Genotoxicity Of Water Research Articles

Analysis of water quality, bioindicators, contaminants and their cytogenetic impacts in a Cerrado reservoir

The fragmentation of Brazilian rivers due to the construction of hydroelectric dams has altered aquatic ecosystems, resulting in the accumulation of residues in sediments. This study evaluated the cytotoxicity and genotoxicity of water and sediments from the Cana Brava reservoir, located in the Tocantins-Araguaia basin in the Cerrado biome, using the Allium cepa test. Sampling points were situated in the Cana Brava reservoir near two tributaries, the Bonito River and the Varjão Stream, areas susceptible to contaminant input due to proximity to urban areas. Physicochemical parameters, metals through atomic absorption spectrometry, toxicity, and analyses of bioindicators such as microalgae and macrophytes were assessed. Near the Varjão Stream, algal richness was higher, with the presence of Chara rusbyana, which indicates good water quality. Near the Bonito River, pollution-indicating microalgae such as Euglena sp., Nitzschia sp., and Oscillatoria sp. were identified, along with a prevalence of Salvinia auriculata, favored by nutrient availability. Cytogenetic tests revealed that sediments, especially from the site near the Varjão Stream, caused chromosomal abnormalities and cytogenotoxic effects, with an increase observed after 72 hours. Principal components analysis showed that phosphorus and potassium in the sediment from the site near the Bonito River correlated with cellular alterations at 48 hours, while sediments near the Varjão Stream resulted in a higher frequency of cytogenetic alterations at 72 hours. These results highlight local impacts on water quality and biological diversity, recommending continuous monitoring to mitigate the adverse effects of pollution in the Cana Brava reservoir.

Assessment of Cytotoxicity and Genotoxicity of Plasma-Treated Perfluorooctanesulfonate Containing Water Using In Vitro Bioassays

The contamination of ground and surface waters with per- and polyfluoroalkyl substances (PFASs) is of major concern due to their potential adverse effects on human health. The carbon–fluorine bond makes these compounds extremely stable and hardly degradable by natural processes. Therefore, methods for PFAS removal from water are desperately needed. In this context, plasma treatment of water has been proposed as an effective method with reported removal rates exceeding 90%. However, the high reactivity of plasma discharge results in the formation of many reactive species, like radicals, ozone, or even solvated electrons, which lead to a complex reaction cascade and, consequently, to the generation of a wide variety of different chemical products. The toxicological properties of these PFAS breakdown products are largely unknown. The present study focuses on a toxicological assessment of PFAS-containing plasma-treated water samples. Aqueous solutions of long-chain perfluorooctanesulfonate (PFOS) were treated with various plasma-atmospheric regimes. Subsequently, plasma-treated water samples were subjected to in vitro bioassays. Cytotoxicity and genotoxicity were assessed with the MTS assay using human liver cells (HepG2) and the Ames MPFTM assay using Salmonella Typhimurium strains. Our results demonstrate varying cyto- and genotoxic properties of water containing PFAS breakdown products depending on the atmosphere present during plasma treatment. Based on the results of this study, the atmosphere used during plasma treatment affects the toxicological properties of the treated sample. Further studies are therefore needed to uncover the toxicological implications of the different treatment parameters, including the PFAS starting compound, the atmosphere during treatment, as well as the quantity of plasma energy applied.

Genotoxicity and Oxidative Stress of Water Concentrates from Recreation Pools After Various Disinfection Methods

Genotoxicity and Oxidative Stress of Water Concentrates from Recreation Pools After Various Disinfection Methods

A high-fungi diet differentially attenuates the gut mycobiota relative to a high meat diet; consequences for chronic disease risk?

The fungal cell wall facilitates an immune response and may be involved in intestinal immune training (1,2). It is also fermentable by the gut microbiome, thus, consumption of fungi changes gut microbial ecology (3). Yet, the specific effects of consuming fungal foods on the gut mycobiota (i.e., gut fungi) have not been well studied. An interesting case study is mycoprotein, a fungal based protein produced from Fusarium Venenatum (4). We have previously reported that mycoprotein consumption attenuates faecal water genotoxicity, a surrogate marker of colorectal cancer risk, as well as modulates faecal metabolite excretion and gut bacterial composition (5). Here, we aimed to evaluate the impact of consuming a diet high in mycoprotein on gut mycobial ecology, and to explore relationships between mycobial composition and faecal genotoxicity.Here we leverage stool samples from Mycomeat: a randomised crossover-controlled trial, recruiting 20 healthy male adults to adhere to 2-week diets comprising 240 g/day of mycoprotein based foods or red and processed meat, separated by a 4-week washout. Internal transcriber spacer (ITS) sequencing was performed to characterise the mycobiota. Alpha diversity before and after study phases was compared using Wilcoxon tests. Beta diversity was compared by permutational multivariate analysis of variance (PERMANOVA) based on Bay-Curtis dissimilarities. Differences in mycobial taxa within and between study phases were compared using Wilcoxon tests. Changes in mycobiota composition was then regressed against faecal excretion of metabolites using mixed- effects models to understand the impact of myco-ecology on the wider colonic environment. Finally, given the abundance of mycobial genotoxins in nature, we regressed mycobial taxa against faecal water genotoxicity.There were significant shifts in the abundance of several taxa following both diets. Notably, mycoprotein consumption was associated with an increase in the abundance of Malasseziales sp. (P = 0.02) and a reduction in Candida Albicans (P = 0.01). Meat consumption was associated with an increase in Phaeoacremonium Tuscanum (P = 0.01) and Rhodotorula Mucilaginosa (P = 0.008), and reduction in Penicillium Commune (P = 0.02). In addition, Aspergillus Caesiellus was associated with lower faecal genotoxicity (P = 0.04), whereas Penicillium Commune (P = 0.04) and Penicillium Olsonii (P = 0.03) were both associated with higher genotoxicity. Regressing mycobial taxa against faecal metabolites revealed a number of significant associations, including between Penicillium Commune and austdiol, a putative mycotoxin (P < 0.001) as well as 1-methyladenine, a methylated DNA base with cytotoxic properties (P = 0.001).The gut mycobiota is malleable through a fungi rich diet alongside changes within the wider microbiome. Members of the gut mycobiota predicted faecal genotoxicity and faecal excretion of toxins in this model, and there may be value in further exploring the gut mycobiota and the contribution of mycotoxins in gut health and colorectal cancer risk.

Mammalian Cell Genotoxicity of Potable Reuse and Conventional Drinking Waters.

Potable reuse water is increasingly part of the water supply portfolio for municipalities facing water shortages, and toxicity assays can be useful for evaluating potable reuse water quality. We examined the Chinese hamster ovary cell acute direct genotoxicity of potable reuse waters contributed by disinfection byproducts (DBPs) and anthropogenic contaminants and used the local conventional drinking waters as benchmarks for evaluating potable reuse water quality. Our results showed that treatment trains based on reverse osmosis (RO) were more effective than RO-free treatment trains for reducing the genotoxicity of influent wastewaters. RO-treated reuse waters were less genotoxic than the local tap water derived from surface water, whereas reuse waters not treated by RO were similarly genotoxic as the local drinking waters when frequent replacement of granular activated carbon limited contaminant breakthrough. The genotoxicity contributed by nonvolatile, uncharacterized DBPs and anthropogenic contaminants accounted for ≥73% of the total genotoxicity. The (semi)volatile DBPs of current research interest contributed 2-27% toward the total genotoxicity, with unregulated DBPs being more important genotoxicity drivers than regulated DBPs. Our results underscore the need to look beyond known, (semi)volatile DBPs and the importance of determining whole water toxicity when assessing the quality of disinfected waters.

Genotoxicity of surface waters in Brazil.

Brazil has abundant surface water resources, huge aquatic biodiversity and is home to 213 million people. Genotoxicity assays are sensitive tools to detect the effects of contaminants in surface waters and wastewaters, as well as to determine potential risks of contaminated waters to aquatic organisms and human health. This work aimed to survey the articles published in 2000-2021 that evaluated the genotoxicity of surface waters within Brazilian territory to unveil the profile and trends of this topic over time. In our searches, we considered articles focused on assessing aquatic biota, articles that conducted experiments with caged organisms or standardized tests in the aquatic sites, as well as articles that transported water or sediment samples from aquatic sites to the laboratory, where exposures were performed with organisms or standardized tests. We retrieved geographical information on the aquatic sites evaluated, the genotoxicity assays used, the percentage of genotoxicity detected, and, when possible, the causative agent of aquatic pollution. A total of 248 articles were identified. There was a trend of increase in the number of publications and annual diversity of hydrographic regions evaluated over time. Most articles focused on rivers from large metropolises. A very low number of articles were conducted on coastal and marine ecosystems. Water genotoxicity was detected in most articles, regardless of methodological approach, even in little-studied hydrographic regions. The micronucleus test and the alkaline comet assay were widely applied with blood samples, mainly derived from fish. Allium and Salmonella tests were the most frequently used standard protocols. Despite most articles did not confirm polluting sources and genotoxic agents, the detection of genotoxicity provides useful information for the management of water pollution. We discuss key points to be assessed to reach a more complete picture of the genotoxicity of surface waters in Brazil.

Daily berry consumption attenuates β-catenin signalling and genotoxicity in colon carcinoma cells exposed to faecal water from healthy volunteers in a clinical trial

Berries are known to have disease preventive and anticancer properties. We studied whether supplementing a habitual diet rich in red meat with berries affects cancer biomarkers in a clinical trial with 43 healthy volunteers. We exposed Caco-2 and HCA-7 colon adenocarcinoma cells and HaCaT cells, representing non-cancerous epithelial tissue, in 2D and 3D cultures to faecal water extracted from stool samples collected at baseline and at the end of the 4-wk trial. Expression of markers from the Wnt/β-catenin and PI3K/AKT/mTOR pathways, the cell proliferation marker Ki67, and the apoptosis marker cleaved caspase-3 were detected by Western blotting and immunofluorescence staining methods. In addition, genotoxicity of faecal water and the concentration of N-nitroso compounds in the faeces were analysed. The diet supplemented with berries caused downregulation of β-catenin, PS6 as well as Ki67 signalling in the cells exposed to faecal water. Our results suggest that consuming berries as part of a habitual Western-type diet could lead to less cancerous colon metabolism and possibly lower the risk for colorectal cancer by modulating the central signalling pathways in cancer.

Evaluation of water genotoxicity using comet assay in two freshwater fish species, Wallago attu and Ompok bimaculatus in Kabul River, Pakistan

The investigation determines the pollution status of river Kabul and its effects on the DNA of Wallago attu and Ompok bimaculatus. River Kabul gets pollutants from Amanghar industries and sewages from Mardan, Nowshera and Peshawar. Water and fish samples are taken to study heavy metals and physical parameters. The overall sequence of physical parameters in water samples was TDS>TSS>EC>TA>Cl>Na>pH>K, and that of heavy metals was Zn>Cr>Mn> Fe>Cu>Pb>Ni>Cd. The studied parameters in all the water samples except TSS are within the proposed limits of national environmental quality standards. The overall trend of analysed water samples was C>B>A. The study determines the effects of water pollution on the DNA of Ompok bimaculatus and Wallago attu tissues. Therefore, degrees of DNA damage such as TCS and comet class are studied in gills, liver, muscles, and intestines of Wallago attu and Ompok bimaculatus. The trend of DNA damage in examined tissues was intestine>skin>liver>gills>muscle, and in studied fish species, it was Ompok bimaculatus>Wallago attu. More significant DNA damage was observed in the intestine and smaller in the muscle. More DNA damage was found in Ompok bimaculatus and less in Wallago attu. The investigation recommended detoxifying the effluents and sewages before discharging them in River Kabul.

Multi-Endpoint Toxicity Tests and Effect-Targeting Risk Assessment of Surface Water and Pollution Sources in a Typical Rural Area in the Yellow River Basin, China

Multi-endpoint toxicity tests were used to evaluate the acute toxicity, estrogenic activity, neurotoxicity, genotoxicity, and ecological risks of surface water and sewage from possible pollution sources in rural areas of the Yellow River (China). Toxicity testing results showed that the luminescence inhibition rates of acute toxicity ranged from not detected (ND) to 38%, the 17β-estradiol equivalent (E2-EQ) values of estrogenic activity ranged from 4.8 to 131.0 ng·L−1, neurotoxicity was not detected, and the protein effect level index (PELI) values of genotoxicity ranged from 1 to 6.06. Neither acute toxicity nor genotoxicity were detected in the tributaries of the Yellow River (River 2) flowing through the investigated rural area. The distribution of high estrogenic activity sites was relatively scattered, but mainly located in the tributaries of River 2. Industrial, domestic, and livestock and poultry breeding sewage were all possible sources of toxicity, and the contribution of livestock and poultry to environmental estrogens in the surface water was significant. Furthermore, the potential effect-targeting risks of toxic substances in the surface water for aquatic organisms were assessed using the risk quotient method, by considering the toxic equivalent concentration. The results indicated that the risk of estrogenic activity was the main ecological risk in the surface water of this rural area. Except for the reservoir site, the other sampling sites showed a moderate to high estrogenic activity risk, especially in the tributaries of River 2.

The role of diet in genotoxicity of fecal water derived from IBD patients and healthy controls.

Certain dietary factors with anti-inflammatory and/or anti-cancer properties would be a promising preventive strategy for inflammatory bowel disease (IBD) patients against developing colitis-associated colorectal cancer (CAC). In this study, fecal water (FW) was obtained from 80 IBD patients and 20 healthy controls (HCs). The comet assay was applied to determine the DNA damage induced by FW, and the protective potential of FW against hydrogen peroxide (H2O2) induced DNA damage in Caco-2cells. Information on diet was obtained via food frequency questionnaires. The results showed that FW from IBD patients, especially patients with flares, induced higher levels of direct DNA damage in Caco-2cells and showed less protection against H2O2-induced DNA damage, when compared to HCs. The DNA damage induced by FW was positively associated with consumption of processed meat and sugary foods, and nutrient intakes including heme iron and added sugars, whereas negatively correlated to intakes of soy products, and a dietary pattern characterized by high consumption of potatoes, white meat, nuts and seeds, eggs, legumes and soy products. FW from subjects with high coffee consumption protected against H2O2-induced DNA damage. These results can help to develop potential preventive strategies for IBD patients to reduce the CAC risk.

ОЦЕНКА СОСТОЯНИЯ ВОДЫ ОЗЕРА СЕВАН В ЛЕТНИЙ ПЕРИОД С ПРИМЕНЕНИЕМ МОДЕЛЬНЫХ ТЕСТ-ОБЪЕКТОВ

The biotesting of the level of genotoxicity and clastogenicity of deep and surface waters of Lake Sevan (Armenia) in the summer period was carried out using two test systems: of the model test object Tradescantia (clone 02) and phytoplankton. The Tradescantia clone 02 stamen hair mutations (Trad-SHM) and Tradescantia micronucleus (Trad-MCN) bioassays are two of the efficient and reliable biomonotory test systems for mutagenicity of air, water and soil polutans. Here we report a significant increase in the level of The Tradescantia clone 02 stamen hair mutations (Trad-SHM) somatic mutations in all investigated probes compared to phone control level. The maximum manifestation of these genetic effects – PC was observed in Gilli water samples with five-fold increase. According to the micronucleus test (Trad-MN), when studying its two main test-criteria: the percentage of tetrads with micronuclei and micronuclei in tetrads, the maximum frequency of test indicators was detected in water samples of Tsapatakh and Arpa, where their level was 4 times higher than the background. A significant positive correlation between the somatic mutation events and consentration of chemical elements Ca, K, Na, Mg, Fe, Mo (p<0.05; p<0.001) was revealed. It also showed a significant correlation between MN in tetrads and consentration of chemical elements Na, Ca, Fe, Mo, Ni, Cd (p<0.05). The analysis of the spatial distribution of phytoplankton in the water area of the Lake Sevan, as well as data on the abundance, biomass and composition of the dominant species in the summer observation period showed an intensive development of Cyanoprokaryota (HAB) and green algae in the all water area of the lake, which caused the process of its eutrophication.

Genotoxicity of Natural Water during the Mass Development of Cyanobacteria Evaluated by the Allium Test Method: A Model Experiment with Microcosms

Cyanobacteria, which develop abundantly in aquatic ecosystems, can be harmful to humans and animals not only by releasing toxins that cause poisoning but also by provoking cytogenetic effects. The influence of the mass development of cyanobacteria on the genotoxic properties of natural water has been studied in model ecosystems (microcosms) with different compositions of biotic components (zooplankton, amphipods and fish). The validated plant test system “Allium test” was used in this study. Genotoxic effects were detected at microcystin concentrations below those established by the World Health Organization (WHO) for drinking water. In all experimental treatments, cells with disorders such as polyploidy and mitotic abnormalities associated with damage to the mitotic spindle, including c-mitosis, as well as lagging chromosomes were found. Genotoxic effects were associated with the abundance of cyanobacteria, which, in turn, depended on the composition of aquatic organisms in the experimental ecosystem. Fish, to a greater extent than other aquatic animals, maintain an abundance of cyanobacteria. After one month, in microcosms with fish, mitotic abnormalities and polyploidy continued to be detected, whereas in other treatments, there were no statistically significant genotoxic effects. In microcosms with amphipods, the number and biomass of cyanobacteria decreased to the greatest extent, and only one parameter of genotoxic activity (frequency of polyploidy) significantly differed from the control.

The comet assay for the evaluation of gut content genotoxicity: Use in human studies as an early biomarker of colon cancer risk

This short narrative review describes the use of the comet assay to evaluate the formation of genotoxic compounds in the gut lumen in human studies. The fecal water genotoxicity assay is based on ability of the gut content to induce genotoxicity in a cellular model, employing the aqueous component of the feces (fecal water) as this is supposed to contain most of the reactive species and to convey them to the intestinal epithelium. This non-invasive and low-cost assay has been demonstrated to be associated with colon cancer risk in animal models, and although the final validation against human tumors is lacking, it is widely used as a colo-rectal cancer risk biomarker in human nutritional intervention studies. The contribution given to the field of nutrition and cancer by the FW genotoxicity assay is highlighted, particularly in conjunction with other risk biomarkers, to shed light on the complex relationship among diet, microbiota, individual subject characteristics and the formation of genotoxic compounds in the gut.

Preferential Halogenation of Algal Organic Matter by Iodine over Chlorine and Bromine: Formation of Disinfection Byproducts and Correlation with Toxicity of Disinfected Waters.

The increasing occurrence of harmful algal blooms (HABs) in surface waters may increase the input of algal organic matter (AOM) in drinking water. The formation of halogenated disinfection byproducts (DBPs) during combined chlorination and chloramination of AOM and natural organic matter (NOM) in the presence of bromide and iodide and haloform formation during halogenation of model compounds were studied. Results indicated that haloform/halogen consumption ratios of halogens reacting with amino acids (representing proteins present in AOM) follow the order iodine > bromine > chlorine, with ratios for iodine generally 1-2 orders of magnitude greater than those for chlorine (0.19-2.83 vs 0.01-0.16%). This indicates that iodine is a better halogenating agent than chlorine and bromine. In contrast, chlorine or bromine shows higher ratios for phenols (representing the phenolic structure of humic substances present in NOM). Consistent with these observations, chloramination of AOM extracted from Microcystis aeruginosa in the presence of iodide produced 3 times greater iodinated trihalomethanes than those from Suwannee River NOM isolate. Cytotoxicity and genotoxicity of disinfected algal-impacted waters evaluated by Chinese hamster ovary cell bioassays both follow the order chloramination > prechlorination-chloramination > chlorination. This trend is in contrast to additive toxicity calculations based on the concentrations of measured DBPs since some toxic iodinated DBPs were not identified and quantified, suggesting the necessity of experimentally analyzing the toxicity of disinfected waters. During seasonal HAB events, disinfection practices warrant optimization for iodide-enriched waters to reduce the toxicity of finished waters.

In vivo and in silico approaches to assess surface water genotoxicity from Tocantins River, in the cities of Porto Nacional and Palmas, Brazil

The main environmental problem in urban areas, especially in Brazil, is the discharge of untreated sewage. The in vivo Drosophila melanogaster Somatic Mutation and Recombination Test (SMART) was used to assess the genotoxicity of surface waters from three different sites in the Tocantins River, Brazil. The in silico approach was used to search for known and predicted interactions between environmental chemicals found in our samples and Drosophila and human proteins. The genotoxicity tests were performed in standard (ST) and high bioactivation (HB) crosses with samples collected at two periods, the rainy and dry seasons. Mutant spot frequencies found in treatments with unprocessed water from the test sites were compared with the frequencies observed in negative controls. The collection points were represented as sites A, B and C along Tocantins River. Sites A and B are located in Porto Nacional City, whereas site C is located in Palmas City. Considering the rainy season collection, positive responses in the ST cross were observed for sites A and C (89.47% and 85% of recombination, respectively) and in the HB cross for sites A, B and C (88.24%, 84.21% and 82.35% of recombination, respectively). The positive results in the dry season were restricted to sites A and B (88.89% and 85.71% of recombination, respectively) in the HB cross. In accordance with in vivo and in silico results, we hypothesize that ribosomal proteins (RPs) in fruit fly and humans are depleted in cells exposed to heavy metal causing DNA damage and chromosome instability, increasing homologous recombination.

Evaluation of Cytotoxicity and Genotoxicity of Water from Nag River, Nagpur, India

The pollution of the river by man-made sewage and waste disposal is not only harmful to animals and plants in it but also for animals higher in the food chain including those close to the food chain. Water is the most vital natural substance, as it plays a role in nearly every aspect of human life. Therefore, there is a great need to ensure that the water used by humans should not contain hazardous substances. Water quality is directly linked to biological life. The Nag River flows from the Lava village of north Ambazari Lake and flows into the center of Nagpur city. As a result of rapid and unstoppable development, significant changes have taken place in the water quality of the Nag River. Because the Nag River’s water is frequently used for irrigation, it should be tested for cytotoxicity and genotoxicity. Since the rate of cancer and genetic disorders has recently increased in the Nagpur region, the Nag River’s water could be a source of carcinogens in the food chain, affecting the population. This study was conducted to analyze the impact of water collected from various points of the Nag River using Allium cepa as a model organism. The results of this study showed that all water samples from the Nag River cause a cytotoxic effect (20-23%) and genotoxic effects (23-28%) in Allium cepa cells. Therefore, before the use of Nag River water, it must be treated to diminish its harmful effect.

Mutagenicity and genotoxicity of water boiled in aluminum pots of different duration of use using SOS chromotest and Ames fluctuation test.

Boiling water before drinking or using it for cooking is a general practice especially in areas where portable water is not readily available. However, boiling water in an aluminum pot could be a route of entry of heavy metals into humans. This study assessed the genotoxic and mutagenic potential of boiled water samples from aluminum pots of different duration of use using the SOS chromotest on Escherichia coli PQ37 and the Ames fluctuation test on Salmonella typhimurium strains TA98 and TA100, respectively. Three aluminum pots from the same manufacturer but of different years of use (6-year-old, 3-year-old, and new aluminum pots) were used for the experiment. Six selected heavy metals (Cadmium, Copper, Arsenic, Nickel, Lead, and Aluminum) were also analyzed in the samples using an Atomic Absorption Spectrophotometer (AAS Buck, Scientific model 210 VGP). Cadmium, Copper, Arsenic, Nickel, Lead, and Aluminum were present in all the test water samples at concentrations that were higher than the maximum limit allowable by standard regulatory organizations. The concentrations of these metals in the samples also increased as the duration of use of the aluminum pots increased. The results further showed that the water boiled in the three aluminum pots is mutagenic and genotoxic in both Ames fluctuation and SOS chromotests. The 6-year-old aluminum pot induced the highest mutagenicity and genotoxicity followed by the 3-year-old aluminum pot. The metals in the tested samples were believed to be responsible for the observed mutagenicity and genotoxicity in the microbial assays. The findings of this study revealed that cooking with Aluminum pots could lead to the leaching of heavy metals into food, and pose mutagenic and genotoxic risks to consumers.

Assessment of aquatic genotoxicity of the Lake Sevan basin, Armenia using natural bioindicators

Water pollution can cause genomic instability, thereby threatening aquatic wildlife and human health․ For a correct assessment of the impact of the mixture of pollutants, chemical analysis of environmental contaminants should be simultaneously applied with genotoxicity assays. The сomet assay is a sensitive, versatile and extensively used method for genotoxicity assessment in a water environment and was successfully applied in aquatic wild species, including fish and crayfish. Earlier we investigated the genotoxicity of waters of the Lake Sevan basin (Simonyan et al. 2016, Simonyan et al. 2019)․ Lake Sevan is the largest lake of the Caucasus Region, situated in the Republic of Armenia, in the Gegharkunik Province. Water pollution in the lake is a result of both anthropogenic and natural pressures. A combination of comet assay (Tice et al. 2000) and chemical analysis was applied for evaluation of water genotoxicity using gibel carp Carassius auratus gibelio and crayfish Astacus leptodactylus as sentinel organisms. Fish and water samples were collected from the south–southwest of the village Shorzha (40028′33″N and 45014′22″E), Peninsula of Lake Sevan (40033′46″N and 45001′37″E), the estuaries of the Rivers Gavaraget (40025′12″N and 45009′53″E) and Dzknaget (40036′55″N and 44058′13″E). Сrayfish and water samples were collected from the estuary of the River Masrik (40013′25″N and 45038′21″E) and near the villages of Artanish (40027′19″N and 45025′12″E) and Tsapatakh (40024′34″N and 45028′22″E). According to the chemical analysis of waters, the south–southwest of the village Shorzha and the estuary of the River Masrik were chosen as reference sites․ The content of contaminants in water was analyzed according to the standard methods in the Environmental Impact Monitoring Center, Ministry of Environment of the Republic of Armenia. The obtained results showed that the levels of DNA damage were significantly higher in both species in polluted areas than in reference sites. A significant positive correlation between DNA damage in C. auratus gibelio and contents of Al, Fe, Cu and Mn in water was shown. DNA damage in A. leptodactylus correlated with Al, Fe, Cu and Mo. C. auratus gibelio and A. leptodactylus were found to be sensitive mostly to the same pollutants, which indicate that these metals may be of primary concern as contaminants of the studied aquatic environment. Thus, the current study indicates that C. auratus gibelio and A. leptodactylus are sensitive bioindicators for monitoring of water pollution in the Lake Sevan basin.

Genotoxicity of esentai and ulken almaty rivers water on animal test-systems

Ecological monitoring, including water resources, is included in a set of measures for the rational use and protection of the environment. Currently, the assessment of water resources' genotoxicity and mutagenicity is an essential component of ecological monitoring.This research aimed to investigate water's genotoxicity from the Esentai and Ulken Almaty rivers flowing in Almaty. It was established that the content of Fe, Cu, Co, Ni, Pb, and Cd in the Almaty rivers water does not exceed the maximum permissible concentration (MPC). In contrast, zinc content in the Esentai and Ulken Almaty rivers' water exceeded the MPC, respectively, by 1.1 and 7.7-folds, manganese – 2.1, and 1.9-folds. It was found that water samples from the Esentai and Ulken Almaty rivers showed a DNA-damaging effect on the studied cells (bone marrow, liver, kidneys, and spleen) of laboratory mice. In the cells of the studied organs in the experimental groups, the frequency of single-strand DNA breaks a statistically significant increase compared to the control group's animal. The genotoxic action's organospecificity of the studied river waters on laboratory mice was established. According to their sensitivity to water's genotoxic effect, experimental mice's organs can arrange in the following order: spleen and bone marrow> liver> kidneys. An increase in lipid peroxidation products was found in the laboratory mice' liver that drank water from the Esentai and Ulken Almaty rivers. Thus, the results of the physicochemical, molecular-genetic, and biochemical analysis of water on animal test objects indicate the presence in the investigated natural surface waters of chemicals with genotoxic and toxic activity. Keywords:surface waters; heavy metals; DNA comet assay, organ specificity, lipid peroxidation

Toxicity evaluation and by-products identification of triclosan ozonation and chlorination

Triclosan (TCS) has attracted increasing concern due to its ubiquitous occurrence in aquatic environments as well as its potential adverse effects on human health. This study investigated the toxicity and transformation characteristics of triclosan ozonation and chlorination. The results showed that two hydroxylated by-products were formed via nucleophilic substitution during ozonation, while three chlorinated compounds were generated via electrophilic substitution during chlorination. The toxicity results demonstrated that the parent compound, triclosan, exhibited mild genotoxicity and anti-estrogenic activity. The chlorination of triclosan resulted in a 30-fold increase in anti-estrogenic activity owing to the generation of toxic polychlorinated transformation by-products. In addition, the chlorination by-products were found to be genotoxic like the parent compound. Fortunately, in contrast to chlorination, ozonation could mitigate the genotoxicity and anti-estrogenic activity of triclosan-containing water.