科研之友
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摘要
N-nitrosamines are a new class of disinfection byproducts with significant toxicity and carcinogenicity that have attracted extensive attention worldwide in recent years. N-nitrosamines in natural and drinking water would have adverse effects on people. The occurrence of N-nitrosamines in surface water, groundwater, and tap water of the Liujiang River Basin was investigated to disclose the source, fate, and cancer risk of N-nitrosamines in a typical karstic river. The origins of N-nitrosamines contamination were investigated using principal component analysis and multiple linear regression (PCA-MLRA). The results indicated that the concentrations of nine Nnitrosamines species were NDMA (1.7-342 ng/L), NMEA (ND, ND represents not detected), NPYR (2.5-53 ng/L), NDBA (ND-87 ng/L), NDEA (0.2-5.7 ng/L), NDPA (ND-34 ng/L), NPIP (ND-32 ng/L), NMOR (0.1-5.2 ng/L), and NDPhA (ND-0.3 ng/L). 71% of N-nitrosamines in the surface water samples of the Liujiang River's mainstream could be attributed to industrial and aquaculture effluents. Furthermore, 29% of N-nitrosamines could originate from domestic sewage and agricultural operations. In addition, we estimated the cancer risks associated with Nnitrosamines in groundwater and drinking water. For lifetime exposure (from birth to age 70), the average estimated carcinogenic risks of groundwater and tap water from oral intake were 7.4 x 10-5 (7.4 extra cancer cases per 100,000 persons exposed) and 9.7 x 10-5, respectively, which were greater than the US EPA standard (1 x 10-5). N-nitrosamines posed the highest cancer risk to children aged one to six. The experimental results would serve as a data foundation for environmental governance in typical karst regions.
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单位桂林理工大学
