| Summary: | This review examines the potential for y-hexachlorocycio-hexane (HCH) to be transformed into other isomers of HCH. HCH residues are among the most widely distributed and frequently detected organochlorine contaminants in the environment. The potential environmental and human health risks associated with these residues have prompted Canada, the United States, and Mexico to consider the development of a North American Regional Action Plan (NARAP) to assess and mitigate HCH pollution. More information on the propensity of y-HCH to transform into other isomers is essential to the development of an effective regional management program. The high relative concentrations of a-HCH in the Arctic suggest that y-HCH may be transformed into other isomers in the environment. Laboratory studies show that significant photoisomerization of y-HCH to a-HCH is possible. However, field studies do not find evidence for significant isomerization of y-HCH, and recent environmental samples suggest that a-HCH residues are declining asthe use of technical HCH has ended in most parts of the world. Alternative explanations for the patterns of isomer contamination are discussed. This manuscript has been reviewed in accordance with the U.S. Environmental Protection Agency's peer and administrative review policies and approved for publication. Mention of trade names or commercial products does not constitutute an endorsement or recommendation for use.
|
|---|