Обоснование предельно допустимой концентрации цилиндроспермопсина в воде хозяйственно-питьевого и культурно-бытового водопользования для минимизации риска здоровью населения

Over the past decades, as a result of anthropogenic pollution and global warming, the frequency, intensity and geographical distribution of the mass development of microalgae and cyanobacteria in water bodies have significantly increased. The Microcystis species are responsible for most cases of the cyanobacterial blooms in freshwater bodies worldwide. Microcystis aeruginosa is the most commonly observed of them. In this work, we assessed the stress effect of isolated from actinobacteria Streptomyces geldanamycininus cyanocidal crude biocide Z374 (CB Z374) on the cyanobacteria M. aeruginosa. The results showed that CB Z374 significantly inhibited M. aeruginosa biomass. The CB Z374 half maximal effective concentration (EC50) for M. aeruginosa after 96 hours of treatment was 5 mg/L. The growth of M. aeruginosa with CB Z374 is characterized by an increase in the duration of the lag-phase, a decrease in the specific growth rate and biomass yield compared to the control. CB Z374 caused oxidative stress in cyanobacteria cells, determined by the elevated levels of hydrogen peroxide (H2O2) and malondialdehyde (MDA) up to 1.6 times, as well as an increased permeability of M. aeruginosa cell membranes by 1.5 times. The levels of superoxide dismutase (SOD) and catalase (CAT) activities and reduced glutathione (GSH) content raised in response to oxidative stress. M. aeruginosa growth inhibition was accompanied by a photosynthesis modification: the photosynthetic pigments phycobiliproteins and carotenoids content increases by 2.3 and 1.6 times respectively and the chlorophyll a content decreases by 1.2 times. CB Z374 inhibited M. aeruginosa photosynthesis, which was expressed in a decline in the maximum quantum efficiency of photosystem II – Fv/Fm by 10% and a reduction in the electron transfer rate (ETR) by 18%. We assume that oxidative stress and, as a result, cell membranes damage and photosynthesis inhibition are the main mechanisms of the cyanocidal action of CB Z374 on M. aeruginosa.

The cyanobacterial toxin cylindrospermopsin (CYN) is a widely distributed contaminant of freshwater systems with the consequent risk for human and wildlife, particularly fish. However, CYN toxicity data on fish are still scarce. It is known that CYN inhibits glutathione synthesis and this could contribute to oxidative damage. In the present work tilapia (Oreochromis niloticus) were exposed by gavage to 200 and 400 μg/kg bw of pure CYN and sacrificed after 24 h. The activity and relative mRNA expression by real-time PCR of antioxidant enzymes glutathione peroxidase (GPx) and soluble glutathione-S-transferases (sGST) and the sGST protein abundance by Western blot analysis were evaluated in liver and kidney. Also the induction of lipid peroxidation (LPO) was assayed. Results show an increase of LPO products in both organs. Moreover, CYN altered the activity, gene expression and protein abundance of the enzymes, indicating the importance of GPx and sGST in CYN pathogenicity. This is the first time that CYN is reported to affect these enzymes in fish and they have shown to be responsive biomarkers of CYN toxicity.

Water is an important pathway for human exposure to heavy metals. Accurate assessment of the health risks that are related to exposure to heavy metals in drinking and household water are required for the preparation of targeted health risk prevention measures. This study explores and identifies the health risks related to exposure to heavy metals via drinking and household water pathways in Xigu District, Lanzhou, northwestern China, using household water samples and survey data obtained during July-September 2015 (wet season) and December 2015-January 2016 (dry season). During each period, drinking water and household water that were available for use by children aged 0-5 and 6-17 years were sampled and a questionnaire on water-related behavior patterns was completed for each household. Cd, Cr, Pb, and As concentrations were analyzed in all water samples, and were used along with water-related exposure factors from the questionnaires to estimate exposure doses and associated health risks using models recommended by the United States Environmental Protection Agency (US EPA). The results showed that the concentrations of Cd, Cr, Pb, and As in both drinking and household water samples did not exceed the relative thresholds defined in China's national water quality standards. The concentrations of heavy metals in household water were more affected by seasonal factors than of those of drinking water. The non-cancer and cancer risks were in the ranges of 2.82×10-8-2.43×10-2 and 7.55×10-9-3.62×10-5, respectively, which are within acceptable levels, although the non-cancer and cancer risks from drinking water were both higher than of those determined for household water. Furthermore, the non-cancer and cancer risks from household water for children aged 0-5 years were lower than of those for children aged 6-17 years in each period. However, the cancer risk from drinking water for children aged 0-5 years was lower than of that for children aged 6-17 years, whereas the reverse was found for non-cancer risks. This study indicates that Cd, Cr, Pb, and As in drinking and household water did not pose significant detrimental effects to human health, and that the refined exposure assessment used could reduce uncertainties in health risk assessments.

Cylindrospermopsin induces abnormal vascular development through impairing cytoskeleton and promoting vascular endothelial cell apoptosis by the Rho/ROCK signaling pathway

Elucidating cylindrospermopsin toxicity via synthetic analogues: An in vitro approach

The purpose of the work is to apply existing methodological approaches to assessing the negative impact of drainage water on a water body, to establish the dynamics of concentrations of substances in the area from the place of discharge of wastewater/ drainage water to the control gate. The object of the study was a collector diverting drainage runoff into the Don River. The problem under study is especially relevant in connection with the ongoing measures to prevent degradation of a water body in accordance with the decree of the Government of the Russian Federation dated 07.21.2021 № 2012-r. The concentrations of substances in the most polluted jet in the area from the place of discharge of wastewater/drainage water to the control gate (l = 500 m) were calculated using the example of a collector diverting drainage runoff into the Don River. It is shown that if the concentration of a substance in the background is equal to or below the maximum permissible concentration, then when drainage water are discharged with excess of the standard concentrations of substances and their subsequent dilution by the flow rate of the river with its multiple excess over the flow rate of drainage water (q/Q = 0,0002), the maximum permissible concentration can be reached in the control range, or the actual concentration exceeds the standard is 1,2 – 2 times lower than that for the outlet. Accordingly, it is recommended that, when determining the amount of damage caused to a water body from the discharge of drainage water, be guided by the actual concentrations in the control range, and not in the drainage water discharge range.

The risk of human exposure to cyanotoxins is partially influenced by the location of toxin-producing cyanobacteria in waterbodies. Cyanotoxin production can occur throughout the water column, with deep water production representing a potential public health concern, specifically for drinking water supplies. Deep cyanobacteria layers are often unreported, and it remains to be seen if lower incident rates reflect an uncommon phenomenon or a monitoring bias. Here, we examine Sunfish Lake, Ontario, Canada as a case study lake with a known deep cyanobacteria layer. Cyanotoxin and other bioactive metabolite screening revealed that the deep cyanobacteria layer was toxigenic [0.03 μg L-1 microcystins (max) and 2.5 μg L-1 anabaenopeptins (max)]. The deep layer was predominantly composed of Planktothrix isothrix (exhibiting a lower cyanotoxin cell quota), with Planktothrix rubescens (exhibiting a higher cyanotoxin cell quota) found at background levels. The co-occurrence of multiple toxigenic Planktothrix species underscores the importance of routine surveillance for prompt identification leading to early intervention. For instance, microcystin concentrations in Sunfish Lake are currently below national drinking water thresholds, but shifting environmental conditions (e.g., in response to climate change or nutrient modification) could fashion an environment favoring P. rubescens, creating a scenario of greater cyanotoxin production. Future work should monitor the entire water column to help build predictive capacities for identifying waterbodies at elevated risk of developing deep cyanobacteria layers to safeguard drinking water supplies.

Many diverse lakes are a natural phenomenon of Volyn Polissya. They are of great ecological, recreational and economic importance. As a result of intensive economic activity, pollution and other anthropogenic factors, many lakes are subject to eutrophication. Excessive enrichment of water bodies with nutrients causes the rapid development of algae, deterioration of water quality and disruption of ecological balance. Global climate change has also had a significant impact on this process in recent years. Lake Zasvitske was chosen for the study. It is located in the north-west of Rivne Oblast, in the Varash district, south of the village of Mlyn and north-west of Lake Nobel. It is part of the Nobel National Nature Park. The area of the lake is 22 hectares. Is 620 m long, 350 m wide, has a maximum depth of 16 m, an average depth of 12.5 m, a coastline of 1.75 km and a capacity more than 5 million m3. The lake is fed primarily by atmospheric precipitation and groundwater from. The ecological condition of the watershed is favorable, there are no potentially dangerous objects, the lake is surrounded by pine forests to the north, east and south, and there are equipped small beaches on the western and northwestern sides. The lake water is quite clean. Concentrations of pollutants are exceeded only by the indicator of biological oxygen consumption by 28% and zinc content by 3.1 times. The NDVI and NDAI indices were used to assess the eutrophication of the lake. NDVI (Normalized Difference Vegetation Index) is a quantitative indicator of photosynthetically active biomass most often used to assess eutrophication processes in water bodies. The value of the index varies from -1 to 1. Negative values of the NDVI index indicate the presence of water in the form of clouds and snow; values close to zero (-0.1 to 0.1) correspond to areas with no vegetation cover. Values from 0.2 to 0.9 indicate active vegetation (including in water bodies). NDAI (Normalized Difference Algae Index) is used to diagnose the process of algae overgrowth in a water body and determine the stage of this process. NDVI values increase with the beginning of the transition of the average daily temperature through 0°C, with maximum values reached in late July - early August. Subsequently, the values decrease until the onset of frost. For example, on April 1, 2022. NDVI acquires small positive values up to 0.1. By mid-May, the index values rise to 0.1-0.2. In the eastern part of the lake, where hygrophytes are found, it increases to 0.3. By the end of the month, the NDVI values for most of the reservoir drop again to 0. At the end of June, the index values increase to 0.1 and decrease again. In the first decade of July, the water is cleared of algae. The index acquires negative values (up to -1), which corresponds to clean water. In August-September, the index values vary in the range (-0.1; -0.5). The NDAI index allows us to better trace the seasonality of vegetation processes in the lake. In early April, the development of vegetation processes begins from the belt of semi-flooded hygrophytes along the shores of the reservoir, covering the island rise in the north of the lake. In summer, the intensity of vegetation processes increases, reaching a peak in September. Subsequently, the vegetation dies off and the process repeats in a new vegetation cycle. Keywords: lake, lake catchment area, limnosystem, geo-ecological state of the catchment area, lake eutrophication, measures to prevent and reduce lake eutrophication.

Surface water bodies are the major source for irrigation in India. Information on surface water bodies such as water spread area, volume of water stored in a water body is useful for understanding the availability of water resources for the crop season in a river basin/sub basin. The study extensively used satellite based techniques for the estimation of surface water spread at regional level and at temporal scale to facilitate mapping, monitoring visualization of the dynamics unlike conventional methods. Geospatial database on water bodies information has been created for the study area Krishna middle sub basin. The study considers only water bodies where water is stored for irrigation purpose such as reservoirs, tanks, ponds, etc excluding rivers. Study is focused on use of RS and GIS techniques with extensive use of Image processing and GIS software like ERDAS Imagine, ARC Desktop GIS and analyses the spatio-temporal water body layers. Quantitative estimates on WSA under water bodies are worked for analyzing inter/intra seasonal/annual analysis. The present study has brought out geospatial database and provided scope for sub regional/regional analysis. Estimation of regional surface water storage is estimated with separate methodology for larger and smaller water bodies. This is demonstrated within a sub basin namely Krishna middle sub basin. Storage in larger water bodies is estimated by developing satellite based Area-Capacity curves related to Elevation values on the date satellite data acquisition. Storage in smaller water bodies is estimated with the help a methodology frame work developed in this study using digital elevation models, stream order and relating to the extensive observations made on elevation difference between upstream and downstream of water bodies. The study has brought out suitable spatio-temporal information of water bodies useful for analyzing operational issues related to water resources availability. The information generated can be made use for web based regional analysis and for public domain with suitable visualization tools.

Best management practices (BMPs) are the tools which are adopted to run any activity while inflicting least negative impacts on the surrounding environment. Since, water pollution is one of the most important issues in today's world; it is indispensable to discuss the activities which are deteriorating its quality. Although, a number of treatment technologies and methods are in place for treating the point sources of pollution, there is a need to address nonpoint sources of pollution. There are many successful practices which are capable of curtailing the impacts of nonpoint source pollution, if adopted. In this paper an attempt has been made to evaluate the performance and trade‐offs of various management practices to address the issues of agricultural nonpoint source pollution. Nevertheless, there is a dearth of guiding principles which can pave a way for adoption of these practices. Therefore, an attempt has also been made to explore the aspects of policy formulations along with emphasizing the factors which can lead to adoption/ non‐adoption of such practices.

The research of the water quality from potable water source - Dniprovsky reservoir near the coastal pump stations of the first lift (CPS-1 and CPS-2) JSC Zaporizhstal (the location of water intake - Dnipro river above the SI DniproHES dam), potable water after the water treatment facilities, and water from water intake cranes of JSC Zaporizhstal was conducted. It was found that water quality within the first sanitation zone of water intake during the research period in all locations of water intake met the 2-3 quality class according to the DSTU4808:2007 “Sources of centralized potable water supply. Hygienic and ecological requirements to water quality and intake rules”. According to SanPiN 4630-88 “Sanitary regulations for the protection of surface water from the pollution” the source water had a steadily high consistent of organic substances: chemical oxygen demand (its content was from 19,2 to79,2 mg/l), biochemical oxygen demand during the 20 days (its content was from 2,16 TO 34,3 mg/l), iron (maximum content-0,44 mg/l), and phenols (from 0,001 to 0,07 mg/l). The determined quality of water from Dnipro in the location of potable water intake characterizes all reservoirs of Dnipro cascade and attributed to natural and anthropogenic factors. It was found that traditional technology of potable water purification on the water treatment facilities of JSC Zaporizhstal does not provide the potable water with required hygienic standards, the determined problematic indicators are: toxic (second class of hazard- chloroform (93,2 – 138 µg/l), sum HMUA (117 – 182,5 µg/l), bromdichlormethan (22,7 – 40,9 µg/l), and “indicator” according to the European legislation (third class of hazard–permanganate demand (5,9 – 10,4mg/l), iron (0,13 – 0,94mg/l), manganese (0 - 0,19 mg/l)), and fourth class of hazard – phenols (maximum content-0,005 mg/l). Toxic substances are formed during the primary chlorination of surface water, other pollutants are transferred with the surface water through the water pipes to the potable water. The water quality in Dniprovsky reservoir (the location of water intake - Dnipro river above the SI DniproHES dam), coastal pump stations of the first lift (CPS-1 and CPS-2), water intake structures in contemporary conditions can be used for the potable water production provided the technologies of potable water preparation which is currently used on the JSC Zaporizhstal will be improved based on current state and water quality in the water source. It can be done using different ways: by adding to the current technology the additional stage of water purification, firstly from the organic substances before the natural water inflow to the main treatment facilities, by using of more effective coagulants and flocculants, sorption bedding for filters, disinfection agents etc.

Establishing reliable and cost-effective tools to identify the occurrence of toxin-producing cyanobacteria could lead to an early warning system to prevent water consumption and recreational activities, especially for low-income agricultural countries. The current study utilised a two-method approach, an enzyme-linked immunosorbent assay and polymerase chain reaction, to enumerate commonly occurring cyanotoxins: microcystin (MC), cylindrospermopsin (CYN), nodularin (NOD), anatoxin-a (ANA-a), and saxitoxin (SAX), and to evaluate the presence of the genes responsible for producing these toxins. Water samples from 43 drinking, recreational and irrigational water bodies in Sri Lanka were collected between November 2019 and July 2020. Results indicated that 24 of the sampled water bodies contained at least one of the toxin-producing genes screened. Notably, the overall MC concentration detected for Beira Lake in Colombo, a recreational waterbody in the country's largest and most populous city, was 3.31 μg/L. Among the different cyanotoxins analysed, MC was found to be the most dominant (37%) in the collected water samples compared to CYN (10%), SAX (10%), NOD (10%), and ANA-a (10%). This is the first such study where molecular approaches were combined with immunological assays to provide an extensive survey highlighting an alarming level of contamination of cyanotoxins in intensively used water bodies.

Brazil has a history of blooms and contamination of freshwater systems by cyanobacterial toxins. The monitoring relevance of toxins from cyanobacteria in reservoirs for public supply is notorious given its high toxicity to mammals, included humans beings. The most recurrent toxins in Brazilian water bodies are microcystins (MC). However, the recent record of cylindrospermopsin (CYN) in northeastern Brazil, Pernambuco state, alerts us to the possibility that this could be escalating. This study reports occurrence of MC and CYN, quantified with ELISA, in 10 reservoirs, devoted to public drinking supply in northeastern Brazil. The composition and quantification of the cyanobacteria community associated with these water bodies is also presented. From 23 samples investigated for the presence of MC, and CYN, 22 and 8 out were positive, respectively. Considering the similarity of the cyanobacteria communities found in reservoirs from Pernambuco, including toxin-producing species associated to MC and CYN, we suggest that geographic spreading can be favored by these factors. These issues emphasize the need for increased monitoring of MC and CYN in drinking supply reservoirs in Brazil.

Hepatotoxic microcystin removal using pumice embedded monolithic composite cryogel as an alternative water treatment method

Destruction of cyanobacterial toxin cylindrospermopsin by hydroxyl radicals and sulfate radicals using UV-254 nm activation of hydrogen peroxide, persulfate and peroxymonosulfate