Health-Risk-Based Remedial Alternatives for Contaminated Aquifer Management

Abstract

In the risk-based management approach, the risks associated with human health and the environment in a contaminated site are evaluated and corrective measures are undertaken to reduce the risk level to acceptable limits. In this study, a risk-based management model is developed and applied to a hypothetical aquifer system. The model couples the simulated contaminant transport in the aquifer and the health risk assessment procedure to predict human health risk level and later relate it to the total cost of a proposed groundwater contamination remedial action. Amongst a number of remedial alternatives considered, those consisting of different combinations of pump and treat remediation system are compared with the bioremediation strategy in the study. Later, the computed residual risk and the cost associated with the risk reduction are taken as parameters used for justification of a better remedial alternative. The results highlight the importance of applying an integrated approach for decision making which may include costs, risk levels, and the cost-effectiveness of the various available alternatives. Furthermore, the uncertainty in risk associated with these remedial alternatives for available aquifer parameters due to a given exposure is also studied applying fuzzy set theory. Amongst the various alternatives considered, the bioremediation method is found to be a better alternative even in cases where there is uncertainty in parameter estimation compared to other technologies used for cleanup of hazardous waste.