| 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. |
