WRRCSR No. 7.0:85 Subsurface Water Quality Organic Chemical Contamination of O'ahu groundwater

Abstract

This progress report is a study of the unprecedented problem of low-level organic chemical contaminants discovered principally in 1983 in potable groundwater sources on O'ahu. A number of inmediate and serious concerns are (1.) extent of the contaminated basal water, (2) treatments capable of removing such low level contaminant concentrations, and (3) health effects to drinking water consumers. Short-term actions were undertaken by the Hawaii State Department of Health (DOH) regarding the potability question of the contaminated water and the associated health risk. (The DOH subsequently proposed 20 ppt as the maxinun limit of EDB and DBCP in drinking water and none for TCP, despite oontroversies and lack of definitive scientific basis.) As a result of closing water wells exceeding these limits, immediate action was needed and taken by the major water purveyors (City and County of Honolulu Board of Water Supply [BWS] and U.S. Navy) to replace the closed water sources and/or to treat the contaminated water to below the maximum level. The BWS and U.S. Navy decided on treatment plants and the State drilled two new wells. Expediency was the priority for these actions.