United States Environmental Protection Agency Office of Water 4601 EPA 811-F-95-004m-T October 1995 National Primary Drinking Water Regulations Ethylbenzene CHEMICAL/ PHYSICAL PROPERTIES CAS NUMBER: 100-41-4 COLOR/ FORM/ODOR: Colorless liquid with a sweet, gasoline- like odor M.P.: -95° C B.P.: 136.2°C VAPOR PRESSURE: 10 mm Hg at 25.9° C DENSITY/SPEC. GRAV.: 0.87 at 20" C OCTANOL/WATER PARTITION (Kow): Log Kow = 3.15 SOLUBILITY: 0.14 g/L of water at 15° C; low solubility in water SOIL SORPTION COEFFICIENT: Koc measured at 164 silt loam; moderate mobility in soil ODOR/TASTE THRESHOLDS: Taste and odor threshold in water is 0.029 mg/L BlOCONCENTRATION FACTOR: Measured log BCF values of 0.67 to 1.9 in fish; not expected to bioconcentrate in aquatic organisms. HENRY'S LAW COEFFICIENT: 0.0084 atm-cu m/mole; rapid evappra- tion from water TRADE NAMES/SYNONYMS: Ethylbenzol, Phenylethane DRINKING WATER STANDARDS MCLG: 0.7 mg/L Met: 0.7 mg/L HAL(child): 1 day: 30 mg/L 10-day: 3 mg/L HEALTH EFFECTS SUMMARY RELEASE PATTERNS Ethylbenzene will enter the atmosphere primarily from fugitive emissions and exhaust connected with its use in gasoline. More localized sources will be emissions, waste water and spills from its production and industrial use. From 1987 to 1993, according to EPA's Toxic Chemi- cal Release Inventory, ethylbenzene releases to water totalled over 47,293 IDS., while releases to land totalled Acute: EPA has found ethylbenzene to potentially cause drowsiness, fatigue, headache and mild eye and respiratory irritation from short-term exposures at levels above the MCL. Drinking water levels which are considered "safe" for short-term exposures: For a 10-kg (22 Ib.) child consum- ing 1 liter of water per day: a one-day exposure to 30 mg/ L; a ten-day exposure to 3 mg/L. Chronic: Ethylbenzene has the potential to cause damage to the liver, kidneys, central nervous system and eyes from long-term exposure at levels above the MCL. Cancer: There is inadequate evidence to state whether or not ethylbenzene has the potential to cause cancer from a lifetime exposure in drinking water. USAGE PATTERNS Production of ethylbenzene has increased: from 6.9 billion Ibs. in 1 982 to 11 .8 billion Ibs in 1 993. The greatest use - over 99 percent - of ethylbenzene is as an interme- Jiate for styrene monomer production. Other use's include: a solvent for coatings, and in the production of synthetic rubber and cellulose acetate. Toxic RELEASE INVENTORY - RELEASES TO WATER AND LAND: 1987 Water TOTALS (in pounds) 47,293 Top Ten States TX 9,870 VI 1,233 IL 31 PR 0 VA 17,997 DE 3,460 NJ 1 ,892 NM 0 WY . 250 LA 4,383 Major Industries Petroleum refining 55,201 Plastics, resins 12,384 Indust. Organics 10,683 Pharmaceuticals 14,090 Metal containers 0 TO 1993 Land 714,580 480,164 72,245 44,789 23,980 1,950 13,324 11,510 13,076 12,755 4,552 718,884 9,212 9,781 0 11,510 * Water/Land totals only include facilities with releases greater than a certain amount - usually 1000 to 10,000 Ibs. October 1995 Technical Version ------- over 714,000 Ibs. These releases were primarily from petroleum refining industries. The largest releases oc- curred in Texas. The largest direct releases to water occurred in Virginia. ENVIRONMENTAL FATE If ethylbenzene is released to the atmosphere, it will exist predominantly in the vapor phase, based on its vapor pressure. There it will photochemically degrade by reaction with hydroxyl radicals (half-life 0.5 to 2 days) and partially return to earth in rain. It will not be subject to direct photolysis. Evaporation and biodegradation are significant in wa- ter. Ethylbenzene will evaporate rapidly from water: a half-life for evaporation from moving, shallow water is 3.1 hr. After a period of inocula adaptation, ethylbenzene is biodegraded fairly rapidly by sewage or activated sludge inoculua. As a component of gas oil, it is completely degraded in groundwater in 8 days and seawater in 10 days. No degradation was observed in anaerobic reac- tors or at low concentrations in batch reactors under denitrifying conditions. Ethylbenzene is resistant to hy- drolysis. Some ethylbenzene may be adsorbed by sedi- ment. Ethylbenzene is only adsorbed moderately by soil. The measured Koc for silt loam was 164. Its presence in bank infiltrated water suggests that there is a good probability of its leaching through soil. It will not significantly hydro- lyze in water or spil. Significant bioconcentration in fish is not expected to occur. Experimental data on the bioconcentration of ethylbenzene include a log BCF of 1.9 in goldfish and 0.67 for clams exposed to the water-soluble fraction of crude oil. This, with a calculated log BCF of 2.16 in fish, indicate that ethylbenzene should not significantly biocon- centrate in aquatic organisms. The primary source of exposure is from the air espe- cially in areas of high traffic. However, ethylbenzene is a contaminant in many drinking water supplies and levels can be quite high for wells near leaking gasoline storage tanks and for many drinking waters taken from surface waters. OTHER REGULATORY INFORMATION MONITORING: FOR GROUND/SURFACE WATER SOURCES: INITIAL FREQUENCY- 4 quarterly samples every 3 years REPEAT FREQUENCY- Annually after 1 year of no detection TRIGGERS - Return to Initial Freq. if detect at > 0.0005 mg/L ANALYSIS: REFERENCE SOURCE EPA 600/4-88-039 METHOD NUMBERS 502.2; 524.2 TREATMENT: BEST AVAILABLE TECHNOLOGIES Granular Activated Charcoal and Packed Tower Aeration FOR ADDITIONAL INFORMATION: 4 EPA can provide further regulatory and other general information: • EPA Safe Drinking Water Hotline - 800/426-4791 4 Other sources of toxicological and environmental fate data include: • Toxic Substance Control Act Information Line - 202/554-1404 Toxics Release Inventory, National Library of Medicine - 301/496-6531 • Agency for Toxic Substances and Disease Registry - 404/639-6000 October 1995 Technical Version Page 2 ------- |