Chemicals as Indicators for Monitoring Ecological Risk
We will focus on two groups of chemicals of current concern in the Great Lakes: photoactivated polycyclic aromatic hydrocarbons (PAHs), and environmental estrogens.
PAHs are compounds produced by the burning of organic material (wood and fossil fuels) and the incomplete combustion of petroleum. PAHs are found throughout the air, water, and sediments of the Great Lakes watershed. Certain PAHs become much more toxic to aquatic organisms when exposed to the ultraviolet radiation in sunlight (called "photoactivated toxicity"). Fish larvae may be particularly vulnerable to photoactivated PAHs because they often live in very shallow water and have little pigmentation, both factors that increase their exposure to ultraviolet radiation. We will measure PAH levels in fish larvae and calculate the UV dose to which they are exposed.
Environmental estrogens are chemicals that mimic the behavior of estrogen when inside an organism. Many chemical contaminants have some amount of estrogenic activity, and in some cases have caused reproductive problems in wildlife. Male fish exposed to environmental estrogens will make vitellogenin, a protein used for egg yolk creation that is normally only produced by female fish. We will correlate exposure to estrogenic chemicals with vitellogenin levels in male fish, allowing us to identify which chemicals have the most estrogenic activity and thus, which ones pose the most threat to fish reproduction.