Overall Human Exposure Based on Spatial Range and Persistence. D. H. Bennett, Ph.D. Candidate, W. E. Kastenberg, Professor, and T. E. McKone, Professor, UC Berkeley, Nuclear Engineering, 4153 Etcheverry Hall MC# 1730, Berkeley, CA 94720-1730 USA, telephone (510) 642-8425, e-mail dhall@nuc.berkeley.edu
Persistent pollutants pose a greater potential concern per unit release because they cannot be rapidly removed from the environment if adverse health or ecological effects are later discovered. Additionally, persistence allows adequate time for environmental interactions and long range transport, allowing these chemicals to cross local or even international regulatory boundaries, potentially exposing individuals far from the source. We have developed methods to quantify the spatial range and persistence for persistent organic pollutants in a multimedia environment. Short or long term health and environmental effects are determined by the persistence; while the spatial range determines whether a chemical will have a local, regional, or global scale effect. Persistence depends on the distribution among the different environmental media because decay rates often differ between environmental media. The spatial range is derived analytically from a moving Lagrangian air cell and non-moving compartments. The concentration in air is reduced with distance based on degradation in air, transfer to and subsequent degradation in other media. These methodologies are appropriate for continual, area-source (non-point) emissions, including urban areas with releases from combustion for energy and transportation and industrial activities. To evaluate the potential adverse health effects of releases of persistent multi-media chemicals, overall human exposure should be based on the spatial range, persistence, and mass distribution of the chemical in the environment through multiple exposure pathways. It is also very desirable to determine which chemicals are likely to be persistent before they are released into the environment. Using the measure for persistence, a classification system is developed to classify a chemical as "persistent" or "non-persistent" based on the chemical properties. The system is based on the results of a multimedia model framework, thus bridging the gap between single media half-lives and modeling efforts with extensive data needs.
Go to . . .
1998 SRA-Europe Table of Contents
1998 SRA-Europe Author Index
Main Abstracts Menu Page
RiskWorld Home Page