SCREENING-LEVEL HAZARD CHARACTERIZATION OF HIGH PRODUCTION VOLUME CHEMICALS SPONSORED CHEMICAL Ethyl (3-methylphenyl)-amino acetonitrile (CAS No. 63133-74-4) [9th CI Name: Acetonitrile, [ethyl (3-methylphenyl)amino]-] March 2008 INTERIM Prepared by High Production Volume Chemicals Branch Risk Assessment Division Office of Pollution Prevention and Toxics Environmental Protection Agency 1200 Pennsylvania Avenue, NW Washington, DC 20460-0001 ------- SCREENING-LEVEL HAZARD CHARACTERIZATION OF HIGH PRODUCTION VOLUME CHEMICALS The High Production Volume (HPV) Challenge Program1 is a voluntary initiative aimed at developing and making publicly available screening-level health and environmental effects information on chemicals manufactured in or imported into the United States in quantities greater than one million pounds per year. In the Challenge Program, producers and importers of HPV chemicals voluntarily sponsor chemicals; sponsorship entails the identification and initial assessment of the adequacy of existing toxicity data/information, conducting new testing if adequate data do not exist and making both new and existing data and information available to the public. Each complete data submission contains data on 18 internationally agreed to "SIDS" (Screening Information Data Set1'2) endpoints that are screening-level indicators of potential hazards (toxicity) for humans or the environment. The Environmental Protection Agency's Office of Pollution Prevention and Toxics (OPPT) is evaluating the data submitted in the HPV Challenge Program on approximately 1400 sponsored chemicals. OPPT is using a hazard- based screening process to prioritize review of the submissions. The hazard-based screening process consists of two tiers described below briefly and in more detail on the Hazard Characterization website3. Tier 1 is a computerized sorting process whereby key elements of a submitted data set are compared to established criteria to "bin" chemicals/categories for OPPT review. This is an automated process performed on the data as submitted by the sponsor. It does not include evaluation of the quality or completeness of the data. In Tier 2, a screening-level hazard characterization is developed by EPA that consists of an objective evaluation of the quality and completeness of the data set provided in the Challenge Program submissions. The evaluation is performed according to established EPA guidance2'4 and is based primarily on hazard data provided by sponsors. EPA may also include additional or updated hazard information of which EPA, sponsors or other parties have become aware. The hazard characterization may also identify data gaps that will become the basis for a subsequent data needs assessment where deemed necessary. Under the HPV Challenge Program, chemicals that have similar chemical structures, properties and biological activities may be grouped together and their data shared across the resulting category. This approach often significantly reduces the need for conducting tests for all endpoints for all category members. As part of Tier 2, evaluation of chemical category rationale and composition and data extrapolation(s) among category members is performed in accord with established EPA2 and OECD5 guidance. The screening-level hazard characterizations that emerge from Tier 2 are important contributors to OPPT's existing chemicals review process. These hazard characterizations are technical documents intended to support subsequent decisions and actions by OPPT. Accordingly, the documents are not written with the goal of informing the general public. However, they do provide a vehicle for public access to a concise assessment of the raw technical data on HPV chemicals and provide information previously not readily available to the public. The public, including sponsors, may offer comments on the hazard characterization documents. The screening-level hazard characterizations, as the name indicates, do not evaluate the potential risks of a chemical or a chemical category, but will serve as a starting point for such reviews. In 2007, EPA received data on uses of and exposures to high-volume TSCA existing chemicals, submitted in accordance with the requirements of the Inventory Update Reporting (IUR) rule. For the chemicals in the HPV Challenge Program, EPA will review the IUR data to evaluate exposure potential. The resulting exposure information will then be combined with the screening-level hazard characterizations to develop screening-level risk characterizations4'6. The screening-level risk characterizations will inform EPA on the need for further work on individual chemicals or categories. Efforts are currently underway to consider how best to utilize these screening-level risk characterizations as part of a risk- based decision-making process on HPV chemicals which applies the results of the successful U.S. High Production Volume Challenge Program and the IUR to support judgments concerning the need, if any, for further action. 1 U.S. EPA. High Production Volume (HPV) Challenge Program; http://www.epa.gov/chemrtk/index.htm. 2 U.S. EPA. HPV Challenge Program - Information Sources; http://www.epa.gov/chemrtk/pubs/general/guidocs.htm. 3 U.S. EPA. HPV Chemicals Hazard Characterization website (http://www.epa.gov/hpvis/abouthc.html). 4 U.S. EPA. Risk Assessment Guidelines; http://cfpub.epa.gov/ncea/raf/rafguid.cfm. 5 OECD. Guidance on the Development and Use of Chemical Categories; http://www.oecd.org/dataoecd/60/47/1947509.pdf. 6 U.S. EPA. Risk Characterization Program; http://www.epa.gov/osa/spc/2riskchr.htm. 2 ------- SCREENING-LEVEL HAZARD CHARACTERIZATION Ethyl (3-methylphenyl)-amino acetonitrile (CAS No. 63133-74-4) Introduction The sponsor, Eastman Chemical Company, submitted a Test Plan and Robust Summaries to EPA for ethyl (3- methylphenyl)-amino acetonitrile (CAS No. 63133-74-4; 9th CI name: acetonitrile, [ethyl (3-methylphenyl)amino]-) on December 10, 2003. EPA posted the submission on the ChemRTK HPV Challenge website on January 13, 2004 (http://www.epa. gov/chemrtk/pubs/summaries/eth3meth/c 14884tc.htm'). EPA comments on the original submission were posted to the website on June 3, 2004. Public comments were also received and posted to the website. The sponsor submitted updated/revised documents on August 12, 2004, which were posted to the ChemRTK website on September 20, 2004. This screening-level hazard characterization is based primarily on the review of the test plan and robust summaries of studies submitted by the sponsor(s) under the HPV Challenge Program. In preparing the hazard characterization, EPA considered its own comments and public comments on the original submission as well as the sponsor's responses to comments and revisions made to the submission. A summary table of SIDS endpoint data with the structure(s) of the sponsored chemical (s) is included in the appendix. The screening-level hazard characterization for environmental and human health effects is based largely on SIDS endpoints and is described according to established EPA or OECD effect level definitions and hazard assessment practices. The sponsor proposed reduced health testing, claiming that ethyl (3-methylphenyl)-amino acetonitrile is a closed- system intermediate (CSI). EPA's evaluation of the original and revised/updated information indicated that the chemical failed to meet some of the criteria to fully support the CSI status for this chemical. In its revised/updated submission the sponsor provided additional information that supported the CSI claim. Therefore, EPA has determined that the chemical qualifies for reduced testing - waiving of repeated-dose and reproductive toxicity testing. Summary-Conclusion The log Kow of ethyl (3-methvlphenvl)-amino acclonilrilc indicates that its potential to bioaccumulalc is expected to be low. Ethyl (3-mclhvlphcnvl)-amino acclonilrilc is not readily biodegradable, indicating thai it has the potential to persist in the environment. The evaluation of available toxicity data indicate thai the potential acute hazard of ethyl (3-mclhylphcnvl)-amino acetonitrile to fish and aquatic invertebrates is low and to aquatic plants is moderate. Acute oral toxicity of ethyl (3-mclhylphcnvl)-amino acetonitrile to rats and mice is moderate and acute dermal toxicity to guinea pigs is low. In a combined reproductive/developmental toxicity study, oral administration of ethyl (3-mclhylphcnyl)-aniino acclonilrilc to rats resulted in decreased body weight and testes weight and clinical signs of toxicity (convulsions, tremors, reduced activity, vasodilation, wet fur. rapid respiration and/or decreased fecal volume) in mid- and high-dose males. Females showed wet fur and vasodilation at the high dose. No adverse effects were seen on reproductive or developmental parameters. Ethyl (3-mclhylphcnvl)-amino acetonitrile did not induce gene mutations or chromosomal aberrations. The potential health hazard of ethyl (3-mcthylphcnyl)-amino acclonilrilc is low. No data gaps were identified under the HPV Challenge Program. 3 ------- 1. Physical-Chemical Properties and Environmental Fate A summary of physical-chemical and environmental fate data submitted is provided in the Appendix. For the purpose of the screening-level hazard characterization, the review and summary of these data were limited to the octanol-water partition coefficient and biodegradation endpoints as indicators of bioaccumulation and persistence, respectively. Octanol-Water Partition Coefficient Log Kow: 2.73 (estimated) Biodegradation In a Modified Sturm test using activated sludge as inoculum, 9 - 13% of ethyl (3-methylphenyl)-amino acetonitrile had degraded after 28 days. Ethyl (3-methylphenyl)-amino acetonitrile is not readily biodegradable. Conclusion: The log Kow of ethyl (3-methylphenyl)-amino acetonitrile indicates that its potential to bioaccumulate is expected to be low. Ethyl (3-methylphenyl)-amino acetonitrile is not readily biodegradable, indicating that it has the potential to persist in the environment. 2. Environmental Effects - Aquatic Toxicity Acute Toxicity to Fish Fathead minnows (Pimephales promelas) were exposed to ethyl (3-methylphenyl)-amino acetonitrile at nominal concentrations of 0, 10, 15, 22.5, 33.8 or 50.6 mg/L under semi-static conditions for 96 hours. The measured concentrations were 0, 9.1, 14, 21.5, 35.6 or 58.8 mg/L, respectively. At 21.5 mg/L, all fish showed depressed activity after 4 hours of exposure. All fish exposed to the two highest doses died after 4 hours of exposure. None of the control fish or fish exposed to 9.1 or 14 mg/L died or demonstrated abnormal behavior during the study. 96-h LCS0 = 27.7 mg/L Acute Toxicity to Aquatic Invertebrates Daphnia magna were exposed to ethyl (3-methylphenyl)-amino acetonitrile at nominal concentrations of 0, 10, 15, 22.5, 33.8 or 50.6 mg/L under semi-static conditions for 48 hours. The analytically determined concentrations were 0, 9.1, 14, 21.7, 34.1 or 51.6 mg/L, respectively. At 21.7, 34.1 and 51.6 mg/L, 10, 30 and 70% immobilization was noted at 48 hours, respectively. None of the daphnia exposed to the control, 9.1 or 14 mg/L were affected during the study. 48-h ECso=40.0 mg/L Toxicity to Aquatic Plants Green algae (Pseudokirchneriella subcapitata) were exposed to ethyl (3-methylphenyl)-amino acetonitrile at nominal concentrations of 0, 0.625, 1.25, 2.5, 5.0 or 10.0 mg/L for 72 hours. The measured concentrations were 0, 0.37, 0.68, 1.37, 3.16 or 6.51 mg/L, respectively. Exposure to 0.37 and 0.68 mg/L had no significant effect on the biomass or growth rate at any point during the study. At > 1.37 mg/L, a concentration- and time-dependant reduction in biomass and inhibition of growth rate were seen. 72-h EC50 (biomass) = 1.40 mg/L 72-h EC50 (growth) = 2.88 mg/L Conclusion: The evaluation of available toxicity data indicates that the potential hazard of ethyl (3-methylphenyl)- amino acetonitrile to fish and aquatic invertebrates is low and to aquatic plants is moderate. 4 ------- 3. Human Health Effects Acute Oral Toxicity (1) Eight rats (sex and strain not specified) were administered ethyl (3-methylphenyl)-amino acetonitrile in corn oil via gavage at 100 - 800 mg/kg-bw and were observed for 14 days. Mortality occurred from 3 hours to 1 day after dosing. Clinical signs of toxicity included weakness, vasodilation, sides caved in and ataxia. No significant findings were noted at necropsy. LDS0 = 200 - 400 mg/kg-bw (2) Ten mice (sex and strain not specified) were administered undiluted ethyl (3-methylphenyl)-amino acetonitrile via gavage at 50 - 800 mg/kg-bw and observed for 14 days. Mortality occurred within 1 day of treatment. Clinical signs of toxicity included weakness, vasodilation, rolling, convulsions when handled, tremor and rough coat. LDS0 = 400 - 800 mg/kg-bw Acute Dermal Toxicity Three guinea pigs (sex and strain not specified) were administered undiluted ethyl (3-methylphenyl)-amino acetonitrile dermally at 5 - 20 mL/kg-bw (approximately 4910 - 19,640 mg/kg-bw) under occluded conditions for an unspecified period and observed for 14 days. No animals died. Slight erythema and edema were observed and cleared by 1 week. LDS0 > ~ 19,640 mg/kg-bw Repeated-Dose Toxicity Data for this endpoint is not required because this chemical is a closed-system intermediate. Reproductive/Developmental Toxicity In a combined reproductive/developmental toxicity study, Sprague-Dawley rats (12/sex/dose) were administered ethyl (3-methylphenyl)-amino acetonitrile via gavage at 0, 25, 75 or 150 mg/kg-bw/day for 14 days prior to mating, throughout mating, gestation and early lactation. Mean body weight and body weight gains were decreased in mid- and high-dose males. At the high dose, clinical signs included reduced activity, vasodilation, rapid respiration, wet fur, transient convulsions and tremors in parental males and fur wet with saliva and vasodilation in parental females. Transient vasodilation was observed in all males and one female at the mid-dose. Absolute testes weights were lower in high-dose males. No treatment-related changes in sperm motility, epididymal spermatozoa counts or testicular spermatid counts were observed. There were no effects on histopathology of reproductive organs, sperm morphology, motility and counts, reproductive performance, fertility index, fecundity index, precoital interval, gestation duration, numbers of implants, number of corpora lutea, pre- and post-implantation loss, pup survival, number of live and dead pups, pup sex ratio and pup body weight. LOAEL (systemic toxicity) = 75 mg/kg-bw/day (based on decreased body weight and clinical signs in males) NOAEL (systemic toxicity) = 25 mg/kg-bw/day NOAEL (maternal toxicity) = 150 mg/kg-bw/day (based on no effects at the highest dose tested) NOAEL (reproductive/developmental toxicity) = 150 mg/kg-bw/day (based on no effects at the highest dose tested) Genetic Toxicity - Gene Mutation In vitro Salmonella typhimurium strains TA98, TA100, TA1535 and TA1537 were exposed to ethyl (3-methylphenyl)- amino acetonitrile at concentrations of 1 - 1000 |.ig/platc without metabolic activation and 3.33 - 5000 |.ig/platc with metabolic activation. Escherichia coli WP2 uvrA(pKM101) were exposed to concentrations of 10 - 5000 |.ig/platc with and without metabolic activation. Positive controls were tested concurrently, but the control responses were not provided. The cytotoxic concentration was 333 |.ig/platc for Salmonella with and without metabolic activation and 1000 |.ig/platc for E. coli with metabolic activation and 3330 |.ig/platc for E. coli without metabolic activation. In one assay, no increases in the number of revertants were observed for any strain with or without metabolic 5 ------- activation. In a second assay, a 3-fold increase was observed in Salmonella strain TA1537 without metabolic activation, but the increase was not concentration-dependent and was within the range of historical controls. A confirmatory assay conducted with only TA1537 without metabolic activation showed no increase in the mean number of revertants. Ethyl (3-methylphenyl)-amino acetonitrile was not mutagenic in these assays. Genetic Toxicity - Chromosomal Aberrations In vitro Chinese hamster ovary (CHO) cells were exposed to ethyl (3-methylphenyl)-amino acetonitrile at concentrations up to 600 (ig/mL in the presence and absence of metabolic activation for 3 hours in one assay and 19.8 hours in a second assay. Positive controls were tested concurrently and responded appropriately. The cytotoxic concentration was between 300 and 400 (ig/mL and precipitation of the test substance was noted at concentrations > 420 (ig/mL. Ethyl (3-methylphenyl)-amino acetonitrile did not induce chromosomal aberrations in these assays. Conclusion: Acute oral toxicity of ethyl (3-methylphenyl)-amino acetonitrile to rats and mice is moderate and acute dermal toxicity to guinea pigs is low. In a combined reproductive/developmental toxicity study, oral administration of ethyl (3-methylphenyl)-amino acetonitrile to rats resulted in decreased body weight and testes weight and clinical signs of toxicity (convulsions, tremors, reduced activity, vasodilation, wet fur, rapid respiration and/or decreased fecal volume) in mid- and high-dose males. Females showed wet fur and vasodilation at the high dose. No adverse effects were seen on reproductive or developmental parameters. Ethyl (3-methylphenyl)-amino acetonitrile did not induce gene mutations or chromosomal aberrations. The potential health hazard of ethyl (3-methylphenyl)-amino acetonitrile is low. 4. Hazard Characterization The log Kow of ethyl (3-methylphenyl)-amino acetonitrile indicates that its potential to bioaccumulate is expected to be low. Ethyl (3-methylphenyl)-amino acetonitrile is not readily biodegradable, indicating that it is expected to persist in the environment. The evaluation of available toxicity data indicate that the potential acute hazard of ethyl (3-methylphenyl)-amino acetonitrile to fish and aquatic invertebrates is low and to aquatic plants is moderate. Acute oral toxicity of ethyl (3-methylphenyl)-amino acetonitrile to rats and mice is moderate and acute dermal toxicity to guinea pigs is low. In a combined reproductive/developmental toxicity study, oral administration of ethyl (3-methylphenyl)-amino acetonitrile to rats resulted in decreased body weight and testes weight and clinical signs of toxicity (convulsions, tremors, reduced activity, vasodilation, wet fur, rapid respiration and/or decreased fecal volume) in mid- and high-dose males. Females showed wet fur and vasodilation at the high dose. No adverse effects were seen on reproductive or developmental parameters. Ethyl (3-methylphenyl)-amino acetonitrile did not induce gene mutations or chromosomal aberrations. The potential health hazard of ethyl (3-methylphenyl)-amino acetonitrile is low. 5. Data Gaps No data gaps were identified under the HPV Challenge Program. 6 ------- APPENDIX Summary Tabic of the Screening Information Data Set as Submitted under the U.S. HPV Challenge Program Endpoints SPONSORED CHEMICAL Ethyl (3-mcthylphcnyl)-amino acctonitrilc (63133-74-4) Structure PT Summary of Physical-Chemical Properties and Environmental Fate Data Melting Point (°C) <0 Boiling Point (°C) >250 Vapor Pressure (hPa at 25°C) 0.027 Log K„w 2.73 Water Solubility (mg/L at 25°C) 252 Direct Photodegradation - Indirect (OH) Photodegradation Half-life (t1/2) 0.6 h Stability in Water (Hydrolysis) (ti/2) Stable to hydrolysis Fugacity (Level III Model) Air (%) Water (%) Soil (%) Sediment (%) 0.08 31.4 68.2 0.33 Biodegradation at 28 days (%) 9-13 Not readily biodegradable Summary of Environmental Effects - Aquatic Toxicity Data Fish 96-h LCS0 (mg/L) 27.7 Aquatic Invertebrates 48-h ECS0 (mg/L) 40 Aquatic Plants 72-h ECS0 (mg/L) (growth) (biomass) 2.88 1.40 Summary of Human Health Data Acute Oral Toxicity LDS0 (mg/kg-bw) 200 - 400 (rat) 400 - 800 (mice) Acute Dermal Toxicity LDS0 (mg/kg-bw) > ~ 19,640 7 ------- Summary Tabic of the Screening Information Data Set as Submitted under the U.S. HPV Challenge Program Endpoints SPONSORED CHEMICAL Ethyl (3-mcthylphcnyl)-amino acetonitrile (63133-74-4) Repeated-Dose Toxicity NOAEL/LOAEL Oral (mg/kg-bw/day) Data not required based on CSI. Reproductive/Developmental Toxicity NOAEL/LOAEL Oral (mg/kg-bw/day) Systemic Toxicity (male) Reproductive/Maternal/Developmental Toxicity NOAEL = 25 I.OAF.I. = 75 NO A F.I. = 150 Genetic Toxicity - Gene Mutation In vitro Negative Genetic Toxicity - Chromosomal Aberrations In vitro Negative - indicates that endpoint was not addressed for this chemical. 8 ------- |