AWWA JAW65068

Algal toxins are an issue of concern because of their widespread occurrence and potential threat to public health. This study monitored algal toxin concentrations in 33 lakes and reservoirs across the United States. Total toxin levels were expressed as microcystin-LR equivalent concentrations using a commercial enzyme-linked immunosorbent assay (ELISA). Although microcystins were detectable in most raw water samples, concentrations exceeded 1 µg/L in only 7% of samples, and drinking water treatment processes proved effective for toxin removal. The composition of different waters appeared to affect the toxin testing methodology, and further research is necessary to improve the technique. The US Environmental Protection Agency has placed cyanobacteria and their toxins on the Candidate Contaminant List for potential future regulation. Where algal blooms are a problem, a simple ELISA test can be used to monitor microcystin levels. However, this research suggests that most utilities do not need to be concerned about high concentrations of microcystin toxins in their raw water supplies or the ability of conventional filtration and disinfection processes to effectively lower toxin levels. Includes 26 references, tables, figures.