European Starlings (Sturnus vulgaris) Suggest That Landfills Are an Important Source of Bioaccumulative Flame Retardants to Canadian Terrestrial Ecosystems

Landfills are used as the primary means for the disposal of municipal solid waste in Canada. In the present study, polybrominated diphenyl ethers (PBDEs) and other flame retardants (FRs) were determined in fresh European starling (Sturnus vulgaris) eggs collected in 2009, 2010, and 2011 from nest boxes established within, adjacent to, and 10 and 40 km distant to five major urban centers across Canada, i.e., Vancouver, British Columbia (BC); Calgary, Alberta (AB); Hamilton, Ontario (ON); Montréal, Québec (QC); and Halifax, Nova Scotia (NS). Nest boxes were located in several land use types: urban industrial areas (districts of industrial activity within city limits), landfill sites (adjacent to cities), and rural (agricultural) sites located 10 and 40 km distant from the major urban centers, as well as a national reference site. Of the 14 PBDE congeners and 16 non-PBDE FR substances determined in the starling eggs, BDE-17, -28, -47, -49, -66, -85, -99, -100, -138, -153, -154, -183, and -209, Dechlorane Plus isomers (anti and syn), and bis(2-ethylhexyl)-3,4,5,6-tetrabromophthalate (BEHTBP) were most frequently quantifiable. The data revealed orders of magnitude greater PBDE concentrations in eggs from starlings nesting in landfill sites (median: 28–280 ng/g wet weight) relative to those from urban industrial and rural environments. However, the percent fractional composition of the PBDE congener patterns did not vary significantly between the types of land uses or between years. Additionally, the median ∑PBDE concentration in eggs from landfill sites and the human population density of the metropolitan region that the landfill serves were highly correlated (r² = 0.998, p < 0.001). As the first transcontinental effort in assessing FR contamination in Canadian terrestrial ecosystems, the present study strongly suggest that landfills are an important FR source to starlings nesting nearby and that other terrestrial organisms could also be similarly exposed.