U.S. EPA Contaminated Site Cleanup Information (CLU-IN)

U.S. Environmental Protection Agency
U.S. EPA Technology Innovation and Field Services Division

Dense Nonaqueous Phase Liquids (DNAPLs)



Human Health Toxicity

1,3-Dichlorobenzene (1,3-DCB) may be released to the atmosphere during its manufacture and use. It is assumed that the general population is exposed to 1,3-DCB by inhaling ambient air. Concentrations of the compound generally are low in soil, water, and food.

No human or animal data are available on the absorption of 1,3-DCB, but the compound (or its metabolites) has been detected in human breast milk, blood, and fat, so absorption can be inferred. In addition, it has been detected in the bile and urine of exposed animals. This compound is metabolized by cytochrome P 450 enzymes, and also undergoes conjugation. The products of 1,3-DCB metabolism are eliminated in urine.

There are no available studies of the toxicity of 1,3-DCB in humans, and there are very few animal toxicity studies. One study of intermediate duration, investigating the oral toxicity of 1,3-dichlorobenzene in rats, showed effects in the thyroid and pituitary glands and liver. Thyroid lesions appeared at doses causing liver and pituitary effects. EPA's Integrated Risk Information System (IRIS) classifies 1,3-DCB as "D; not classifiable as to human carcinogenicity," based on no available human or animal data, and limited genetic data.

No data are available for the reproductive effects of 1,3-DCB in either humans or animals. One developmental study in rats, reported only as an abstract, did not note any effects on prenatal development; however, no detailed findings from this study are available.

There is limited evidence for the genotoxicity of 1,3-DCB, but results from a study of the fungus Aspergillus nidulans, though positive, did not achieve statistical significance.


Toxicological Profile for Dichlorobenzenes
Agency for Toxic Substances and Disease Registry (ATSDR), 493 pp, 2006

This profile provides information on human health effects, fate and transport, production, and uses of all three dichlorobenzenes: 1,2-, 1,3-, and 1,4-DCB.

1,3-Dichlorobenzene (CASRN 541-73-10)
U.S. EPA, Integrated Risk Information System (IRIS)

Ecological Toxicity

Little information is available on the ecological toxicity of 1,3-DCB; however, Malcolm et al. (2004) report the results of acute 1,3-DCB studies that used fresh and saltwater invertebrates and fish as test subjects. In addition, results are reported of chronic toxicity tests that employed the water flea Daphnia magna, and green algae for the endpoints EC50 reproduction, and EC50 population.

A preliminary remediation goal (PRG) and aquatic toxicity reference values (TRVs) for 1,3-DCB are provided in DOE (1999) and Efroymson et al. (1997), respectively.


Chlorobenzenes Other Than Hexachlorobenzene: Environmental Aspects
Malcolm, H.M., P.D. Howe, and S. Dobson.
World Health Organization, Concise International Chemical Assessment Document 60, 2004

Aquatic Toxicity Reference Values
U.S. DOE. Manual ERD-AG-003 Revision 0, 1999

A 10-page Department of Energy document with toxicity reference value tables for surface water organisms.

Preliminary Remediation Goals for Ecological EndpointsAdobe PDF Logo
Efroymson, R.A., G.W. Suter II, B.E. Sample, and D.S. Jones.
ES/ER/TM-162/R2, 41 pp, 1997

Other DNAPLs Toxicology Topics: