Particulate arsenic release in a drinking water distribution system

Abstract

Trace contaminants have been shown to accumulate in solids found in drinking water distribution systems and can potentially be released to the consumer—s tap water. The objective of this study was to identify and evaluate the source of high arsenic in consumers— tap water at a small drinking water system and assess the effect of the installation of a treatment system for iron/arsenic removal. Before treatment, water samples collected from home taps showed high arsenic concentrations (as high as 299 μg/L) that were attributable to iron solids found in the distribution system. In 29% of the tap water samples, arsenic concentrations in first‐draw water samples were greater than arsenic levels in water entering the distribution system. Color measurements proved to be good predictors of arsenic and iron levels in the tap water, and turbidity was a relatively poor predictive measurement.