Biotransformation of Halogenated Organic (HOCs) and Associeted Biological Effects in Artics Seabirds

Due to their high trophic levels Arctic seabirds are exposed to relatively high amounts of halogenated organic contaminants (HOCs). Contaminant metabolism influences both tissue levels and patterns. In addition, it plays a critical role in contaminant-ind uced biological effects because of the formation of biologically active metabolites and oxygen radicals. Consequently, contaminant biotransformation may induce a variety of physiological effects, including oxidative stress and endocrine effects. As a resu lt of this physiological imbalance, energy expenditure might be increased, affecting the basal and field metabolic rates. Arctic seabirds are thought to be particularly vulnerable to contaminant exposure because they go through large seasonal lipid cycles resulting in possible peak exposures of contaminants during periods of emaciation. Generally, there is a lack in knowledge about the biotransformation capacity and long term biological effects of HOCs in Arctic seabirds. In order to gain insight into sea birds toxicokinetics and cause-effect relationships of contaminant exposure, the project will use a combination of experimental feeding studies, field and theoretical studies. Special attention will be given to the role of seasonal lipid cycles on biotran sformation processes and subsequent biological effects. The theoretical study will combine molecular properties of the HOCs with novel multivariate statistical methods in order to assess direct relationships and causalities between contaminant exposure an d effects in Arctic seabirds.