A framework for evaluating bioaccumulation in food webs

As the ability to quantify contaminant uptake and clearance from individual organisms improves and modeling efforts are devoted to describing transpor t in increasingly complex food webs, including vegetation, there is a need to establish a consistent framework within which contaminant sources and tr ansfer in food webs can be characterized. It is shown that a convenient and general framework is established by compiling the set of mass balance equa tions describing uptake in each organism by food and respiration in a matri x format using the fugacity concept. The matrices and vectors can be manipu lated to gain valuable insights into how contaminant concentrations in the four abiotic media of air, water, soil, and sediment translate into concent rations in organisms throughout a food web. The framework is illustrated fo r a simple six organism food web including aquatic, terrestrial, and avian species. Methods of obtaining input parameters are outlined, and advantages of the approach are discussed.