Differential Accumulation of Polychlorinated Biphenyl Congeners in the Terrestrial Food Web of the Kalamazoo River Superfund Site, Michigan

Abstract

A series of field studies was conducted to determine the bioaccumulation of polychlorinated biphenyl (PCB) congeners in the terrestrial food web of the Kalamazoo River flood plain. Samples included colocated soils, native plants likely to be consumed by wildlife, several taxa of terrestrial invertebrates, small mammals, passerine bird eggs, nestlings, and adults, and great horned owl plasma and eggs. Mean concentrations of total PCBs in samples from the former Trowbridge impoundment were 6.5 mg/kg dry weight for soils and 0.023, 0.13, 1.3, 1.3, 1.6, and 8.2 mg/kg wet weight for plants, small herbivorous mammals, depurated earthworms, shrews, great horned owl eggs, and house wren eggs, respectively. Historical data from the Kalamazoo River have reported Aroclor-equivalent total PCB concentrations in the terrestrial food web; however, the degree of environmental weathering of the parent PCB mixtures was unknown. In this study, earthworms and composite samples of coleoptera exhibited PCB congener patterns that were similar to patterns in colocated soils. However, in plants, less chlorinated PCBs (e.g., mono-, di-, tri-, and tetrachlorinated biphenyls) were predominant, and in small mammals, there was a notable enrichment of PCBs 153, 180, 138, 118, and 99. In general, concentrations of PCBs were lower in most biota than in soil from the Kalamazoo River Area of Concern (KRAOC) although there was a modest biomagnification of PCBs from lower trophic level biota to highertrophic levels. As a consequence of environmental weathering of PCBs in the terrestrial food web of the KRAOC, the relative potency of the PCBs (expressed as mg TEQs/kg PCBs) decreased from soil to most biota. While there was a general trend, as expected, in which concentrations of 2,3,7,8-tetrachlorodibenzo-p-dioxin equivalents (TEQs) increased with total PCBs, this relationship was rather poor (R2 = 0.13). Taken together, these data suggest that the differential accumulation of PCB congeners in the terrestrial food web can be explained by congener-specific differences in bioavailability from soil, exposure pathways, and metabolic potential of each of the food web components.

Spatial distribution of chlordanes and PCB congeners in soil in Cedar Rapids, Iowa, USA

“…Nevertheless, Cedar Rapids values are in the same range or higher than values reported around the world for urban locations (Figure 4). As expected, sites near known PCB contamination sites present much higher concentrations than Cedar Rapids, such as New Bedford Harbor, MA (Vorhees et al, 1999), the Superfund site in Kalamazoo, MI (Blankenship et al, 2005), and Wenling, China (e-waste recycling city) (Tang et al, 2010). In Gadsden, AL, PCBs are about 5 times higher than Cedar Rapids- perhaps because the samples were collected in 1971 when PCB production was near its peak (Carey et al, 1979).…”

Organochlorine compounds in red deer (Cervus elaphus L.) and fallow deer (Dama dama L.) from inland and coastal Croatia

“…Their concentration medians follow this pattern: PCB-153> PCB138 > PCB-180 > PCB-118,PCB-52 > PCB-28 > PCB-170. Although their levels were low, this pattern is often repeated in animal fat (Blankenship et al 2005;Liem and Theelen 1997;Naso et al 2004). A similar PCB pattern was found in the fat of human milk samples (Herceg Romanić and Krauthacker 2006;Liem and Theelen 1997).…”

Risk profile related to production and consumption of insects as food and feed

“…No maximum level for PCB6 has been set for insects as food, however for comparison the maximum level for fishery products is 75 µg/kg wet weight (Commission Regulation EU 1259/2011). Accumulation of PCBs from polluted soils in wild insects, especially ground dwelling species has previously been shown (Davis et al, 1981;Blankenship et al, 2005;Walters et al, 2009 …”