Mutagenicity Of Water Research Articles

Detection of ultra-low levels of DNA changes by drinking water: epidemiologically important finding.

The safety of drinking water is essential to our health. In this context, the mutagenicity of water needs to be checked strictly. However, from the methodological limit, the lower concentration (less than parts per million) of mutagenicity could not be detected, though there have been of interest in the effect of less concentration mutagens. Here, we describe a highly sensitive mutation assay that detects mutagens at the ppb level, termed genome profiling-based mutation assay (GPMA). This consists of two steps; (i) Escherichia coli culture in the medium with/without mutagens and (ii) Genome profiling (GP) method (an integrated method of random PCR, temperature gradient gel electrophoresis and computer-aided normalization). Owing to high sensitivity of this method, very low concentration of mutagens in tap water could be directly detected without introducing burdensome concentration processes, enabling rapid measurement of low concentration samples. Less expectedly, all of the tap waters tested (22 samples) were shown to be significantly mutagenic while mineral waters were not. Resultantly, this article informs two facts that the GPMA method is competent to measure the mutagenicity of waters directly and the experimental results supported the former reports that the city tap waters contain very low level of mutagenicity reagent trihalomethanes.

Survey of the mutagenicity of surface water, sediments, and drinking water from the Penobscot Indian Nation

U.S. Environmental Protection Agency (US EPA) Regional Applied Research Effort (RARE) projects address the effects of environmental pollutants in a particular region on the health of the population in that region. This report is part of a RARE project that addresses this for the Penobscot Indian Nation (PIN), Penobscot Island, Maine, U.S., where the Penobscot River has had fish advisories for many years due to high levels of mercury. We used the Salmonella mutagenicity assay with strains TA100, TA98, YG1041, and YG1042 with and without metabolic activation to assess the mutagenic potencies of organic extracts of the Penobscot River water and sediment, as well as drinking-water samples, all collected by the PIN Department of Natural Resources. The source water for the PIN drinking water is gravel-packed groundwater wells adjacent to the Penobscot River. Most samples of all extracts were either not mutagenic or had low to moderate mutagenic potencies. The average mutagenic potencies (revertants/L-equivalent) were 337 for the drinking-water extracts and 177 for the river-water extracts; the average mutagenic potency for the river-sediment extracts was 244revertants(g-equivalent)−1. This part of the RARE project showed that extracts of the Penobscot River water and sediments and Penobscot drinking water have little to no mutagenic activity that might be due to the classes of compounds that the Salmonella mutagenicity assay detects, such as polycyclic aromatic hydrocarbons (PAHs), nitro-PAHs (nitroarenes), and aromatic amines. This study is the first to examine the mutagenicity of environmental samples from a tribal nation in the U.S.

Characterization, DBPs formation, and mutagenicity of different organic matter fractions in two source waters

Dissolved organic matters (DOM) are critical in the formation of the mutagenic disinfection byproducts (DBPs). In this study, five DOM fractions were isolated and investigated from a contaminated river and a clean reservoir source waters using resin adsorption. The DOM fractions were characterized with excitation-emission matrix, and several typical DBPs formation potentials and the mutagenicity of each DOM fraction were measured. Among these fractions, hydrophobic neutrals (HON), hydrophilic acids (HIA) and hydrophilic bases (HIB) generated the highest carbon-containing DBPs in the river source water, as did HIB and hydrophobic bases (HOB) in reservoir water. Hydrophobic acids (HOA), HON, and HIA were the three most important fractions forming nitrogen-containing DBPs. Following chlorination, the mutagenicity of HON, HIA, HOA and HIB was 1503, 626, 422 and 116 ng 4-NQO/mg DOC in river water, respectively. Only HIA and HOA were mutagenic with 85 and 10 ng 4-NQO/mg DOC in reservoir water, respectively. The soluble microbial products like substances and aromatic proteins contributed significantly to the mutagenicity of river water; whereas the humic acid-like and fulvic acid-like substances were the primary contributors to the mutagenicity of reservoir water.

Integrated biological–chemical approach for the isolation and selection of polyaromatic mutagens in surface waters

Many environmental mutagens, including polyaromatic compounds are present in surface waters, often in complex mixtures and at low concentrations. The present study provides and applies a novel, integrated approach to isolate polyaromatic mutagens in river water using a sample from the River Elbe. The sample was taken downstream of industrial discharges using blue rayon (BR) as a passive sampler that selectively adsorbs polyaromatic compounds and was subjected to effect-directed fractionation in order to characterise the compounds causing the detected effect(s). The procedure relies on three complementary fractionation steps, the Ames fluctuation assay with strains TA98, YG1024 and YG1041 with and without S9 activation and analytical screening. Several mutagenic fractions were isolated by combining mutagenicity testing with fractionation. The enhanced mutagenicity in the nitroreductase and/or O-acetyltransferase overexpressing strains YG1024 and YG1041 strains suggested amino- and/or nitro-compounds causing mutagenicity in several fractions. Analytical screening of mutagenic fractions with LC-HRMS/MS provided a list of molecular formulas typically containing one to ten nitrogen and at least two oxygen atoms supporting the presence of amino and nitro-compounds in the mutagenic fractions.

Mutagenicity and cytotoxicity of liquid waste, press water and pond water, produced in the cassava flour industry, and of antitoxic sodium thiosulfate

Cassava (Manihot esculenta Crantz), a plant used as food and an ingredient in industry, contains cyanogenic glycosides. The cassava root contains wastewater, popularly known as manipueira, which is a toxic substance. Its ingestion by animals causes poisoning although they react positively to treatment with sodium thiosulfate. The present research evaluates the cytotoxicity and the mutagenicity of liquid waste produced in the process of industrialization of the bitter cassava, olho-junto variety. The liquid wastes are characterized as press water, which is obtained when the cassava roots are pressed; pond water, which is press water stored in impounded ponds; and a solution of sodium thiosulfate, pure and with other waste. The system tests comprised root meristematic cells of Allium cepa L. and bone marrow cells of Rattus norvegicus. Treatment with saline solution was cytotoxic for Allium cepa L. and significantly reduced cell division rate. Although no treatment was cytotoxic in any of the tests with rats, the thiosulfate solution was clastogenic for the chromosomal aberrations test. Since it is harmful to the genetic material submitted within the conditions of current research, sodium thiosulfate should only be used in emergency conditions in which the benefits exceed the risks.

Nonexperimental Screening of the Water Solubility, Lipophilicity, Bioavailability, Mutagenicity and Toxicity of Various Pesticides with QSAR Models Aid

Nonexperimental Screening of the Water Solubility, Lipophilicity, Bioavailability, Mutagenicity and Toxicity of Various Pesticides with QSAR Models Aid

Quality and mutagenicity of water and sediment of the streams impacted by the former uranium mine area Olší–Drahonín (Czech Republic)

The water quality research performed in the years 2003–2010 demonstrated an impact of the mine water pumped from the closed Olší uranium mine and discharged from the mine water treatment plant (MWTP) and groundwater from springs in the area on the water quality of the Hadůvka stream. The water ecosystems of the lower part of the Hadůvka stream are impacted mainly by water originated from the springs located in the stream valley and drained syenit subsoil, naturally rich in uranium. Those inflows caused a very high concentration of uranium measured in the water of the stream, which exceeds the given limit value. No negative impact on the water ecosystems of the receiving Bobrůvka River was found. This reduction of impact is caused by five times higher average daily flow rate of the Bobrůvka River in comparison with the Hadůvka stream, which results in a sufficient dilution of pollution from the Hadůvka.

International round‐robin study on the Ames fluctuation test

An international round-robin study on the Ames fluctuation test [ISO 11350, 2012], a microplate version of the classic plate-incorporation method for the detection of mutagenicity in water, wastewater and chemicals was performed by 18 laboratories from seven countries. Such a round-robin study is a precondition for both the finalization of the ISO standardization process and a possible regulatory implementation in water legislation. The laboratories tested four water samples (spiked/nonspiked) and two chemical mixtures with and without supplementation of a S9-mix. Validity criteria (acceptable spontaneous and positive control-induced mutation counts) were fulfilled by 92-100%, depending on the test conditions. A two-step method for statistical evaluation of the test results is proposed and assessed in terms of specificity and sensitivity. The data were first subjected to powerful analysis of variance (ANOVA) after an arcsine-square-root transformation to detect significant differences between the test samples and the negative control (NC). A threshold (TH) value based on a pooled NC was then calculated to exclude false positive test results. Statistically, positive effects observed by the William's test were considered negative, if the mean of all replicates of a sample did not exceed the calculated TH. By making use of this approach, the overall test sensitivity was 100%, and the test specificity ranged from 80 to 100%.

Study on water quality and mutagenicity of a surface water from a semi-arid region by micronucleus assays

Study on water quality and mutagenicity of a surface water from a semi-arid region by micronucleus assays

Research of waste dump water mutagenicity of bacterial detection system SOS chromotest

The paper deals with a possible use of the bacterial detection system of SOS chromotest to test mutagenicity of waste dump water checking the mutagenicity degree on real samples from Praksice waste dump, which is a controlled waste dump with mixed industrial, municipal and inert wastes. The waste dump surface water samples were taken from a no-name influent stream springing below the waste dump body between 2005 and 2009. After metabolic activation by microsomal fraction in vitro, medium to high mutagenicity was registered in all the samples. The SOS chromotest is assessed as an effective and economically acceptable method to check and determine the mutagenicity degree of contaminated water.

A level change in mutagenicity of Japanese tap water over the past 12 yr

A relative comparison study of mutagenicity in Japanese tap water was conducted for 1993 and 2005 surveys. It intended to assess the effects of advanced water treatment installations to water works, improvement of raw water quality and improvement of residual HOCl concentration controlling. Sampling points (taps) were the same in both surveys. The results of 245 samples obtained by the Ames Salmonella mutagenicity test (Ames test) were analyzed. The Ames tests were conducted by using Salmonella typhimurium TA98 and TA100 strains with and without exogenous activation (S9). With the exception of TA100-S9, the other conditions needed no discussion as a factor in the mutagenicity level change. The average mutagenicity in 1993 and 2005 under the conditions of TA100-S9 were 2600 and 1100 net revertant L −1, respectively. This indicated that the mutagenicity level of Japanese tap water decreased during the 12-yr period. Particularly a remarkable decrease in mutagenicity was observed in the water works where the advanced water treatments were installed during the 12-yr period. The advanced water treatments were effective in decreasing the mutagenicity of tap water. Mutagenicity also decreased in the water works with conventional water treatments; the improvement of residual HOCl concentration controlling was also considered to be effective in decreasing the mutagenicity of tap water.

The Genotoxicity of the Organics in Effluent From Different Treating Processes of 6 Water Works in Shenzhen

PP-31-192 Background/Aims: To detect and assess the genotoxicity of the organic extracts in effluent of 6 water works in Shenzhen. Methods: The Salmonella mutagenicity test was used to detect the mutagenicity of water samples collected from 6 water works (A, B, C, D, E, and F) on May and June, 2008, Shenzhen. Results: Except for the water sample from active carbon pool of B water works, all other showed positive result for Ames test, and the type of mutagenicity was mainly code-shifting. The intensities of mutagenicity of every water samples during the treatment were as follows: A: output water > precipitated-filtrated water > source water > second chlorinated water > tap water > prechlorinated water; B: source water > second chlorinated water > precipitated-filtrated water > tap water > output water > active carbon filtrated water; C: prechlorinated water > output water > precipitated-filtrated water > source water > tap water > second chlorinated water; D: tap water > precipitated, filtrated water > prechlorinated water > output water > source water; E: output water > prechlorinated water > tap water > precipitated-filtrated water > second chlorinated water > source water; F: second chlorinated water > precipitated-filtrated water > source water > output water > tap water. The comparisons of mutagenicity of output water among 6 water works: TA98 (−S9): E > D > C > A > F > B; TA98(+S9):E > C > F > D (A, B were negative); TA100 (−S9): E > F > C > A (D, B were negative); TA100 (+S9): only E was positive. Conclusion: The mutagenicity of Dongjiang river decreased after the treatment of B and F water works, increased after the treatment of A and C; the mutagenicity of Dongjiang river plus reservoir water source increased after the treatment of D and E. The treatment techniques of pre-O3-O3-bioactive carbon filtration had positive effect in reducing the mutagenicity of output water. During the treatment techniques, cancelling of the prechlorination or using the dioxochloride replaced for chlorine as the disinfectant might have positive effect toward optimizing the quality of output water.

Micronucleus study of the quality and mutagenicity of surface water from a semi-arid region

The present study evaluated the mutagenic potential of surface water from the Lucrecia dam. The Tradescantia-micronucleus (Trad-MCN) test and CBMN assay in human peripheral blood lymphocytes were applied, corresponding to an in vivo and in vitro system, respectively. Heavy metals and some physicochemical properties were also measured. Water samples were collected in November 2009 (dry season) and May 2010 (rainy season) at three different points. Results of both assays for raw water showed positive responses for the points analyzed when compared to the negative control. The CBMN assay showed that diluted water was still able to induce a significant increase in micronucleus frequency. For both assays, the highest mean MN was observed in the dry season. Chemical analyses detected an increase in heavy metal levels at the sampling points and in the different seasons. These findings indicate the presence of genotoxins, such as heavy metals, in the water, which may be affecting the entire ecosystem, as well as human health. More prolonged monitoring is recommended in order to better characterize this public water supply.

Temporal changes in the mutagenicity of roof runoff water

Temporal changes in the mutagenicity of roof runoff water

Surveying the mutagenicity of tap water to elicit the effects of purification processes on Japanese tap water

The mutagenicity levels of tap water in Japan were surveyed using the Ames test. Tap water samples (179) were collected at 17 sampling sites located from the northern tip (Hokkaido) to the southern tip (Kagoshima Prefecture). The mutagenicity values ranged from under the detection limit to 3600 net rev. L −1. The average mutagenicity was 1100 net rev. L −1 and the levels were significantly higher in the wintertime than in the summertime. The average mutagenicity of each site ranged from under the detection limit to 2000 net rev. L −1. There was no significant correlation of the mutagenicity with TOC, A 260 or THMs. The highest positive ratios of the Ames test and the umu test were 92% under the condition TA100 − S9 and 9% under the condition NM2009 − S9, respectively, which indicated that the Ames test has higher sensitivity for the test of tap water than the umu test. This survey incorporated the 1992–1993 survey. The comparison of these survey-results in a further study will reveal the improvement of Japanese tap water quality from the perspective of mutagenicity.

Integrated Disinfection By-Products Research: Salmonella Mutagenicity of Water Concentrates Disinfected by Chlorination and Ozonation/Postchlorination

Although chemical disinfection of drinking water is a highly protective public health practice, the disinfection process is known to produce toxic contaminants. Epidemiological studies associate chlorinated drinking water with quantitatively increased risks of rectal, kidney, and bladder cancer. One study found a significant exposure-response association between water mutagenicity and relative risk for bladder and kidney cancer. A number of studies found that several types of disinfection processes increase the level of mutagens detected by the Salmonella assay. As part of a comprehensive study to examine chlorinated and ozonated/postchlorinated drinking water for toxicological contaminants, the Salmonella mutagenicity assay was used to screen both volatile and nonvolatile organic components. The assay also compared the use of reverse osmosis and XAD resin procedures for concentrating the nonvolatile components. Companion papers provide the results from other toxicological assays and chemical analysis of the drinking water samples. The volatile components of the ozonated/postchlorinated and chlorinated water samples and a trihalomethane mixture were mutagenic to a Salmonella tester strain transfected with a rat theta-class glutathione S-transferase and predominantly nonmutagenic in the control strain. In this study, the nonvolatile XAD concentrate of the untreated water possessed a low level of mutagenic activity. However, compared to the levels of mutagenicity in the finished water XAD concentrates, the contribution from the settled source water was minimal. The mutagenicity seen in the reverse osmosis concentrates was < 50% of that seen in the XAD concentrates. Overall, mutagenic responses were similar to those observed in other North American studies and provide evidence that the pilot plant produced disinfection by-products similar to that seen in other studies.

Comparison of the use of mussels and semipermeable membrane devices for monitoring and assessment of accumulation of mutagenic pollutants in marine environment in combination with a novel microbiological mutagenicity assay

A novel microbiological mutagenicity assay, based on bioluminescence of a marine bacterium Vibrio harveyi mutant strain, potentially suitable for monitoring and assessment of mutagenic pollution of marine environment, has been described recently. Here, we tested the use of this assay, in combination with either mussels (Mytilus sp.) or semipermeable membrane devices (SPMDs), in assessment of accumulation of mutagens in marine water (samples of Baltic Sea water were tested). Either similar results were obtained in both systems or higher signals in the SPMD-based system were detected, depending on the tested water samples. We conclude that the use of both mussels and SPMDs in combination with the V. harveyi bioluminescence mutagenicity assay is a method suitable for monitoring and assessment of accumulation of mutagenic pollutants in marine environment, but in some cases the SPMD-based system may provide a more sensitive test.

Mutagenicity analysis of water samples from Seydisuyu (Kırka, Turkey) stream under the influence of boron production complex

Kırka region in Turkey is naturally high in boron content. There is also a boron production complex in our study area. Although boron was found to be neither genotoxic nor carcinogenic, mutagenicity of boron can still be discussed. In this connection, the aim of the present study was to evaluate the potential mutagenicity of Seydisuyu stream water in Kırka due to high boron content. Salmonella/microsome test was performed with and without metabolic activation. Total boron contents were determined by inductively coupled plasma optical emission spectrometer (ICP-OES). IRA 743 extracts of water samples from four stations of Seydisuyu stream were tested for mutagenicity in Salmonella typhimurium strains TA 98 and TA 100, and environmental boron toxicity was discussed.

Limitations of chlorine dioxide as an alternative disinfectant in comparison with chlorine from the viewpoint of mutagenicity

The change in the mutagenicity of water treated with chlorine dioxide was compared with that of chlorinated water to estimate the mutagenicity of drinking water in distribution systems. We carried out chromosomal aberration tests using Chinese hamster lung (CHL) cells to evaluate the mutagenicity. First, the levels of chloroform and TOX produced by chlorine dioxidation were approximately 1% and 5–7%, respectively, of those produced by chlorination. However, in water treated with chlorine dioxide, the activity that induced chromosomal aberrations was stronger than would be expected based on the quantity of by-products. The observed decreasing rate constant of the activity inducing chromosomal aberrations in chlorinated water was 1.4 to 1.9 times greater than that of water treated with chlorine dioxide, indicating that the mutagenicity of water treated with chlorine dioxide is more stable than that of chlorinated water. The mutagenicity of drinking water treated with chlorine dioxide was estimated to be 70–80% of that of chlorinated drinking water. However, these differences in mutagenicity are reduced when drinking water remains in distribution systems for long periods. The use of chlorine dioxide instead of chlorine can drastically reduce the production of trihalomethanes (THMs). However, the results of this study demonstrate that chlorine dioxide does not have much advantage in terms of the mutagenicity of drinking water. There were no disinfection by-products that demonstrated similar tendencies of change compared to the changes in the activity that induced chromosomal aberrations.

Contamination of the Shinano River Water with Mutagenic Substances after the Niigata Chuetsu Earthquake

While normally monitoring the Shinano River water quality, including examinations for mutagenicity, the Niigata Chuetsu Earthquake suddenly occurred on October 23, 2004. However, the influence of this earthquake on the mutagenicity of river water has not yet been well studied. To clarify the regional and seasonal changes in mutagenicity of the Shinano River water, blue rayon was suspended for 24 hrs at 4 sampling sites, once a month from September 2004 through August 2005. Mutagenicity was evaluated by the Ames test using Salmonella typhimurium TA98 (TA98) and TA100 with or without metabolic activation by S9 mixture. To detect and identify poly-aromatic hydrocarbons that may be responsible for the mutagenicity of the river water, we analyzed benzo[a]pyrene, benzophenone, 4-nitrotoluene, or other compounds using gas chromatography-mass spectrometry and total ion chromatogram spectra. Positive manifestations of TA98 with S9 mixture were observed at the 4 sampling sites throughout the 12-month test, showing a tendency to be higher at the downstream site and in winter. However, the highest mutagenicity was observed in the sample collected at the most upstream sampling site in December 2004, and fluoranthene or pyrene consisting mainly in coal tar was detected only in the samples collected in December 2004. Although benzo[a]pyrene, benzophenone, and 4-nitrotoluene were below the detection limits, non-mutagens such as aliphatic hydrocarbons or esters were frequently detected. Our findings indicate that either fluoranthene or pyrene was mainly responsible for the mutagenicity of the river water in December 2004, suggesting the possibility of oil contamination caused by the Niigata Chuetsu Earthquake.