Persistent organic pollutants (POPs): state of the science.

The environmental chemistry and ecotoxicology of persistent organic pollutants (POPs) are fascinating areas of scientific research. Our objective in this paper is to provide a brief, focussed overview of what constitutes a POP, highlight the harmful effects they may have on biota, make some comments on their environmental sources and analysis, their environmental trends and processes, their movement through foodchains and highlight some important regional-and global-scale environmental transport issues. Finally, we offer some personal thoughts on some current and future areas of scientific enquiry on POPs.

Persistent organic pollutants (POPs): the state of science.

Bioaccumulation assessment is important in the scientific evaluation of risks that chemicals may pose to humans and the environment and is a current focus of regulatory effort. The status of bioacc...

A review of bioconcentration factor (BCF) and bioaccumulation factor (BAF) assessments for organic chemicals in aquatic organisms

Bioaccumulation of persistent organic chemicals: mechanisms and models

The present study examines a new bioaccumulation model for hydrophobic organic chemicals in aquatic food webs. The purpose of the model is to provide site-specific estimates of chemical concentrations and associated bioconcentration factors, bioaccumulation factors, and biota-sediment accumulation factors in organisms of aquatic food webs using a limited number of chemical, organism, and site-specific data inputs. The model is a modification of a previous model and incorporates new insights regarding the mechanism of bioaccumulation derived from laboratory experiments and field studies as well as improvements in model parameterization. The new elements of the model include: A model for the partitioning of chemicals into organisms; kinetic models for predicting chemical concentrations in algae, phytoplankton, and zooplankton; new allometric relationships for predicting gill ventilation rates in a wide range of aquatic species; and a mechanistic model for predicting gastrointestinal magnification of organic chemicals in a range of species. Model performance is evaluated using empirical data from three different freshwater ecosystems involving 1,019 observations for 35 species and 64 chemicals. The effects of each modification on the model's performance are illustrated. The new model is able to provide better estimates of bioaccumulation factors in comparison to the previous food web bioaccumulation model while the model input requirements remain largely unchanged.

A food web bioaccumulation model for organic chemicals in aquatic ecosystems.

A fugacity-based model is developed to simulate the phenomena of bioconcentration and biomagnification of organic contaminants in complex food webs in aquatic systems comprising contaminated water and sediment. The food web consists of N classes of organisms, which may feed on all organisms including their own class, and in which each organism may experience chemical uptake from benthic or pelagic food organisms and water with clearance by respiration, egestion, and metabolism. The expressions reduce to a single equation involving an N × N matrix of food preference parameters that is readily solved to give concentrations and fluxes throughout the food web. The model is applied illustratively to bioaccumulation of PCB congeners in Lake Ontario yielding results generally within a factor of 3 of measured values. This approach quantifies the roles of exchange with water, food uptake, and food web structure as determinants of bioaccumulation in aquatic systems and has the potential to be extended to treat broa...

Jan Campfens

Papers

Fugacity-Based Model of PCB Bioaccumulation in Complex Aquatic Food Webs