High-performance size exclusion chromatography of chlorinated natural humic water and mutagenicity studies using the microscale fluctuation assay

Carlberg, Georg E.; Gjessing, Egil T.; Hongslo, Jan K.; Monarca, Silvano

doi:10.1021/es00135a006

Cited by 71 publications

(30 citation statements)

References 17 publications

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“…Humic substances aggregate in solution depending on pH, ionic strength and concentration, causing variations in molecular size (14,20,29). We validated our findings by repeated experiments on Skagen tap water at changing pH and ionic strength with unaltered concentration, and by preincubation with iodine.…”

Section: Discussionsupporting

confidence: 77%

“…The HPLC elution pattern of organic matter in our study corresponded to humic substances (14,17,28,29). Humic substances are heterogeneous mixtures of naturally occurring organic molecules.…”

Section: Discussionmentioning

confidence: 57%

“…Freeze drying provided gentle and sufficient preconcentration of organic matter in drinking water (27) and size exclusion chromatography on a single column gave information on both molecular weight and quantity (14,20,28,29). Using these techniques, we found dissolved organic matter in the drinking water from all six locations investigated, with the highest content in Skagen drinking water.…”

Section: Discussionmentioning

confidence: 97%

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Iodine in drinking water in Denmark is bound in humic substances

Andersen

Petersen

Laurberg

2002

European Journal of Endocrinology

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Objective: The iodine intake level is important for the occurrence of thyroid disorders in a population. We have previously found that iodine in drinking water is related to iodine excretion but whether iodine is present as iodide or bound in other molecules remains unknown. Design: We measured iodine in drinking water from 22 locations in Denmark. Six locations were selected by iodine content for further tap water analysis (Skagen 140 mg/l, Samsoe 56 mg/l, Nykoebing S. 50 mg/l, Nakskov 40 mg/l, Ringsted 38 mg/l, Copenhagen 19 mg/l). Methods: HPLC size exclusion before (Skagen) and after (all sites) freeze drying and measurement of absorbance (280 nm) and iodine in fractions, and fluorescence spectroscopy of bulk organic matter in Skagen drinking water. Results: Iodine content was unaltered after 3 years ðP ¼ 0:2Þ: All samples contained organic molecules with characteristics similar to humic substances. Most iodine eluted with humic substances (Skagen 99%, Ringsted 98%, Nykoebing S. 90%, Copenhagen 90%, Samsoe 75%, Nakskov 40%). Changing pH and ionic strength and preincubation with iodide indicated that iodine was bound in humic substances. Humic substances may affect thyroid function but differ with geology. Geological and geochemical data agree with tap water humic substances having been released from marine deposits. Iodine is abundant in the marine environment and marine deposits are particularly rich in iodine. Correlation analysis ðr ¼ 0:85; P ¼ 0:03Þ conform to iodine in drinking water, suggesting marine humic substances at the source rock. Conclusion: Iodine in Danish drinking water varied considerably. In drinking water with a high iodine content, the iodine mainly eluted with humic substances derived from marine source rock. We hypothesize that iodine in drinking water in general suggests coexisting humic substances of marine origin.

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Section: Discussionsupporting

confidence: 77%

Section: Discussionmentioning

confidence: 57%

Section: Discussionmentioning

confidence: 97%

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Iodine in drinking water in Denmark is bound in humic substances

Andersen

Petersen

Laurberg

2002

European Journal of Endocrinology

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“…Other factors that affect the nature of the products include pH, duration of chlorination, and extent of available analytical procedures brought to bear on the problem. The nonvolatile, high molecular weight products formed during the chlorination of humic acids have recently received some attention as well (14).…”

Section: Introductionmentioning

confidence: 99%

“…B6C3F1 mice were also used recently in this laboratory for the chronic bioassay of potential metabolites of the carcinogen dibromoethane administered in drinking water (18). While the chronic bioassay described in this report was underway, there were developments in other laboratories concerning the mutagenicity of chlorinated humic acids (11,14,15,19) and their possible initiating activity in two-stage carcinogenesis in SENCAR mice (15).…”

Section: Introductionmentioning

confidence: 99%

Chronic Bioassays of Chlorinated Humic Acids in B6C3F1 Mice

Duuren¹,

Melchionne²,

Seidman³

et al. 1986

Environmental Health Perspectives

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Humic acids (Fluka), chlorinated to carbon:chlorine (C:Cl) ratios of 1:1 and 1:0.3, were administered to B6C3F1 mice, 50 males and 50 females per group, in the drinking water at a total organic carbon (TOC) level of 0.5 g/L. The mice were 6 to 8 weeks old at the beginning of the bioassays. The doses used were based on short-term (8 weeks) evaluations for toxicity, palatability, and weight gain. The chronic bioassays included the following control groups: unchlorinated humic acids (0.5 g/L), no-treatment (100 males and 100 females), dibromoethane (DBE, 2.0 mM in drinking water; positive control) and 0.44% sodium chloride in drinking water, i.e., at the same concentration as those receiving chlorinated humic acids. The chlorinated humic acids were prepared freshly and chemically assayed once per week. All chemicals were, with the exception of DBE, administered for 24 months; DBE was administered for 18 months. The volumes of solutions consumed were measured once weekly. All treatment groups showed normal weight gain except the DBE group. At the completion of exposure, the animals were sacrificed and necropsied, and tissue sections were taken for histopathology. No markedly significant increases in tumor incidences were evident in any of the organs and tissues examined in the chlorinated humic acid groups compared to unchlorinated humic acids and the no-treatment control groups. DBE caused the expected high incidence of squamous carcinomas of the forestomach. The chlorinated humic acids tested contained direct-acting alkylating agents, based on their reactivity with p-nitrobenzylpyridine (PNBP), and showed mutagenic activity in S. typhimurium.

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Mutagenic potency of chlorofuranones and related compounds in salmonella

Ishiguro

Santodonato

Neal

1988

Environ and Mol Mutagen

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One of the mutagenic byproducts associated with chlorinated humic waters and kraft pulp bleaching effluents was recently identified as 3-chloro-4-(dichloromethyl)-5-hydroxy-2(5H)-furanone. This compound and several related chlorofuranones and precursors were synthesized and evaluated for direct-acting mutagenicity in Salmonella typhimurium tester strain TA100. Mutagenicity was greatest for 3-chloro-4-(dichloromethyl)-5-hydroxy-2(5H)-furanone, its 5-methoxy derivative, and the precursor in their synthesis, 3-(dichloromethyl)-2,4,4-trichloro-2-butenoic acid. Several of the compounds were tested in the presence of added rat liver homogenate S9 fraction, and in all cases mutagenicity was substantially reduced. An important structural feature which may govern the mutagenic response in these instances appears to be the cis arrangement of CHCl2 and Cl substituents on a carbon-carbon double bond. These compounds may also be transformed in vitro to the same acyclic chlorine substituted alpha, beta-unsaturated aldehyde derivative, which is proposed to be the agent responsible for the observed mutagenicity.

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High-performance size exclusion chromatography of chlorinated natural humic water and mutagenicity studies using the microscale fluctuation assay

Cited by 71 publications

References 17 publications

Iodine in drinking water in Denmark is bound in humic substances

Iodine in drinking water in Denmark is bound in humic substances

Chronic Bioassays of Chlorinated Humic Acids in B6C3F1 Mice

Mutagenic potency of chlorofuranones and related compounds in salmonella

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