Page 845 - The Toxicology of Fishes
P. 845

Reproductive Impairment of Great Lakes Lake Trout by Dioxin-Like Chemicals  825


                                         25
                                                                Total PCB (µg/g ww)
                                                             Lake Trout - Lake Michigan
                                         20
                                       Total PCB (µg/g ww)  15




                                         10

                                         5


                                         0
                                               1970       1980       1990      2000
                                                                A
                                         22
                                                                Total DDT (µg/g ww)
                                         20
                                                             Lake Trout - Lake Michigan
                                         18
                                         16
                                       Total DDT (µg/g ww)  14

                                         12
                                         10
                                         8
                                         6
                                         4
                                         2
                                         0
                                               1970       1980      1990       2000
                                                                B

                       FIGURE 21.3 Concentrations (µg/g ww) of (A) total polychlorinated biphenyls (PCBs) and (B) 2,2-bis(p-chlorophenyl)-
                       1,1,1-trichloroethane (DDT) in lake trout from Lake Michigan, 1970 to 2000. (Data are from DeVault, D.S. et al., J. Great
                       Lakes Res., 22, 884–895, 1996; Hickey, J.P. et al., Arch. Environ. Contam. Toxicol., 50, 97–110, 2006.)


                       slow release of these contaminants from sediments in point-source river beds. Concentrations of both
                       PCBs and DDT in lake trout from Lake Michigan have declined greatly, from a maximum of greater
                       than 20 mg/kg in 1973 to a current average of approximately 1.0 mg/kg (Figure 21.3). The rate of
                       decrease in concentrations of PCBs during the last two decades of the 20th century was greatest in fish
                       from Lake Michigan compared to the other Great Lakes (Hickey et al., 2006). Concentrations of both
                       PCBs and DDT in lake trout from Lake Superior have always been the least of all of the Great Lakes
                       (Baumann and Whittle, 1988).
                        The concentrations of AhR agonists in the Great Lakes food web have declined over the past four
                       decades; however, with the exception of PCB concentrations, documentation of these declines in Great
                       Lakes fish is not as complete as that of organochlorine pesticides. The information on temporal trends
                       in PCDD and PCDF concentrations in Great Lakes fish is limited. A single monitoring program that has
                       sustained measurements of these analytes in Great Lakes fish does not exist; however, based on the
                       various studies that have been reported on the concentrations of PCDDs and PCDFs in fish, declines
                       appear to follow those of organochlorine pesticides and PCBs. DeVault and coworkers (1989) reported
                       concentrations of  HAHs in lake trout collected in 1984 from  Lakes Michigan, Ontario, Huron, and
                       Superior and in walleye collected from Lake Erie that same year. The concentrations of PCDDs and
   840   841   842   843   844   845   846   847   848   849   850