Evaluation of temporal and age‐related trends of chemically and biologically generated 2,3,7,8‐tetrachlorodibenzo‐p‐dioxin equivalents in lake Ontario lake trout, 1977 to 1993

Abstract

Levels of selected non-, mono-, and di-ortho-substituted polychlorinated biphenyl (PCB) congeners, polychlorinated dibenzo-p-dioxins (PCDDs), and polychlorinated dibenzofurans (PCDFs) were determined in 4-year-old lake trout from the eastern basin of Lake Ontario, collected from 1977 to 1993. Results confirm that overall levels of contaminants have decreased steadily in lake trout since 1977, and that coplanar PCB levels do not appear to be increasing over time in relation to levels of other PCBs. Contaminant levels in lake trout from 3 to 9 years old, collected in 1988 from the western end of Lake Ontario, show the body burden of contaminants increases with age. Relative levels of coplanar PCBs to other PCBs for the age study samples showed no change, except for PCB 77, which exhibited a slight decrease in relation to total PCB levels. Toxic equivalents (TEQs) were calculated from fish contaminant concentrations measured for the time study using toxic equivalence factors (TEFs) from both mammalian and teleost studies. The relative contributions of PCBs, PCDDs, and PCDFs to total TEQs were examined. When TEFs used for risk assessment are applied to temporal trend data, 15 to 20% of the total TEQs were due to mono-ortho-substituted PCBs; 40 to 50% to non-ortho coplanar PCBs; and 20 to 30% to 2,3,7,8-substituted PCDD and PCDFs. The TEQs determined from lake trout extracts by an H4IIE cell bioassay technique are compared to those determined by chemical analyses, using a variety of TEFs.

Polychlorinated Dibenzo-p-Dioxins (PCDDs) and Dibenzofurans (PCDFs) in Muscle and Eggs of Salmonid Fishes from the Great Lakes

“…Coho salmon Lake Michigan: Coho salmon Ͼ Chinook salmon Ϸ Lake trout Lake Huron: Chinook salmon Ͼ Lake trout Ͼ Coho salmon Although earlier studies have reported concentrations of PCDDs and PCDFs in coho salmon and lake trout (Fehringer et al 1985;Kuehl et al 1989;Niimi and Oliver 1989;Huestis et al 1997), chinook salmon from the Great Lakes has been rarely analyzed for PCDDs and PCDFs (Ankley et al 1989(Ankley et al , 1991. Our results suggest the accumulation of greater concentrations of PCDDs and PCDFs in chinook salmon than in coho salmon or lake trout.…”

“…The ratios of PCDF to PCDD concentrations in lake trout collected in 1984 from Lakes Superior, Michigan, and Huron were 2.9, 2.7, and 1.7, respectively . A few other studies have reported the predominance of PCDD over PCDF, such as those in Lake Ontario (Niimi and Oliver 1989;Huestis et al 1997).…”

“…PCDDs and PCDFs have been found in various environmental compartments in the Great Lakes including air, water, sediment, fish, and birds (Stalling et al 1985;Fehringer et al 1985;De Vault et al 1989;Niimi and Oliver 1989;Smith et al 1989;Kuehl et al 1989;Braune and Norstrom 1989;Kubiak et al 1989;Zacharewski et al 1989;Bishop et al 1991;Ankley et al 1992;Hebert et al 1994;Firestone et al 1996;Pearson et al 1997;Gale et al 1997;Giesy et al 1997). A wide variety of sources, including combustion-related atmospheric deposition, polychlorinated biphenyls (PCBs), historical chlorophenol production, and kraft pulp mills, have been implicated for the presence of PCDDs and PCDFs in the Great Lakes (O'Keefe et al 1983;Czuczwa and Hites 1986;De Vault et al 1989;Hebert et al 1994;Pearson et al 1997;Huestis et al 1997). Although concentrations of PCDDs and PCDFs have declined in wildlife from several locations in the Great Lakes (Herbert et al 1994;Pearson et al 1997), concentrations measured in fish in the Great Lakes waters still remain greater than those reported from several other locations in the United States (Firestone et al 1996;Giesy et al 1997).…”

Trends of persistent organic pollutants in American eel (Anguilla rostrata) from eastern Lake Ontario, Canada, and their potential effects on recruitment

“…These dioxin-like compounds (DLCs) act additively on the aryl-hydrocarbon receptor (AhR), have a common receptor-mediated mechanism of toxicity (van den Berg et al, 1998), and biomagnify in fish (Norstrom, 2006;Hornbuckle et al, 2006). Temporal trends are well established for many legacy POPs in LO lake trout (Salvelinus namaycush), including PCDD/Fs (Huestis et al, 1997;Bhavsar et al, 2008;Gewurtz et al, 2009), PCBs, several organochlorine pesticides (OCPs) (Borgmann and Whittle, 1991;Huestis et al, 1996;De Vault et al, 1996;Hickey et al, 2006;Bhavsar et al, 2007a;Carlson et al, 2010) and polybrominated diphenyl ethers (PBDEs) (Luross et al, 2000;Zhu and Hites, 2004;Batterman et al, 2007;Ismail et al, 2009;Carlson et al, 2010). These trends reflect their discharge to LO by industry and agriculture, and subsequent bans on their use (Table 1).…”

Assessing the fish consumption beneficial use impairment in the Bay of Quinte

“…Temporal changes in contaminant concentrations are not a simple reflection of external loading. There may be a loose coupling between external loading and fish contaminant concentrations as a result of food web dynamics and other factors that affect bioaccumulation such as fish size, age, lipid content, fish growth rates and growth efficiency (Borgmann and Whittle, 1991;Rasmussen et al, 1990;Gobas et al, 1995;Huestis et al, 1997). These factors will vary over time and sampling event.…”