U.S. Environmental Protection Hazard Characterization Document December 2012 SCREENING-LEVEL HAZARD CHARACTERIZATION SPONSORED CHEMICAL p-Cymene (CASRN 99-87-6) SUPPORTING CHEMICAL Cumene (CASRN 98-82-8) 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 Set2) 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. 2 3 The evaluation is performed according to established EPA guidance ' 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.) and 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 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 December, 2012 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 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 of the 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 December, 2012 Chemical Abstract Service Registry Number Sponsored Chemical (CASRN) 99-87-6 Supporting Chemical 98-82-8 Sponsored Chemical Benzene, l-methyl-4-(l-methylethyl)- (p-Cymene) Supporting Chemical Benzene, (1-methylethyl)- (Cumene) Structural Formula Sponsored Chemical Supporting Chemical Chemical Abstract Index Name ------- U.S. Environmental Protection Agency Hazard Characterization Document December, 2012 Summary p-Cymene (CASRN 99-87-6) and the supporting chemical, Cumene (CASRN 99-82-8), are liquids at room temperature having moderate water solubility and high vapor pressure. Both are expected to have moderate mobility in soil. Volatilization from water is expected to be high given the Henry's Law constants of these substances. The rate of hydrolysis is negligible. The rate of atmospheric photooxidation is moderate. Both substances are expected to have low persistence (PI) and low bioaccumulation potential (Bl). Acute oral toxicity forp-cymene and the supporting chemical cumene in rats, acute dermal toxicity ofp-cymene and cumene in rabbits and acute inhalation toxicity of />cymene in guinea pigs, rats and rabbits are all low. Following repeated oral (gavage) exposures of rats to cumene for 6 months; the NOAEL is 769 mg/kg-day (highest dose tested). In a 13-week study in rats via whole-body inhalation exposure to cumene, the LOAEC is 1.23 mg/L-day based on increased liver and kidney weights, increased alpha-2u-globulin nephropathy and decreased in alanine aminotransferase activity. The NOAEC is 0.62 mg/L-day. In a 13-week study in mice via whole-body inhalation exposure to cumene, the LOAEC is 2.46 mg/L-day based on decreased body weights, in males and increased incidence of squamous hyperplasia and inflammation of the forestomach mucosa in females. The NOAEC is 1.23 mg/L-day. Additional 90-day inhalation repeated-dose exposure studies with cumene showed increased number of leukocytes and/or decreased body weight gains in rats at 0.146 mg/L-day with aNOAEC of 0.018 mg/l-day and no effects in dogs when tested up to 0.146 mg/L-day. No reproductive toxicity studies are available. No compound-related changes were observed on the reproductive organs or on epididymal sperm count and sperm morphology in 13-week inhalation toxicity study with cumene. In a prenatal inhalation developmental toxicity study in rats with cumene the LOAEC for maternal toxicity is 5.95 mg/L-day based on decreased body weight gain and increased liver weight; the NOAEC was 2.40 mg/L-day. No developmental toxicity was observed in this study with a NOAEC of 5.95 mg/L-day (highest dose tested). In a prenatal developmental toxicity study in rabbits with cumene, the LOAEC for maternal toxicity is 11.29 mg/L-day based on mortality and decreased body weight gain; the LOAEC for developmental toxicity is 11.29 mg/L-day based on changes in gestational parameters. The NOAEC for both maternal and developmental toxicity is 5.93 mg/L-day. Neitherp-cymene nor cumene induced gene mutation in bacteria or mammalian cells in vitro. Cumene was negative for chromosomal aberrations in mammalian cells in vitro; however, it induced an increase in micronuclei in two in vivo rat micronucleus assays. Forp-cymene, the 96-h LC50 for fish is 48 mg/L. The 48-h EC50 for aquatic invertebrates is 6.5 mg/L. The 72-h EC50 values for aquatic plants are 2.04 and 4.03 mg/L for biomass and growth rate, respectively. No data gaps were identified under the HPV Challenge Program. 4 ------- U.S. Environmental Protection Agency Hazard Characterization Document December, 2012 The sponsor, the Terpene Consortium of the Flavor and Fragrance High Production Volume Consortia, submitted a Test Plan and Robust Summaries to EPA for Aromatic Terpene Hydrocarbons (p-Cymene, CAS No. 99-87-6; 9th CI name: benzene, 1-methyl-4- (1-methylethyl)-) on June 26, 2002. EPA posted the submission on the ChemRTK HPV Challenge website on September 30, 2002 (http://www.epa.gov/oppt/chemrtk/pubs/summaries/aroterhc/cl3972tc.htm). EPA comments on the original submission were posted to the website on January 27, 2003. Public comments were also received and posted to the website. The sponsor submitted updated/revised documents on June 16, 2005, which were posted to the ChemRTK website on June 30, 2005. Justification for Supporting Chemical EPA agrees that data for cumene are appropriate to address the human health endpoints for p-cymene, based on toxicokinetic data for both compounds. In various species both chemicals are rapidly absorbed, oxidized and excreted directly and as conjugates. In rabbits, the oxidation of the cumene isopropyl group is similar to that for p-cymene (Ishida and Matsumoto, 1992). For ecotoxicity endpoints, supporting chemical data were not used since there were no data gaps for p-cymene. p-Cymene has been assessed in the OECD HPV program (SIAM 5) and the data can be viewed at: http://webnet.oecd.org/HPV/UI/SIDS Details.aspx?Key=cll59420-4716-4047-96c2- 147a9b8a544b&idx=0. 1. Chemical Identity 1.1 Identification and Purity In the robust summaries, the purity ofp-cymene was cited as being 80% at a minimum. 1.2 Physical-Chemical Properties The physical-chemical properties ofp-cymene and cumene are summarized in Table 1. p-Cymene and cumene are liquids at room temperature having moderate water solubility and high vapor pressure. 5 ------- U.S. Environmental Protection Agency Hazard Characterization Document December, 2012 Table 1 Physical-Chemical Properties of Aromatic Terpene Hydrocarbons1 Property SPONSORED CHEMICAL SUPPORTING l-Methyl-4-(l- CHEMICAL methylethyl)benzene (/j-Cymene) (1-Methylethylbenzene (Cumene) CASRN 99-87-6 98-82-8 Molecular Weight 134.22 120.19 Physical State Liquid Liquid Melting Point -68 °C (measured) -96 °C (measured)2 Boiling Point 176 - 177.1 °C (measured) 152.4 °C (measured)2 Vapor Pressure 1.46 mm Hg at 25 °C (measured); 1.50 mm Hg at 20 °C (measured) 4.5 mm Hg at 25 °C (measured)2 Dissociation Constant (pKa) Not applicable Henry's Law Constant 0.011 atm-nrVmole 0.012 atm-nrVmole (measured)2 (measured)2 Water Solubility 23.35 mg/L at 25 °C (measured) 500 mg/L at 25 °C in synthetic seawater; 61.3 mg/L at 25 °C (measured) Log Kow 4.1 (measured) 3.66 (measured)2 1 Flavor and Fragrance High Production Volume Consortium. The Terpene Consortium. Test Revised Plan and Robust Summary for Aromatic Terpene Hydrocarbons, htto://www.et>a.eov/chemrtk/r>ubs/summaries/aroterhc/cl3972tc.htm as of March 21. 2011 2 SRC. The Physical Properties Database (PHYSPROP). Syracuse, NY: Syracuse Research Corporation. Available from lUtD://\vww. SYrrcs.com/csc/DhvsDroD.htm as of March 21. 2011. 2. General Information on Exposure 2.1 Production Volume and Use Pattern p-Cymene (CASRN 99-87-6) had an aggregated production and/or import volume in the United States between 500,000 pounds and one million pounds during calendar year 2005. Non-confidential information in the IUR indicated that the industrial processing and uses for the chemical include all other chemical product and preparation manufacturing as functional fluids and odor agents; other basic organic chemical manufacturing as intermediates. Non-confidential commercial and consumer uses of this chemical include polishes and sanitation goods, soaps and detergents and "other." 6 ------- U.S. Environmental Protection Agency Hazard Characterization Document December, 2012 2.2 Environmental Exposure and Fate The environmental fate properties of CASRN 99-87-6 are summarized in Table 2. p-Cymene and the supporting chemical cumene are expected to have moderate mobility in soil. p-Cymene achieved 88% of its theoretical biochemical oxygen demand (BOD) with an activated sludge inoculum in the modified MITI test (OECD 301C) over the course of a 28-day incubation period. Cumene achieved 40% of its theoretical BOD within 14 days in the MITI test (OECD 301C) and was determined to be readily biodegradable. It also degraded 70% within 20 days using a modified BOD procedure using synthetic seawater. Volatilization is expected to be high given the Henry's Law constants of these substances. The rate of hydrolysis is negligible since neither substance has functional groups that are susceptible to hydrolysis under environmental conditions. The rate of atmospheric photooxidation is moderate. p-Cymene and cumene are expected to have low persistence (PI) and low bioaccumulation potential (Bl). Table 2. Environmental Fate Properties of Aromatic r "erpene Hydrocarbons1 Property SPONSORED CHEMICAL SUPPORTING l-Methyl-4-(l- CHEMICAL methylethyl)benzene (/j-Cymene) (1-Methylethylbenzene (Cumene) CASRN 99-87-6 98-82-8 Photodegradation Half-life 15.0 hours (estimated) 18.6 hours (estimated) Hydrolysis Half-life Stable Stable Biodegradation 88%) after 28 days (readily biodegradable) 70%) after 20 days (readily biodegradable); 40%o after 14 days (readily "3 biodegradable) Bioaccumulation Factor BAF = 522 (estimated)2 BAF = 168 (estimated)2 Log Koc 3.0 (estimated)2 2.8 (estimated)2 Fugacity (Level III Model)2 Air (%) 6.6 14.7 Water (%) 30.3 34.6 Soil (%) 61.9 49.8 Sediment (%) 1.2 0.9 Persistence4 PI (low) PI (low) Bioaccumulation4 Bl (Low) Bl (Low) 1 Flavor and Fragrance High Production Volume Consortium. The Terpene Consortium. Test Revised Plan and Robust Summary for Aromatic Terpene Hydrocarbons, htto://www.er)a.sov/chemrtk/r)ubs/summaries/aroterhc/cl3972tc.htm as of March 21. 2011 2U.S.EPA. 2011. Estimation Programs Interface Suite™ for Microsoft® Windows, v4.10. U.S. Environmental Protection Agency, Washington, DC, USA. Available online from: htto://www.er)a.sov/or)r)tintr/exr)osure/r)ubs/er)isuitedl.htm as of February 28. 2011. 3 National Institutes of Technology and Evaluation. 2002. Chemical Risk Information Platform (CHRIP). Available online from: httt>://www.safe.nite.eo.ir>/enelish/db.html as of March 21. 2011. 4 Federal Register. 1999. Category for Persistent, Bioaccumulative, and Toxic New Chemical Substances. Federal Register 64, Number 213 (November 4, 1999) pp. 60194-60204. 7 ------- U.S. Environmental Protection Agency Hazard Characterization Document December, 2012 Conclusion: Aromatic Terpene Hydrocarbons consists of />cymene and the supporting chemical cumene. Both substances are liquids at room temperature having moderate water solubility and high vapor pressure. Both are expected to have moderate mobility in soil. Volatilization is expected to be high given the Henry's Law constants of these substances. The rate of hydrolysis is negligible. The rate of atmospheric photooxidation is moderate, p-Cymene and cumene are expected to have low persistence (PI) and low bioaccumulation potential (Bl). 3. Human Health Hazard A summary of the human health toxicity data submitted for SIDS endpoint is provided in Table 3. Acute Oral Toxicity p-Cymene (CAS No. 99-87-6) (1) Male and female rats (1 - 3/dose) were dosed by oral gavage with 620, 940, 1400, 2100, 3200, 4700, 7100 or 10,700 mg/kg. Following a 14-day observation period, all rats in the 620, 940, 1400 and 2100 mg/kg groups survived and 1/2, 2/2, 3/3 and 1/1 had died in the 3200, 4700, 7100 and 10,700 mg/kg groups, respectively. LD50 = 3200 mg/kg (2) Osborne-Mendel rats (10/sex/dose) were administered various unspecified doses of the test substance. Rats were monitored for up to 2 weeks. LD50 = 4750 mg/kg Cumene (CASRN 98-82-8, supporting chemical) (1). Rats (number and strain not provided) were administered cumeme via gavage at 2910 mg/kg and observed for 14 days. No mortality was seen. LD50 > 2910 mg/kg (2) Wistar rats (20/sex/dose) were administered cumene (purity > 98%) in olive oil emulsified with gum Arabic, via gavage and observed for 2 weeks. Specific doses and mortality per dose were not reported. LD50 = 1400 mg/kg 8 ------- U.S. Environmental Protection Agency Hazard Characterization Document December, 2012 Acute Inhalation Toxicity p-Cymene (CASRN. 99-87-6) Guinea pigs, rats and mice (2-3 animals per species, sex not indicated) were exposed to a concentration of 9.7 mg/L for 5 hours. Animals were observed for 1 week following exposure. No deaths were reported in guinea pigs or rats. All exposed mice died during or within 24 hours of exposure. LC5o (guinea pig) > 9.7 mg/L LC50 (rat) > 9.7 mg/L LC50 (mouse) < 9.7 mg/L Acute Dermal Toxicity p-Cymene (CASRN 99-87-6) (1) Ten rabbits (number per sex not reported) were exposed top-cymene at a dose of 5000 mg/kg. Animals were observed for 14 days. No animals died during the observation period. LD50 > 5000 mg/kg (2) One rabbit (sex not indicated) was exposed to p-cymene at a dose of 5144 mg/kg. The animal was observed for 1 month after exposure. There was no mortality. LD50 > 5144 mg/kg Cumene (CASRN 98-82-8, supporting chemical) (1) In a range-finding study, rabbits (number and strain not provided) were administered cumeme dermally at 10,545 mg/kg and observed for 14 days. The exposure duration was not reported. No mortality was seen. LD50 = 10,545 mg/kg Repeated-Dose Toxicity Cumene (CASRN 98-82-8, supporting chemical) Oral Wistar rats (10 females/dose) were administered cumene oral gavage at 0, 154, 462 or 769 mg/kg-day 5 days/week for 6-months. The only effect reported was an increase in kidney weight at the two highest doses which was not accompanied by any histopathological changes. NOAEL = 769 mg/kg-day (highest dose tested) Inhalation (1) In an NTP 13-week study, F344 rats (20/sex/concentration) were exposed via whole-body inhalation to cumene (purty >99.9%) to 0, 62.5, 125, 250, 500 or 1000 ppm (approximately 0, 0.31, 0.62, 1.23, 2.46 or 4.92 mg/L) for 6 hours/day, 5 days/week. Animlas were observed for survival, clinical signs and body weight changes. At study termination, any organ weight 9 ------- U.S. Environmental Protection Agency Hazard Characterization Document December, 2012 changes or histopathological effects were noted. Hematology and clinical chemistry parameters were evaluated. All animals survived without significant effects on body weight. Mild ataxia was observed in the high-dose group in the early part of the study. In males exposed to 250 ppm and higher, absolute and relative liver weights and absolute kidney weights were increased. Relative kidney weights were increased in males of all treated groups. In females, relative liver weight was increased at 250 ppm and higher and relative kidney weights at 500 and 1000 ppm. Effects on hematology parameters were unremarkable. At terminal sacrifice, alanine aminotransferase activity was significantly decreased in both sexes at 250 ppm and higher. In males, kidney weight increase was accompanied by increase in hyaline droplets and tubular regeneration in renal cortical tubules and granular casts in the corticomedullary junction area. The severity and incidence of granular casts was exposure related. These findings were not observed in females. The amount of alpha-2u-g\ obulin in the kidney of male rats increased in an exposure-related manner, reaching a statistical significance at 125 ppm and higher. Proliferating cell nuclear antigen was measured and showed no difference from controls. LOAEC -1.23 mg/L-day (based on increased liver and kidney weights4 and decrease in alanine aminotransferase activity) NOAEC ~ 0.62 mg/L-day. (2) In an NTP 13-week study, B6C3F1 mice (10/sex/concentration) were exposed to cumene (purity >99.9%) at 0, 62.5, 125, 250, 500 or 1000 ppm (approximately 0, 0.31, 0.62, 1.23, 2.46 or 4.92 mg/L) for 6 hours/day, 5 days/week. Animals were observed for survival, clinical signs, and body weight changes. At study termination, any organ weight changes or histopathological effects were noted. Hematology also was evaluated but not described in detail. All male mice survived to the end of the study. Eight of ten females at the high-dose level died during the first week of exposure. Transient signs of ataxia were noted in males and females of the high-dose group during the first week of exposure. Male mice at the two highest dose levels showed statistically significant decreases in body weight; female body weights were not affected. No effect on hematology was reported. Absolute liver weight was significantly increased at 1000 ppm in both sexes and relative liver weight was increased in both sexes at 250 ppm and higher. Centrilobular hypertrophy of the liver was noted in all high-dose males. Squamous hyperplasia and inflammation of the mucosa of the forestomach were reported in females at 500 and 1000 ppm. LOAEC -2.46 mg/L-day (based on decreased body weights in males, squamous hyperplasia and inflammation of the mucosa of the forestomach in females) NOAEC -1.23 mg/L-day (3) In the 13-week study, Fischer 344 rats (15/sex/concentration) were exposed to cumene (purity >99.9%) via whole-body inhalation at 0, 50, 100, 500 or 1200 ppm (approximately 0, 0.25, 0.49, 2.46 or 5.90 mg/L) for 6 hours/day, 5 days/week with a 4-week post-exposure period. The following observations were made: mortality, clinical signs, body weight measurement, "Nephropathy seen in male rats may be occurring by an alpha 2 |i-globul in-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 2|i-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 10 ------- U.S. Environmental Protection Agency Hazard Characterization Document December, 2012 motor activity assessment, tone-pip auditory brain stem responses. Eyes were examined. All rats were necropsied and liver, kidney, lungs, adrenal, gonad and brain weights were measured. In this study, only the eyes were histopathologically examined. Mean body weights and motor activity was not affected by treatment. Absolute and relative liver weights were statistically increased in males at 500 ppm and females at 1200 ppm. Only absolute liver weight was increased in males at 1200 ppm. Relative kidney weights and absolute and relative adrenal weights were statistically increased in females exposed to 1200 ppm. LOAEC -5.90 mg/L-day (based on increased kidney weights and absolute and relative adrenal weights) NOAEC -2.46 mg/L-day (4) In the 13-week study, Fischer 344 rats (21/sex/concentration) were exposed to cumene (purity >99.9%) via whole-body inhalation at 0, 100, 500 or 1200 ppm (approximately 0, 0.49, 2.46 or 5.90 mg/L) for 6 hours/day, 5 days/week. The following observations were made: clinical signs, mortality, body weight and food and water consumption, functional observational battery and motor activity assessments and hematology and serum chemistry parameters. At study termination, 6 rats/sex/concentration were necropsied and microscopic evaluation of the brain, spinal cord, and peripheral nerves was made. All remaining rats were necropsied and liver, kidney, lungs, adrenal, gonad and brain weights were measured. In addition to microscopic examination of standard tissues from high-dose rats, lung tissues from both the 100 and 500 ppm groups were examined and kidney sections from all male rats were evaluated for tubular hyaline droplet formation. In addition, sperm count, sperm morphology and the stages of spermatogenesis were evaluated. One rat at the high-concentration level was sacrificed for humane reasons following a caging accident. Rats showed ataxia, exhibited blepharospasm and showed a delayed or absent startle reflex at the high-dose level. At 500 and 1200 ppm, rats showed increased incidence of periocular tissue swelling, urine staining, urogenital wetness, perinasal encrustation and hypoactivity. At week 13, male rats at 500 or 1200 ppm showed a decrease in total motor activity. Water consumption was increased in males and females throughout most of the study. Leukocytes and platelets were increased significantly at the two highest exposure concentrations and lymphocytes increased in males only at the same concentrations. At the high-dose level, males and females had significantly increased absolute and relative liver, kidney and adrenal gland weights. At 500 ppm, absolute and relative liver weights, relative kidney weights and absolute adrenal weights were increased in both sexes. The only microscopic findings reported were in the kidneys of male rats exposed to 500 or 1200 ppm and consisted of tubular proteinosis, interstitial nephritis and tubular cell hyperplasia/hypertrophy. An increase in hyaline droplet formation within the proximal tubules of male rats was reported. Testicular sperm head and epididymal spermatozoa counts were similar for all dose groups and there was no effect on epididymal sperm morphology. [The robust summary indicated that a 1997 EPA document determined that the LOAEL was 1200 ppm based on relative and absolute weight alterations that were both biologically and statistically significant.] LOAEC = -5.90 mg/L-day (based on increased absolute and relative kidney and adrenal gland weights) NOAEC -2.46 mg/L-day 11 ------- U.S. Environmental Protection Agency Hazard Characterization Document December, 2012 (5) In a 90-day study, groups of 14-15 Sprague-Dawley or Long Evans rats (sex distribution not specified) were exposed to cumene (purity >99.9%) via inhalation at concentrations of 0, 3.7 or 30 ppm (approximately 0, 0.018 or 0.146 mg/L), continuously. At the end of the exposures, animals were sacrificed and necropsied. Histopathological examinations were conducted on heart, lung, liver, spleen and kidneys. Blood was collected for hematological evaluations (leukocyte count, hemoglobin and hematocrit). One rat died on day 11 in the 3.7 ppm group. Body weight gain was not affected by treatment and no histopathological effects were noted in the treated animals. An increase in the number of leukocytes and slight decrease in hematocrit were reported following exposure. LOAEC = 0.146 mg/L-day (based on increased number of leucocytes) NOAEC = -0.018 mg/L-day (6) In a 90-day study, groups of 15 Princeton-derived guinea pigs (sex distribution not reported) were exposed to cumene at concentrations of 0, 3.7 or 30 ppm (approximately 0, 0.018 or 0.146 mg/L) continuously. At the end of the exposures, animals were sacrificed and necropsied. Histopathological examinations were conducted on heart, lung, liver, spleen and kidneys. Blood was collected for hematological evaluations (leukocyte count, hemoglobin and hematocrit). Body weight gain was decreased in animals exposed to 30 ppm, but was increased in animals exposed to 3.7 ppm. No histopathological effects were reported. No effects on hematological parameters were apparent. LOAEC -0.146 mg/L-day (based on decreased body weight gain) NOAEC -0.018 mg/L-day (7) In a 90-day study, groups of two male Beagle dogs were exposed to cumene at concentrations of 0, 3.7 or 30 ppm (approximately 0, 0.018 or 0.146 mg/L) continuously. The control group consisted of 10 male dogs. At the end of the exposures, animals were sacrificed and necropsied. Histopathological examinations were conducted on heart, lung, liver, spleen, brain, spinal cord and kidneys. Blood was collected for hematological evaluations (leukocyte count, hemoglobin and hematocrit). Body weight gain did not appear to be affected by exposure. No histopathological effects were reported. No effects on hematological parameters were apparent. NOAEC -0.146 mg/L-day (highest dose tested) Reproductive Toxicity Cumene (CASRN 98-82-8, supporting chemical) In the 13-week subchronic inhalation study in rats described previously, testicular sperm head and epididymal spermatozoa counts were similar for all groups. At 1200 ppm, one rat out of 15 was reported to show diffuse testicular atrophy; however, all other animals showed normal morphology and stages of spermatogenesis in the testes. In epididymal spermatozoa, there were no individual abnormalities of the sperm head; however, at 500 ppm, when total abnormalities where grouped by total number per category, there appeared to be a slight increase (statistical significance not reported) in the incidence of head abnormalities. No effects on epididymal sperm morphology were reported based on more than 96% normal epididymal sperm. 12 ------- U.S. Environmental Protection Agency Hazard Characterization Document December, 2012 Developmental Toxicity Cumene (CASRN 98-82-8, supporting chemical) (1) Pregnant CD rats (25 mated animals/group) were exposed to cumene (purity >99.9%) via whole-body inhalation at concentrations of 0, 100, 500 or 1200 ppm for 6 hours/day during gestation days 6-15. Measured concentrations were 0, 99, 488 or 1211 ppm (approximately 0.49, 2.40 or 5.95 mg/L). Rats were observed daily for clinical signs. Body weight and food consumption were measured on gestation days 0, 6, 9, 12, 15, 18, and 21. On gestation day 21, maternal rats were killed and the gravid uterus, ovaries (including corpora lutea), cervix, vagina, abdominal and thoracic cavities, and respiratory tracts (including nasal turbinates) were examined. Live and dead fetuses and resorption sites were recorded. Any early resorptions were evaluated. Live fetuses were examined for gender, external malformations, and variations and skeletal malformations and variations. Fifty percent of the live fetuses were examined for thoracic and abdominal visceral abnormalities, and for craniofacial structures. All dams survived with no abortions or early deliveries. The pregnancy rate ranged from 88- 100%. At the high-dose, perioral wetness, encrustation and significantly increased liver weight were reported. During exposure, the high-dose rats showed a significant reduction in body weight gain but no significant differences in maternal corrected gestational body weight were reported at necropsy. At 500 and 1200 ppm, food consumption was significantly reduced. Evaluation of the female reproductive organs showed no abnormalities. No statistically significant effects were reported in the fetuses. Parameters examined included number of corpora lutea, number of total nonviable or viable implantations, percent pre- or post- implantation loss, sex ratio, fetal body weights, malformations, or variations. Although there was a significant increase in the incidence of skeletal and visceral variations; they were not exposure related. LOAEC (maternal toxicity) -5.95 mg/L-day (based on decreased body weight gain during exposure and increased relative liver weight) NOAEC (maternal toxicity) = -2.40 mg/L-day NOAEC (developmental toxicity) -5.95 mg/L-day (highest dose tested) (2) Pregnant New Zealand White rabbits (15/concentration) were exposed to cumene (purity >99.9%) at 0, 500, 1200 or 2300 ppm for 6 hours/day during gestation days 6-18. Measured concentrations were 0, 492, 1206 or 2297 ppm (0, -2.42, 5.93 or 11.29 mg/L). Rabbits were observed daily for clinical signs. Food consumption was measured daily and body weight was measured on gestation days 0, 6, 12, 18, 24, and 29. On gestation day 29, maternal rabbits were killed and the gravid uterus, ovaries (including corpora lutea), cervix, vagina, abdominal and thoracic cavities, and respiratory tracts (including nasal turbinates) were examined. Live and dead fetuses and resorption sites were recorded. Early resorptions, if any, were evaluated. Live fetuses were killed immediately upon removal were examined for gender, external malformations, and variations, skeletal malformations and variations, and thoracic and abdominal visceral abnormalities. Fifty percent of the fetuses were decapitated and examined for craniofacial structures. 13 ------- U.S. Environmental Protection Agency Hazard Characterization Document December, 2012 At the highest concentration, two does died and one aborted. At the low- and mid-concentration levels, one doe in each group contained non-viable implants. All does in all groups were pregnant. During exposure, high concentration animals had significantly reduced body weight gain and all groups had significantly reduced food consumption. High concentration animals also showed increased incidence of perioral wetness. At necropsy, lung color change was noted in 4 of 12 high-dose animals. Relative liver weight was significantly increased in high-dose animals. No statistically significant effects were reported in the fetuses. Parameters examined included number of corpora lutea, number of total nonviable or viable implantations, percent pre- or post-implantation loss, sex ratio, fetal body weights, malformations, or variations. Although there was a significant increase in the incidence of skeletal and visceral variations, they were not exposure related. At 500 ppm, there was a statistically significant increase in the incidence of ecchymosis (small hemorrhage) on the head, which was not significant at the higher exposure concentrations. [The robust summary indicated that a 1991 EPA document determined that the LOAEL for developmental toxicity was 2297 ppm based upon "changes in gestational parameters" which, though not significant, were consistent in indicating possible developmental effects.] LOAEC (maternal toxicity) -11.29 mg/L-day (based on mortality, decreased body weight gain) LOAEC (developmental toxicity) -11.29 mg/L-day (based on "changes in gestational parameters") NOAEC (maternal and developmental toxicity) -5.93 mg/L-day Genetic Toxicity — Gene Mutation In vitro p-Cymene (CASRN 99-87-6) In a reverse mutation assay, Escherichia coli strain Sd-4-73 was exposed to />cymene at concentrations of 0.01 - 0.025 mL in the absence of metabolic activation. Information on positive and negative controls was not provided. p-Cymene was not mutagenic in this assay. Cumene (CASRN 98-82-8, supporting chemical) (1) In an Ames Reveres mutation assay, Salmonella typhimurium strains TA 97, TA 98, TA 100 and TA 1535 were exposed to cumene (purity >98%) at concentrations of 1, 3, 10, 33, 100, 166 or 333 |j,g/plate in the presence and absence of metabolic activation. Strains TA 1535 and TA 97 were not tested at 333 |j,g/plate. Positive control responded appropriately. Cytotoxicity was noted >166 |ig/plate. There was no increase in the revertants in this assay Cumene was not mutagenic in this assay. (2) In an Ames reverse mutation assay, S. typhimurium(strains TA 98, TA 100, TA 1535 and TA 1537 were exposed to cumene (purity >98%) at concentrations of 33, 67, 100, 333, 667, 1000 or 2000 |j,g/plate in the presence and absence of metabolic activation. Positive controls were tested but the results of control tests were not presented. Signs of cytotoxicity were noted at 2000 Hg/plate. There was no increase in the revertants in this assay. Cumene was not mutagenic in this assay. 14 ------- U.S. Environmental Protection Agency Hazard Characterization Document December, 2012 (3) In an HGPRT assay, Chinese Hamster Ovary (CHO) cells (K-l) were exposed to cumene at concentrations ranging from 8 to 175 |j,g/mL in the presence and absence of metabolic activation. The cytotoxic concentration was 128 |j,g/mL. Positive controls were tested and the response was appropriate. Cumene did not increase mutations in this assay. Cumene was not mutagenic in this assay. (4) In an HGPRT assay, CHO cells (K-l) were exposed to cumene at concentrations ranging from 100 to 225 |j,g/mL in the presence and absence of metabolic activation. The cytotoxic concentration was 150 |j,g/mL. Positive controls were tested and the response was appropriate. Cumene did not increase mutations in this assay. Cumene was not mutagenic in this assay. Genetic Toxicity — Chromosomal Aberrations In vitro Cumene (CASRN 98-82-8, supporting chemical) In a chromosomal aberration test, CHO cells were exposed to cumene (purity 99.7%) at concentrations of 0, 19, 31, 49, 78, 125 or 200 |j,g/mL in the absence of metabolic activation and 0, 24, 38, 61, 98, 156 or 225 |j,g/mL in the presence of metabolic activation. Positive and negative controls were tested, but the response to positive controls was not presented. Cytotoxicity was observed at the highest concentration both with and without activation. No statistically significant increase in structural or numerical chromosomal aberrations was noted compared to untreated control cells. The increase was within the historical control range and was possibly due to low vehicle control values. Cumene did not induce chromosomal aberrations in this assay. In vivo Cumene (CASRN 98-82-8, supporting chemical) (1) In a micronucleus assay, Swiss mice (10/sex/dose) were administered cumene (purity > 98%) at 0, 250, 500 or 1000 mg/kg-bw/day by oral gavage for 2 days and another group of 15 mice/sex was given a single dose of 1000 mg/kg-bw. Cyclophosphamide was used as a positive control. Animals were sacrificed 24, 48 or 72 hours after the last dose. The positive control did not appear to produce a statistically significant increase in micronuclei. Cumene did not induce micronuclei in mice. Cumene did not induce micronuclei in this assay. (2) In a micronucleus assay, F344 rats (5 males/dose) were administered cumene (> 95%) at 0, 78.13, 156.25, 312.5, 625, 1250 or 2500 mg/kg-bw by the intraperitoneal route daily for 3 days. At the highest dose, 3/5 rats died. Animals were sacrificed 24 hours after the last dose. Cyclophosphamide was used as a positive control and responded appropriately. There was an increase in micronuclei at all dose levels. Cumene induced the formation of micronuclei in this assay. 15 ------- U.S. Environmental Protection Agency Hazard Characterization Document December, 2012 (3) In an micronucleus assay, F344 rats (5 males/dose) were administered cumene (> 95%) at 0, 312, 625, 1250 or 2500 mg/kg-bw by the intraperitoneal route daily for 3 days. At the highest dose, 2/5 rats died. Animals were sacrificed 24 hours after the last dose. Cyclophosphamide was used as a positive control and responded appropriately. There was an increase in micronuclei at all dose levels. Cumene induced the formation of micronuclei in this assay. Additional Information Neurotoxicity p-Cymene (CASRN 99-87-6) Male Long Evans rats (group size not indicated) were exposed to concentrations of 0, 50 or 250 ppm (approximately 0, 0.25 or 1.23 mg/L) 6 hour/day, 5 days/week for 4 weeks. No overt toxicity, no effects on body weight or terminal brain weight were observed at any dose level. There were no changes in enzyme activities, regional protein synthesis or regional neurotransmitter concentrations. However some statistically significant changes in protein level and enzyme activity were seen at 0.25 and 1.23 mg/L in the synaptosomal fraction of whole brain. Cumene (CASRN 98-82-8, supporting chemical In a single-exposure neurobehavioral test, Fischer 344 rats (10/sex/concentration) were exposed to a single exposure of cumene (purity > 99.94%) via inhalation at 0, 100, 500 or 1200 ppm (0, -0.5, 2.5 or 6.0 mg/L) for 6 hours. Body weights were measured and a functional observation battery was conducted. No effects were reported at 100 ppm in both groups of male and female rats. Alterations in the functional observational battery 1 hour post-exposure were increased incidence and severity of gait abnormalities in high-dose males, increased horizontal activity in both male and female high-dose rats and in female rats exposed to 500 ppm cumene, and decreased rectal temperature of high-dose rats of both sexes. At 6 hours post-exposure, alterations were limited to decreased toe pinch withdrawal reflexes in males rats exposed to 500 or 1200 ppm cumene. At 24 hours post-exposure, no significant differences in the functional observational battery were observed. Body weights were not affected by cumene exposure. Conclusion: Acute oral toxicity for/;-cymene and the supporting chemical cumene in rats, acute dermal toxicity ofp-cymene and cumene in rabbits and acute inhalation toxicity of />cymene in guinea pigs, rats and rabbits are all low. Following repeated oral (gavage) exposures of rats to cumene for 6 months; the NOAEL is 769 mg/kg-day (highest dose tested). In a 13-week study in rats via whole-body inhalation exposure to cumene, the LOAEC is 1.23 mg/L-day based on increased liver and kidney weights, increased alpha-2u-globulin nephropathy and decreased in alanine aminotransferase activity. The NOAEC is 0.62 mg/L-day. In a 13-week study in mice via whole-body inhalation exposure to cumene, the LOAEC is 2.46 mg/L-day based on decreased body weights, in males and increased incidence of squamous hyperplasia and inflammation of the forestomach mucosa in females. The NOAEC is 1.23 mg/L-day. Additional 90-day inhalation repeated-dose exposure studies with cumene showed increased number of 16 ------- U.S. Environmental Protection Agency Hazard Characterization Document December, 2012 leukocytes and/or decreased body weight gains in rats at 0.146 mg/L-day with a NOAEC of 0.018 mg/l-day and no effects in dogs when tested up to 0.146 mg/L-day. No reproductive toxicity studies are available. No compound-related changes were observed on the reproductive organs or on epididymal sperm count and sperm morphology in 13-week inhalation toxicity study with cumene. In a prenatal inhalation developmental toxicity study in rats with cumene the LOAEC for maternal toxicity is 5.95 mg/L-day based on decreased body weight gain and increased liver weight; the NOAEC was 2.40 mg/L-day. No developmental toxicity was observed in this study with a NOAEC of 5.95 mg/L-day (highest dose tested). In a prenatal developmental toxicity study in rabbits with cumene, the LOAEC for maternal toxicity is 11.29 mg/L-day based on mortality and decreased body weight gain; the LOAEC for developmental toxicity is 11.29 mg/L-day based on changes in gestational parameters. The NOAEC for both maternal and developmental toxicity is 5.93 mg/L-day. Neitherp-cymene nor cumene induced gene mutation in bacteria or mammalian cells in vitro. Cumene was negative for chromosomal aberrations in mammalian cells in vitro; however, it induced an increase in micronuclei in two in vivo rat micronucleus assays. 17 ------- U.S. Environmental Protection Agency Hazard Characterization Document December, 2012 Table 3. Summary Table of the Screening Information Data Set as Submitted under the U.S. HPV Challenge Program - Human Health Data Endpoints SPONSORED CHEMICAL /;-Cymene (CASRN 98-87-6) SUPPORTING CHEMICAL Cumene (CASRN 98-82-8) Acute Oral Toxicity LDS0 (mg/kg) (rats) 3200-4750 1400-2910 Acute Dermal Toxicity LDjo (mg/kg) (rabbits) >5000 (rabbit) >10,545 Acute Inhalation Toxicity LCso (mg/L) (mouse) <9.7 (rat, guinea pigs) >9.7 Repeated-Dose Toxicity NOAEL/LOAEL Oral (mg/kg-day) No Data NOAEL = 769 (hdt) RA NOAEL = 769 (hdt) Repeated-Dose Toxicity NOAEC/LOAEC Inhalation (mg/L-day) No Data NOAEC = 0.62 LOAEC = 1.23 (Rat, Guinea pigs) NOAEC = 0.018 LOAEC = 0.146 (RA) (Rat) NOAEC = 0.62 LOAEC = 1.23 (Rat, Guinea pigs) NOAEC = 0.018 LOAEC = 0.146 Reproductive Toxicity NOAEC/LOAEC Inhalation (mg/L-day) Reproductive Toxicity No data No effects were seen in following evaluation of reproductive organs of rats in a 90- day inhalation repeated- exposure toxicity study 18 ------- U.S. Environmental Protection Agency Hazard Characterization Document December, 2012 Developmental Toxicity N O AEC/L O AEC Inhalation (mg/L-day) Maternal Toxicity No Data (rat) NO AEC = 2.40 LOAEC = 5.95 (rat) NO AEC = 2.40 LOAEC = 5.95 Developmental Toxicity NO AEC = 5.95 (RA) NO AEC = 5.95 Maternal Toxicity (rabbit) NO AEC = 5.93 LOAEC = 11.29 (rabbit) NO AEC = 5.93 LOAEC = 11.29 Developmental Toxicity NO AEC = 5.93 LOAEC = 11.29 (RA) NO AEC = 5.93 LOAEC = 11.29 Genetic Toxicity - Gene Mutation In vitro Negative - Genetic Toxicity - Chromosomal Aberrations In vivo No Data Negative RA Negative Measured data in bold text; (hdt) = highest dose tested; RA= Read Across; NE = not established; — indicate that the endpoint was not addressed for this chemical; 4. Hazard to the Environment A summary of aquatic toxicity data submitted for SIDS endpoints is provided in Table 4. Acute Toxicity to Fish p-Cymene (CASRN 99-87-6) Sheepshead minnow (Cyprinodon variegatus) were exposed to nominal concentrations of p-cymene ranging from 10 to 500 ppm for 96 hours under static conditions. The use of a solvent was not described. 96-h LC50 = 48 mg/L Acute Toxicity to Aquatic Invertebrates p-Cymene (CASRN 99-87-6) Daphnia magna were exposed top-cymene for 48 hours under static conditions. The dissolved oxygen concentration ranged from 6.5-9.1 mg/L. The pH ranged from 7.4-9.4. The water hardness in the test water was 173 mg CaCCb/L. Nominal concentrations were not provided. 48-h EC50 = 6.5 mg/L 19 ------- U.S. Environmental Protection Agency Hazard Characterization Document December, 2012 Toxicity to Aquatic Plants p-Cymene (CAS No. 99-87-6) Pseudokirchneriella subcapitata was exposed to nominal concentrations of 0.65, 1.3, 2.5, 5.0 and 10.0 mg/L for 72 hours in a static toxicity test. Initial measured concentrations were 0.623, 1.40, 1.91, 3.52 and 5.32 mg/L and final measured concentrations were 53 - 108% of nominal concentrations. 72-h EC50 (biomass) = 2.04 mg/L 72-h EC50 (growth) = 4.03 mg/L Conclusion: For/>-cymene, the 96-hour LC50 for fish is 48 mg/L. The 48-hr EC50 for aquatic invertebrates is 6.5 mg/L. The 72-hour EC50 values for aquatic plants are 2.04 and 4.03 mg/L for biomass and growth rate, respectively. Table 4. Summary Table of the Screening HPV Challenge Pro Information Data Set as Submitted under the U.S. gram - Aquatic Toxicity Data Endpoint SPONSORED CHEMICAL /;-Cymcnc (99-87-6) Fish 96-h LC50 (mg/L) 48 Aquatic Invertebrates 48-h EC50 (mg/L) 6.5 Aquatic Plants 72-h EC50 (mg/L) (biomass) (growth rate) 2.40 4.03 5. References Ishida, T. and T. Matsumoto. 1992. Enantioselective metabolism of cumene. Xenobiotica. 22(11): 1291-1298. [cited in NTP Nomination History and Review for Cumene CAS No. 98-82- 8. online at http://ntp-server.niehs.nih.gov/Chem_Background/ExecSumm/Cumene.html] 20 ------- |