Eawag, Swiss Federal Institute of Aquatic Science and Technology, Dübendorf, Switzerland.
Water Res. 2013 Jan 1;47(1):79-90. doi: 10.1016/j.watres.2012.09.034. Epub 2012 Sep 26.
N-Nitrosamines, in particular N-nitrosodimethylamine (NDMA), are carcinogens, which occur as chlorine disinfection by-products (DBPs) in swimming pools and hot tubs. UV treatment is a commonly used technique in swimming pools for disinfection and DBP attenuation. UV irradiation is known to efficiently degrade N-nitrosamines. However, UV irradiation (at λ = 254 nm) of chlorinated dimethylamine (CDMA) and monochloramine, two NDMA precursors present in swimming pool water, resulted in a substantial UV-induced NDMA formation (~1-2% molar yield based on initial CDMA concentration) simultaneously to NDMA photolysis. Maximum NDMA concentrations were found at UV doses in the range used for advanced oxidation (350-850 mJ cm(-2)). Very similar behaviour was found for other chlorinated secondary amines, namely diethylamine and morpholine. Effectiveness of UV irradiation for N-nitrosamine abatement depends on initial N-nitrosamine and precursor concentrations and the applied UV dose. N-Nitrosamine formation is hypothesized to occur via the reaction of nitric oxide or peroxynitrite with the secondary aminyl radical, which are products from the photolysis of monochloramine and chlorinated secondary amines, respectively. Experiments with pool water showed that similar trends were observed under pool water conditions. UV treatment (UV dose: ~360 mJ cm(-2)) slightly increased NDMA concentration in pool water instead of the anticipated 50% abatement in the absence of NDMA precursors.
亚硝胺，尤其是亚硝二甲胺（NDMA），是一种致癌物质，它作为游泳池和热水浴缸中的氯消毒副产物（DBP）而存在。紫外线处理是游泳池中常用的消毒和 DBP 衰减技术。已知紫外线照射能有效地降解亚硝胺。然而，对游泳池水中存在的两种 NDMA 前体，即氯化二甲胺（CDMA）和一氯胺进行紫外线照射（λ=254nm），同时会导致大量的紫外线诱导 NDMA 形成（基于初始 CDMA 浓度，摩尔产率约为 1-2%），同时 NDMA 光解。在用于高级氧化（350-850mJcm(-2)）的紫外线剂量范围内，发现最大 NDMA 浓度。其他氯化仲胺，即二乙胺和吗啉，也表现出非常相似的行为。紫外线照射对亚硝胺去除的效果取决于初始亚硝胺和前体浓度以及应用的紫外线剂量。亚硝胺的形成被假设是通过一氧化氮或过氧亚硝酸盐与仲氨自由基的反应发生的，这分别是一氯胺和氯化仲胺光解的产物。对游泳池水的实验表明，在游泳池水条件下观察到了类似的趋势。紫外线处理（紫外线剂量：~360mJcm(-2)）仅略微增加了游泳池水中的 NDMA 浓度，而在没有 NDMA 前体的情况下，预计会有 50%的去除率。
