摘要 :
Petroleum or creosote contamination of surface waters, soils, or groundwaters introduces countless aromatic compouds to these environments. Among these are condensed thiophenes that were shown to be oxidized to sulfoxides, sulfone...
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Petroleum or creosote contamination of surface waters, soils, or groundwaters introduces countless aromatic compouds to these environments. Among these are condensed thiophenes that were shown to be oxidized to sulfoxides, sulfones, and 2, 3- diones by microbial cultures. In this study, the acute toxicities of 12 compounds (benzothiophene, benzothiophene sulfone, ben- zothiophene-2, 3,dione, 3-, and 5-methylbenzothiophenes, 3-, and 5-methylbenzothiophene sulfones, 5-, and 7-methylbenzothio- phene-2, 3-diones, dibenzothiophene, dibenzothiophene sulfoxide, and dibenzothiophene sulfone) were determined by the Microtox~R and Daphnia magna bioassays.
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摘要 :
Formation of nine N-nitrosamines has been investigated when seven different source waters representing various qualities were each treated with eleven bench-scale disinfection processes, without addition of nitrosamine precursors....
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Formation of nine N-nitrosamines has been investigated when seven different source waters representing various qualities were each treated with eleven bench-scale disinfection processes, without addition of nitrosamine precursors. These disinfection treatments included chlorine (OCl~-), chloramine (NH_2Cl), chlorine dioxide (ClO_2), ozone (O_3), ultraviolet (UV), advanced oxidation processes (AOP), and combinations. The total organic carbon (TOC) of the seven source waters ranged from 2 to 24 mg·L~(-1). The disinfected water samples and the untreated source waters were analyzed for nine nitrosamines using a solid phase extraction and liquid chromatography-tandem mass spectrometry method. Prior to any treatment, N-nitrosodimethylamine (NDMA) was detected ranging from 0 to 53 ng·L~(-1) in six of the seven source waters, and its concentrations increased in the disinfected water samples (0-118 ng·L~(-1)). N-nitrosodiethylamine (NDEA), N-nitrosomor-pholine (NMor), and N-nitrosodiphenylamine (NDPhA) were also identified in some of the disinfected water samples. NDPhA (0.2-0.6 ng·Lz~(-1)) was formed after disinfection with OCl~-, NH_2Cl, O_3, and MPUV/OCl~-. NMEA was produced with OCl~-and MPUV/OCl~-, and NMor formation was associated with O_3. In addition, UV treatment alone degraded NDMA; however, UV/ OCl~- and AOP/OCl~- treatments produced higher amounts of NDMA compared to UV and AOP alone, respectively. These results suggest that UV degradation or AOP oxidation treatment may provide a source of NDMA precursors. This study demonstrates that environmental concentrations and mixtures of unknown nitrosamine precursors in source waters can form NDMA and other nitrosamines.
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