Impacts of contaminants on the health of aquatic organisms

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I am applying to NSERC to continue my long-term research goal of investigating the impacts of exposure to contaminants on the health of aquatic organisms.  In this study, I propose to examine: i) factors that influence the bioaccumulation and metabolism of contaminants in fish and marine mammals, and ii) the mechanisms for biological effects observed in fish exposed to contaminants. With respect to the first research goal, we will study the potential for relatively water-soluble contaminants to bioaccumulate in fish. Using both laboratory and field studies, we will evaluate whether water soluble contaminants can move from water into blood plasma, and from there into other tissues.  We will also study the uptake and metabolism of contaminants in marine mammals.  Specifically, we will determine whether the levels of hydroxy-PCB compounds (i.e. thyroidogenic metabolites) in the blood plasma of ringed seals and polar bears is related to concentrations of PCBs in the fat, or to the age, sex or condition of the animals. In relation to the second research goal to study the biological effects of contaminants in fish, we will extend the research programme related to our previous observations of large numbers of "inter-sex" testes in white perch collected at several locations in the lower Great Lakes. Using both laboratory and field studies, we will examine the possible relationship between parasite-induced damage to the testis of fish and the development of gonadal inter-sex.  Finally, as a continuation of our previous observations of developmental abnormalities in early life stages of Japanese medaka exposed to the fungicide, pentachloronitrobenzene (PCNB), we will investgate whether these abnormalities are caused by alterations to the production or binding properties of fibronectin, a glycoprotein important for the differentiation of tissues in the early development of vertebrates. We will utilize our previously developed in vitro assay for fibronectin production with trout gonadal cells, and a novel technique to determine binding of PCNB to fibronection using two-dimensional heteronuclear NMR spectroscopy.