Development and application of non-destructive biomarkers for biomonitoring endocrine disruption in pinnipeds

Over the past years there has been an increased concern regarding widespread pollution of the environment with persistent organic pollutants (POPs) that biomagnify and bioaccumulate along the food chain. Marine mammals, especially seals being top predators of the marine food chain, are significantly exposed to biomagnified levels of POPs that bioaccumulate in the blubber which acts as a reservoir for these lipophilic compounds. POPs have been associated with a number of pathological changes in the seals, thus early detection of the adverse health effects resulting from pollutant exposure is vital, since exposure may cause irreversible damage to entire populations or ecosystems in the long term. Biomonitoring studies to investigate changes in fecundity of marine mammal populations due to exposure to POPs are needed. Biological indicators (biomarkers) that reflect the exposure levels or toxic effects of the contaminant load in wildlife populations can be used as early warning system for the reproduction and survival of the animals with non-destructive or minimal invasion. The aim of this study was to research and develop new and existing exposure and effect biomarkers for biomonitoring endocrine disruption in Ringed (Phoca hispida), Grey (Halichoerus grypus) and Harbour (Phoca vitulina) seals from different geographical areas using non-destructive/non-invasive sampling. Sex steroids, lactoferrin and blood chemistry parameters were investigated ill seal faecal and serum samples as potential biomarkers. Exposure level (PCBs, DDT, PBDEs) was determined using chromatographic and immunoassay techniques. Estrogens in the exposed populations showed a negative correlation with contaminant exposure and higher LTF, glucose and lipoprotein levels showed a positive correlation with contaminant exposure and negative correlation with sex steroids, thus they are proposed as biomarkers of endocrine disruption. This is the first study to quantify and measure LTF as well as sex steroids in seal faecal samples and to investigate their correlation with environmental exposure and the promising results justify further research in this area. Since the biomarkers in this study are influenced by endogenous hormones it is recommended that they should be used in conjunction with sex steroids