Department of Environmental & Aquatic Animal Health - News, Events & Recent publication

VIMS Environmental Scientists Spearheading New Research in USA

By Robert Hale and Wanda Cohen
The Crest: Volume 3, No. 2, Fall 2001

In a recent issue of Nature Dr. Rob Hale, Mark La Guardia and colleagues at the Virginia Institute of Marine Science reported on their recent work investigating BDEs (brominated diphenyl ethers), a class of environmentally persistent organic pollutants. These compounds serve as flame-retardants in a variety of polymers, such as furniture foam and in plastics used in the casings of electronics, including TVs and computers. Currently, North America accounts for 98% of the world’s demand for the particular BDE product viewed as the most environmentally problematic. BDEs are structurally related to PCBs and PBBs. The use of the latter compounds are banned or restricted in the U.S. Hale's group has detected BDEs in fish, sediments and sewage sludges. They also detected these pollutants in high concentrations in "biosolids", sewage sludges used in agriculture, landscaping and land reclamation. This finding is particularly noteworthy as millions of tons of sludge are recycled in this manner each year and thus the practice may reintroduce BDEs to the environment. The lower brominated BDEs bioaccumulate in wildlife and have begun to be detected in humans. Limited toxicity studies have been conducted to date, mostly in Europe. Results suggest a possible interaction with the endocrine system.

While BDEs have been a concern in Europe for several years and will be banned there in 2003, research in the U.S. is just beginning. According to Hale, "Europeans have been particularly concerned over increasing concentrations of BDEs in human breast milk. We know about some of the effects of PCBs and PBBs. Since these compounds are related, we feel more information on their sources, effects and fate are needed. In addition, further attention to possible organic contaminants present in land applied "biosolids" is merited."

In this light, a paper documenting high concentrations of nonylphenols and related detergent breakdown products in these same sludges, authored by La Guardia, Hale and coworkers, has also recently been accepted in Environmental Science and Technology. These findings further indicate the need to fully examine the chemical constituents of sludge and possible repercussions of their land application. The papers have been provided to the National Academy of Sciences review panel evaluating the current risk assessment underlying the regulations developed by the US EPA pertaining to biosolids safety.

The researchers publicly released their BDE findings at the invitation of the Swedish Chemical Society at the Brominated Flame Retardants Workshop held at the University of Stockholm in May 2001. They also were recently invited to present their results at the US EPA's National Health and Environmental Effects Research Laboratory in Research Triangle Park, NC in September 2001, as well as by organizers of a conference at the Boston University School of Public Health entitled "Sewage Sludge on Land: Public Health and Environmental Impacts", scheduled for November 2001.

Ongoing work being conducted by graduate students Mike Gaylor and Serena Ciparis is examining the bioavailability of BDEs to aquatic and terrestrial organisms. Researchers in the lab are also investigating improved methods for detecting these chemicals in the environment and establishing sources of their release and ultimate fate.