Cats’ Internal Exposure to Selected Brominated Flame Retardants and Organochlorines Correlated to House Dust and Cat Food

Abstract

Pet cats may be used as a biomarker for assessing exposures to organohalogen compounds (OHCs) adsorbed to household dust in home environments. This study explores two exposure routes of OHCs, ingestion of OHCs (i) via house dust and (ii) via cat food. House dust from 17 Swedish homes and serum from the participating families' pet cats were collected, and cat food was purchased matching the diet reported. Paired samples of cat serum, house dust, and cat food were analyzed for brominated flame retardants/natural products (polybrominated diphenyl ethers (PBDEs), decabromobiphenyl (BB-209), decabromodiphenyl ethane (DBDPE), 2,4,6-tribromophenol (2,4,6-TBP), OH-PBDEs) and organochlorines (polychlorinated biphenyls (PCBs), 1,1-bis(4,4'-dichlorodiphenyl)-2,2,2-trichloroethane (4,4'-DDT), 1,1-bis(4,4'-dichlorodiphenyl)-2,2-dichloroethene (4,4'-DDE), hexachlorobenzene (HCB), pentachlorophenol (PCP)). Significant correlations were found between serum and dust samples from the living rooms for BDE-47 (p < 0.035), BDE-99 (p < 0.035), and BDE-153 (p < 0.039), from the adult's bedroom for BDE-99 (p < 0.019) and from all rooms for BDE-99 (p < 0.020) and BB-209 (p < 0.048). This is the first time a correlation between cat serum levels and household dust has been established, a finding that supports the hypothesis that dust is a significant exposure route for cats. Serum levels were also significantly correlated with concentrations found in cat food for 6-OH-BDE47 (p < 0.002), 2,4,6-TBP (p < 0.035), and BB-209 (p < 0.007). DBDPE was found in high concentrations in all dust (median 154 pmol/g) and food samples (median 0.7 pmol/g lw) but was below detection in serum samples, suggesting low or no bioavailability for DBDPE in cats.

Potential Role of Pet Cats As a Sentinel Species for Human Exposure to Flame Retardants

“…Currently, the only compound of the BDE family that is still approved for use is BDE-209 (), and it has to be taken into account that unfortunately this chemical was not included in this study, because it can not be determined in our laboratory due to technical limitations. In any case, and even without having included the BDE 209, our results are very similar to those reported in cats from Pakistan (median ∑BDEs = 6.1 ng/g fat) (29), USA—Georgia, Massachusetts, and North Carolina—(median ∑BDEs = 5.9 ng/g fat) (17), but lower than those reported in Sweden (median ∑BDEs = 24.1 ng/g fat) (34), and than in those cats from California, in which the authors reported extraordinarily high levels of BDEs (median ∑BDEs = 2904 ng/g fat), mainly due to the high levels of BDE-99 detected in those animals (19). While diet, mainly through fish intake, is considered the main route of exposure for PCBs (23, 35–37), the ingestion of dust from the environment is considered the most important route of exposure for BDEs in cats (38).…”

“…Thus, due to their grooming habits, cats have been classically used to evaluate the level of human exposure to BDEs through the indoor dust (39). In this sense, a positive correlation between serum cat levels and dust has been consistently reported in the literature (34), although the serum levels tend to be several times higher in cats than in humans. Compared to humans, ∑BDE levels in cats are often 20- to 100-fold greater than median levels in US adults (17, 38), but the correlation of levels and the pattern of contamination (congener distribution and proportions) between both species has been reported to be very good.…”

Brominated and organophosphorus flame retardants in South African indoor dust and cat hair

“…Humans and pets are ubiquitously exposed to various FRs, via diet, through direct contact with consumer products, and through household dust, which is used to measure indoor chemical contamination and to assess human exposure risks (Jones-Otazo et al, 2005;Whitehead et al, 2011). Children and indoor pet cats may, therefore, have greater exposures to FRs through dust ingestion than adults (Norrgran Engdahl et al, 2017). Since pet cats have previously been presented as a potential bio-sentinel for indoor pollution exposure, cats might therefore, have relevance as indoor exposure models for children (Dirtu et al, 2013).…”

Thyroid disruption properties of three indoor dust chemicals tested in Silurana tropicalis tadpoles

“…Ingestion of dust is considered an important exposure route to organic contaminants, including THDCs (Fromme et al, ; Hammel et al, ; Jones‐Otazo et al, ; Mercier, Glorennec, Thomas, & Le Bot, ; Norrgran Engdahl et al, ; Sahlström, Sellström, De Wit, Lignell, & Darnerud, ; Whitehead et al, ). Indoor dust contains a multitude of industrial chemicals originating from, e.g., furniture, textile, plastics and electronic products as reviewed by Lucattini et al ().…”