United States Environmental Protection Agency Office of Water 4601 EPA811-F-95-003k-T October 1995 National Primary Drinking Water Regulations Dinoseb CHEMICAL/ PHYSICAL PROPERTIES CAS NUMBER: 88-85-7 COLOR/ FORM/ODOR: Yellow/orange crystals; pungent odor M.P.: 38-42° C B.P.: N/A VAPOR PRESSURE: 1 mm Hg at 151.1° C OCTANOL/WATER PARTITION (Kow): N/A DENSITY/SPEC. GRAV.: 1.26 at 45° C SOLUBILITY: 0.052 g/L of water at 25° C; tends to form salts which are highly soluble in water SOIL SORPTION COEFFICIENT: Koc =124 (measured); high mobility in soil ODOR/TASTE THRESHOLDS: N/A BlOCONCENTRATION FACTOR: BCF = 68 (est.); not expected to bioconcentrate in aquatic organisms. HENRY'S LAW COEFFICIENT: 5.04x10-* atm-cu m/mole (est.) TRADE NAMES/SYNONYMS: 2,4-dinitro-6-(1 -methyl-propyl) phenol; Dinitrobutylphenol; Aatox; Chemox; Gebutox; Knox-weed; Basantte; BNP 20; Butaphene; Dibutox; Dinitrall; Dinitro; Desicoil; Dow Selective Weed Killer; Hivertox; Ladob; Laseb; Nitropone C; Dytop; Premerge; Hel-fife; Caldon; Kiloseb; Sinox General; Subitex. DRINKING WATER STANDARDS MCLG: 0.007 mg/L MCL: 0.007 mg/L HAL(child): 1 to 10 day: 0.3 mg/L Longer-term: 0.01 mg/L HEALTH EFFECTS SUMMARY Acute: EPA has found dinoseb to potentially cause the following health effects from acute exposures at levels above the MCL: sweating, headache, mood changes. 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- to ten- day exposure to 0.3 mg/L or tip to a 7-year exposure to 0.01 mg/L. Chronic: Dinoseb has the potential to cause the following health effects from long-term exposures at levels above the MCL: decreased body and thyroid weight, degeneration of testes; thickening of intestinal lining. Cancer: There is inadequate evidence to state whether or not dinoseb has the potential to cause cancer from lifetime exposure in drinking water. \JSAGE PATTERNS Dinoseb is a contact herbicide used as the ammonium oramine salt for post-emergence weed control in cereals, undersown cereals, seedling lucerne and peas. Oil solutions of dinoseb are used for pre-emergence control of annual weeds in beans, peas and potatoes, for pre-harvest dessication of hops, leguminous seed crops, potatoes and for control of runners and suckers in straw- berries and raspberries. Dinoseb is also used as a com yield enhancer and an insecticide and miticide. 1982 production of dinoseb was reported as 6.2 million Ibs., with consumption estimates as follows: as an herbi- cide for soybeans, 32%; vegetable, 23%; deciduous fruits and nuts, 11%; peanuts, 8%; citrus, 3%; grain crops, 2%; other field crops, 6%; industrial/commercial uses, 15%. RELEASE PATTERNS Release of dinoseb has resulted primarily from its use as an herbicide on a variety of weeds. Since dinoseb is not a listed chemical in the Toxics Release Inventory, data on releases during its manufac- ture and handling are not available. ENVIRONMENTAL FATE Dinoseb is expected to biodegrade in slowly and bind weakly to soil. Therefore, leaching in soil is possible and dinoseb has been detected in groundwater. However, it may bind more strongly to clay soils, especially at acidic pH. Photolytic degrdration of dinoseb from soil surface may be important. Volatilization is not expected to be significant. The laboratory-measured evaporation half- October 7995 Technical Version Printed on Recycled Paper ------- life for dinoseb from a soil surface was 26 days. In the absence of volatilization, the half-life of dinoseb in the vadose zone sandy loam soil was estimated to be about 100 days. Dinoseb may photodegrade in surface water with a half-life of 14-18 days. The estimated Henry's Law con- stant of 5.04X10-4 atm cu m/mol suggests that volatiliza- tion of dinoseb from water will be slow. It is unlikely to undergo significant biodegradation in most natural wa- ters. Volatilization from water is expected to be slow. . The half-life for the reaction of vapor phase dinoseb with photochemically generated hydroxyl radicals in the atmosphere was estimated to be 14.1 days. Wet deposi- tion may remove some of the compound from air. Bioconcentration is expected to be insignificant. A bioconcentration factor (BCF) of 68 for dinoseb was estimated from its water solubility (50 mg/L). Exposure to dinoseb in humans is expected to occur primarily in workers using the herbicide. OTHER REGULATORY INFORMATION MONITORING: FOR GROUND/SURFACE WATER SOURCES: INITIAL FREQUENCY- 4 quarterly samples every 3 years REPEAT FREQUENCY- If no detections during initial round: 2 quarterly per year if serving >3300 persons; 1 sample per 3 years for smaller systems TRIGGERS - Return to Initial Freq. if detect at > 0.0002 mg/L ANALYSIS: REFERENCE SOURCE METHOD NUMBERS EPA 600/4-88-039 515.1; 515.2; 555 TREATMENT: BEST AVAILABLE TECHNOLOGIES Granular Activated Charcoal FOR ADDITIONAL INFORMATION: * EPA can provide further regulatory and other general information: • EPA Safe Drinking Water Hotline - 800/426-4791 4 Other sources of lexicological 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 • National Pesticide Hotline - 800/858-7378 October 1995 Technical Version Page 2 ------- |