Polychlorinated biphenyl congener distributions in burbot: Evidence for a latitude effect

Abstract

The authors compared the distributions of the congeners of polychlorinated biphenyls (PCBs) detected in whole-body samples of burbot (Lota lota) from Great Slave Lake and Lake Erie. Total PCB concentrations in Great Slave Lake burbot were about one-sixtieth of the concentrations in Lake Erie burbot. Burbot from Great Slave Lake contained a higher proportion of lower-chlorinated (2-6 chlorines) congeners than did burbot from Lake Erie; the reverse occurred for more highly chlorinated (7-9 chlorines) congeners. Hexachloro congeners, followed by pentachloro congeners, dominated the proportions of total PCBs in burbot from both lakes. There were no differences between sexes in whole-body samples or between gonad and somatic tissues in the proportions of the 39 congeners and 3 sets of coeluters detected in burbot from Great Slave Lake. In contrast, there were distinct sex differences in congener distributions for older burbot from Lake Erie. The results generally supported a prediction of higher proportions of lower-chlorinated PCB homologs in organisms in remote polar areas. However, the latitudinal effect on PCB congener distribution may be more complex than that portrayed in previous studies.

Sex differences in contaminant concentrations of fish: a synthesis

“…In this case, the suspected PCB hot spot was the mouth of the Ashtabula River, a tributary to Lake Erie [28]. A substantial difference in PCB congener distributions between the sexes typically accompanies a hot spot effect [29, 30]. PCB congener distributions varied dramatically between the sexes of these older (ages 14–17) burbot from Lake Erie, whereas PCB congener distributions varied little between the sexes of younger (ages 6–13) burbot from Lake Erie [29].…”

“…PCB congener distributions varied dramatically between the sexes of these older (ages 14–17) burbot from Lake Erie, whereas PCB congener distributions varied little between the sexes of younger (ages 6–13) burbot from Lake Erie [29]. Likewise, a sex difference in PCB congener distributions was not detected in burbot from Great Slave Lake or in summer flounder from New Jersey coastal waters, two fish populations in which a hot spot effect was not realized [27, 30]. In sum, a hot spot effect appeared to occur in relatively few fish populations.…”

Can traditional methods of selecting food accurately assess fish health?

“…It is conceivable that, due to the lipophilic nature of these compounds, selecting for the largest and fattiest livers also selects for livers with higher concentrations of contaminants as they cannot be seen directly. In a recent study, Burbot in a heavily industrialised area of Lake Erie and a point source for PCB pollution had 60 times the levels of PCBs per gram of tissue than Burbot from Great Slave Lake (Stapanian et al 2014). Inability of traditional methods to avoid contaminated subsistence fish could be problematic where fish could be exposed to such contaminant "hot spots".…”

“…Such an expansion in geographic scope would permit the investigation of regional variation. Burbot could also be sampled from an area that is known to be contaminated (e.g., areas of Lake Erie; see Stapanian et al 2014), and their livers could be visually assessed by northern harvesters (through photos that were taken using a standardized approach). This would act as a surrogate to a traditional harvest scenario in a polluted area.…”

“…Northern environments have received contaminant loading via long-range atmospheric transport from industrial and agricultural activities in southern latitudes (Donaldson et al 2010). These contaminants accumulate in a variety of taxa: fish (e.g., Kidd et al 1995Kidd et al , 1998Carrie et al 2009;Stapanian et al 2014), birds (e.g., Guzzo et al 2013), and mammals (e.g., Muir et al 2000;Riget et al 2005)including humans (e.g., Kuhnlein et al 1995;Donaldson et al 2010). Atmospheric contaminants tend to bioaccumulate and biomagnify with trophic position, with the highest concentrations in predatory animals (Donaldson et al 2010).…”