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Toxicokinetics and Biomarkers/Environmental Sources of Exposure Biomonitoring Levels

General Populations Toxicokinetics Biomarkers TM

. There are no known natural sources of . There are no data regarding the . Hexachlorobutadiene can be measured in ToxGuide hexachlorobutadiene. The predominant toxicokinetics of hexachlorobutadiene in blood and adipose tissue. source of hexachlorobutadiene is its humans, but there are limited data from . Hexachlorobutadiene metabolites can be

production as a waste byproduct of studies in animals. detected in urine. for

chlorinated synthesis. . Based on health effects and excretion . The general population can be exposed data in animals, hexachlorobutadiene is Environmental Levels to low levels of hexachlorobutadiene absorbed following inhalation, oral, or Hexachloro- through ingestion of contaminated food dermal exposure. Air and water and inhalation. . Absorbed hexachlorobutadiene is . There are no recent monitoring data for distributed throughout the body, with the levels of hexachlorobutadiene in air. Occupational Populations highest concentrations found in the . In the late 1970 and early 1980s, . kidney, liver, and fat. hexachlorobutadiene levels ranged from Occupational exposure is most likely to 2 to 11 ppt. occur for workers employed at . The predominant pathway for chlorinated hydrocarbon production hexachlorobutadiene metabolism is C4Cl6 plants or involved in manufacturing conjugation with glutathione in the liver Water rubber compounds. and subsequent metabolism to form . There are no recent monitoring data for (CAS # 87-68-3) cysteine conjugates. The cysteine levels of hexachlorobutadiene in water. March 2021 conjugates can be further metabolized by . In the mid-1980s, concentrations of 1.6– β-lyase to form reactive intermediates. . 2.7 ppt were detected in drinking water The major route of excretion of samples from two cities. hexachlorobutadiene is expiration of the U.S. Department of Health and parent compound or metabolite (carbon Sediment and Soil Human Services dioxide) through the lung, urinary Public Health Service excretion of metabolites and parent . There are no recent monitoring data for Agency for Toxic Substances compound, and fecal excretion of parent levels of hexachlorobutadiene in compound and metabolites. sediment or soil. and Disease Registry www.atsdr.cdc.gov

NHANES Biomonitoring Reference . Hexachlorobutadiene has been detected Agency for Toxic Substances and Disease in human adipose and liver tissue. Registry (ATSDR). 2021. Toxicological However, information regarding levels in Profile for Hexachlorobutadiene. Atlanta, the general population is lacking. GA: U.S. Department of Health and Human Services, Public Health Services.

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

Hexachlorobutadiene is a . Inhalation – Most likely route of Health effects are determined Health Effects Manufactured Substance exposure route for the general and by the dose (how much), the . Studies in experimental animals suggest occupational population. duration (how long), and the that the kidney, respiratory tract, and . Hexachlorobutadiene is a colorless liquid developing organisms are sensitive targets . Oral – Most likely route of exposure for with a -like odor. route of exposure. of hexachlorobutadiene toxicity. the general population through ingestion . Hexachlorobutadiene is manufactured by of contaminated food stuffs and water. . Kidneys are the most sensitive target to the chlorination of hexyl oxide. It is also . Dermal – Not likely an exposure route of hexachlorobutadiene. Renal toxicity, produced as a waste byproduct of concern for the general population. Minimal Risk Levels (MRLs) characterized as histological damage and manufacturing certain chlorinated Inhalation alterations in biomarkers of impaired . renal function, has been observed . No acute-, intermediate-, or chronic- Hexachlorobutadiene in the following inhalation, oral, and dermal duration inhalation MRLs were derived . Hexachlorobutadiene’s principal use is as exposures of hexachlorobutadiene in Environment for hexachlorobutadiene. a chemical intermediate in the experimental animals. manufacture of rubber compounds. . Hexachlorobutadiene may be released . Respiratory effects, characterized as nasal into the environment from industrial Oral . To a lesser extent, hexachlorobutadiene is facilities or by disposal of waste in landfill irritation, decreases in respiratory rate, used as a , a fluid for gyroscopes, operations. . An acute-duration (≤14 days) oral MRL and breathing difficulties, have been a heat transfer liquid, a hydraulic fluid, of 0.006 mg/kg/day was derived for observed in rats and mice exposed to . Hexachlorobutadiene adsorbs to soil with and a chemical intermediate in hexachlorobutadiene. hexachlorobutadiene vapor. high organic carbon content. production of chlorofluorocarbons and Volatilization from surface soils is . An intermediate-duration (15–364 days) . Inhalation and oral exposure of lubricants. relatively low. oral MRL of 0.002 mg/kg/day was hexachlorobutadiene in rats resulted in derived for hexachlorobutadiene. decreased fetal or pup body weights and . Hexachlorobutadiene has preferential decreased maternal body weight gain. partitioning to sediment and biota over . A chronic-duration (≥365 days) oral water. Surveys report higher levels of MRL was not derived for . The U.S. Environmental Protective hexachlorobutadiene in sediments than in hexachlorobutadiene. Agency (EPA) classified the waters that contain them. hexachlorobutadiene as a possible human carcinogen (Group C). The . Hexachlorobutadiene can exist in the International Agency for Research on atmosphere as a vapor or adsorbed to Cancer (IARC) categorized airborne particulate matter. Volatilization hexachlorobutadiene as not classifiable occurs from surface water, yet is reduced as to its carcinogenicity in humans by adsorption to organic material in the (Group 3). water.

. In air, it will likely react with reactive oxygen species and have a half-life Children’s Health ranging from 60 days to 1.6 years. The . It is not known if children are more estimated half-life in surface water is sensitive to hexachlorobutadiene estimated to be between 3 and 300 days. exposure than adults.