Second moment method for evaluating human health risks from groundwater contaminated by trichloroethylene

Area of Science:

• Environmental Science
• Hydrogeology
• Toxicology
• Risk Assessment

Background:

• Groundwater aquifer contamination presents significant human health risks.
• Individual responses to carcinogenic contaminants like trichloroethylene (TCE) vary widely.
• Variability in aquifer properties necessitates stochastic models for exposure assessment.

Purpose of the Study:

• To evaluate the probability of exceeding safe dose levels in contaminated aquifers.
• To incorporate spatial variability of hydrogeologic parameters and human response variability into risk assessment.
• To assess health risks and inform remediation strategies for contaminated groundwater.

Main Methods:

• Utilized stochastic transport models to quantify exposure concentration variability.
• Employed a second moment method, based on first and second moments of random variables.
• Integrated variability in contaminant concentration (including hydrogeologic parameters) and human population response.

Main Results:

• The second moment method provides a probabilistic assessment of exceeding safe dose levels.
• Risk severity is a function of both contaminant concentrations and human health variability.
• Demonstrated method applicability using TCE groundwater contamination data from Hill Air Force Base, Utah.

Conclusions:

• The second moment method offers a robust framework for assessing health risks from contaminated aquifers.
• This approach accounts for critical uncertainties in hydrogeology and human toxicology.
• Findings support informed decision-making for effective aquifer remediation strategies.