Evaluation of bioaccumulation factors in regulating metals

Regulating metals on the basis of simple measures of bioaccumulation in aquatic organisms gives misleading results. Simple bioaccumulation factors are useful in characterizing the hazard posed by hydrophobic organic compounds, but the bioaccumulation of metals is more complex. For metals that are essential for health, many organisms have the ability to control and maintain internal metal concentrations in the presence of significant variations in external concentrations. Hence bioaccumulation factors expressed as the ratio of wet tissue concentration and water concentration must vary according to external concentration. Regulations that specify a single generic accumulation factor are thus inappropriate.