ABSTRACT
Fish concentrations can be estimated directly from water concentrations, but meat, vegetable, and dairy product concentrations are poorly understood functions of the concentrations of chemical in air, water, soil, and animal feeds, and of agrochemical usage. This chapter discusses briefly the principles by which these concentration data can be used to assess the impact of chemicals on humans and other organisms. Large numbers of new chemicals are produced each year, presenting a significant regulatory challenge. A regulatory issue in which evaluative mass balance models are playing an increasingly important role is in assessing the persistence, bioaccumulation, toxicity (PBT) and long-range transport attributes of chemicals. The PBT approach is favored by many regulatory agencies because it is relatively simple, requiring only the basic physico-chemical properties, estimates of production and emission rates, some environmental monitoring data and some toxicity data.
