Dense Nonaqueous Phase Liquids (DNAPLs)
Environmental Occurrence
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Halogenated Monoaromatics
1,2-Dichlorobenzene
1, 2-dichlorobenzene (1,2-DCB) is employed primarily as a precursor to 3,4-dichloroaniline, which is used in the production of herbicides. The compound is also used as a solvent, in the synthesis of dyes, and in odor control products. The chemical formerly was used as a soil fumigant, insecticide, and herbicide (HSDB).
1,2-DCB had been reported at at least 281 NPL sites (ASTDR 2006).
EPA's Toxics Release Inventory reports that 95,682 pounds of 1,2-DCB were released or disposed of in 2007. This is a minimum estimate as some emissions do not fall under EPA's reporting requirements. The reported releases generally were point source or fugitive emissions to the air (38,025 pounds) or injections into deep wells (29,813 pounds).
In a U.S. Geological Survey nationwide investigation of water quality in public and private water wells, 1,2-DCB was detected in both domestic and public supply wells at very low levels, with none exceeding the 600 µg/L maximum contaminant level (MCL) for drinking water. The compound was detected in 0.41 percent of samples taken from aquifers, also at very low levels (Zogorski et al. 2006).
References
1,2-Dichlorobenzene, CASRN: 95-50-1
Hazardous Substances Data Base (HSDB)
TOXNET, National Library of Medicine Web site.
The Quality of Our Nation's Waters: Volatile Organic Compounds in the Nation's Ground Water and Drinking-Water Supply Wells
Zogorski, J., J.M. Carter, T. Ivahnenko, W.W. Lapham, M.J. Moran, B.L. Rowe, P.J. Squillace, and P.L. Toccalino.
U.S. Geological Survey Circular 1292, 112 pp, 2006
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.