01 June 2017
chloramination, chlorination, cyanobacteria, disinfection by‐products, N‐nitrosamines, Toxicity, Chloramination, Chlorination, Cyanobacteria, Disinfection Byproducts, Western Australia, Australia, Case Studies, N‐Nitrosamines
This study investigated the formation of eight N‐nitrosamines after laboratory chlorination and chloramination of Western Australian source waters (from protected catchments), which experience periodic cyanobacterial blooms. All measured N‐nitrosamines, except N‐nitrosodipropylamine, were detected at least once, and total N‐nitrosamine formation was higher after chloramination than after chlorination. While previous studies have shown that some cyanobacteria can be related to the formation of N‐nitrosamines, formation of N‐nitrosamines in the waters tested did not correlate with total cyanobacteria count. Estimates of toxicity, using published 50% lifetime excess cancer risk values, indicated that N‐nitrosodimethylamine (NDMA) was the highest contributor to the total measured N‐nitrosamine toxicity, suggesting that other measured N‐nitrosamines will only influence toxicity when they are present at significantly higher concentrations than NDMA. When assessing the overall health impact of disinfection by‐products, it is important to also consider the formation of disinfection by‐products other than N‐nitrosamines, which may be present at higher concentrations and thus may present higher toxicity.