serum and Rat Liver Homogenates: Lab Project Number: ATBC/ TEC 51147 2. Unpublished study prepared by Oratech. 23 p. Reliability: High. It is a non guideline study, but the information is essential for understanding the metabolism of ATBC. It satisfies the purpose fors which it was conducted: to demonstrate that human serum and rat liver homogenates are capable of metabolizing acetyl tributyl citrate resulting in n butanol and tributyl citrate as intermediate products. Page 42 of 48 Species: Human serum and rat liver homogenates Conclusion: Human serum and rat liver homogenates metabolize ATBC and TBC and that TBC metabolism is relatively fast. Butanol was observed as a metabolite of ATBC and TBC. Method: ATBC ( 100 µ g [ 248 nmoles]/ mL) , TBC ( 100 µ g [ 252 nmoles]/ mL) and butanol ( 14.8 µ g [ 200 nmoles]/ mL) in DMSO were added to aliquots of human serum and liver homogenates and were incubated in a circulating water bath at 37oC. Samples were collected for metabolite analysis from serum at 0 and 20 minutes and 1, 2, 4, 6, 11, 24, and 48 hours; and from liver homogenate at 0, 15, and 30 minutes and 1, 2, 4, and 9 hours. The concentrations of ATBC, TBC and butanol were determined using GC. GLP: Yes Test Substance: ATBC, TBC, and butanol of highest purity ( unspecified) Results: In human serum, ATBC incubations demonstrated a linear decline over a 48 hour period, at which time only 25% of the starting material remained. The half life was 32 hours. Only traces of TBC were detected, which was consistent with a rapid metabolism of TBC. TBC incubations demonstrated an exponential decline with almost complete conversion shown in the 24 hour sample. The half life was 4 hours. In the liver homogenate, ATBC incubations demonstrated a linear decline in the first hour with almost complete conversion . The half life was 10 minutes. No trace of TBC was detected, which was consistent with a rapid metabolism of TBC. TBC incubations demonstrated complete conversion within 15 minutes. The half life was estimated as seconds. Reference: MRID 45221204. Davis, P. ( 1991) Metabolism of Acetyl Tributyl Citrate ( ATBC) and Tributyl Citrate ( TBC) in Human Serum and Rat Liver Homogenates: Lab Project Number: ATBC/ TEC 51147 4. Unpublished study prepared by The University of Texas. 40 p. Reliability: High. It is a non guideline study, but the information is essential for understanding the metabolism of ATBC. It satisfies the purpose for which it is conducted: to demonstrate that human serum and rat liver homogenates are capable of metabolizing acetyl tributyl citrate and its metabolite tributyl citrate and that n butanol is a metabolite of both.

10. Toxicity of Triethyl Citrate ( TEC)

Primary Eye Irritation Species/ Strain: Rabbits/ Albino Conclusions: TEC induced ocular irritation, characterized by slight or mederate erythema in one animal for up to 3 hours and irritation subsided by 24 hours post instillation. Not a severe ocular irritant. Toxicity Category IV based on the degree of irritation which subsided from all treated eyes by 24 hours. Method: 0.1 ml TEC ( purity unknown) was instilled in the left conjunctival sac of 3 male albino rabbits and observed for 72 hours post dosing for eye irritation. GLP: Yes Test Substance: TEC, purity unknown Results: Moderate erythema was observed in 1/ 3 rabbits for up to 3 hours and was cleared by 24 hours. Reference: MRID 45221213. Chas. Pfizer ( 1975) Eye and Dermal Irritation of Page 43 of 48 Citroflex A2 ( Triethylcitrate) and Citroflex A4: Lab Project Number: ATBC/ TEC 51147 15. Unpublished study. 5 p. Reliability: Provides sufficient information for regulatory purposes.

Primary Dermal Irritation Species/ Strain: Rabbits/ Albino Conclusions: TEC did not induce dermal irritation. Toxicity Category IV. Method: 1 ml TEC ( purity unknown) was applied to abdominal skin, daily, for 4 days. Animals were observed for dermal irritation for 36 hours post last application. In addition, two 3 week dermal studies in rabbits, one with intact skin and another with abraded skin were also performed. GLP: Yes Test Substance: TEC, purity unknown Results: No dermal irritation. Reference: MRID 45221213. Chas. Pfizer ( 1975) Eye and Dermal Irritation of Citroflex A2 ( Triethylcitrate) and Citroflex A4: Lab Project Number: ATBC/ TEC 51147 15. Unpublished study. 5 p. Reliability: Provides sufficient information for regulatory purposes.

Dermal Sensitization Species/ Strain: Guinea Pig Conclusions: TEC is strong dermal sensitizer. Method: Maximization method was employed to evaluate the sensitization potential of TEC GLP: Yes Test Substance: TEC, purity unknown Results: 9/ 9 animals showed positive signs of sensitization, at both 24 and 48 hour observations in the first and second challenges. Barely perceptible erythema was observed during the first challenge phase ( 1/ 4) in the controls. No dermal irritation was observed in any untreated controls. Reference: MRID 45221220 Philp, J. ( 1976) Sensitization Potential of Citroflex A2, Citroflex A4 and Citroflex 2 in Guinea Pigs: Lab Project Number: ATBC/ TEC 51147 25. Unpublished study prepared by Unilever Research Laboratory. 40 p. Reliability: High  Guideline method was used.

Human Sensitization Species: Human volunteers Conclusions: TEC is not a dermal sensitizer to humans Methods: Human volunteers were applied with Webril patch moistened with 0.4 mL of test substance to the upper arm for 24 hours followed by a 24 or 48 hour recovery period according to the method of Draize. Nine induction treatments followed by single challenge treatment were performed. Test sites were observed for dermal irritation immediately prior to patch application at the second through ninth visits and following the tenth visit. GLP: Yes Test Substance: TEC, unknown purity Results: No evidence of dermal irritation was observed following any induction Page 44 of 48 treatment or the challenge treatment. Reference: MRID 45221201 Guillaume, R. ( 1978) Repeated Insult Patch Test: Acetyl Tributyl Citrate ( in Humans): Lab Project Number: ATBC/ TEC 51147 1. Unpublished study prepared by Hill Top Research. 24 p. Reliability: High. Tested in the population of concern. It satisfies the purpose for which it was intended: to evaluate the irritative properties of TEC and to determine if hyperactivity to TEC would occur following repeated application in humans.

Chronic Oral Toxicity  Rat Species/ Strain: Rat/ Sprague Dawley Conclusions: Inconclusive for lack of details Method: TEC was administered in diet at concentrations of 0, 0.33, 1.0, or 3.0% ( 0, 30, 200, or 600 mg/ kg/ day) to 15 rats/ sex/ dose for 104 weeks. Body weights were recorded weekly for 12 weeks then every 4 weeks for remainder of the study. Food consumption was recorded for 12 weeks. Blood and urine parameters were evaluated, however, intervals not specified. On study weeks 6, 12, 55, and/ or 91 to 104, 2 4 rats/ sex/ dose were sacrificed and their kidneys, liver, spleen, lung, heart, stomach, small intestine, ovaries, testes and/ or adrenals were examined microscopically. GLP: Unknown Test Substance: TEC, unknown purity Results: No adverse effects of hematologic, urinalysis, survival, gross or histopathological parameters were effected due to treatment. In males, at 600 mg/ kg/ day decreased body weights and food consumption were observed. Reference: MRID 45221214. Harrison, J. ( 1954) Triethyl Citrate, Life Time Study on Rats: Lab Project Number: ATBC/ TEC 51147 17. Unpublished study prepared by LaWall and Harrison. 14 p. Reliability: Low given that this is a 1954 study, the lack of details, and the unknown TEC purity Range Finding Oral Toxicity  Dog Species/ Strain: Dog/ beagle Conclusions: Liver toxicity was observed at 2.5 to 3.5 mL/ kg (  2.5 to 3.5 g/ kg). No effects were observed at 0.25 mL/ kg ( 250 mg/ kg). Method: In one range finding study, dogs were dosed with TEC in the diet at concentrations of 0, 0.05 and 0.25 mL/ kg for up to 6 months. In the second study, dosing was increased to 2.5 to 3.5 mL/ kg for 7 to 12 weeks. GLP: No Test Substance: TEC, 99.1  99.6% pure Results: No treatment related findings were observed in mortality, clinical signs, body weights, food consumption, organ weights and microscopic changes up to 0.05 to 0.25 mL/ kg. Urinalysis parameters ( sugar and protein) and clinical chemistry parameters ( non protein nitrogen, glucose and serum calcium) were also unaffected by treatment. In the second range finding study, at doses of 2.5 to 3.5 mL/ kg caused severe liver damage, however the findings were not described. Hematological parameters ( specific parameters not stated) indicated anemia. No treatment related findings were observed in body weights. Urinalysis indicated the presence of a Page 45 of 48 reducing substance in the urine of the one dog dosed at 3.5 mL/ kg. Clinical chemistry parameters ( non protein nitrogen, sugar, serum calcium and several indices of liver damage) were unaffected by treatment. Reference: MRID 45221219. Hodge, H. ( 1956) Chronic Oral Toxicity Studies of Triethyl Citrate in Dogs: Lab Project Number: ATBC/ TEC 51147 24. Unpublished study prepared by University of Rochester School of Medicine and Dentistry. 12 p. Reliability: Low given that this is a 1956 study and the unknown TEC purity Gene Mutation Species/ Strain: Bacteria/ Salmonella and Saccharomyces Conclusion: TEC is not considered to be mutagenic in S. typhimurium when tested up to 1.6% ( v/ v) or in Saccharomyces cerevisiae when tested up to 1.7% ( v/ v) with or without S9 activation. Method: Histadine requiring mutagenic strains of salmonella typhimurium strains TA1535, TA1537, and TA1538 and adenine and tryptophan deficient Saccharomyces cerevisiae strain D4 were exposed to TEC in dimethylsulfoxide at concentrations of 0.4, 0.8, or 1.6% ( v/ v) ( salmonella strains) and 0.425, 0.85, or 1.7% ( Saccharomyces) in the presence and absence of S9 activation, and reversion to prototrophy determined after 48 or 72 hours incubation at 37  C ( Salmonella) or 30 hours for 3  5 days ( Saccharomyces). The suspension test was performed using the Salmonella and Saccharomyces strains and the standard plate incorporation method was performed using Salmonella strains only. No precipitation or cytotoxicity was observed at any dose level in any strain in either test. GLP: No Test Substance: TEC, unknown purity Results: No significant increases in the number of revertants/ plate or mutation frequency were observed in any bacterial or yeast strain at any dose level of TEC in the presence or absence of S9 activation, compared to vehicle controls. Reference: MRID 45221217. Brusick, D. ( 1976) Mutagenic Evaluation of Triethyl Citrate: Lab Project Number: ATBC/ TEC 51147 21. Unpublished study prepared by Litton Bionetics, Inc. 44 p. Reliability: Provides sufficient information for regulatory purposes.

Species/ Strain: Mouse fibroblasts Conclusions: Time and concentration of TEC had affect on cell death and ultrastructural changes. Method: Mosue fibroblasts eight hours into anaphase in cell suspension were exposed to 7.9, 9, 12, 24, and 48 mM TEC. Cultures were studied with an inverted phase contrast microscope, chiefly with a 100X oil immersion phase contrast objective while the cultures were maintained at 35  C. Images were recorded with both a movie camera and a 35mm camera. Time lapse microphotography was conducted for 4 hours after TEC administration with exposures taken every 3.6 seconds. GLP: Unknown Test Substance: TEC, unknown purity Results: The ID 50 is 6 mM and the ID 100 is 12 mM for the 72 hour cultures. At all concentrations, the plasma membrane retracted resulting in a decreased Page 46 of 48 cellular cross sectional area within two to three minutes at the lower concentrations and seconds at the higher concentrations. Simultaneously, cytoplasmic particle movement slowed ( cytoplasmic gelation) and this effect appeared to be dose dependent. At 7.9, 9 and 12 mM TEC, mitochondrial swelling was observed, which would presumably interfere with ATP production and thereby inhibit growth. At 12, 24, and 48 mM TEC, the optical density of the nuclear membrane increased ( presumably due to precipitated proteins) within 1.5 3.5 hours ( onset dependent on dose). At 48 mM TEC, plasma membrane retraction was followed by the appearance of superficial vacuoles at two hours, and with lysis following within minutes. Immediately prior to lysis, all cellular movement ceased. At 12 and 24 mM TEC, cells also had superficial vacuoles and lysis occurred within 24 hours. Reference: MRID 45221215. Jones, A. et al. ( 2000) Mechanistic Toxicology of Triethyl Citrate in Cultured Mammalian Cells by Cinematography: Lab Project Number: ATBC/ TEC 51147 19. Unpublished study prepared by The University of Texas. 28 p. Reliability: Recently conducted, provides sufficient information for regulatory purposes.

Species/ Strain: Mouse fibroblasts Conclusion: Inconclusive Method: Mouse fibroblast cells in static tube culture were exposed to 6, 9, and 12 mM TEC for 1.5, 48, and 78 hours. The cells were then pulsed with 14Clabeled purine and pyrimidine dissolved in sterile deionized water ( 0.15

Ci/ mL). The cells were incubated for an hour before liquid scintillation and U. V. spectrophotometric analyses. GLP: Unknown Test Substance: TEC, unknown purity Results: At 1.5 hours, uridine, thymidine, and adenine were decreased significantly at all doses, except thymidine was not decreased by exposure to 6 mM TEC. At 48 hours, thymidine and adenine was decreased significantly at 9 and 12 mM TEC. At 78 hours, only adenine was decreased significantly at 12 mM TEC. Adenine uptake levels remained significantly lower than thymidine and uridine uptake at all doses and did not recover to normal values within 78 hours. Uridine uptake increased significantly over adenine and thymidine at 48 and 78 hours at 9 and 12 mM TEC. The U. V. spectrophotometric data substantiated the liquid scintillation data, indicating an overall increase in uridine content when compared to the other purines and pyrimidines. Thus, only exposure to 9 and 12 mM TEC resulted in significant effects on cellular utilization of the test precursors ( except at 1.5 hours). This study indicated that DNA content of the cell does not increase sufficiently to support mitosis at 9 and 12 mM TEC under the conditions of this study. Reference: MRID 45221216. Golaz, M. et al. ( 2000) Mechanistic Toxicology of Triethyl Citrate in Mouse Fibroblast Cells by Liquid Scintillation Techniques: Lab Project Number: ATBC/ TEC 51147 20. Unpublished study prepared by The University of Texas. 25 p. Reliability: Recently conducted, provides sufficient information for regulatory purposes. Page 47 of 48 Appendix 3 Re Evaluation of ATBC Multigeneration Reproduction Study ( MRID 45257702)

According to the Data Evaluation Record ( DER), ATBC was administered in the diet of rats to achieve nominal dose levels of 0, 100, 300 or 1000 mg/ kg body weight during the two generations of the study. The results of the Agency review and evaluation of that study ( performed in 2002) are given below:

2 generation reproductive ( rat) ( in the diet)

dose levels: ( 0, 100, 300, 1000 mg/ kg/ day) Parental NOAEL = 100 mg/ kg/ day LOAEL = 300 mg/ kg/ day, based on decreased body weights and water consumption Reproductive NOAEL is equal to or greater than 1000 mg/ kg/ day, the highest dose tested ( HDT) LOAEL not determined, but would be greater than 1000 mg/ kg/ day Offspring NOAEL = 100 mg/ kg/ day LOAEL = 300 mg/ kg/ day, based on increased pup mortality and decreased pup weights Tables 3 5 in the Agency's DER indicated statistically significant changes in body weight, food consumption and water consumption. If there are decreases in food and water consumption, it is reasonable to expect a similar effect on body weight, but in a feeding study, food consumption decreases could be related to decreased palatability of the treated diet rather than toxicity of the chemical   a possibility that should be considered in the endpoint selection process. Decreases in water consumption may be related to systemic problems caused by the test material ( e. g., increased blood volume because of fluid retention which inhibits the thirst reflex and might account for a body weight increase), but water consumption may also vary for other reasons such as a leaking water delivery system. Therefore, consistency of response, dose response, reversibility of the response, and effects on other observations in the study are important considerations.

In this case, the variations noted in these parameters were equal to or less than the coefficient of variation for these data ( standard deviation divided by the group mean times 100), and there was almost no change in response when the dose level was tripled. The only effect observed in both generations was decreased body weight and food consumption in the 1000 mg/ kg/ day males. Because this is a limit dose, the effects are minimal, and results from the subchronic feeding study at the same dose level indicated that male rats can recover from the initial decrease in body weight ( see DER for MRID 45257701) during treatment, it is reasonable to conclude that the 1000 mg/ kg dose level approaches a minimally toxic dose. This conclusion is further supported by results from the 2 year feeding study in rats summarized in the Science Assessment ( Table 2, page 3) where the NOAEL is greater than or equal to 1000 mg/ kg/ day. Therefore, it is reasonable to Page 48 of 48 conclude that the parental NOAEL is also equal to or greater than 1000 mg/ kg/ day for parental toxicity in the reproduction study.

The number of pups dying during lactation days 7 21is of questionable toxicological significance when mean litter sizes and viability indexes at days 7, 14, and 21 are not significantly different, and the pup body weights follow a similar pattern to that described above for adults. It is unreasonable to attribute the deaths to the chemical when they occur only in one of the two generations, the pups do not show other responses that would likely be associated with lethality ( e. g., clinical signs, larger decreases in body weight, etc). It is also important that other DERs where similar decreases in body weights were noted did not identify those effects as toxicologically significant.

There are two options for interpreting these results. First and most conservative would be to call the NOEL at 300 mg/ kg/ day based on the decreases in body weight for both adults and offspring. Second, be consistent with the other toxicity studies and call the NOEL at 1000 mg/ kg/ day, and for risk assessment purposes simply compare the exposure estimates to acceptable levels as defined by other organizations. Hopefully, the worst case pesticidal exposure estimates are less than exposures used in the other assessments from other sources, then we can all be on the same page.