Five-stage environmental exposure assessment strategy for mixtures: gasoline as a case study.

A five-stage strategy is suggested for conducting an exposure assessment of mixtures that may contain numerous chemical components. The stages are: (1) determination of mixture composition and variability, (2) selection of component groups within the mixture and documentation of criteria used for this selection, (3) compilation of relevant property data for each group, (4) assessment of environmental fate of each group, and (5) assessment of environmental and human exposure to each group and to the mixture as a whole. A subsequent step is the assessment of environmental and/or human risk associated with the individual and aggregate exposure to each group.

The role of cannibalism and contaminant source on bioaccumulation in aquatic food webs.

Two aspects of bioaccumulation in an aquatic food web are explored. First, the possible implications of cannibalism, including the scavenging of conspecifics, as a factor influencing food web bioaccumulation and biomagnification are explored by examining the behavior of total polychlorinated biphenyls (PCBs) in a simple aquatic food web consisting of plankton, juvenile and adult Mysis relicta, Diporeia, and alewife. From an analysis of trophic transfer efficiencies and food consumption rates, it is concluded that, for M.