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Toxicokinetics and Biomarkers/Environmental Sources of Exposure TM Normal Human Levels Levels ToxGuide

General Populations Toxicokinetics Biomarkers for . The principal source of human exposure . Bromoform and dibromochloromethane . Both compounds can be found in the to bromoform and dibromochloro- are readily absorbed from the blood and expired air; however, methane is chlorinated water supplied to gastrointestinal tract, and are likely well quantification of exposure is difficult Bromoform and homes, work, and public places. absorbed through the respiratory tract because these compounds are rapidly . The general population is primarily and skin. cleared from the body. Dibromochloro- exposed to bromoform or . In the liver, bromoform and dibromo- methane dibromochloromethane through chloromethane are metabolized by Environmental Levels ingestion of chlorinated tap water. cytochrome P-450 enzymes into carbon Air . Some bromoform and dibromochloro- dioxide or carbon monoxide. . Infrequently found in air samples, and CHBr3 and CHBr2Cl methane will volatilize into the air from . Bromoform and dibromchloromethane only at biologically irrelevant levels. normal household use of water. Thus, are rapidly eliminated from the body bathing and showering may result in almost exclusively via exhalation in either Sediment and Soil CAS# 75-25-2 and 124-48-1 April 2005 significant inhalation and dermal the unmetabolized form or as carbon . Rarely detected in sediment and soil exposure. dioxide. samples. U.S. Department of Health and . Water The general population may also be Human Services exposed to bromoform and dibromo- Normal Human Levels . Both compounds are rarely detected in Public Health Service chloromethane during swimming in nonchlorinated water samples. In . In a national survey, bromoform and Agency for Toxic Substances chlorinated pools. chlorinated water samples, studies have dibromochloromethane were infrequently and Disease Registry reported mean concentrations ranging detected (<15%) in blood samples; the www.atsdr.cdc.gov from 0.1–12 µg/L for bromoform and 1– maximum concentrations were 0.034 Occupational Populations 28 µg/L for dibromochloromethane. µg/L for bromoform and 0.024 µg/L for Contact Information: . There are limited occupational uses for bromoform and dibromochloromethane. dibromochloromethane. Division of Toxicology Reference and Environmental Medicine . Individuals who work at indoor pool facilities may be at more risk of exposure Agency for Toxic Substances and Disease Applied Toxicology Branch than the general population. Registry (ATSDR). 2005. Toxicological Profile for Bromoform and 1600 Clifton Road NE, F-62

Dibromochloromethane. Atlanta, GA: U.S. Atlanta, GA 30333 Department of Health and Human 1-800-CDC-INFO Services, Public Health Services. 1-800-232-4636

CHBr3 and CHBr2Cl

Chemical and Physical Information Routes of Exposure Relevance to Public Health (Health Effects)

Bromoform and . Inhalation – Significant route of exposure Health effects are determined Health Effects for general population from volatilized dibromochloromethane are . The main effect of swallowing or compounds. by the dose (how much), the liquids breathing large amounts of bromoform is . Oral – Predominant route of exposure duration (how long), and the . a transient slowing of normal brain Bromoform and dibromochloromethane for the general population through route of exposure. activities, resulting in sleepiness or are colorless to yellow heavy, ingestion of chlorinated tap water. sedation. nonburnable liquids with a sweet odor. They are typically found dissolved in . Dermal – Significant route of exposure Minimal Risk Levels (MRLs) . Exposure to high doses of bromoform or water or as airborne vapors. for general population through bathing, Inhalation dibromochloremethane can result in liver showering, and possibly swimming in and kidney injury within a short time. . These chemicals are possible chlorinated pools. Can be a major route . No inhalation MRLs were derived for . Oral exposure to high levels of contaminants of chlorinated drinking during occupational exposures. bromoform or dibromochloromethane. bromoform or dibromochloromethane water. They may also form when Oral can result in accumulation of fat in the chlorine reacts with decomposing plant . material in water. Bromoform and An MRL of 0.7 mg/kg/day was derived for liver, serum chemistry changes, and focal acute-duration oral exposure to bromoform . hepatocellular necrosis. Renal effects Bromoform is only produced in small Dibromochloromethane in the (≤14 days). have been observed following exposure amounts for use in laboratories and in Environment of lab animals to dibromochloromethane. geological and electronics testing. . An MRL of 0.2 mg/kg/day was derived . Bromoform and dibromochloromethane for intermediate-duration oral exposure . . Exposure to low levels of bromoform or Dibromochloromethane is only used on a enter the environment through the to bromoform (15–364 days). dibromochloremethane do not appear to small scale in laboratories at present. disposal of chlorinated water or as vapors . An MRL of 0.02 mg/kg/day was derived seriously affect brain, liver, or kidneys. emitted from chlorinated water. for chronic-duration oral exposure to . Death has been reported in humans after . Bromoform and dibromochloromethane bromoform (≥1 year). accidental overdose of bromoform when are broken down much slower in surface . An MRL of 0.1 mg/kg/day was derived used as a sedative. Toxic effects included water than in deep or underground water. for acute-duration oral exposure to severe central nervous system depression . Bacteria in water and soil may break dibromochloromethane (≤14 days). and respiratory failure. down these compounds, but the speed at . No intermediate-duration oral MRL was . In animal studies, oral exposure to very which they do so in unknown. derived for dibromochloromethane (15– high doses of both compounds resulted . Bromoform and dibromochloromethane 364 days). in labored breathing and death due to central nervous system depression. are mobile in soil and may seep into . An MRL of 0.09 mg/kg/day was derived groundwater. for chronic-duration oral exposure to . Bioconcentration in fish does not appear dibromochloromethane (≥1 year). Children’s Health to occur. . It is not known if children are more susceptible to bromoform or dibromochloromethane poisoning than adults.