SETAC Globe - Environmental Quality Through Science
  21 January 2011
Volume 12 Issue 1

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Pyrethroids in the Environment Session at 2010 SETAC North America Annual Meeting, Portland, Oregon

Patti TenBrook and Elin Ulrich, U.S. Environmental Protection Agency

Pyrethroids encompass over 40 different chemicals in over 3,500 registered pesticide products and are among the most widely used insecticides in both agricultural and household products. Although they are known for their low toxicity to mammals and tendency to degrade when exposed to sunlight, pyrethroids are still of concern in the environment because of their toxicity to  non-target organisms, particularly aquatic invertebrates, and accumulation in sediments.

Pyrethroids are a topic of interest for the SETAC community primarily because of their impact on ecosystems. Using laboratory and field measurements we can better understand the exposure and fate pathways, toxicity, and risk of pyrethroids in the environment. Product registration, design, and use practices can then move toward more sustainable and protective alternatives. The last SETAC NA session that focused on pyrethroids (“Evaluation of the Synthetic Pyrethroids in the Urban and Agricultural Environment”) was held in 2007 in Milwaukee. To highlight the current state of knowledge across a broad range of topics, the “Pyrethroids in the Environment” session was presented at the 31st Annual Meeting of SETAC North America.

In this session co-chaired by Renee Falconer, Pete Halpin, Patti TenBrook, and Elin Ulrich, 23 speakers presented papers all day Monday and Tuesday morning, with six posters presented on Wednesday. The contributing researchers explored many aspects of pyrethroids in the environment, including ecological risk assessment, mammalian metabolism, integration and reconciliation of laboratory and field data, occurrence in a variety of settings, fate processes and modeling, endocrine disruption, analytical methods, biomagnification and bioaccumulation, urban pyrethroid use and fate, derivation of water quality criteria, toxicity, and toxicity identification evaluations. Several presentations noted that laboratory toxicity tests may not be correctly predicting environmental impacts. For example, researchers reported cases in which pyrethroids were detected in sediment or water samples at concentrations expected to be toxic, but samples were not found to be toxic. Further research on the bioavailability, enantiomer-specific toxicity and degradation, habitat effects, and co-occurrence of pyrethroids and sensitive aquatic life is needed to determine what factors may mitigate toxicity in the environment.

A discussion at the end of the day-and-a-half session highlighted the need for more and better analytical methods and for reference materials for pyrethroids in environmental matrices. A participant noted that it appears that a small fraction of pyrethroid applications contribute to a large fraction of the water quality problems we are seeing, and that by focusing on those few active ingredients, application methods and/or formulations many problems could be resolved. Another participant noted that the session did not offer much in the way of new information, and that it was time to start working on solving the problems that have been identified.

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