Dense Nonaqueous Phase Liquids (DNAPLs)

Halogenated Alkanes

1,2-Dichloropropane

Human Health Toxicity

1,2-Dichloropropane (1,2-DCP), sometimes referred to as propylene dichloride, has industrial use as a solvent and feedstock in the production of other chlorinated solvents, such as carbon tetrachloride and tetrachloroethene. Although no longer used as a soil fumigant in the U.S., the compound might be present as an impurity in soil fumigant preparations containing closely related chemicals. The general population could be exposed to 1,2-DCP by the ingestion of contaminated drinking water, or by inhaling the compound in ambient air. Any occupational exposure could be expected to occur via inhalation or dermal contact (Polakoff 1999).

Animal studies indicate that 1,2-DCP is absorbed rapidly from the gastrointestinal tract and lung, and its lipophilic nature suggests that it can be absorbed via dermal contact. Once absorbed, the compound is distributed throughout the body, achieving the highest concentrations in liver and kidney. 1,2-DCP is metabolized in the liver, and some of its metabolic products are excreted in urine and, to a lesser extent, in expired air (ATSDR 1989).

Humans (truck drivers, highway patrol officers, fire fighters, and hospital employees) exposed to DCP following the accidental spill of 2000 gallons from a truck complained of chest discomfort, dyspnea, and cough, and some had persistent chest pain or discomfort and fatigue (IRIS). High doses of 1,2-DCP are acutely toxic to humans via inhalation or ingestion. Case reports of accidental poisoning and suicide attempts describe adverse effects on the central nervous system, liver, and kidney. There are no data describing the carcinogenicity of 1,2-DCP to humans. A long-term rodent study performed by the National Toxicology Program found equivocal evidence for 1,2-DCP carcinogenicity in female rats, and some evidence of carcinogenicity in male and female mice (Polakoff 1999).

No human data are available that describe the reproductive and developmental toxicity of 1,2-DCP. A two-generation study did not identify reproductive effects on male and female rats. An increase in neonatal mortality and lower birth-weight were observed in the high dose group, but were considered to be secondary to maternal toxicity (Polakoff 1999).

1,2-DCP gave negative and positive results in an array of standard in vitro genotoxicity assays that employ microbiological and mammalian test systems. In vivo assays, using the fruit fly and rat as test subjects, yielded negative results (Polakoff 1999).

References

1,2-Dichloropropane (CASRN 78-87-5)
U.S. EPA, Integrated Risk Information System (IRIS)

Public Health Goal for 1,2-Dichloropropane in Drinking Water
Polakoff, J.
California EPA, Office of Environmental Health Hazard Assessment, 31 pp, 1999

For Further Information

1,2,-Dichloropropane, CAS No: 78-87-5
OECD SIDS: OECD Initial Assessment Reports for High Production Volume Chemicals, including Screening Information Datasets (SIDS).
United Nations Environment Program, 219 pp, 2006

1,2-Dichloropropene, 1,2-Dichloropropane and Mixtures: Health and Safety Guide
World Health Organization (WHO), Health and Safety Guide No. 76, 1992

Toxicological Profile for 1,2-Dichloropropane
Agency for Toxic Substances and Disease Registry (ATSDR), 2021

Ecological Toxicity

The Pesticide Action Network (PAN) North America Pesticides Database summarizes the acute toxicity data for 1,2-DCP as "not acutely toxic to slightly toxic" to crustaceans and fish, and "slightly toxic" to zooplankton. DOE (1999a) provides an aquatic toxicity reference value (TRV) for surface water organisms. No studies were found that describe the toxicity of 1,2-DCP to terrestrial receptors, but DOE (1999b) provides a TRV for earthworms.

References

1,2-Dichloropropane: Identification, Toxicity, Use, Water Pollution Potential, Ecological Toxicity, and Regulatory Information
Kegley, S.E., B.R. Hill, S. Orme, and A.H. Choi.
PAN Pesticide Database. Pesticide Action Network, San Francisco, CA, 2009

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

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

Terrestrial Toxicity Reference Values
U.S. DOE
Manual ERD-AG-003 Revision 0 (TRVs), 1999b

This 13-page Department of Energy manual provides toxicity reference values for earthworms, various mammals, and various bird species.