Wednesday, March 23, 2011

PBDEs and Biosolids

A decade has passed since I first heard the term “PBDEs.” Having been intimately engaged in a response to illegal discharge of PCBs to Philadelphia sewers a few years prior, I had experience which informed my intuition that this class of compounds, disconcertingly alliterative with PCBs, would prove to be no friend to biosolids.

Science has now provided a picture of the exposures to PBDEs in the world environment. The recent issue of Environmental Science & Technology contains an article by David Trudel, et al, “Total Consumer Exposure to Polybrominated Diphenyl Ethers in North America and Europe” (Environ. Sci. Technol. 2011, 45, 2391–2397; It synthesizes an enormous body of work across the world and across ecological systems—water, air and land.

Trudel’s article sparked in me some sharp memories from a full ten years ago. In July 2001, against the backdrop of the crashing waves in Ocean City, MD, on an outdoor patio on which biosolids folks gathered to confer, Rhonda Bowen from Hampton Roads took a cellphone call from her boss. A researcher at the Virginia Marine Institute, Rob Hale, had a Nature magazine article reporting concentrations of a class of persistent organic pollutants known as “PBDEs” in sediments from the same watershed in which land application of biosolids had been practiced. Dr. Hale had intended to implicate biosolids as a source, although even with the meager information available to us on such pollutants, a meaningful link seemed farfetched. A response by the biosolids profession was needed. A full year would go by before the scientific community would see a thorough, peer-reviewed article sources and potential pathways of this class of contaminants (De Wit, C. A. “An overview of brominated flame retardants in the environment.” Chemosphere 2002, 46, 583–624. ).

The present article in ES&T, based on the vigorous response by the scientific community, has now put the issue in perspective. Biosolids is nowhere to be found in the article, as household dust and widespread atmospheric deposition on animal-grazed fields are now understood to be major sources.

I take solace in the observation that biosolids both concentrates persistent organics like PBDEs as well as concentrates the scientific community’s attention to emerging issues, like society’s use of high production chemicals.

Perhaps, the biosolids profession should take a leadership role in advocating responsible stewardship by industries in their choices for chemical inputs to consumer products that may persist in the environment. While the biosolids profession may be the unwitting recipients of the residuals from manufactured goods, all too often the profession takes the public blame for its presence in the environment. Against this tendency we need to have a strategy that deploys sound science and risk assessment, and one that anticipates, rather than merely reacts to, issues of public concern.

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