Trace Contaminants in Water Treatment Chemicals: Sources and Fate

Abstract

This article describes a comprehensive national investigation of trace contaminants in water treatment chemicals. In general, no pervasive problems with trace contaminants in US water treatment chemicals were found, but serious isolated contamination incidents continue to occur. The most commonly identified problems were transport‐related, typically the result of improperly cleaned or maintained delivery vehicles and transfer hoses. These and other related problems were routinely averted when utilities developed and implemented inspection and evaluation programs for incoming chemical deliveries. This research produced compositional data from more than 50 treatment‐chemical products. Trace contaminants contributed by coagulants partitioned primarily into residuals rather than finished water during full‐ and pilot‐scale studies conducted during this investigation. Mass balance calculations from these partitioning studies confirmed the compositional data reported for coagulants in this research, results that are much lower than limited data reported previously in the literature for samples collected before 1990.