Impact/Purpose:

Develop reference dose and preliminary remediation goal for weathered toxaphene to evaluate contaminated fish and sediment at Tery Creek and Hercules 009 landfill sites. Identify key data gaps and suggest research to gain further information on toxic mode of action of weathered toxaphene.

Description:

Coastal/estuarine sediments are repositories for persistent organic pollutants (POPs). Sediment-associated POPs such as the chlorinated pesticide toxaphene accumulate in aquatic wildlife with the potential for transferred to higher organisms (fish, marine mammals, birds, humans) through the food web. Toxaphene is a mixture of chlorinated camphenes and bornanes that was produced and used in the United States until 1982. Toxaphene has the distinction of being the most used pesticide in history with 1.3 million tons having been released worldwide. So-called "Technical" Toxaphene (TT) consists of a mixture of up to 800 different chemicals, known as congeners. Once in the environment, technical toxaphene undergoes "weathering" by both biotic and abiotic processes and the number and identity of the chemicals in "weathered" toxaphene (WT) are different than TT. One aspect of the weathering of TT is that the current human body burden consists of five congeners only, with three congeners predominant. These are considered the three persistent congeners (p-26, p-50 and p-62) (�3PC). A significant gap in our knowledge of the WT toxicity is the mode of action: is it the persistent congeners that make up the human body burden or the metabolism and/or metabolites of the non-persistent congeners that account for the adverse effects of WT? This project culminated in a publication: Simon T, Manning R. Development of a reference dose for the persistent congeners of weathered toxaphene based on in vivo and in vitro effects related to tumor promotion. Regulatory Toxicology and Pharmacology 44 (2006) 268–281.

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