Water Chemistry Parameters Research Articles

Shellfish Meat Safety on the Montenegro Coast

Exploitation of natural resources of the marine ecosystem to feed a growing human population has led to the possibility of their application in the future. In order to solve this problem, mariculture develops and the create adequate conditions for the breeding of marine organisms which are using in human nutrition and one of them are shellfish known as nutritionally valuable food. Microflora of marine organisms, and therefore shells largely depends on environmental factors such as time of the year, temperature of the sea water etc. This work was focused on growing shells on the Montenegrin coast, and a special emphasis was put on placing health-safe shells on the Montenegrin food market. In addition to meat shells, physical and chemical parameters of sea water were studied: water temperature, salinity, oxygen saturation, pH, transparency, nitrate concentration, Examination of these parameters is related to the period of one year. The own results of the microbiological examination of the samples of shellfish sampled in six production zones in April according to presence of Escherichia coli in the value of ˂18 MPN – (Most Probably Number) per 100 g of meat and intra-shell liquid, which means that shellfish in general at the Montenegrin coasts satisfy and meet microbiological criteria in view of the presence of Escherichia coli. When its own results compare with the results of the SVL (Specialist Veterinary Laboratory) for the same time in each zone, it can be determined that the results match, thus confirming the accuracy of the test results shown.

Environmental Diagnosis through a Flow Cytometric Approach.

In an era when ecological and environmental needs and responsibilities apply pressure on the world's countries and sustainability takes centre stage, ecologic/environmental (E/E) laboratories stand as beacons of scientific inquiry, innovating, optimising, and applying various tests for a better knowledge of our natural resources and the quality status of ecosystems. The purpose of this review is to provide an overview of the use of flow cytometry (FC) as a tool for assessing environmental quality, mainly using living organisms and their biological changes as bioindicators. Cytometric approaches applied to both marine and terrestrial ecosystems ensure the detection of biochemical and functional status of the cells composing either an organ thereof or the organism itself. In addition to cytometric evaluations of the biotic matrix, a brief overview of the techniques for the environmental assessment of biotic and abiotic matrices using mass spectrometry is given. The technique involving the continuous monitoring of the chemical and physical parameters of water, sediment, and soil is basically incapable of detecting any additive and synergetic effects of toxicants on living organisms. Therefore, techniques employing bioindicators provide valuable information for environmental diagnosis, and several studies have demonstrated the strong relationship between specific environmental data and cell/organ behaviour.

Flora and vegetation in the Lake Arbakalir and the spring Charsky Goryachy Klyuch (Charskaya Basin, Transbaikalia)

As a result of comprehensive researches in the Lake Arbakalir and the Spring Charsky Goryachi klyuch during the growing season in 2021, the physical and chemical parameters of water, species and phytocenotic diversity of vegetation were studied. 56 taxa from 7 divisions of which 31 species belong to flowering plants, 22 species to macroalgae, one species in each to bryophytes, horsetails and lycophytes were identified in the flora of water bodies. Two species are included in the Red Book, both at the federal and regional levels. Two species are classified as relict. The structure of the flora contains species of three ecotypes, of which 38 species (67.9 %) belong to true aquatic plants. 18 associations from 12 formations were identified in the syntaxonomic structure of aquatic and coastal aquatic vegetation. Based on factor analysis, the main factors influencing the distribution of phytocenoses are water temperature, pH, mineralization, and main cation, anion and nutrient contents.

Response of the Cyanobacteria Plankton Community to Anthropogenic Impact in Small Lakes of Urbanized Territory in the Permafrost Zone of Northeast Asia (Eastern Siberia, Yakutia)

In the conditions of growing anthropogenic pressure, aquatic ecosystems all over the world are subject to transformation, expressed in the growth of eutrophication, increase in acidity, changes in water exchange, etc. In the region of Eastern Siberia we studied, located in Yakutia in the middle reaches of the Lena River basin, there is a significant population growth accompanied by advancements in agriculture and public utilities. The region is rich in small lakes, which have been under pressure from human activities for the past few decades. The studied region is located in the permafrost zone and is characterized by severe climatic conditions, cold long winters, short hot summers, and a short ice-free period on reservoirs. We studied 17 lakes of various genesis, with varying degrees of anthropogenic pressure, located in the largest city of the region, small villages, and at different distances from them. Previous studies have established that cyanobacteria constitute the phytoplankton main group in these lakes during the summer period. Therefore, we selected them as the focus for our bioindication analysis. An integrated assessment of the bioindication properties of cyanobacteria, along with chemical water parameters, was undertaken using statistical mapping methods, JASP, and Redundancy Analysis (RDA). This analysis revealed the impact of urbanized areas, characterized by a decrease in pH, runoff of nitrogen compounds, and an increase in organic matter. Despite the cryolithozone harsh conditions, in small lakes of urbanized areas, cyanobacteria exhibit their competitive advantages within the plankton community. The prospect of continuing our work is associated with the need to determine the risk of cyanoHAB development since potentially toxic cyanobacteria have a mass development in a number of lakes.

Detection and Prediction of Toxic Aluminum Concentrations in High-Priority Salmon Rivers in Nova Scotia.

Elevated concentrations of toxic cationic aluminum (Ali) are symptomatic of terrestrial and freshwater acidification and are particularly toxic to salmonid fish species such as Atlantic salmon (Salmo salar). Speciated metal samples are rarely included in standard water monitoring protocols, and therefore the processes affecting Ali dynamics in freshwater remain poorly understood. Previous analysis of Ali concentrations in Nova Scotia (Canada) rivers found that the majority of study rivers had concentrations exceeding the threshold for aquatic health, but a wide-scale survey of Ali in Nova Scotia has not taken place since 2006 (Dennis, I. F., & Clair, T. A., 2012, Canadian Journal of Fisheries and Aquatic Sciences, 69(7), 1174-1183). The observed levels of dissolved aluminum in Atlantic salmon (Salmo salar) rivers of Atlantic Canada have potential serious and harmful effects for aquatic populations. We present the findings of the first large-scale assessment of the Ali status of Nova Scotia rivers in 17 years; we measured Ali concentrations and other water chemistry parameters at 150 sites throughout the Southern Uplands region of Nova Scotia from 2015 to 2022. We found that Ali concentrations exceeded toxic thresholds at least once during the study period at 80% of the study sites and that Ali concentrations increased during the study period at all four large-sample study sites. Modeling of relationships between Ali concentrations and other water chemistry parameters showed that the most important predictors of Ali are concentrations of the dissolved fractions of Al, iron, titanium, and calcium, as well as dissolved organic carbon and fluoride. We developed a fully Bayesian linear mixed model to predict Ali concentrations from a test data set within 15 μg/L. This model may be a valuable tool to predict Ali concentrations in rivers and to prioritize areas where Ali should be monitored. Environ Toxicol Chem 2024;00:1-12. © 2024 The Author(s). Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC.

Effect of Vermicompost Supplement on Rainbow Trout Performance

Vermicompost is the product of organic waste digestion by earthworms besides aerobic decomposition at ambient temperature. It is a rich composition containing plant nutrients and beneficial microorganisms. Some fishes, especially predatory species such as rainbow trout, need nutritive feed so that they can be healthy; a useful and cheaper additive such as vermicompost can supply this aim. In this study, the effect of different percentages of vermicompost in the diet of rainbow trout was investigated. For this purpose, 100 rainbow trout with an average weight of 120±3 g were distributed in 5 groups in concrete tanks. Their nutrition and physical and chemical water parameters were determined according to the standard. Vermicompost with confirmable analysis was added to their daily feed (2, 4, 6, and 10%). After 2 months, the feed conversion ratio and survival rate were examined. The results showed that there was a significant relationship between the performance of the control group and the treatment groups (p

PEMETAAN TEMATIK KESESUAIAN LAHAN BUDIDAYA RUMPUT LAUT PADA PERAIRAN TELUK KAYELI KABUPATEN BURU

Background: Seaweed is widely cultivated in coastal areas of Indonesia, one of which can be found in Kayeli Bay, Buru Regency. One of the problems faced by farmers in cultivating seaweed in this area is that there is no division of suitable areas for cultivation land in the form of thematic maps, especially using physical-chemical parameters of waters. Method: This activity includes several stages, namely location survey, data collection or collection and preparation of a database. Measurements of physical and chemical parameters of waters are carried out directly in the field (in situ) and in the laboratory (ex situ). The measurement parameters include temperature, brightness, wave height, current speed, pH, salinity, DO, nitrate and phosphate. To create a thematic map of land suitability, the ArcGis application was used. Results: Most of the physical and chemical parameters of the waters are still suitable for seaweed cultivation, except for temperature and phosphate. The results of land suitability evaluation/analysis based on water physical-chemical parameters produce two land suitability categories, namely suitable (S2) and very suitable (S1). The category corresponds to an area of ​​110.2 ha or 29% and very corresponds to an area of ​​269.8 ha or 71%. Conclusion: The thematic map of Kayeli Bay waters, Buru Regency shows that the suitability of seaweed cultivation land is divided into two categories, namely suitable at 29% and very suitable at 71%. However, the temperature and phosphate parameters at the time of measurement were in the category not suitable for seaweed cultivation.

Efisiensi Kerapatan Tananaman Pakcoy (Brassica Rapa) terhadap Kualitas Air untuk Mendukung Kelangsungan Hidup Ikan Nila

Asnan Ridoanrisna. Efficiency Of Pakcoy Plants (Brassica Rapa) In Maintaining Water Quality To Support The Survival Rate Of Tilapia. Under Guidance By Robin And Novita Mz. Tilapia is a freshwater fish commodity with high economic value. According to data from the Central Bureau of Statistics (BPS), tilapia exports reached 12.29 thousand tons with a value of USD 78.44 million. Tilapia farming faces the risk of mortality which can lead to economic losses, one of which is caused by organic pollution. To address this issue, this research employs phytoremediation methods with varying plant densities to improve water quality and tilapia survival. The study was conducted with four treatments: A75 (plant density 75% of the aquarium surface area), A50 (50%), A25 (25%), and A0 (no plants), using an aquarium size of 60 x 30 x 50 cm³. Each treatment received chicken manure at 1.8 grams per aquarium and 40 tilapia fish per aquarium. Observations were made over 15 days in March 2023, measuring physical and chemical water parameters including DO, pH, TDS, temperature, and ammonia, as well as calculating the survival rate of tilapia. Using a Completely Randomized Design (CRD), the study found that treatment A75 achieved the highest survival rate at 62.5%. This result indicates that higher plant density in the phytoremediation method is more effective in maintaining water quality and supporting tilapia survival.

Assessment of Groundwater Quality for Human Uses

Evaluating the quality of groundwater holds utmost importance in determining its suitability for safe consumption. This study delved into the groundwater conditions in selected regions of southern Iraq (Thiqar government), specifically Al-shatra and Al-naser districts. Physical and chemical water parameters were examined including, pH, electrical conductivity, turbidity, total dissolved solids, alkalinity, nitrates, nitrites, fluoride, sulfate, hexavalent chromium, copper, manganese, and iron. The results demonstrated the quality of ground water was not suitable for human uses according to WHO and Iraqi guidelines. Heavy metals and anions contaminates have not influenced on the human health and the environment due to their higher concentrations less than the acceptable value. However, other parameters have concentrations higher than the allowable value. The maximum concentration of TDS was 1955 mg/l at Al-zamil (Al-naser) (W8) and the turbidity was slightly more than the WHO standard. The concentration of alkalinity was higher than the healthy value.

Drivers of spatio-temporal variation in organic matter decomposition across a river network

Rivers are biodiverse ecosystems that play an essential role in the processing of organic matter from headwaters to the lower reaches. The biodiversity within these spatially complex ecosystems is often subject to huge seasonal variation, particularly in temperate regions, for example seasonal peaks in emergence of aquatic insects or migration of fish through the river network. However, these ecosystems are also subject to strong anthropogenic pressures that affect not only the biodiversity within this system, but the functions this biodiversity provides to key ecosystem processes. Therefore, spatial and temporally dynamics must be considered to effectively assess and understand the biodiversity and functioning within an ecosystem. Here, we assessed ecosystem function at a high spatial and temporal resolution across a large river network, specifically focussing on standardised organic–matter decomposition. Our results show—even when correcting for temperature—significant effects of both season and water chemistry parameters on microbial decomposition. However, we found no effect of space (i.e., site location within the network) on ecosystem function, contrary to expectations. We also found no imprint of the microbial community richness assessed in the water column (α–diversity and Shannon Index) on the patterns of organic–matter decomposition, however, this may be due to our focus on potential colonising microbes rather than benthic communities. Our study highlights the need to include functional indicators for the assessment of ecosystems.

In-depth analysis of the removal mechanisms behind neonicotinoid pesticides and bimetal ZIF derived-magnetic carbon

Emerging organic contaminants, such as pesticides, pose significant environmental challenges and necessitate the development of advanced materials and technologies for their efficient removal. This study explored various morphologies of bimetal ZIF-derived magnetic carbon for the removal of three representative neonicotinoid pesticides from water. Among the materials investigated, Co-NP3-1000, carbonized at 1000℃ from Zn/Co-ZIF with a Zn/Co molar ratio of 3:1, demonstrated outstanding adsorption performance, even in the presence of varying water chemistry parameters (e.g., humic acid and particulate matter), and effectively removed neonicotinoid pesticides at low concentrations from diverse actual water samples. Due to its strong magnetic properties, Co-NP3-1000 could be easily separated from solutions and maintained over 70% adsorption efficiency after five consecutive cycles. Moreover, Co-NP3-1000 exhibited high efficiency in removing other neonicotinoid pesticides (i.e., acetamiprid, nitenpyram, and thiamethoxam). Microstructure analysis and density functional theory calculation identified pore filling, hydrogen bonding, and π-π interactions as the primary forces driving NEOs adsorption. Notably, the relative contribution of these interactions was quantitatively assessed across different solution pH levels, and their sequence was elucidated using two-dimensional Fourier transform infrared correlation spectroscopy. This work advances both the design of versatile materials for the removal of emerging organic contaminants and quantitative insights into the interaction mechanisms between advanced adsorbents and these contaminants.

Analysis on Spatial Variability of Hydrochemical Characteristics and Control Factors of Jinan Baotu Spring Area

To understand the karst groundwater hydrochemical characteristics and ion sources of the Jinan Baotu Spring area, this study focused on the three functional zones as an indirect recharge area, direct recharge area, and discharge area. Through water sample collection and testing, the spatial variability of groundwater chemical characteristics in different functional zones and the formation mechanism were analyzed using hydrochemistry parameter statistics, multivariate statistics, self-organizing map, hydrochemistry graphical analysis, ion ratios, and other methods, guided by the theory of groundwater flow system and combined with regional physical geography and hydrogeological conditions. The results showed that： the groundwater of each functional zone was alkaline as is typical in the dissolution of carbonate minerals. Owing to the different groundwater runoff pathways, the variability of water chemistry parameters in different functional areas was obvious. The groundwater of the discharge area was recharged by both the direct recharge area and the indirect recharge area. The hydrochemistry type changed from HCO3-Ca type to HCO3·SO4-Ca type through the indirect recharge area to the discharge area. The presence of a small amount of gypsum dissolution within the aquifer generated Ca2+ and SO42-. The ions in groundwater mainly came from the dissolution and filtration of aquifer rock minerals, and at the same time, they were affected by cation exchange, mineral dissolution equilibrium, and the combined effects of human activities. The groundwater in the Baotu Spring area was greatly influenced by human activities, which to some extent affected the evolution of groundwater hydrochemistry in the spring area.

Comparative Study of Water Quality Across Different Seasons in the Gregório River Watershed, São Paulo, Brazil

The goal of this study was to monitor the water quality in the Gregório river, São Carlos, São Paulo during the dry and rainy seasons using traditional methods such as physical and chemical analysis of the water and biological indicators. Six sampling points were monitored, ranging from the nearest location to the source of the river to its confluence with the Monjolinho river. Physical and chemical parameters of water (water surface temperature, dissolved oxygen, pH, and conductivity) were measured using a multiparameter probe. The distance between the points was determined according to the access to the site: from P1 to P2 (1328 m), from P2 to P3 (1278 m), from P3 to P4 (201 m), from P4 to P5 (820 m), and finally from P5 to P6 (1814 m). The biotic index used in conjunction with the environmental variables was the Biological Monitoring Working Party (BMWP), a qualitative index that utilizes benthic macroinvertebrates to classify water quality. Ceratopogonidae, Chironomidae, Chironomus, Enchytraeidae, Hirudinea, and Naididae were recorded at sites P1, P2, and P6 during both the dry and rainy seasons. This study, particularly at P6, it was observed that despite the higher concentration of dissolved oxygen compared to the other analyzed sites, which would indicate good water quality, the BMWP indicated that the location had a strongly polluted water quality, suggesting that environmental factors must be associated with biological indicators. It was concluded that the use of biological indicators along with environmental data provided a more reliable understanding of water quality.

Impact of Filtration on Grey Water Quality: A Comprehensive Analysis of Christian Hospital Taxila's Grey Water before and after Treatment

Grey water, defined as wastewater excluding toilet effluents, contains varying levels of contaminants and necessitates precise reuse strategies. This study focuses on the treatment of grey water sources with relatively lower levels of contaminants, specifically excluding those from toilets which contribute the majority of harmful substances such as chemicals, body lipids, and oils. The study evaluated the physical, chemical, and microbiological parameters of household grey water, including pH, conductivity, turbidity, and the presence of elements such as calcium, magnesium, and potassium, as well as contaminants like nitrates and sulfates. The treatment system employed consisted of multiple filtration stages using sand, coconut husk, pebbles, activated charcoal, limestone, and gravel, complemented by reverse osmosis. Results indicated significant improvements post-treatment: normalization of pH, reduced conductivity, elimination of color, and substantial reductions in major contaminants. Notably, the system achieved 100% removal of E. coli, total coliforms, and fecal coliforms. The findings underscore the effectiveness of greywater treatment in reducing water toxicity and enhancing its suitability for various applications, thereby contributing to pollution reduction and resource conservation. Such recycling initiatives can significantly address water scarcity issues and encourage sustainable water resource management.

Subsurface flow pathway and hydrochemistry of a geographically isolated depression wetland in the Serra Geral Diabase Formation, São Paulo State, Brazil

Connectivity among water bodies is crucial for hydrological and ecological processes and fundamental for water management. Hydrochemistry and potentiometric studies on an isolated wetland allow to assess landscape influence, flow pathways, and subsurface connection. This study focuses on an isolated wetland over diabase on a topographic depression, with no visible river connection, and aims to determine the influence of rainfall and landscape on water composition and investigate subsurface flow toward the Santa Gertrudes stream. Water levels were monitored, and samples were collected from four wells during wet and dry seasons. Physical and chemical water parameters were measured, and ion concentrations determined. Pearson’s correlations highlighted codependence between physical and chemical parameters and ions and Piper’s diagram classified water composition. Six potentiometric maps were generated using interpolated hydraulic loads from monitoring campaigns. The findings show fluctuations in water level (0.11 to 0.93 m during wet periods and 1.25 to 1.79 m during dry periods), indicating rainwater directly affects water availability. Water composition was categorized as Sodium Bicarbonate and electrical conductivity values (greater than 100 µS/cm) may indicate that upstream wells are retaining salts from the surrounding crops. Strong positive correlation between sodium, bicarbonate and carbonate, and sulfate with electrical conductivity suggests simultaneous release of ions due to rock and soil mineral alteration. Potentiometric data reinforce the hypothesis of a subsurface connection between the studied area and the Santa Gertrudes stream. Future studies could benefit from expanding the monitoring network to include more GIWs and applying additional methods, such as isotope tracers.

Dynamics of Phytoplankton Communities and Environmental Drivers in Chinese Mitten Crab Aquaculture Ponds: Highlighting the Need for Cyanobacteria Control

Pond culture is the primary method for cultivating Chinese mitten crab (Eriocheir sinensis), with phytoplankton significantly influencing their growth. Green algae benefit crab growth by serving as supplementary food, while cyanobacteria, particularly during blooms, hinder it and pose health risks. Environmental changes in nutrient levels, temperature, and light significantly affect phytoplankton communities in ponds, impacting both ecosystem stability and crab growth. However, there is a limited understanding regarding the patterns of phytoplankton changes within adult Chinese mitten crab culture ponds. This study conducted monthly collection and analysis of phytoplankton throughout the culture cycle in typical adult Chinese mitten crab culture ponds, concurrently measuring physical and chemical water parameters to explore the correlation between phytoplankton changes and environmental factors. The results revealed distinct seasonal variations in phytoplankton composition. Chlorophyta and Bacillariophyta, such as Chlorella, Pediastrum, and Cocconeis, predominated in spring, while Chlorophyta and cyanobacteria, such as Volvox, Anabaena, and Microcystis, dominated in summer, and cyanobacteria and Bacillariophyta, such as Microcystis, Dolichospermum, and Cocconeis, prevailed in autumn. Total phytoplankton density consistently increased throughout the culture period. Microcystis constituted the majority of cyanobacteria biomass throughout most months. Although the total phytoplankton biomass fluctuated, cyanobacteria biomass consistently rose each month, reaching a peak of 61.7 mg/L in October. Water temperature and pH emerged as the primary environmental drivers influencing changes in phytoplankton community structure. Cyanobacteria density reached its peak between 18 and 26 °C and at a pH range of 7.5–8.5. These findings highlight the need for environmental regulation and cyanobacteria control in Chinese mitten crab culture ponds, thus promoting the health and sustainability of the Chinese mitten crab culture.

Study of Babak River water quality using physical and chemical parameters in Kebon Kongok landfill (Lombok, Indonesia)

The study has been conducted on the water quality level of the Babak River around Kebon Kongok landfill, Lombok. This research was conducted considering that water has many benefits in the daily lives of people. This research uses an experimental method by analyzing physical parameters (temperature, conductivity, pH, and total dissolved solids (TDS)), and chemical parameters in the form of heavy metal content lead (Pb), iron (Fe), manganese (Mn), and copper (Cu)). Analysis results were compared with quality standards based on Ministry of Health Regulation No. 32 of 2017 concerning water quality. Based on the study, it was found that the farther the distance of water measured from the source of pollution, the value of the physical and chemical parameters of water will be smaller. Most of the physical parameter test results show the Babak River water quality is still at the safe threshold limit but there is 1 point of river water that is polluted due to the distance that is too close to the active zone. Chemical parameters show the results of heavy metal content below the threshold limit. Analysis of the water quality shows that the water is still in good condition, which is below the threshold set by the Indonesian government.

High‐Resolution Forensic Evaluation of Nitrate‐Contaminated Groundwater

AbstractDetermining the source(s) of nitrate contamination in agricultural areas is complicated; doing this as a forensic evaluation for litigation in one field week is especially challenging. The objective of this 2021 investigation, conducted for an agricultural producer who began applying animal waste in 2007, was to determine whether animal waste was the source of nitrate reported at downgradient residential wells. The test Site was a 180 acre, irrigated field that overlies a thick sand aquifer with the water table at about 20 ft below ground level (fbgl). We used multiple lines of evidence to resolve the source(s) of nitrate at three test locations at the Site using continuous vertical testing for hydraulic conductivity and high‐resolution vertical testing of selected chemical and isotopic parameters in water at 5‐ft depth intervals between 5 and 80 fbgl. We found that beneath the Site at the depth interval of most of the impacted residential wells: (1) groundwater travel time indicates nitrate at the impacted residential wells could not have originated from the Site, (2) the groundwater age based on tritium (3H) pre‐dates the establishment of manure spreading, and (3) the nitrogen‐15 concentrations (δ15N) in nitrate indicate the nitrate is not all, if in any part, due to animal waste. This high‐resolution investigation clearly indicated that the agricultural producer was not responsible for the impacted residential wells and was completed in only 1 week.

Seasonal Variability of Water Quality for Human Consumption in the Tilacancha Conduction System, Amazonas, Peru

This study evaluated the seasonal variability of water quality in the Tilacancha River, the water source that supplies Chachapoyas, and the rural communities of Levanto and San Isidro del Maino of Perú. Eighteen physical, chemical, and microbiological water parameters were evaluated at five sampling points in two seasons (rainy and dry). To determine water quality, the results obtained for the parameters evaluated were compared with the Maximum Permissible Limits (MPL) established in the Regulation on Water Quality for Human Consumption (DS Nº 031-2010-SA), approved by the Environmental Health Directorate of the Ministry of Health. In addition, a Pearson correlation was performed to estimate the correlation between the variables evaluated. The results showed that microbiological parameters exceeded the MPLs in both periods evaluated, such as the case of total coliforms (44 MPN.100 mL-1), fecal coliforms (25 MPN.100 mL-1), and E. coli (5.45 MPN.100 mL-1), these microbiological parameters reported a positive correlation with turbidity, temperature, total dissolved solids, and flow rate. In addition, aluminum (Al) and manganese (Mn) exceeded the MPL in the rainy (0.26 mg Al.L-1) and dry (1.41 mg.Mn-1.L-1) seasons, respectively. The results indicated that the water of the Tilacancha River is not suitable for human consumption. Therefore, it must be treated in drinking water treatment plants to be used as drinking water.

Cyanotoxins bioaccumulation by fish in an anthropized reservoir in central Mexico

The bioaccumulation of cyanotoxins has been well documented in exposed organisms including fish, which represent a potential route to cyanotoxins transfer to humans by consumption of contaminated food. We determined the bioaccumulation of neurotoxic saxitoxins and hepatotoxic microcystins in muscle and liver/viscera of native (Goodea atripinnis), introduced (Poeciliopsis gracilis), and commercially important (Oreochromis niloticus) fish in Santa Catarina, an anthropized reservoir in Central Mexico. Additionally, we calculated the potential risk of human exposure due to the consumption of the studied species. The Santa Catarina Reservoir showed some physical and chemical water parameters generally associated with cyanobacterial blooms (e.g., high phycocyanin, chlorophyll-a, dissolved phosphorus concentrations, and alkaline pH) with presence of cyanotoxins produced by the cyanobacteria genera Microcystis, Dolichospermum, and Planktothrix, which were found in dissolved and particulate (sestonic) fractions of water. Moreover, we detected the presence of saxitoxins and microcystins in the tissues of all species studied. The risk of intoxication for humans was lower for the consumption of Nile tilapia muscle than for the other analyzed species, whose consumption should be avoided since it exceeds the recommended daily intake of microcystins for a short-term (i.e., two-week exposure time). These findings are remarkable because commercial fishing in reservoirs and the consumption of these fish could represent a route to human exposure to toxins, particularly microcystins. Our results highlight the need for the detection of cyanotoxins and the evaluation of their bioaccumulation by fish in unstudied eutrophic waterbodies, to reduce the potential health risk for humans and the environment.