Factors Affecting Public-Supply-Well Vulnerability to Contamination: Understanding Observed Water Quality and Anticipating Future Water Quality.

摘要

As part of the U.S. Geological Survey (USGS) National Water-Quality Assessment (NAWQA) Program, a study was conducted from 2001 to 2011 to shed light on factors that affect the vulnerability of water from public-supply wells* to contamination. The study was designed as a follow-up to earlier NAWQA studies that found mixtures of contaminants at low concentrations in groundwater near the water table in urban areas across the Nation and, less frequently, in deeper groundwater typically used for public supply. Although contaminants were less frequently detected in public-supply wells than in shallower monitoring wells, a separate study showed that contaminant concentrations were greater than drinking-water standards or other human health benchmarks in about 22 percent of public-supply-well samples.