(19f) Evaluation of Drinking Water Contaminants Using Modeling

A wide variety of chemicals are used in manufacturing facilities and transported near water bodies. When preparing emergency response plans for spills of these chemicals, it is important to know where the released chemical may be transported as well as potential concentrations in the water and atmosphere. To help address these needs, the 3D chemical spill model CHEMMAP is used to estimate the fate and concentrations of selected chemicals in water and the atmosphere, as well as the potential human health impacts resulting from a spill into a river. CHEMMAP uses environmental data forcing (currents and wind) and physical-chemical properties to simulate fate processes over time after the release, including: (1) slick spreading, transport, and entrainment of floating materials, (2) transport of dissolved and particulate materials, (3) evaporation and volatilization, (4) dissolution and adsorption, (5) sedimentation and re-suspension, (6) and degradation.

Organic chemicals contained on the Environmental Protection Agency (EPA)'s list of drinking water contaminants will be classified into groups based on physical-chemical characteristics and evaluated using CHEMMAP for representative chemicals and release volumes. Based on model outputs, it will be possible to select chemicals that would have the highest human health consequences when released via the consumption of water and inhalation pathways. The model results can be used to indicate safe distances for responders using National Institute for Occupational Safety's (NIOSH) thresholds, as well as the volume of water that may be contaminated above EPA's Maximum Contaminant Level (MGL).