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The impact of spawning salmon on disinfection by-product formation.

机译:产卵鲑鱼对消毒副产物形成的影响。

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In the mid-1990s, the Alaska Department of Environmental Conservation began working with the city of Deering, Alaska to improve overall sanitation including construction of new water treatment facilities. Preliminary testing indicated that the city would have problems meeting the then-proposed Stage 1 Disinfection By-Products Rule (DBPR1). Further investigation suggested that part of the problem might be caused at least partially by the annual salmon returns that occurred in the city's water source, the Inmatchuk River.;The data presented in this dissertation show that the annual salmon run does have a significant impact on the organic loading of the river. In addition, the data clearly show that salmon decomposition products can substantially increase formation of regulated disinfection by-products (DBPs) while causing specific UV absorbance (SUVA) values to decrease. The data show that, as a consequence of the returning salmon, protein becomes a major part of the dissolved organic carbon (DOC) content. Since protein decay released a variety of free amino acids, it was expected that this would increase the loading of amino acids in the river as well, but interference from unknown substances in the river water prevented conclusive amino acid analysis. However, using the protein level determined in the raw water as a basis, testing of chlorination of the amino acids that were identified demonstrated that one of the major amino acids, aspartic acid, would convert nearly quantitatively to dichloroacetic acid (DCAA, a regulated DBP) when exposed to excess chlorine at neutral pH. These results are consistent with the DBP formation potential work done on raw water from the river. The data also show that conversion of ASP to DCAA requires that the chlorine:amino acid ratio reach a critical level prior to the conversion occurring.;All the amino acids tested consumed large quantities of chlorine, as much as 5-8 mols of chlorine per mol of amino acid. During the early stages of chlorination (chlorine:amino acid molar ratios of 2:1 or less), before any significant DBP formation had occurred, both mono- and dichloramine were found in the reaction products. This suggests that during the early stages of chlorination, the amine group is cleaved from the amino acid. This conflicts with the proposed chlorination process proposed by earlier researchers.;The test data also showed that, when chlorinated at elevated pH, aspartic acid as well as threonine and glutamic acid would produce significant quantities of chloroform (another regulated DBP). These results suggest that the characteristic amino acid root structure (--CHNH2--COOH) may be a significant contributor of chloroform in chlorinated water.
机译:在1990年代中期,阿拉斯加环境保护部开始与阿拉斯加Deering市合作,以改善整体卫生条件,包括建设新的水处理设施。初步测试表明,该市可能无法满足当时提议的第一阶段消毒副产品规则(DBPR1)。进一步的调查表明,部分问题可能至少部分是由于该城市水源-Inmatchuk河中的鲑鱼年度回报所致。本论文提供的数据表明,鲑鱼年度运行确实对鲑鱼的繁殖产生了重大影响。河流的有机负荷。此外,数据清楚地表明,鲑鱼分解产物可以显着增加受控消毒副产物(DBP)的形成,同时导致特定的UV吸收率(SUVA)值降低。数据表明,由于鲑鱼的返回,蛋白质成为溶解有机碳(DOC)含量的主要部分。由于蛋白质的腐烂释放了多种游离氨基酸,因此预计这也会增加河水中氨基酸的含量,但是河水中未知物质的干扰阻止了最终氨基酸的分析。但是,使用原水中确定的蛋白质水平作为基础,对鉴定出的氨基酸进行氯化测试表明,一种主要氨基酸天冬氨酸几乎可以定量转化为二氯乙酸(DCAA,一种受管制的DBP )在中性pH下暴露于过量的氯气中。这些结果与对河流原水进行的DBP形成潜力工作相吻合。数据还表明,ASP转化为DCAA要求在转化发生之前氯:氨基酸比率达到临界水平。;所有测试的氨基酸消耗大量的氯,每氯多达5-8摩尔氯摩尔的氨基酸。在氯化的早期阶段(氯:氨基酸摩尔比为2:1或更小),在未发生任何明显的DBP形成之前,反应产物中同时发现了单氯胺和二氯胺。这表明在氯化的早期阶段,胺基是从氨基酸上裂解的。这与早期研究人员提出的拟议的氯化过程相矛盾。测试数据还表明,在较高的pH下进行氯化时,天冬氨酸,苏氨酸和谷氨酸会产生大量的氯仿(另一种受管制的DBP)。这些结果表明,特征性氨基酸根结构(--CHNH2--COOH)可能是氯化水中氯仿的重要成分。

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