Contamination of local wildlife following a fire at a polychlorinated biphenyls warehouse in St Basile le Grand, Quebec, Canada.

This study on wildlife contamination, one to ten months after the polychlorinated biphenyls (PCB) fire in St Basile le Grand, Quebec, shows that the fire increased PCB and polychlorinated dibenzofuran (PCDF) levels in animals. From the data, it was not possible to detect a significant increase in polychlorinated dibenzodioxin (PCDD) levels after the fire. Given the relatively small sample size, the differences in concentrations could not be estimated precisely. However, it can be asserted with a 95% confidence level that mean concentrations of total PCBs were roughly 2 to 6 times higher in the area contaminated by the plume of smoke, concentrations of homologues with 3 chlorine atoms were 1 to 4 times higher, and levels of homologues with 5 to 9 chlorine atoms were 3 to 13 times higher. The relative deviations between concentrations in areas under the plume and those outside it were similar for all animals sampled. With regard to total PCDFs, mean concentrations were significantly higher under the smoke plume than outside it for all species. This observation is linked to homologues with 4, 5 and 7 chlorine atoms for which significant differences were detected between the two areas. The fire had no effect on the pattern of PCB congeners found in the tissue of animals in the region. Congeners Nos. 153, 180, 138 and 118 represent approximately 50% of total PCBs. Although PCB and PCDF concentrations were higher in the tissue of local wildlife species exposed to the fire, they were nonetheless comparable to those found in other urban and agricultural areas in Canada. These concentrations, in 2,3,7,8-TCDD toxic equivalents, were much lower than those observed in the wake of three other major incidents involving PCDDs (Elgin, Florida; Times Beach, Missouri; and Seveso, Italy).(ABSTRACT TRUNCATED AT 250 WORDS)