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)

Chemistry and Behavior

Halogenated Monoaromatics

1, 3-Dichlorobenzene

1,3-Dichlorobenzene (1,3-DCB CAS# 541-73-1) has a vapor pressure of 2.15 mmHg at 25oC (ATSDR 2006) and is a combustible liquid (flash point 63oC) (OSHA 2007). The log Koc of 1,3-DCB is 2.47, the log Kow is 3.53, and the Henry's constant is 2.8 e-3 atm-m3/mol at 25oC. The solubility of the compound is about 125 mg/L at 20oC (ATSDR 2006), and its specific gravity is about 1.29 (20oC). The toxicological profile for dichlorobenzenes developed by the Agency for Toxic Substances and Disease Registry contains a useful summary tableAdobe PDF Logo of the physical properties of 1,2-, 1,3-, and 1,4-DCB.

The calculated Koc value for 1,3-DCB in soil indicates that the chemical is likely to have a moderate mobility in soil and sediment. Some sorption to suspended sediments can be expected (HSDB).

Based on a Henry's law constant of 1.92 e-3 atm-m3/mol at 25oC, 1,3-DCB is expected to volatilize rapidly from water surfaces (ATSDR 2006). Modeling information for this chemical in the Hazardous Substances Data Bank (HSDB) suggests that the half life of 1,3-DCB in a model river is about 4 hours, and about 120 hours in a model lake.

Because of the relatively high Kow of 1,3-DCB, bioaccumulation is expected (ATSDR 2006), with moderate to high bioaccumulation in aquatic organisms (HSDB). Microbial degradation of 1,3-DCB can occur under anaerobic conditions, but it is slow (HSDB). The compound DCB will degrade under aerobic conditions (Lawrence 2006, Werner and Tiehm 1999).

When released to the atmosphere, hydroxyl radicals are expected to degrade 1,3-DCB with a half life of about 22 days. Direct photolysis is not expected to occur (HSDB).


1,3-Dichlorobenzene, CASRN: 541-73-1
Hazardous Substances Data Bank (HSDB)
TOXNET, National Library of Medicine Web site.

Chemical Sampling Information: m-Dichlorobenzene
Occupational Safety & Health Administration (OSHA), 2007

Description, Properties, and Degradation of Selected Volatile Organic Compounds Detected in Ground Water: A Review of Selected LiteratureAdobe PDF Logo
Lawrence, S.J.
U.S. Geological Survey Open-File Report 2006-1338, 65 pp, 2006

This report contains a discussion of the biodegradation of chorobenzenes under aerobic and anaerobic conditions and provides degradation routes.

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.

For Further Information

DNAPL Site Evaluation
Cohen, R. and J. Mercer.
EPA 600-R-93-022, 369 pp, 1993

This document has a broad discussion of DNAPL site evaluation and contains a comprehensive table of physical properties of selected DNAPL chemicals, including 1,2-DCB, in its Appendix A.

Reductive Dehalogenation of Dichlorobenzenes and Monochlorobenzene to Benzene in Microcosms
Fung, J.M., B.P. Weisenstein, E.E. Mack, J.E. Vidumsky, T.A. Ei, and S.H. Zinder.
Environmental Science & Technology 43(7):2302-2307(2009)
View abstract