Nitrosamines from pipeline materials in drinking water distribution systems

Abstract

The formation of nitrosamines in drinking water was first reported in the early 1990s. These compounds are classified as probable human carcinogens, so their control presents a challenge to authorities in providing a safe water supply to the public. Generally, nitrosamines in water supplies are the result of disinfection by chlorine or chloramines, and the standard control strategy has been to minimize their formation by changing treatment processes, often including the addition of an ultraviolet irradiation stage. This problem has now been exacerbated by the discovery that high levels of N‐nitrosodimethylamine (NDMA) in newly constructed pipelines result from NDMA leaching from the rubber sealing rings used to connect the pipes. This study strongly suggests that NDMA and other nitrosamines could be present for several years in distribution systems with rubber components. Furthermore, the occurrence of nitrosamines in drinking water was independent of both the type and presence of disinfectant.