You know, sometimes when I pop open my email and read the morning news, I just scratch my noggin and wonder, just what the
bleep are they going to contaminate pet food with next? It just boggles my little pea brain. Rationale, well, that’s simply out of the question. Let’s see, if I was in that product development meeting, I might have heard something like this…”Ok Bob, we know the fish and the animal fat is contaminated with PBDEs, so why don’t we market it with a quirky twist like…hold on now…wait…it’s coming to me…I’ve got it! We’ll call it Flame Proof Fido! And, Fire Retardant Fluffy! OMG, I am sooo brilliant!” “Thanks Bob, listen, I really would rather have the black Porsche instead of the Christmas in Monte Carlo for my bonus this year.”
in the Serum of Pet Dogs and in Their Food
Indiana University scientists have found chemical flame retardants in the blood of pet dogs at concentrations five to 10 times higher than in humans, but lower than levels found in a previous study of cats.
Their study, “Flame Retardants in the Serum of Pet Dogs and in their Food,” appears this month in the journal Environmental Science & Technology. Authors are Marta Venier, an assistant research scientist in the School of Public and Environmental Affairs, and Ronald Hites, a Distinguished Professor in SPEA.
Venier and Hites explore whether pets could serve as “biosentinels” for monitoring human exposure to compounds present in the households that they share.
Dogs may be better proxies than cats, they say, because a dog’s metabolism is better equipped to break down the chemicals.
The study focuses on the presence of polybrominated diphenyl ethers (PBDEs) in the blood of dogs and in commercial dog food. PBDEs have been widely used as flame retardants in household furniture and electronics equipment. The compounds can migrate out of the products and enter the environment.
“Even though they’ve been around for quite a while, we don’t know too much about these compounds’ toxicological effects on humans or animals,” Venier said. “The bottom line is that we still need to keep measuring them, particularly in homes.”
PBDE mixtures made up of less-brominated compounds are regarded as more dangerous because they bioaccumulate in animal tissues. These mixtures were banned by the European
Union and were voluntarily removed from the U.S. market in 2004, but remain in the environment. Mixtures with more-brominated compounds remain in use in the U.S. but will be phased out by 2013.
Venier and Hites report on an analysis of flame retardants in blood from 17 pet dogs, all of whom live primarily indoors. They also examined samples of the dry dog food that made up the pets’ diet, attempting to determine if food was a major source of PBDE exposure.
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.”
Source: Indiana University April 26, 2011, Marta Venier and Ronald A. Hites, School of Public and Environmental Affairs, Indiana University
The study can be read online at http://pubs.acs.org/doi/full/10.1021/es1043529.
Elevated PBDE Levels in Pet Cats: Sentinels for Humans?
PBDEs have been used since the late 1970s as flame retardants in upholstered furniture, carpet padding, and electronics. During the same time period, feline hyperthyroidism has gone from being almost never reported to being a common disease in older cats, prompting researchers to wonder if there was a connection. The chemicals have been shown in lab tests to impair thyroid and liver function.
Co-incident with the introduction of polybrominated diphenyl ethers (PBDEs) into household materials nearly 30 years ago, feline hyperthyroidism (FH) has increased dramatically. Risk of developing FH is associated with indoor living and consumption of canned cat food. We hypothesized that increases in FH were, in part, related to increased PBDE exposure, with key routes of exposure being diet and ingestion of house dust. This study was designed to determine whether body burdens of PBDEs in hyperthyroid (HT) cats were greater than that of young or sick non-HT cats. Serum samples and clinical information were collected from 23 cats. Serum and dry and canned cat food were analyzed for PBDEs. A spectrum of BDE congeners was detected in all cats, with BDE-47, 99, 207, and 209 predominating.
Venier and Hites also tested dry and canned cat food purchased at a Bloomington discount store and found surprisingly high concentrations of PBDEs in some varieties.
Both dry and canned food samples were tested, accounting for a variety of “flavors” such as turkey, beef, chicken and seafood. Interestingly, dry food showed on average higher concentrations than canned food. Among the “flavors” tested, the highest amount of PBDEs was found in the seafood based ones.
Overall, PBDE levels in cats were 20- to 100-fold greater than median levels in U.S. adults. Our results support the hypothesis that cats are highly exposed to PBDEs; hence, pet cats may serve as sentinels to better assess human exposure and adverse health outcomes related to low-level but chronic PBDE exposure.
A mysterious epidemic of thyroid disease among pet cats in the United States may be linked to exposure to dust shed from flame retardants in household carpeting, furniture, fabrics and pet food, scientists are reporting in a new study.
Veterinarian and toxicologist Janice A. Dye of the Environmental Protection Agencyin Research Triangle Park, N.C., realized that indoor cats-already known to be at high risk of hyperthyroidism-consume a lot of dust when they groom themselves. Data have suggested that sick cats are also more likely than healthy felines to
have eaten canned cat food, especially fish varieties.
Dye’s team tested blood samples from 23 cats, including 11 with hyperthyroidism. Although all carried PBDEs, the animals with the thyroid disease had higher average concentrations. Sick cats and well cats also had different mixes of PBDEs, the researchers report in an upcoming Environmental Science & Technology.
Tests of 20 types of dry and wet cat foods showed that all contained PBDEs, although canned, fish-flavored food had the highest amounts and could deliver 12 times as much of the chemicals as dry foods typically did. The canned, fish-flavored foods also had concentrations of PBDEs that were up to 100 times as high as those in the human diet.
In addition, the researchers suspected that diet might be another risk factor for developing FH. To see if a link existed, they analyzed PBDE content in several cat food brands.
Their analysis found that PBDE content of canned fish/seafood flavors, such as salmon and whitefish, was higher than dry or non-seafood canned items. Based on the analysis, they estimate that diets based on canned food could have PBDE levels 12 times as high as dry-food diets. The researchers indicate that pet cats might be receiving as much as 100 times greater dietary PBDE exposure than American adults.
“It sure as heck looks like there’s something going on,” says coauthor Linda S. Birnbaum of EPA. “Our data beg for additional studies.”
My beloved cat, Midnight, died a few days ago — possibly because of toxic chemicals in my furniture. In two years with hyperthyroid disease, Midnight went from a plump 14 pounds to a skeletal five. A year ago, a veterinary epidemiologist found that Midnight’s blood contained among the highest levels of PBDEs documented in animal research. That’s when I learned that the chemicals in my cat came from my couch. And that my furniture is uniquely toxic because I live in California.
Since the 1980s, fire-retardant chemicals such as PBDEs have been added to furniture to meet a California-only requirement that the foam inside resist a 12-second exposure to an open flame. The chemicals evaporate from the foam, settle in dust and coat walls with a thin film. Cats that groom themselves and toddlers who crawl in dust show especially high levels of PBDEs, but everyone with this chemically treated furniture gets some exposure.
In dozens of animal studies, these fire retardants also have been shown to harm reproduction and scramble brain development. Studies are underway to determine if PBDEs are contributing to increases in autism, hyperactivity, birth defects, infertility, diabetes and obesity in people.
On average, dust in California homes contains 10 times the PBDEs found in dust from other states and 200 times the amount in houses in Europe, according to a new study from the Silent Spring Institute. Worse, Californians have twice the level of this fire retardant in their blood as do people in other states. A recent research report by the nonprofit Environmental Working Group showed that American toddlers have, on average, a level of fire retardant in their bodies that is three times higher than that found in their mothers.
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