AN ENVIRONMENTAL RISK MODEL FOR GROUNDWATER

A model for estimating environmental risk to groundwater is developed. The predictor variable is a composite of contaminant, surface, and subsurface risk factors. The contaminant risk factor is a description of a specific hazardous substance mobility, persistence, and potency to the environment and humans. The surface risk factor is a description of the probability that a release of a hazardous substance(s) will occur at a particular location. The subsurface factor is a description of the probability that the geological environment will permit migration of a specific contaminant(s) to a potential receptor. Calibration of the model was performed at 83 sites in an urbanized watershed with diverse surficial geology in southeastern Michigan. These test sites were contaminated with several different contaminants that exhibited wide variation of contaminant extents, including sites where only near-surface soils were impacted while others exhibited soil and groundwater contamination. The model was then applied to 86 sites with multiple contaminant and contaminant extents within different watersheds in North America, South America, Asia, Europe, Africa, and Australia. The results indicate a very high correlation between actual and predicted environmental impact and remedial costs. This model thus has the potential for providing reliable estimates of environmental impact across a broad array of soil and groundwater contamination scenarios.