Genotoxicity Of Water Samples Research Articles

Removal of trace organic pollutants and generation of halogenated disinfection by-products in membrane UV/chlorine combined process

In this study, the degradation kinetics and degradation mechanism of 23 trace organic pollutants (TrOCs) in the secondary effluent of sewage by the combined membrane-UV/chlorine process were investigated, and the halogenated disinfection by-products (X-DBPs) in the combined process were investigated and its generation potential (X-DBPsFP), and the cytotoxicity and genotoxicity of the treated water samples were also evaluated. The results showed that membrane pretreatment could effectively promote the degradation of TrOCs in UV/chlorine system, and nanofiltration (NF) was more effective than ultrafiltration (UF). Compared with UF, NF intercepts more dissolved organic matter (DOM), thus weakening the light shielding effect, chlorine consumption and radical quenching to a greater extent. It is found that the degradation mechanism of TrOCs can be divided into the following four categories: Ho˙ dominated, RHS dominated, chlorine and RHS jointly dominated and chlorine dominated. Membrane pretreatment can well reduce the formation of X-DBPs, among which UF and NF reduce the formation of haloacetamide (HAMs) and trihalomethanes (THMs) most significantly, while NF reduces the formation of X-DBPs and X-DBPsFP and the toxicity of water samples much stronger than UF. In addition, NF UV/chlorine can significantly remove the precursors of X-DBPs, so as to effectively control the enhancement of cytotoxicity and genotoxicity of water samples in the post chlorination process. The research results promote the development of advanced sewage treatment technology and provide theoretical guidance for related research.

Double-endpoint Genotoxicity Quantification and PAHs Characterization of Drinking Water Source alongside Polluted Yinghe River with High Tumor Mortality.

The etiology for the high tumor mortality in heavy polluted Yinghe river basin is still unclear and polycyclic aromatic hydrocarbons (PAHs) belong to the priority pollutants in water based on the former surveillance data. In order to explore the potential genotoxicants contributing to the double-endpoint genotoxicity of polluted drinking water source, 12 groundwater and 3 surface water samples were collected from 3 villages and the nearby rivers alongside Yinghe river basin, respectively and their comprehensive genotoxicity was estimated with a bioassay group of SOS/umu test and micronucleus (MN) test (MNT). Some groundwater samples showed positive genotoxicity and all surface water samples were highly genotoxic. Eight groundwater samples showed DNA genotoxic effect with the average 4-NQO equivalent concentration (TEQ(4-NQO)) of 0.067 µg/L and 0.089 µg/L in wet and dry season, respectively. The average MN ratios of groundwater samples were 14.19‰ and 17.52‰ in wet and dry season, respectively. Groundwater samples showed different genotoxic effect among 3 villages. The total PAHs concentrations in all water samples ranged from 8.98 to 25.17 ng/L with an average of 14.97±4.85 ng/L. BaA, CHR, BkF, BaP and DBA were the main carcinogenic PAHs contributing to the genotoxicity of water samples. In conclusion, carcinogenic PAHs are possibly related to the high tumor mortality in the target area. Characterization of carcinogenic PAHs to genotoxicity of drinking water source may shed light on the etiology study for high tumor mortality in Yinghe river basin.

Anti-inflammatory drugs degradation during LED-UV365 photolysis of free chlorine: roles of reactive oxidative species and formation of disinfection by-products

Light-emitting diode (LED) is environmentally friendly with longer life compared with traditionally mercury lamps. This study investigated the non-steroidal anti-inflammatory drugs (NSAIDs)- phenacetin (PNT) and acetaminophen (ACT)- removal during LED-UV (365 nm) photolysis of free available chlorine (FAC). Degradation of PNT and ACT during LED-UV365/FAC treatment at pH 5.5-8.5 followed the pseudo-first order kinetics. The presence of hydroxyl radicals (·OH), reactive chlorine species (RCS), and ozone (O3, transformed from O (3P)) were screened by using scavengers of ethanol (EtOH), tert-Butanol (TBA), and 3-buten-2ol, and 4-hydroxy-2,2,6,6-tetramethylpiperidine (TEMP), and quantified by competition kinetics with probing compounds of nitrobenzene (NB), benzoate acid (BA), 1,4-dimethoxybenzene (DMOB). Higher pH would lead to decrease of ·OH contribution and an increase of FAC contribution to PNT and ACT degradation. It has been determined that the contribution of O3 to degradation of PNT and ACT was less than 5% for all pHs, and O3(P) reacts toward EtOH with second-order constant of 1.52 × 109 M−1s−1. LED-UV365/FAC system reduced the formation of five typical CX3-R type disinfection by-products (DBPs) as well as the cytotoxicity and genotoxicity of water samples at pH 5.5 and 8.5, compared with FAC alone. The decrease of DBPs formation resulted from fast FAC decomposition upon LED-UV365 irradiation. A feasible reaction pathway of DBPs formation in the LED-UV365/FAC system was examined with density functional theory (DFT). For FAC decay during LED-UV365/FAC with effluent from wastewater, the residual FAC in 15 min was 0.8 mg/L (lower than limit of 0.2 mg/L) once initial FAC was 2.0 mg/L. The results indicate that more tests on the balance of target pollutant removal efficiency, residual FAC and cost should be explored in LED-UV365/FAC system for application.

Complex study of potential toxicity and genotoxicity of water samples from natural sources of the suburban zone of Almaty

Background. Natural aquatic ecosystems are the habitat of many organisms, a source of drinking water, a resource for human activities and are subjected to anthropogenic pressure. In this regard, interest in studying the genotoxicity and mutagenicity of surface waters has increased significantly. The aim of this study is to investigate the cytotoxic, genotoxic and mutagenic effects of the surface waters of the suburban area of Almaty.
 Material and methods. The research materials were water samples of the rivers Esik, Turgen and Lake Esik. The atomic absorption method, lux-test, cytogenetic tests (Hordeum vulgare L.), phytotoxicity test (Allium cepa L.) and embryotoxicity (Danio rerio H.) were used.
 Results. Physico-chemical water analysis revealed an excess of MPC for Mn, Pb, Cd, Zn. Using the lux-test on E. coli KatG strains, the pro-oxidant activity of Esik R. water. On the plant test objects revealed toxicity and mutagenicity of water samples. The results of bio-testing of natural waters with D. rerio revealed their high toxicity and teratogenicity for embryos at all stages of development.
 Conclusion. The results of this study obtained on various test-systems and test-objects indicate that surface waters are contaminated by environmentally dangerous factors that pose a threat to biota and human health.

Genotoxicity of water samples from an area of the Pampean region (Argentina) impacted by agricultural and livestock activities.

The aim of this study was to assess the genotoxic potential of surface waters located in a rural area in the north east of Buenos Aires province (Argentina) using the Allium cepa test. Water samples were collected at four sites located in a drainage channel and two sites on the Burgos stream that receives water from the channel, taking into account the sowing and harvesting months and rainfall periods. Analytical determinations revealed high total concentrations of Cd, Cu, Pb, and Zn (maximum values: 0.030, 0.252, 0.176, and 0.960mgL-1, respectively), and concentrations of glyphosate and its metabolite aminomethylphosphonic acid (AMPA), with maximum values of 13.6 and 9.75μgL-1, respectively. Statistically positive correlations were observed between the total metal concentrations and precipitation. No cytotoxicity (mitotic index MI) was observed in A. cepa. However, several water samples showed significant increases in micronucleus (MN) frequencies with respect to the controls. No correlations were observed between MN and the abiotic variables or precipitation. These results showed a state of deterioration in the water quality at the rural area studied in Buenos Aires province, and heavy metal contamination may contribute to the genotoxic activity. A. cepa was shown to be a useful tool for the detection of genotoxicity in water samples from areas with agricultural and livestock activities.

Cytotoxic, genotoxic and mutagenic evaluation of surface waters from a coal exploration region

Coal mining generates a considerable amount of waste, which is disposed of in piles or dams near mining sites. As a result, leachates may reach rivers and streams, promoting the wide dispersion of contaminants in solution and as particulate matter. The present study evaluated the cytotoxic, genotoxic, and mutagenic action of surface waters collected around a thermoelectric power plant and the largest mining area in Brazil (Candiota). Four sites in Candiota stream were selected, and samples were collected in winter and summer. Water samples were analyzed using the comet and CBMN assays in V79 and HepG2 cells. Furthermore, genotoxicity of water samples was evaluated in vivo using the SMART in Drosophila melanogaster. In addition, polycyclic aromatic hydrocarbons and inorganic elements were quantified. The results indicate that water samples exhibited no genotoxic and mutagenic activities, whether in vitro or in vivo. On the other hand, surface water samples collected in sites near the power plant in both summer and winter inhibited cell proliferation and induced increased frequencies of V79 cell death, apoptosis, and necrosis. The cytotoxicity observed may be associated with the presence of higher concentration of inorganic elements, especially aluminum, silicon, sulfur, titanium and zinc at sites 1 and 2 in the stream, as well as with the complex mixture present in the coal, in both seasons. Therefore, the results obtained point to the toxicity potential of water samples with the influence of coal mining and combustion processes and the possible adverse effects on the health of exposed organisms.

Moving beyond classical markers of water quality: detection of enteric viruses and genotoxicity in water of the Sinos River.

It is well recognized that the classical biological and chemical markers of environmental pollution do not necessarily indicate the presence or absence of emerging threats to public health, such as waterborne viruses and genotoxicants. The purpose of this preliminary study was to evaluate the presence of material of enteroviruses (EV), rotavirus (RV) and adenovirus (AdV) and genotoxicity in water samples from points of routine monitoring of water quality in the main course of the Sinos River. The points are classified into different levels of pollution in accordance to the Brazilian federal regulations. Viral genomes from EV, AdV were detected in two of the 4 collection points regardless of the level of urbanisation of the surrounding areas. In contrast, genotoxicity was not observed in piava (Leporinus obtusidens) fingerlings cultivated on these same water samples. Results were compared with classical physical, chemical and microbiological parameters. There was no clear evidence of association between any of the classical markers and the presence of viral genomes in the water samples tested.

Genotoxic Potential and Physicochemical Parameters of Sinos River, Southern Brazil

The present study aimed to evaluate the physicochemical parameters and the genotoxic potential of water samples collected in the upper, middle, and lower courses of the Sinos River, southern Brazil. The comet assay was performed in the peripheral blood of fish Hyphessobrycon luetkenii exposed under laboratory conditions to water samples collected in summer and winter in three sampling sites of Sinos River. Water quality analysis demonstrated values above those described in Brazilian legislation in Parobé and Sapucaia do Sul sites, located in the middle and in the lower courses of the Sinos River, respectively. The Caraá site, located in the upper river reach, presented all the physicochemical parameters in accordance with the allowed limits in both sampling periods. Comet assay in fish revealed genotoxicity in water samples collected in the middle course site in summer and in the three sites in winter when compared to control group. Thus, the physicochemical parameters indicated that the water quality of the upper course complies with the limits set by the national guidelines, and the ecotoxicological assessment, however, indicated the presence of genotoxic agents. The present study highlights the importance of combining water physicochemical analysis and bioassays to river monitoring.

Toxicity assessment of natural waters from the Obninsk radioactive waste repository

The assessment of cyto- and genotoxicity of water samples from a regional radioactive waste repository using the Allium- test was carry out. Biotesting of natural waters from the site has demonstrated that negative biological effects are generated under the influence of water from well, located near the source of contamination. The percentage of aberrant cells in water samples from this well 4 is 2 times higher than in the control or other sources. Effects of water composition at the genome level are season independent. The Allium- test was shown to be highly sensitive and effective in testing a combined effect from radiation and chemical factors in field conditions.

Comprehensive Analysis of Radioactive and Chemical Contamination of Water Bodies in the Area of Radium-Industry Waste Storage

Genotoxicity and cytotoxicity of water samples from the creeks flowing through the area of radium mining waste storage into the Ukhta River and from this river were assessed using biological tests with Allium schoenoprasum L. Chemical analysis of the samples indicated that concentrations of parent heavy natural radionuclides, 210Pb, and 210Po do not exceed the allowable level. Of ten heavy metals, only Zn and Mn concentrations exceeded MACs. The results of biological tests provided evidence for the significantly increased genotoxicity of water samples. The mitotic index increased with an increase in the concentration of Zn ions and manifested an inverse dependence on the activity of 238U. The genotoxic effect linearly depended on Zn concentration. Possible mechanisms responsible for the induction of these biological effects are discussed.

Genotoxicity of water samples from Dianchi lake detected by the Vicia faba micronucleus test

Dianchi Lake covers about a 300 km 2 area. Kunming city on the edge of the lake is surrounded by industrial establishments. Farm land surrounds the remaining areas of the lake. The lake water is polluted by the Kunming city municipal sewage from 3 million inhabitants, the industrial effluent and farm runoff. Water samples were collected from 12 sites along the shore of the lake during the dry (May) and rainy (August) seasons for genotoxicity testing with the Vicia micronucleus assay during the year 1995. Genotoxicity in terms of micronuclei (MCN) frequencies in the root tip cells of Vicia showed a consistent elevated frequency of MCN over the control sample at the 0.05–0.01 levels of significance in both seasons. The MCN frequencies of sites A (Daguanhe), B (Gaoqiao) and C (Xiyuan) were 3.5–4 times as high as the control values (5.25/1000 cells) in the dry season. In the rainy season, the MCN frequencies of water samples from most of the 12 sites were relatively lower than those of the dry season except sites J (Haikou), and K (Kunyang). The average MCN frequency of the dry season samples was 14.97 per 1000 cells and that of the rainy season samples was 12.24 per 1000 cells while the average control value was around 5.00/1000 cells.

Toxicity evaluation using bioassays in rural developing district 063 Hidalgo, Mexico

One of the oldest and biggest irrigation districts that use wastewater in Mexico is the Rural Developing District 063 (RDD-063). The water supplies of this district are the industrial and domestic discharges of Mexico City and its metropolitan area. RDD-063 production of grains, vegetables, and fruits as well as cattle products supplies the Mexico City market, so it is important to evaluate the chemical risks to which this population is exposed. Fourteen sampling sites were selected for collection of water, soil, and sediment samples in March, July, and October 1993. Bioassays with Daphnia magna, Spirillum volutans, and Panagrellus redivivus were used to estimate acute toxicity and genotoxicity in water samples, sediment pore water, and Milli-Q water extracts of soil. Acute toxicity effects were detected in March and October, while in July genotoxicity responses were found. The results demonstrate that RDD-063 had serious ecological damage, and its waters, soils, and sediments represent a hazard to animal and human health. Bioconcentration and persistence of toxic substances in drinking and irrigation water is a major problem that requires a long-term solution. © 1996 by John Wiley & Sons, Inc.