What Have Biomarkers Told Us About the Effects of Contaminants on the Health of Fish-eating Birds in the Great Lakes? The Theory and a Literature Review

The molecular, biochemical, and cellular precursors to disease are common to wildlife and humans. Colonial fish-eating birds have been used as convenient sentinel biological systems for detection and monitoring of the effects of chronic exposure to complex mixtures of persistent toxic environmental contaminants within the Great Lakes ecosystem. Studies of impairments to health using such biomarkers as induction of mixed function oxidases, alterations in heme biosynthesis, retinol homeostasis, thyroid function and DNA integrity and various manifestations of reproductive and developmental toxicity in these birds suggests the severity varies with time and location and generally decreased between the early 1970s and late 1980s. However, these studies confirm the continued presence of sufficient amounts of PCBs and related persistent halogenated aromatic hydrocarbons in forage fish to cause physiological impairments in these birds over much of the Great Lakes basin. The elimination of such impairments will be a measures our success in remediation of Areas of Concern and “virtual elimination” of persistent polyhalogenated aromatic hydrocarbon contaminants from the Great Lakes ecosystem.