Polychlorobiphenyl levels in the serum of cats from residential flats in Italy: Role of the indoor environment

The domestic cat (Felis catus) was used as a sentinel of exposure to polychlorobiphenyls (PCBs) in indoor urban environments y. Sera from 120 cats were pooled to form 30 different groups selected by age ( 2 64 8\ua0years; > 8\ua0years), sex, municipality (Bologna and Turin) and environment (indoor vs. outdoor). Test portions of 1\ua0mL were analyzed by means of gas chromatography coupled to high-resolution mass spectrometry (GC-HRMS) for six selected indicators non-dioxin-like PCBs ( 116 PCBs: congeners #28, #52, #101, #132, #153 and #180) and the results were computed in the upper-bound mode. The internal dose of PCBs attributable to the cats' alimentary lipid intake ranged from 32.4 to 1,446\ua0ng/g (P50 165; mean 258). The Wilcoxon test revealed significantly lower PCB burden in \u201coutdoor\u201d groups than in \u201cindoor\u201d groups. Age correlated well with the heptachlorinated and most bio-accumulative congener, PCB #180, and slightly with hexachlorinated PCBs #138 and #153. Contamination attributable to house dust collected in 15 living-rooms ranged from 10.0 to 279\ua0ng/g dry weight (P50 97.4; mean 94.4). Exposure estimates indicated a 0.6\u201316\ua0ng/kg bw range of daily 116 PCB intake from a default value of 200\ua0mg/cat of dust ingestion. The intake of PCBs due to dust ingestion fell within the same order of magnitude as that computed from a 60\ua0g daily intake of commercial dry pet foods, while inhalation accounted for 0.21\u20138.2\ua0ng/kg bw/day, on setting the nominal 116 PCB contamination in outdoor and indoor air at 0.37 and 15\ua0ng/m3, respectively. Italian indoor cats could be exposed to higher levels of 116 PCBs than the Reference Dose (RfD) of 10\ua0ng/kg/bw/day; this supports the World Health Organization's statement that the quality of the indoor environment is a major determinant of health