Chlorination humic acids

Van Duuren BL, Melchionne S, Seidman I, et al. 1986. Chronic bioassays of chlorinated humic acids in B6C3F1 mice. Environ Flealth Perspect 69 109-117. 

None of the extracts from unchlorinated model compounds were significantly different from the negative controls. Extracts of chlorinated purines-pyrimidines and chlorinated nucleosides-nucleotides were also found to be not significantly mutagenic. However, the extracts of all three chlorinated humic acids and the chlorinated amino acids were... 

The mutagenic activities of the chlorinated humic acid and amino acid solutions are of the same order of magnitude as that observed in treated water. (The low numbers of revertants at the higher dose levels indicate toxicity). Therefore, these compounds may be precursors of the mutagenicity that is observed in XAD-2/ethyl ether extracts of treated water and that is the direct result of chlorination in drinking water treatment. 

Chlorination of Individual Amino Acids. HPLC analysis of an extract of chlorinated humic acids indicated that the chlorination products compose a highly complex mixture of organic material. Thus, the task of identification of mutagenic products of chlorination would not be simplified by the use of the humic acid model. In contrast, the amino acid model of production of mutagenic compounds can be readily simplified by the use of individual compounds as precursors. 

Carlsen L, Lassen P (1992) Enzymatically Mediated Formation of Chlorinated Humic Acids. Org Geochem 18 477... 

Becker et al. [2] have discussed the application of size exclusion chromatography to the determination of chlorinated humic acids in potable waters. 

Gas chromatography has also been applied to the determination of the following types of organic compounds in potable waters (see Table 15.11) aliphatic hydrocarbons, phenols, nitrophenols, chlorinated dioxins, anticholisterinase insecticides, chlorinated humic acid and chlorolignosulphonic acids. 

Coleman, W. E., J. W. Munch, P. A. Hodakievic, F. C. Kopfler, J. R. Meier, R. P. Streicher, and H. Zimmer. 1988. GC/MS identification of mutagens in aqueous chlorinated humic acid and drinking waters following HPLC fractionation of strong acid extracts. In Larson, R. A., Ed. Biohazards of Drinking Water Treatment. (Chelsea, MI Lewis Pub.), pp. 107-121. 

Pretreatment For most membrane applications, particularly for RO and NF, pretreatment of the feed is essential. If pretreatment is inadequate, success will be transient. For most applications, pretreatment is location specific. Well water is easier to treat than surface water and that is particularly true for sea wells. A reducing (anaerobic) environment is preferred. If heavy metals are present in the feed even in small amounts, they may catalyze membrane degradation. If surface sources are treated, chlorination followed by thorough dechlorination is required for high-performance membranes [Riley in Baker et al., op. cit., p. 5-29]. It is normal to adjust pH and add antisealants to prevent deposition of carbonates and siillates on the membrane. Iron can be a major problem, and equipment selection to avoid iron contamination is required. Freshly precipitated iron oxide fouls membranes and reqiiires an expensive cleaning procedure to remove. Humic acid is another foulant, and if it is present, conventional flocculation and filtration are normally used to remove it. The same treatment is appropriate for other colloidal materials. Ultrafiltration or microfiltration are excellent pretreatments, but in general they are... 

Finneran KT, HM Foirbush, CVG VanPraagh, DR Lovley (2002) Desulfitobacterium metalUreducens sp. nov., an anaerobic bacterium that couples growth to the reduction of metals and humic acids as well as chlorinated compounds. Int J Syst Evol Microbiol 52 1929-1935. 

Park J-W, Dec J, Kim JE, Bollag J-M (2000) Transformation of chlorinated phenols and anilines in the presence of humic acid. J Environ Qual 29 214-240... 

Organic matter in unpolluted freshwater is usually in the form of humic acids (Section 13.6), which may discolor drinking water, foul ion-exchange resins, transport toxic metal ions, or generate carcinogenic chlorocarbons if the water is chlorinated (see below). Humic compounds may be removed by coagulation. Low levels of organic solutes can be removed by sorption on activated charcoal. 

However, the chief source of chloroform is probably chlorination of naturally formed humic acids, especially in the tropics and subtropics. The World Health Organization has set a limit of 30 fig L-1 as the acceptable chloroform concentration in drinking water. Overzealous use of chlorine to sterilize sewage-plant effluent has also led to major fish kills in rivers. 

Gundersen, J. L., W. G. Macintyre, and R. C. Hale, pH-dependent sorption of chlorinated guaiacols on estuarine sediments The effects of humic acids and TOC , Environ. Sci. Technol., 31, 188-193 (1997). 

Elemental Analysis. The elemental analyses are presented in Table IV. The atomic ratios H/C for all drinking water samples (nos. 1-10) were between 1.28 and 1.39. These values were comparable to humic acid derived from lake sediments. However, H/C ratios were much lower when compared to the chlorinated model humic substances (e.g., 1.04-1.08 for CFH-1 and CFH-2). Bromine was present in almost negligible quantities, whereas Cl varied between 0.3 and 2.4, and S varied between 0.9 and 2.7 in the drinking water organic matter. All fractions from drinking water showed similar elemental composition. However, they differed from the elemental composition of the CFH samples in all respects, especially in chlorine content. 

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