The average concentration of PBDEs in blood from the dogs was about 2 nanograms per gram, about five to 10 times higher than the levels found in humans in the few studies of human exposure that have been done in North America.
In dog food samples, the researchers found PBDEs at levels averaging about 1 nanogram per gram. That is much higher than levels found in meat and poultry sold as food for humans, suggesting the PBDEs in dog food may result from processing rather than from the food sources.
A 2007 study by Venier, Hites and several co-authors found concentrations of PBDEs in house cats that were 20 to 100 times higher than levels found in humans. A 2010 article by Venier, Hites and two Clemson University researchers also reported high levels of PBDEs in nesting bald eagles.
Venier said the evidence shows dogs metabolize the compounds more rapidly than cats. A previous study showed that dogs produce an enzyme that breaks down organochlorine pesticides, and a similar mechanism may be at work with brominated compounds.
The current study also detected newer flame retardants that have come onto the market as PBDEs have been removed, including Dechlorane Plus, decabromodiphenylethane, and hexabromocyclododecane. The chemicals are largely unregulated but pose concerns because they are structurally similar to organic pollutants that have been linked to environmental and human health effects.
"The concentrations of these newer flame retardants were relatively low compared to the PBDEs," Venier said, "but the fact that they are new and not regulated suggests their levels are going to increase in the future."
|Contact: Steve Hinnefeld|