N-nitrosodimethylamine Formation During Chlorination of Diuron with Influence Analysis of the Sacramento-San Joaquin Delta Water Quality for Urban Uses
Author | : |
Publisher | : |
Total Pages | : |
Release | : 2009 |
ISBN-10 | : OCLC:461066969 |
ISBN-13 | : |
Rating | : 4/5 (69 Downloads) |
Book excerpt: Diuron is a widely used phenylurea herbicide for control of broad leaf and annual grassy weeds for both agricultural and nonagricultural uses. With the combination of the heavy usage and its persistence in typical environmental conditions due to its physical and chemical properties, diuron has been observed frequently in California's water sources. In this study diuron is of concern due to the potential formation of N-nitrosodimethylamine (NDMA), a potent carcinogen that has been identified as an emerging disinfection byproduct (DBP) in drinking water. The first results identified that diuron is a specific NDMA formation precursor that arises from non-point sources, and highlighted the difficulties associated with determining the environmental safety of chemicals and their associated potential byproducts. The influence of additional nitrogen sources on the NDMA formation mechanism during chlorination of diuron was also studied with consideration that the dominant nitrogen-containing specie may vary between surface water and groundwater. The risks posed by representative concentrations of diuron and other reagents with respect to NDMA formation during chlorine-based disinfection may be limited even in the presence of multiple nitrogen species. A broader picture exploring the current and long-term effects of water quality on public health risks from DBP formation and drinking water treatment costs was investigated by considering the Sacramento-San Joaquin Delta system, one of the most important drinking water sources in California. The present DBPs with Delta supplies are manageable within the current treatment regulations. However, the management of Delta water as a drinking water supply would become more difficult and expensive due to a possible sea level rise in the future and western island failures, with residual health risks remaining from residual and unregulated DBPs after treatment. It is likely that water drawn directly from the Delta will pose a higher risk to public health and be more difficult to treat by conventional treatment technologies, indicating that modification of existing treatment operations or addition of new technologies may be required, with higher treatment costs.