U.S. Environmental Protection Agency Hazard Characterization Document September, 2014 SCREENING-LEVEL HAZARD CHARACTERIZATION Acetophenone (CASRN 98-86-2) The High Production Volume (HPV) Challenge Program1 was conceived as 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 sponsored chemicals; sponsorship entailed the identification and initial assessment of the adequacy of existing toxicity data/information, conducting new testing if adequate data did 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 Setl1'2) 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 by developing hazard characterizations (HCs). These HCs consist of an evaluation of the quality and completeness of the data set provided in the Challenge Program submissions. They are not intended to be definitive statements regarding the possibility of unreasonable risk of injury to health or the environment. The evaluation is performed according to established EPA guidance2'3 and is based primarily on hazard data provided by sponsors; however, 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. In order to determine whether any new hazard information was developed since the time of the HPV submission, a search of the following databases was made from one year prior to the date of the HPV Challenge submission to the present: (ChemID to locate available data sources including Medline/PubMed, Toxline, HSDB, IRIS, NTP, AT SDR, IARC, EXTOXNET, EPA SRS, etc.), STN/CAS online databases (Registry file for locators, ChemAbs for toxicology data, RTECS, Merck, etc.), Science Direct and ECHA4. OPPT's focus on these specific sources is based on their being of high quality, highly relevant to hazard characterization, and publicly available. OPPT does not develop HCs for those HPV chemicals which have already been assessed internationally through the HPV program of the Organization for Economic Cooperation and Development (OECD) and for which Screening Initial Data Set (SIDS) Initial Assessment Reports (SIAR) and SIDS Initial Assessment Profiles (SIAP) are available. These documents are presented in an international forum that involves review and endorsement by governmental 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. Risk Assessment Guidelines; http://cfpub.epa.gov/ncea/raf/rafguid.cfm. 4 European Chemicals Agency, http://echa.europa.eu. ------- U.S. Environmental Protection Agency Hazard Characterization Document September, 2014 authorities around the world. OPPT is an active participant in these meetings and accepts these documents as reliable screening-level hazard assessments. These hazard characterizations are technical documents intended to inform 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 ofthe raw technical data on HPV chemicals and provide information previously not readily available to the public. 2 ------- U.S. Environmental Protection Agency Hazard Characterization Document September, 2014 Chemical Abstract Service Registry Number (CASRN) 98-86-2 Chemical Abstract Index Name Ethanone, 1-phenyl- O Structural Formula ^ // CH= SMILES: Q=C(c(cccc 1 )c 1 )C Summary Acetophenone is a liquid with moderate vapor pressure and high water solubility. It is expected to have high mobility in soil. Volatilization is moderate given the Henry's Law constant. The rate of hydrolysis is negligible. The rate of atmospheric photooxidation is slow. Acetophenone is readily biodegradable. Acetophenone is expected to have low persistence (PI) and low bioaccumulation potential (Bl). Acetophenone has low acute oral and inhalation toxicity in rats. The acute dermal toxicity of acetophenone in guinea pigs is low. In an oral gavage combined repeated-dose/reproductive/ developmental toxicity screening test in rats, increased relative liver weight that appeared to correlate with dose-related increases in total protein, albumin and globulin was noted in females and males, increased wobbly gait in females and males and reduced forelimb grip strength and motor activity in males were observed at 750 mg/kg-day; the NOAEL for systemic toxicity is 225 mg/kg-day. In the same study, decreases in mean body weight gain and food consumption were observed in dams at 750 mg/kg-day, the NOAEL for maternal toxicity is 225 mg/kg-day. An increase in the number of stillbirths, reduced pup survival and lower body weights were observed at 750 mg/kg-day; the NOAEL for reproductive and developmental toxicity is 225 mg/kg-day. In a 17-week dietary study, no effects were observed in rats exposed to doses up to 423 mg/kg-bw/day (highest dose tested). Acetophenone did not induce gene mutations in bacteria in vitro. Acetophenone induced chromosomal aberrations in Chinese Hamster Ovary (CHO) cells in vitro, but did not induce micronuclei formation in mouse peripheral blood erythrocytes in vivo. Acetophenone is irritating to rabbit skin and eyes and guinea pig skin. Acetophenone is not a skin sensitizer in guinea pigs. The 96-h LCso value of acetophenone for fish is 162 mg/L. The 48-h LCso value of acetophenone for aquatic invertebrates is 528 mg/L. The 72-h EC so value of acetophenone for aquatic plants is 40 mg/L and 86.4 mg/L for biomass and growth rate, respectively. No data gaps were identified for the purposes of the HPV Challenge Program. 3 ------- U.S. Environmental Protection Agency Hazard Characterization Document September, 2014 The sponsor, Acetophenone Task Force (ATF), submitted a Test Plan and Robust Summaries to EPA for acetophenone (CASRN 98-86-2; CA Index name: Ethanone, 1-phenyl-) on May 3, 2010. The ATF is comprised of Aceto Corporation and Blue Island Phenol LLC (change in membership from JLM Chemicals, Inc.) and transferred sponsorship from the Organisation of Economic Cooperation and Development (OECD) Screening Information Data Set (SIDS) program to the HPV Challenge Program. EPA has not posted the submission on the ChemRTK HPV Challenge website. 1. Chemical Identity 1.1 Identification and Purity In the robust summaries, the test substance is identified as 98.8% pure, where indicated. 1.2 Physical-Chemical Properties The physical-chemical properties of acetophenone are summarized in Table 1. Table 1. Physical-Chemical Properties of Acetophenone1 Property Value CASRN 98-86-2 Molecular Weight 120.15 Physical State Liquid that forms laminar crystals at low temperature Melting Point 20.5°C (measured) Boiling Point 202°C (measured) Vapor Pressure 0.397 mm Hg at 25°C (measured) Dissociation Constant (pKa) Not applicable Henry's Law Constant 1.04xl0"5 atm-m3/mole (measured) Water Solubility 6,130 mg/L at 25°C (measured) Log Kow 1.58 (measured) 1 HSDB. 2012. Hazardous Substance Databank. National Library of Medicine. Available online at http://toxnet.nlm.nih. gov/cgi-bin/sis/htmlgen?HSDB as of March 9, 2012. 2. General Information on Exposure 2.1 Production Volume and Use Pattern Acetophenone had an aggregated production and/or import volume in the United States between 500,000 to 1 million pounds during calendar year 2005. Non-confidential information in the IUR indicated that the industrial processing and uses of the chemical include all other chemical product and preparation manufacturing as intermediates; photosensitive chemicals, flame retardants and solvents (which become part of product formulation or mixture); and support activities for mining as functional fluids. Non-confidential 4 ------- U.S. Environmental Protection Agency Hazard Characterization Document September, 2014 commercial and consumer uses of this chemical include adhesives and sealants; fabrics, textiles and apparel; paints and coatings; and "other." 2.2 Environmental Exposure and Fate Acetophenone is expected to have high mobility in soil. It achieved 61- 68% of its theoretical biochemical oxygen demand (BOD) after 14 days using an activated sludge inoculum and the MITI (OECD 301C) test. Acetophenone had a reported half-life of 32, 8, and 4.5 days in groundwater, river water, and lake water, respectively. Volatilization is expected to be moderate given the Henry's Law constant for this substance. The rate of hydrolysis is negligible. The rate of atmospheric photooxidation is slow. Acetophenone is expected to have low persistence (PI) and low bioaccumulation potential (Bl). The environmental fate properties of acetophenone are summarized in Table 2. Table 2. Environmental Fate Properties of Acetophenone1 Property Value CASRN 98-86-2 Photodegradation Half-life 5.7 days (estimated)2 Hydrolysis Half-life Stable Biodegradation 61-68% in 14 days (readily biodegradable); Half-life of 32 days (groundwater); Half-life of 8 days (river water); Half-life of 4.5 days (lake water) Bioaccumulation Factor BAF = 3.9 (estimated)2 Log Koc 1.0-2.34 (measured in several soils and sediment); 1.0 (estimated)2 Fugacity (Level III Model)2 Air (%) 4.6 Water (%) 29.6 Soil (%) 65.7 Sediment (%) 0.1 Persistence3 PI (low) Bioaccumulation3 Bl (low) 1HSDB. 2012. Hazardous Substance Databank. National Library of Medicine. Available online at http://toxnet.nlm.nih.gov/cgi-bin/sis/htmlgen7HSDB as of March 9, 2012. 2U.S. EPA. 2012. Estimation Programs Interface Suite™ for Microsoft® Windows, v4.10. U.S. Environmental Protection Agency, Washington, DC, USA. Available online at http://www.epa.gov/opptintr/exposure/pubs/episuitedl.htm as of March 8, 2012. 3Federal Register. 1999. Category for Persistent, Bioaccumulative, and Toxic New Chemical Substances. Federal Register 64, Number 213 (November 4, 1999) pp. 60194-60204. Conclusion: Acetophenone is a liquid with moderate vapor pressure and high water solubility. It is expected to have high mobility in soil. Volatilization is moderate given the Henry's Law constant. The rate of hydrolysis is negligible. The rate of atmospheric photooxidation is slow. Acetophenone is readily biodegradable. Acetophenone is expected to have low persistence (PI) and low bioaccumulation potential (Bl). 5 ------- U.S. Environmental Protection Agency Hazard Characterization Document September, 2014 3. Human Health Hazard A summary of the health effects data submitted for SIDS endpoints is provided in Table 3. Acute Oral Toxicity (1) Osborne-Mendel rats (5/sex/dose) were administered acetophenone (purity not stated, undiluted) via oral gavage at unspecified dose levels and observed for up to 14 days. Deaths occurred between 1 hour to 4 days after exposure. No information on mortalities per dose group was provided. The LD50 was calculated using the Litchfield and Wilcoxon method. The confidence limits of the calculated LD50 are 2460-4160 mg/kg (Information on times of death was obtained from: Jenner P.M., 1964, FdCosmet. Toxicol., (2):327-343). LD50 = 3200 mg/kg (2) Wistar rats (6 males/dose) were administered acetophenone (purity not stated) via gavage at unspecified dose levels that differed by a factor of 10 and observed for up to 14 days. This procedure was applied with additional animals until 2 doses differing by a multiple of 10 produced deaths in some and none of the animals. No information on mortalities per dose group was provided. LD50(estimated)= 3000 mg/kg (3) Sherman rats (6 males/dose) were administered acetophenone (purity not stated) via gavage at unspecified dose levels that differed by a factor of 10 and observed for up to 14 days. This procedure was applied with additional animals until 2 doses differing by a multiple of 10 produced deaths in some and none of the animals. No information on mortalities per dose group was provided. LD50(estimated)= 900 mg/kg Acute Inhalation Toxicity Albino rats (6 males/dose, 24 total) were exposed to a flowing stream of air saturated with acetophenone (purity not stated) at a maximum concentration of 430 ppm (equivalent to 2130 mg/m3 or 2.13 mg/L) for various periods of times up to 8 hrs. The procedure was repeated until an exposure time was found that killed all six rats and another that killed none of the rats within 2 weeks after exposure. None of the animals died after 8 hours of exposure. 8-hr LDso > 2.130 mg/L (saturated vapor concentration) Acute Dermal Toxicity Guinea pigs (6/dose, sex not stated) were administered acetophenone (purity not stated) via the dermal route at unspecified doses that differed by a factor of 10. Doses were placed on absorbent cotton that was in contact with the clipped abdomen of the animal for 4 days. The 6 ------- U.S. Environmental Protection Agency Hazard Characterization Document September, 2014 animals were observed for 10 days after dosing. The number of deaths at each dose was not reported. LD50 > 20,600 mg/kg Repeated-Dose Toxicity (1) In a combined repeated-dose/reproductive/developmental toxicity screening test, Sprague- Dawley rats (10 males, 5 females/dose) were administered acetophenone (purity 98.8%) in corn oil via gavage at concentrations of 0, 75, 225 or 750 mg/kg-day from at least 14 days before mating and continuing up to lactation day 3. Measured endpoints included survival, detailed clinical observation (once/week and at termination), and neurobehavioral examination including a full functional observational battery (FOB), measurements in body weight, body weight change, food consumption, hematology, clinical chemistry, organ weights and histopathology on all major organs as well as accessory genital organs and selected tissues. Blood samples were collected from the orbital plexus and vena cava of 5/sex/dose for hematological and coagulation parameters. No mortalities were observed. No treatment-related effects were observed on hematology, gross pathology or histopathology. Notable clinical signs included post-dose wobbly gait at the highest dose, as well as post-dose salivation in the mid-dose group. Forelimb grip strength and motor activity were significantly reduced in males of the high-dose group. On days 0-3 in the highest dose group, lower level of food consumption was observed in both males and females, as well as reduced body weight gain in males; however, these effects were not considered treatment-related. A significant increase in cholesterol levels was observed in both males and females of the high-dose group. These changes in clinical chemistry parameters were indicated to be within the historical control data. Significant increases in relative liver weight were observed in males and females of the high-dose group and females at 225 mg/kg-day; a significant increase in absolute liver weight was observed in high-dose females. A dose-related increase in liver weight appeared to correlate with the dose-related increase in total protein, albumin and globulin, which remained within historical control levels. A significant decrease in absolute heart and a significant increase in relative kidney weight were observed in high-dose males and females, respectively. In males of all dose groups, minimal to mild hyaline droplet formation was observed in the kidney; however, this finding was not dose-related.4 LOAEL = 750 mg/kg-day (based on increased relative liver weight in both sexes and FOB parameters (increased wobbly gait in both sexes, decreased forelimb grip strength and motor activity in males) NOAEL = 225 mg/kg-day (2) Osborne-Mendel rats (10/dose/sex) were exposed to 0, 1000, 2500 and 10,000 ppm acetophenone in the diet for 17 weeks. Body weights, food consumption and clinical signs were recorded weekly. At the end of the feeding period, hematological measurements and gross necropsy were performed in animals from all doses. Histopathological examination was 1 Nephropathy seen in male rats may be occurring by an alpha 2u-globulin-mediated mechanism (which is male rat- specific and not considered relevant to humans). EPA's Risk Assessment Forum has outlined key events and data that are necessary to demonstrate this mode of action (Alpha 2u-Globulin: Association with Chemically Induced Renal Toxicity and Neoplasia in the Rat, EPA/625/3-91/019F). In the absence of these data, observed effects are considered adverse. 7 ------- U.S. Environmental Protection Agency Hazard Characterization Document September, 2014 conducted in 6-8 animals from the high-dose group. No toxic effects were observed at any dose. No effects on growth, hematological values or macroscopic tissue changes were observed. Histopathological examination of the 10,000 ppm group revealed no effects. Some loss of the compound from the feed due to volatization was reported; therefore, the dietary concentration of 10,000 ppm was multiplied by a factor of 0.845 (based on data provided by the investigators) yielding a NOAEL of 8450 ppm or 423 mg/kg bodyweight-day assuming that a rat consumes a daily amount of food equivalent to 5% of its body weight/day as food. (Additional details and calculations were obtained from the U.S. EPA Integrated Risk Information System's (IRIS) Toxicological Review for Acetophenone) NOAEL = 423 mg/kg body weight-day (highest dose tested) Reproductive Toxicity In the combined repeated-dose/reproductive/developmental toxicity screening test described previously, Sprague-Dawley rats (10/sex/dose; additional 10 females for reproductive portion of study) were administered acetophenone at doses of 0 (2.0 mL/kg corn oil), 75, 225 or 750 mg/kg-day in corn oil via oral gavage from at least 14 days before mating, during mating, and contined up to lactation day (LD) 3. Dams were sacrificed on LD4, with complete necropsies performed as well as accessory genital organs and selected tissues. Females with confirmed copulation that failed to deliver were sacrificed 25 days post-copulation. Females with no evidence of mating were sacrificed 25 days after completion of the mating period. Dams that lost entire litters were sacrificed on the day that no surviving pups remained. Individual body weights were recorded on days 0, 3, 7, and 12 prior to mating and on gestation days (GDs) 0, 7, 14, and 20 and lactation days 1 and 4. Females with no evidence of mating were weighed twice weekly until sacrifice. For all sacrificed females, the number of corpora lutea per ovary was recorded, as well as the number of implantation sites. No mortalities were observed among maternal females. However, 3 females in the control group were euthanized on post breeding day-25 and 6 females at the high-dose group were euthanized on LDs 1-4 due to total litter loss. All other females survived to study termination on LD 4. All high-dose females exhibited post- dose salivation and wobbly gait. The mean body weight change of females treated with 750 mg/kg-day was lower than controls on gestation days GDs 0-7; the absolute weight of these females was 6% lower than controls on GD 7. The mean body weight change of females treated with 750 mg/kg-day was one-third lower than controls on LDs 1-4. Mean food consumption of females in the mid- and high-dose groups was significantly lower than controls during the pre- mating period days 0-3 (9 vs. 16 g/kg/day). No significant treatment-related effects were observed on mating index, fertility index or mean gestation length. No remarkable findings were noted at necropsy or histopathology. An increase of stillborn pups was observed at the high-dose group (7/10, compared to 2/10 in the control group). LOAEL (reproductive toxicity) = 750 mg/kg-day (based on increased incidence of stillbirths, total litter loss) NOAEL (reproductive toxicity) = 225 mg/kg-day 8 ------- U.S. Environmental Protection Agency Hazard Characterization Document September, 2014 Developmental Toxicity In the combined repeated-dose/reproductive/developmental screening test previously described, dams and pups from all dose groups were sacrificed on LD4, with complete necropsies performed on both. Dams that lost entire litters were sacrificed on the day that no surviving pups remained. Pups were examined for viability, sex and body weight (recorded on LDs 1 and 4). Pups that were stillborn or died were examined for evidence of developmental anomalies, while internal gross lesions were retained for possible future evaluation. All surviving pups from all dose groups were examined macroscopically for abnormalities, with special attention to organs of the reproductive system. No treatment effect on sex ratio of pups was observed. Seventy-nine pups in the highest dose group either died or were likely cannibalized during LDs 1-4. Comparable values for other dose groups were 6, 5, and 8 at doses of 0, 75 and 225 mg/kg-day, respectively. Pup survival was attenuated in the highest dose group compared to controls: the number of pups surviving to LD 4 was 99, 131, 137 and 25 at 0, 75, 225 and 750 mg/kg-day, respectively. The viability index for these same treatment groups was 94.3, 96.3, 94.5 and 22.9%, respectively. Six litters with live born pups from high-dose dams had total litter loss by LD4. Pups in the highest treatment group had significantly lower body weights than controls on LDs 1 (5 vs. 6.3 g) and 4 (5.4 vs. 8.7 g). Other gross necropsy findings for the high-dose pups that were stillborn include cleft palate, distended ureter, milk not present in stomach, incomplete dermal development and lung collapse. Auto cell destruction was observed in 22 pups in the high-dose group that died during lactation. Findings in pups that survived to termination included scabbing and peeling skin in the mid- and high-dose groups, as well as distended ureter in the high-dose group. LOAEL (maternal toxicity) = 750 mg/kg-day (based on decreased mean body weight gain and food consumption and on FOB parameters (increased wobbly gait)) NOAEL (maternal toxicity) = 225 mg/kg-day LOAEL (developmental toxicity) = 750 mg/kg-day (based on reduced pup survival and lower body weights) NOAEL (developmental toxicity) = 225 mg/kg-day Genetic Toxicity — Gene Mutations In vitro In an Ames test, Salmonella typhimurium strains TA98, TA100 and TA1537 were exposed to acetophenone (purity unknown) in DMSO at concentrations up to 3000 |ig/plate in the presence and absence of metabolic activation. Both negative and positive controls were used, but positive controls were not run for all test conditions. No information was provided regarding the results of the positive control or the cytotoxic concentration. No evidence of mutagenicity was noted in any of the strains. Acetophenone was not mutagenic is these assays. 9 ------- U.S. Environmental Protection Agency Hazard Characterization Document September, 2014 Genetic Toxicity - Chromosomal Aberrations In vitro Chinese hamster ovary (CHO) cells were exposed to acetophenone (purity unknown) in DMSO at concentrations of 0, 0.6, 0.8 or 1.0 |ig/plate with metabolic activation and at concentrations of 0, 0.8, 1.0 and 1.2 |ig/plate without metabolic activation. No increase in frequency of aberrant cells was noted in testing conducted without activation. With activation, incubation at 0, 0.6, 0.8 and 1.0 |ig/plate resulted in aberration frequencies of 2.0, 7.0, 17.0 and 16.0, respectively. No information was provided on use or outcome of positive controls. Negative controls responded appropriately. Acetophenone induced chromosomal aberrations in this assay. In vivo In a micronucleus assay, NMRI mice (5/sex/dose) were administered CASRN 98-86-2 (99.36% purity) in cotton seed oil as a single 10 mL/kg intraperitoneal injection at dosages of 103, 257.5 or 515 mg/kg. Micronuclei of peripheral blood erythrocytes were examined at 44 and 68 hours post-treatment. Positive and negative controls responded appropriately. This study was obtained from European Chemicals Agency, http://echa.europa.eu (Exp Key Genetic toxicity in vivo.001, http://apps.echa.europa.eu/registered/data/dossiers/DISS-9d9cad6b-e2e7-6c45-e044- 00144f67d249/AGGR-d85241f9-39cb-4d89-86af-3f36242c8013 DISS-9d9cad6b-e2e7-6c45- e044-00144f67d249.html#AGGR-d85241f9-39cb-4d89-86af-3f36242c8013Y Acetophenone did not induce micronuclei in this assay. Additional Information Skin Irritation (1) Six rabbits (strain and sex not specified) were exposed to 0.5 mL of acetophenone (purity not specified) via the dermal route under occlusive conditions on intact and abraded skin for 24 hours. Observations for irritation were made over 72 hours and were scored according to the Draize method. At the end of the 24-hour exposure period, slight edema and erythema was observed. All reactions had normalized within 48 hours after termination of application. The primary dermal irritation index was 0.63 (combined assessment for intact and abraded skin). Acetophenone was mildly irritating to rabbit skin in this study. (2) In a primary irritation test for the dermal sensitization study described below, Hartley Albino guinea pigs of the same sex (4 total, sex not stated) were injected intradermally on the shaved flanks with 0.1 mL aliquots of acetophenone (purity not stated) in solvent (solvent not stated) at various concentrations. The shaved flanks were examined for erythema, edema and reaction size 24 hrs after application. The 0.25% acetophenone solution produced slight but perceptible irritation with no edema. Acetophenone was mildly irritating to guinea pig skin in this study. 10 ------- U.S. Environmental Protection Agency Hazard Characterization Document September, 2014 Eye Irritation Albino rabbits (number, strain and sex not specified; study indicates that usual number of animals was 5) were given an ocular administration of 0.005 mL of either 5 or 15% solution of acetophenone in either water or propylene glycol. Irritation was scored at 18-24 hours post- application. A score of 5 represented severe irritation, corresponding to necrosis visible after staining covering three fourths of the cornea's surface or a more severe necrosis in a smaller area. The 15% solution received a score of > 5; the 5% solution received a score of < 5. Based on these scores, the assigned injury grade is 8 out of 10. Additional details obtained from original study (Carpenter, P.C. and Smyth H.F., 1946, Am J Ophthalmol. Nov; 29(11): 1363- 1372). Acetophenone was irritating to rabbit eyes in this study. Dermal Sensitization In a modified Draize test, 10 Hartley guinea pigs (4 males and 6 females, or vice versa) were provided induction treatment of 0.1 mL aliquots of acetophenone (purity not specified) at a dose of 0.625%) administered as intradermal injections at 4 sites over the auxiliary and inguinal lymph nodes. The induction dose was selected based on findings of slight and perceptible irritation with no edema on a primary irritation test. After a 14-day induction time, a challenge treatment was provided, consisting of an intradermal injection in one flank (0.1 mL of a 0.25% solution) and uncovered topical application (0.1 mL of a 20% solution) on the other flank. Reactions were scored at 24 hours post-injection. No sensitization reaction was observed. The test was repeated including confirmatory challenge with controls. Acetophenone was not a skin sensitizer in guinea pigs in this assay. Conclusion: Acetophenone has low acute oral and inhalation toxicity in rats. The acute dermal toxicity of acetophenone in guinea pigs is low. In an oral gavage combined repeated- dose/reproductive/ developmental toxicity screening test in rats, increased relative liver weight that appeared to correlate with dose-related increases in total protein, albumin and globulin was noted in females and males, increased wobbly gait in females and males and reduced forelimb grip strength and motor activity in males were observed at 750 mg/kg-day; the NOAEL for systemic toxicity is 225 mg/kg-day. In the same study, decreases in mean body weight gain and food consumption were observed in dams at 750 mg/kg-day, the NOAEL for maternal toxicity is 225 mg/kg-day. An increase in the number of stillbirths, reduced pup survival and lower body weights were observed at 750 mg/kg-day; the NOAEL for reproductive and developmental toxicity is 225 mg/kg-day. In a 17-week dietary study, no effects were observed in rats exposed to doses up to 423 mg/kg-bw/day (highest dose tested). Acetophenone did not induce gene mutations in bacteria in vitro. Acetophenone induced chromosomal aberrations in Chinese Hamster Ovary (CHO) cells in vitro, but did not induce micronuclei formation in mouse peripheral blood erythrocytes in vivo. Acetophenone is irritating to rabbit skin and eyes and guinea pig skin. Acetophenone is not a skin sensitizer in guinea pigs. 11 ------- U.S. Environmental Protection Agency Hazard Characterization Document September, 2014 Table 3. Summary Table of the Screening Information Data Set under the U.S. HPV Challenge Program - Human Health Data Endpoint Acetophenone (98-86-2) Acute Oral Toxicity LD50 (mg/kg) 3200 Acute Inhalation Toxicity LD50 (mg/L) 2.13 (8 hrs; saturated vapor) Acute Dermal Toxicity LD50 (mg/kg) 20,600 Repeated-Dose Toxicity NOAEL/LOAEL (mg/kg-day) Oral LOAEL= 750 NOAEL=225 Reproductive/Developmental Toxicity NOAEL/LOAEL Oral (mg/kg-day) Reproductive Toxicity LOAEL= 750 NOAEL = 225 Developmental Toxicity NOAEL/LOAEL Oral (mg/kg-day) Maternal/Developmental Toxicity LOAEL= 750 NOAEL = 225 Genetic Toxicity - Gene Mutation In vitro Negative Genetic Toxicity - Chromosomal Aberrations In vitro In vivo Positive Negative Additional Information Skin Irritation Eye Irritation Skin Sensitization Irritating Irritating Not sensitizing 4. Hazard to the Environment A summary of aquatic toxicity data submitted for SIDs endpoints is provided in Table 4. Acute Toxicity to Fish Fathead minnow (Pimephalespromelas) (25 fish/replicate, 2 replicates/concentration) were exposed to CASRN 98-86-2 (99% purity) at nominal concentrations of 0, 31.9, 53.1, 88.6, 148 or 246 mg/L under flow-through conditions for 96 hours. Measured concentrations averaged over the two chambers per concentration at 96 hours were < 1 (both controls), 26.4, 51, 75.3, 117 and 222.5 mg/L. 96-h LCso = 162 mg/L 12 ------- U.S. Environmental Protection Agency Hazard Characterization Document September, 2014 Acute Toxicity to Aquatic Invertebrates Daphnia magna (15 daphnids/replicate, 8 replicates/treatment concentration, 2 control replicates) were exposed to CASRN 98-86-2 (> 98% purity) at unreported nominal concentrations under static conditions in sealed chambers for 48 hours. Test concentrations were not measured. Additional details were obtained from: European Chemicals Agency, http://echa.europa.eu/web/guest/information-on-chemicals/registered-substances. 48-h LCso=528 mg/L Toxicity to Aquatic Plants Green algae (Pseudokirchneriella subcapitata; 7 cultures/concentration) were exposed to CASRN 98-86-2 (98.7% purity) in sealed chambers at nominal concentrations of 0, 12.5, 25, 50, 100 or 200 mg/L for 72 hours. Measured concentrations at 72 hours were 97.6 to 99.7% of nominal. Mean measured concentrations were < 0.45, 12.2, 24.8, 48.8, 99.7 and 196 mg/L. Additional details were obtained from: European Chemicals Agency, http://echa.europa.eu/web/guest/information-on-chemicals/registered-substances. 72-h ECso (growth rate) = 86.4 mg/L 72-h EC50 (biomass) = 40 mg/L Conclusion: The 96-h LC50 value of acetophenone for fish is 162 mg/L. The 48-h LC50 value of acetophenone for aquatic invertebrates is 528 mg/L. The 72-h EC50 value of acetophenone for aquatic plants is 40 mg/L and 86.4 mg/L for biomass and growth rate, respectively. Table 4. Summary of the Screening Information Data Set as Submitted under the U.S. HPV Challenge Program - Aquatic Toxicity Data Endpoint Acetophenone (98-86-2) Fish 96-h LCso (mg/L) 162 Aquatic Invertebrates 48-h ECso (mg/L) 528 Aquatic Plants 72-h ECso (mg/L) (growth rate) (biomass) 86.4 40 Bold = experimental data (i.e., derived from testing) 13 ------- |