High polybrominated diphenyl ether levels in California house cats: House dust a primary source?

Abstract

Polybrominated diphenyl ethers (PBDEs) are brominated flame retardants that act as endocrine disruptors, affecting thyroid hormone homeostasis. As a follow-up to a recent study showing high PBDE levels in household cats and linking PBDE levels with cat hyperthyroidism, we measured PBDEs, polychlorinated biphenyls (PCBs), and organochlorinated pesticides (OCPs) in serum samples from 26 California household cats (16 hyperthyroid, 10 controls) using liquid-liquid extraction and high-resolution gas chromatography/high-resolution mass spectrometry. In the present pilot study, we found that PBDE levels in California house cats were extremely high (ΣPBDEs median = 2,904 ng/g lipid; range, 631-22,537 ng/g lipid). This is approximately 50 times higher than levels in California residents (ΣPBDEs geomean = 62 ± 8.9 ng/g lipid, National Health and Nutrition Examination Survey), who have among the highest human levels in the world. Polybrominated diphenyl ethers congener patterns (BDE-99 major congener, BDE-209 significant) differed markedly from patterns found in California residents (BDE-47 major) or wildlife but resembled patterns found in house dust. Polychlorinated biphenyls and OCPs in cats were highly correlated, consistent with a shared dietary source or pathway of exposure, but did not correlate with PBDEs. This suggests a different source or pathway of exposure for PBDEs, which was most likely house dust. The authors found no evidence that linked levels of PBDEs, PCBs, or OCPs with hyperthyroidism. This may be because of the small sample size, competing or confounding risk factors, or complicated causal mechanisms.

Organohalogenated contaminants (OHCs) in the serum and hair of pet cats and dogs: Biosentinels of indoor pollution

“…This finding suggests differences in the exposure sources or in the uptake and metabolic efficiencies for the PBDE congeners among three species. The PBDE congener pattern in cats was similar to that of US cats where BDE 99 was also the major PBDE congener (Dye et al, 2007;Environmental Working Group, EWG, 2008;Guo et al, 2012). Other congeners, e.g.…”

“…Recent studies have suggested that they may serve as biosentinels of human exposure to various indoor contaminants (Environmental Working Group, EWG, 2008;Guo et al, 2012;Venier and Hites, 2011). Studies have documented that serum levels of polybrominated diphenyl ethers (PBDEs) were 20 to 100 fold higher in pet cats than the median levels in US adults (Dye et al, 2007;Environmental Working Group, EWG, 2008;Guo et al, 2012). However, scarce information is available on the contamination status of other OHCs, such as PCB and their metabolites, OCPs, novel BFRs (NBFRs) and bromophenols (BPs) in pets.…”

ANIMAL MODELS OF DISEASE: Feline hyperthyroidism: an animal model for toxic nodular goiter

“…For example, the polyphenolic compound bisphenol A, which is used as a plasticizer in can linings, has been detected in canned cat food and may act as a thyroid disruptor (Edinboro et al 2004, Schecter et al 2010. In a similar vein, recent studies both in the USA and Sweden have reported high levels of polybrominated diphenyl ethers (PBDEs) in cats, a fire-retardant with known thyroid-disrupting properties (Dye et al 2007, Guo et al 2012, Mensching et al 2012, Norrgran et al 2012. As PBDEs migrate out of the flame-protected materials (e.g.…”

“…plastics, textiles, furniture, or electronics), these chemicals end up in house dust as the natural sink (Suzuki et al 2008). Therefore, in addition to dietary sources of PBDEs, domestic cats living indoors and lying on the floor will normally collect dust in their fur and ingest these dust-enriched chemicals through grooming (Guo et al 2012, Johnson et al 2013. In the study of PBDEs and other endocrine-disrupting compounds, human beings and domestic cats share the same environments and tend to be chronically exposed to same chemical disruptors; however, because of their shorter life spans, companion animals may serve as good sentinels for human disease.…”

Combined Analysis of Results on Single and Multiple Contacts: Potting Soil, Sand and Clay Transfers to Cloth for the Estimate of Soil Adherence to Human Skin

“…The sources of contaminants in household dust can be from the outdoor sources listed above or indoor sources resulting from activities (e.g., smoking, pets in the home) or chemicals and products used in the home (e.g., new carpets, and sofas, pesticides, cleaning products) (Guo et al, 2012;Hwang et al, 2008;Thorne, Cohn, May, Arbes, & Zeldin, 2009). …”