A 2007 study conducted at Indiana University (IU) found significant concentrations of flame retardants in the blood of pet dogs.
Polybrominated diphenyl ethers (PBDEs) were discovered at levels 5 to 10 times higher in dogs, and in a previous study, 20 to 100 times higher in cats than levels found in humans in North America. Research indicates dogs metabolize the compounds faster than cats do. 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.
PBDEs are used as flame retardants in furniture and electronics. The compounds are known to leak from these products into the environment.
The study, Flame Retardants in the Serum of Pet Dogs and in Their Food, was performed at the Indiana University School of Public and Environmental Affairs (SPEA), and published in the journal Environmental Science & Technology.
Research scientists measured the presence and levels of PBDEs in the blood of 17 dogs of various breeds. These were primarily indoor pets. They also measured levels of PBDEs in commercial dry dog food to find out whether the pets' diets were the main source of PBDE exposure.
PBDE levels in dog food samples were found to be much higher than levels found in meat and poultry for human consumption. The study pointed to the probability PBDEs in dog food result from processing rather than from ingredients.
According to Marta Venier, assistant research scientist, IU SPEA:
"We confirmed the predominance of one specific compound among PBDEs, BDE-209, in dry dog food (in the cats study we showed that dry food, as opposed to canned food, contained high levels of this compound). We suspect that its presence in the food is not due to the raw materials used (i.e. poultry or meat) but to the industrial processing (i.e. extrusion or packaging)."