Intestinal absorption and biomagnification of organic contaminants in fish, wildlife, and humans.
Methods for the regulatory assessment of the bioaccumulation potential of organic chemicals are founded on empirical measurements and mechanistic models of dietary absorption and biomagnification. This study includes a review of the current state of knowledge regarding mechanisms and models of intestinal absorption and biomagnification of organic chemicals in organisms of aquatic and terrestrial food chains and also includes a discussion of the implications of these models for assessing the bioaccumulation potential of organic chemicals. Four mechanistic models, including biomass conversion, digestion or gastrointestinal magnification, micelle-mediated diffusion, and fat-flush diffusion, are evaluated. The models contain many similarities and represent an evolution in understanding of chemical bioaccumulation processes. An important difference between the biomagnification models is whether intestinal absorption of an ingested contaminant occurs solely via passive molecular diffusion through serial resistances or via facilitated diffusion that incorporates an additional advective transport mechanism in parallel (i.e., molecular ferrying within gastrointestinal micelles). This difference has an effect on the selection of physicochemical properties that best anticipate the bioaccumulative potential of commercial chemicals in aquatic and terrestrial food chains. Current regulatory initiatives utilizing Kow threshold criteria to assess chemical bioaccumulation potential are shown to be unable to identify certain bioaccumulative substances in air-breathing animals. We urge further research on dietary absorption and biomagnification of organic chemicals to develop better models for assessing the bioaccumulative nature of organic chemicals.
Kelly
Barry C
BC
School of Resource and Environmental Management, Simon Fraser University, Burnaby, British Columbia V5A 1S6, Canada.
Gobas
Frank A P C
FA
McLachlan
Michael S
MS
D000042:Absorption; D000818:Animals; D000835:Animals, Wild; D018533:Biomass; D004785:Environmental Pollutants / Q000493:pharmacokinetics*; D005399:Fishes; D020387:Food Chain; D006801:Humans; D008962:Models, Theoretical; D009930:Organic Chemicals / Q000493:pharmacokinetics; D018570:Risk Assessment; D014018:Tissue Distribution
D004785:Environmental Pollutants; D009930:Organic Chemicals