Collected Water Samples Research Articles

Influence of mesoscale eddies on the spring phytoplankton groups in the Southern Gulf of Mexico

Abstract In this study, we analyzed the abundance and distribution of eight major phytoplankton groups and their relationship to hydrography and nutrient concentrations in oceanic waters of the southern Gulf of Mexico based on 63 stations sampled during April and May 2017. At each location, a CTD/Rosette system configured with Niskin bottles was used to acquire high-resolution hydrographic data and collect water samples at standard depths for chemical determination (nutrients and chlorophyll-a) and identification of phytoplankton cells. Cold and warm cores corresponding to cyclonic/anticyclonic eddies were recorded, which influenced the vertical and horizontal distributions of nutrients and chlorophyll-a. In terms of phytoplankton, Dinophyceae was the most abundant group, accounting for 454,160 cells l−1. Phytoflagellates recorded 171,939 cells l−1; Cyanophyceae 50,720 cells l−1; Bacillariophyceae 25,457 cells l−1; Haptophyta 15,851 cells l−1; and Silicoflagellata 7,940 cells l−1. The two groups with the lowest abundances were Raphidophyceae and Chlorophyceae, with 1,557 and 882 cells l−1, respectively. The vertical distributions and abundances of the eight groups showed different patterns. Three main large regions of high abundance (>10,000 cells l−1) coincided with nutrient-rich cold cores, particularly in the southern portion. Each phytoplankton group is related to specific hydrographic and chemical parameters.

Factors controlling basalt weathering in the Deccan traps: A small catchment perspective

Chemical weathering fluxes from small basalt catchments, the Ambika and the Girna in the Deccan Traps, have been compared. The two catchments are characterized by distinct climates: humid in the Ambika and semi-arid in the Girna River. We collected water samples at the sub- catchment scale of these basins and analysed concentrations of major ions and dissolved Sr in them to estimate the weathering rates and to assess their controlling factors. The catchment area, slope and relief of the catchments were derived using Digital Elevation Model (DEM) on ArcGIS platform whereas the Soil and Water Assessment Tool (SWAT) was used to derive the sub-catchment scale runoffs. The SWAT simulated annual discharge shows a nearly three times larger discharge in the Ambika River compared to the Girna River. The various sources, viz., basalt, carbonates, sea-salts and saline alkaline soils (SAS) contributing to major ions in dissolved load, were quantified using inverse modelling approach. The total chemical denudation rates (TCDR*) during monsoon, 1033 ± 512 tons km−2 y-1, is ∼ 12 times higher compared to non-monsoon (82 ± 42 tons km−2 y-1) in the Ambika River, and ∼ 3 times higher in the Girna River (monsoon: 185 ± 155 tons km−2 y-1 vs. non-monsoon: 51 ± 25 tons km−2 y-1). Annually, TCDR* is around 6-fold higher in the Ambika River (∼683 tons km−2 y-1) than in the Girna River (∼113 tons km−2 y-1) at their outlets. Basalt (silicate) weathering rates (BasWR) in the Ambika and the Girna rivers are 88 ± 19 and 12 ± 3 tons km−2 y-1, respectively. The chemical weathering rates in the two adjacent catchments is primarily controlled by rainfall/runoff, while relief plays secondary control. CO2 consumption rates (CCR) of the Ambika with higher rainfall are much higher ((13 ± 4) × 105 mol km−2 y-1) compared to most of the inactive basalt cathchments globally.

Bacteriophages carry auxiliary metabolic genes related to energy, sulfur and phosphorus metabolism during a harmful algal bloom in a freshwater lake.

Cyanophages play an important role in nutrient cycling in lakes since they can modulate the metabolism of cyanobacteria. A proper understanding of the impact of cyanophage infection on the metabolism and ecology of cyanobacteria is critical during a complete cycle of harmful algal bloom (HAB). The ecology of cyanophages in marine environments has been well-delineated, but cyanophages in freshwater lakes remain less studied. Here, we studied the diversity of cyanophages and their impact on host ecology and metabolism in through the succession of HAB in Utah Lake, which is a shallow eutrophic freshwater lake, in 2019. We collected water samples at three different periods from two locations in freshwater Utah Lake. The three sampling periods represented the pre- bloom, peak- bloom, and post-bloom events. We observed that the Utah Lake virome was dominated byfamilies Myoviridae, Siphoviridae, and Podoviridae under the order Caudovirales. We detected photosystem-related genes, sulfur assimilation genes, and pho regulon (phosphorus metabolism) genes in genomes of predicted cyanophages. We were able to capture the changes in relative abundance and expression of functional genes in genomes of cyanophage at different stages of the bloom. We observed higher relative abundance and expression of cyanophage-encoded pho-regulon genes in the “pre-bloom” period. The higher expression of pho-regulon genes in P-limited ecosystem of Utah Lake indicated the possible contribution of cyanophage to enhance the fitness of the host cyanobacteria. Our study provides some insightful findings on the role of cyanophages in controlling the ecology and relative abundance of host cyanobacteria in freshwater lakes.

Aqua Quadcopter an Engineering Solution for Water Sample Collection

An “Aqua Quadcopter” designed for water sample collection is a specialized quadcopter capable of flying over water bodies and collecting water samples for analysis. This type of drone combines aerial mobility with aquatic capabilities, making it suitable for environmental monitoring, scientific research, and pollution detection in rivers, lakes, oceans, and other water bodies. Traditional methods of water sample collection are often labour- intensive, time consuming, and may require boats or human intervention in potentially hazardous environments. This project addresses the need for a more efficient, safer, and autonomous solution that can access remote or hard-to-reach areas and provide real-time data for environmental analysis. We are going to design drone and water sampler, adding some specifications like GPS system to target the area where it is polluted and observe the stability of quadcopter.

Ease and Limitations in Using Environmental DNA to Track the Spread of Invasive Host–Parasite Complexes: A Case Study of the Freshwater Fish Pseudorasbora parva and the Cryptic Fungal Parasite Sphaerothecum destruens

The spread of non-native species threatens biodiversity and exacerbates societal challenges like food security. To address this, effective conservation programs require detection methods that are easy to implement, accurate, and non-invasive. Over the past 15 years, environmental DNA (eDNA) techniques have gained popularity, surpassing traditional sampling methods. In this context, our study focused on tracking the invasive host–pathogen complex Pseudorasbora parva and Sphaerothecum destruens using eDNA metabarcoding. We collected water samples from freshwater canals over five months in the Camargue region, and once in Corsica Island, both in southern France. Total DNA was extracted from filtered water samples, and PCR-amplicons were sequenced using Illumina or Nanopore technologies. Our results revealed a high detection rate of P. parva in lentic ecosystems, aligning with habitat preferences of this small freshwater fish. Additionally, the detection rate in Camargue increased in May and June, likely due to the peak of the spawning season, which leads to more DNA being released into the environment (i.e., concentration and interaction of individuals). While eDNA successfully detected this invasive fish, we were unable to detect its cryptic fungal parasite, S. destruens, highlighting the challenges of identifying intracellular and cryptic fungal pathogens through eDNA methods.

Seasonal Abundance and Types of Microplastics in Surface Waters of River Sabaki Estuary, Kenya

Increased demand for plastics has resulted in the generation of plastic waste, which poses a threat to the environment in general, and ultimately the marine environment. Estuaries and deltas are the main filters of marine ecosystem pollutants from inland sources. There have been limited studies on temporal variations in microplastic (MP) pollutants in tropical estuaries of Africa. In 2022, a twelve-month sampling survey study was conducted at Sabaki river estuary, in Kenya. A bucket was used to collect water samples, that were sieved through a 225μm sieve. A stereo microscope was used to identify microplastics and their polymer confirmed using FTIR spectroscopy. Data analysis on seasonal difference in abundance of microplastics in surface waters was performed using Minitab software at α ≤ 0.05. The results indicated that the April-June (A-J) long rains season had significantly (P ≤ 0.05) higher levels of MPs due to rainfall runoff, compared to other seasons, namely January –March (J-M), July-October (J-O) and November –December (N-D). The (J-M), (J-O) and (N-D) seasons had similar levels of MPs, which were lower compared to those observed during (A-J) long rains season by 44.3%, 54% and 25% respectively, compared to the highest concentration of 264 MPs m-3 observed during the A-J season. Fragments type of MPs were higher during the wet season, while fiber type of MPs dominated during the dry season. Film and form type of MPs were least abundant. Seasons significantly (P ≤ 0.05) influenced distribution of the different sizes of MPs. Small and medium sized category of MPs occurred and dominated during the dry season, while larger particles dominated during the wet season. Seven (7) differently colored MPs were observed during the study. White colored MPs were most prevalent (33%), followed by blue (23%), black (17%), brown (12%), yellow (5%), red (5%), and green (4%). Five types of plastic polymers were found in surface waters of river Sabaki estuary, namely polyethylene (PE), polypropylene (PP), polystyrene (PS), Polyethylene terephthalate (PET), and Acrylonitrile-butadiene-styrene (ABS).

To the Studies on Pollution of Under Ground Water Mau City

The study focuses on the environmental evaluation and classification of the Mau City area, located in the eastern part of Uttar Pradesh, India. The investigation covers an area of approximately 20 km2 and includes a diverse population in terms of socio- economic, cultural, and geographical characteristics. The population data reveals significant growth, with a population increase from 168,716 in 1991 to 2,205,968 in 2011. Animal populations, including cattle and poultry, have also shown an increasing trend from 2018 to 2020. Fertilizer usage data between 2017 and 2020 indicates fluctuations in the consumption of nitrogen, phosphorus, and potassium, demonstrating potential agricultural impacts on the environment. Water quality analysis is a major part of this study, employing various methods to determine salinity, dissolved oxygen, biological oxygen demand (BOD), and chemical oxygen demand (COD). Salinity was measured through titration with silver nitrate, while oxygen levels were analyzed using different methods, including dissolved oxygen (DO) analysis. Results indicate variations in water quality across different sampling sites (S1-S6), with key parameters such as pH, turbidity, temperature, and bacterial contamination being recorded monthly for the years 2019 and 2020.The research also involves the collection and analysis of water samples using various devices, including water samplers, bottom samplers, and biological samplers. Methods such as the EDTA method for water hardness, the gravimetric method for sulfate determination, and the colorimetric analysis for iron and chromium concentrations were utilized to evaluate the pollutants in the water. The study provides critical insights into water quality degradation, highlighting the presence of various pollutants, including nitrates, sulfates, and heavy metals like chromium, copper, and iron.

Groundwater Quality Prediction and Analysis Using Machine Learning Models and Geospatial Technology

The most prominent source of drinking water is groundwater, followed by lakes and reservoirs. Hydrological parameters like temperature, dissolved oxygen, pH, conductivity, ORP, and turbidity often change due to waste dumping into natural drinking water sources, particularly in densely populated areas. As a result, the water quality must be tested before public consumption to ensure healthy living in society. This research collected water samples from 129 wells in the Kanchipuram district in Tamil Nadu, India. An efficient integrated machine-learning-based prediction model has been proposed and modeled to determine the groundwater quality index (GQI). Several machine learning models were used to predict the water’s quality, including the naïve Bayes model, the KNN classifier, and the XGBoost classifier. Water quality predictions in 2024 were made using a combination of classification algorithms and models based on long short-term memory (LSTM) neural networks. The projected water quality characteristics were analyzed using geographical information system (GIS) technology to better understand and visualize the results. The XGBoost classifier model outperforms prior findings in the literature, with an accuracy of roughly 94.6%. The classification and prediction model was validated using collected and tested current data samples from a selected well. The findings were accurate within the 5% error range, promoting sustainability.

Lead (Pb) Accumulation in Water, Sediment and Distribution of Macro-Invertebrates in Delimi River, Jos, Nigeria

Background: This study assessed the concentrations of lead (Pb) in the water column and sediment as well as macro-invertebrates in River Delimi with a view to determining its ability to support aquatic life. Methodology: Water and sediment samples were collected simultaneously between August and November 2019 at designated stations: A (Abattoir), B (British America bridge), and C (Farin Gada bridge). Composite method was employed to collect water samples from different points in each station in 250 ml capacity plastic bottles with screw caps. The plastic bottles had previously washed with detergent and finally rinsed using distilled water. The water samples were filtered using 0.4 mm Whatman filter paper. Samples were then digested with few drops of concentrated nitric acid (HNO3). Sediment samples were collected in decontaminated airtight polythene bags measuring 500_g each. Sub-samples of the material were sun-dried for three (3) days and homogenized by grinding in laboratory mortar and pestle and sieved (aperture 125 µm). Sediment samples were digested with 20 cm3 aqua regia (3HCl:1HNO3), filtrate were stored in glass bottles and transported to the laboratory for chemical analyses. Macroinvertebrates were collected using a D-frame kick-net (30) at each site over a three-minute period. The collected specimens were preserved in 70% formalin and transported to the laboratory for sorting, identification, and enumeration. Result: Showed that the concentration of lead (Pb) in all the water samples were found to be less than the permissible limit set by WHO/FAO except site WA3 (0.0874ppm) and WC3 (0.0678 ppm) which were higher than the permissible limit. The concentration of lead (Pb) in sediment was higher than the WHO/FAO permissible limit in all sampling stations which is most likely to pose serious health risks to macrobenthos. Also, 7 Micro-invertebrate taxa were identified in the sampling stations. Chironomidae, Eristalis Larva (Syrphidae), Tabanidae and Whirligig beetle (Gyrinidae) comprised more than 79% of the total abundance while stone fly Larva, hydrophilidae and beetle larva constituted the remaining. Conclusion: water samples suggest potential environmental contamination of lead in some locations while sediment samples indicate a significant contamination with lead, posing potential health risks to organisms living in the sediment, including macrobenthos.

Mineral pollutants and coliform contamination in groundwater pose health risks to consumers: a spatiotemporal study in a mining-impacted area

The presence of mineral pollutants, combined with bacterial contamination, has significantly impacted groundwater quality and led to various health-related issues in mining-impacted areas. Therefore, we measured the concentration of fluoride (F-), phosphate (PO43-), sulphate (SO42-), ammonium (NH4+), nitrate (NO3-), the total coliforms (TCs), and physiochemical characteristics in groundwater samples of South Khorasan, Eastern Iran. For this, we collected water samples from 100 wells in spring and autumn across this mining-impacted area. We then measured the concentrations of mineral pollutants and assessed their associated health risks to children and adults using the Environmental Protection Agency (EPA) models and spatiotemporal zoning maps in ArcGIS. The concentrations of PO43-, NH4+, SO42-, NO3-, and F- were 0.70 ± 0.34, 0.82 ± 0.9, 175.45 ± 123, 15.26 ± 9.41, and 0.53 ± 0.68 mg/L in spring, and 0.71 ± 3.18, 4.68 ± 31, 306.72 ± 615.80, 19.30 ± 15.61, and 0.72 ± 0.65 mg/L in autumn, respectively. PO43-, NH4+, and SO42- exceeded both the World Health Organization (WHO) and EPA, but NO3- exceeded only EPA standards. TCs in both seasons exceeded the standards set by the EPA and WHO. The hazard quotient (HQ) values indicated non-carcinogenic risks for F⁻ and NO3⁻, while posing no risks NH4⁺ and PO43⁻ in both adults and children during autumn and spring.Hazard index (HI) was greater than 1 for all minerals in both children and adults in autumn and spring. No correlation was observed between mineral compounds and TCs in the study area, yet the water samples were highly contaminated by coliform with a significant risk to adults and children. In essence, both mineral pollutants and TCs potentially pose serious risks to human, and more efforts are required to improve the quality of water in this area.

Exploring Spatial Dynamics of Water Quality in a Tropical Lake Affected by Aquaculture

Lake Maninjau, like many surface water bodies worldwide, faces significant water pollution challenges due to extensive aquaculture activities, making it an ideal site to study the impact of fish farming on water quality, which has contributed to eutrophication and declining water quality. This study investigates the physicochemical parameters and pollution levels in the lake, aiming to provide insights into its environmental health. In August 2022, a comprehensive sampling campaign was undertaken at nine stations within the upper layers of open water and littoral zones of Lake Maninjau. In situ measurements, including temperature, dissolved oxygen, and pH, were conducted, accompanied by water sample collection for laboratory analysis of trace elements and heavy metals. Our study revealed notable variability in water parameters across different sites, with surface water layers exhibiting the greatest differences. While certain parameters such as temperature and conductivity remain relatively stable, pH levels show a decreasing trend with increasing water depth. Dissolved oxygen levels vary widely, while oxidation–reduction potential indicates water pollution, particularly in littoral zones. Potassium dominance within cations likely suggests anthropogenic influences, notably from aquaculture activities, that may also contribute to nutrient enrichment and heavy metal pollution. Elevated levels of total nitrogen and ammonia underscore the lake’s moderate pollution levels, with heavy metals such as mercury exceeding permissible limits, posing risks to aquatic life and human health.

Mining and urbanization affect river chemical water quality and macroinvertebrate communities in the upper Selenga River basin, Mongolia (revised version)

Mongolia is a country with a quickly growing economy mainly based on the mining of gold, copper, coal, and other minerals. Mining, urbanization, and agriculture impact the water quality in the upper Selenga River basin in northern Mongolia, which is the center of the Mongolian economy. Previous measurements of pollution loads were alarming, but restricted to chemical measurements. Here, for the first time, we combine freshwater biomonitoring and laboratory water quality data across a broad gradient of water quality and land use intensity. We track the effects of different types of pollution on aquatic invertebrates and test their use as bioindicators. We collected water samples, environmental parameters, and macroinvertebrates at 36 sampling sites at the rivers of Tuul, Kharaa, and Orkhon and their tributaries Sugnugur, Boroo, Sharyn Gol, Gatsuurt, and Yeröö. PCA of catchment water quality distinguished three groups of pollutants prevalent at the sites, (1) nutrients, (2) salt ions (Cl−, Na+, Mg2+, So42−, Ca2+) and mining by-products (B, Sr, U, Mo), and (3) (heavy) metals, which often exceeded regulatory standards. We recorded a total of 59 macroinvertebrate taxa belonging to 31 families in seven insect orders plus Amphipoda and Gastropoda. Species diversity declined with higher impact. Five environmental factors structured macroinvertebrate community composition in RDA: elevation of sample location, site total nitrogen, dissolved oxygen, electrical conductivity, and water chemistry. We conclude that macroinvertebrate communities are an appropriate and inexpensive tool for monitoring water quality in Mongolia and suggest government action to establish a long-term monitoring program.

Automated pretreatment of environmental water samples and non-targeted intelligent screening of organic compounds based on machine experiments

The complexity of environmental pollutants poses significant challenges for monitoring and analysis, especially with the emergence of numerous emerging contaminants. Traditional analysis methods rely mainly on laboratory analysis, which involves labor-intensive and time-consuming sample preparation procedures and non-target data analysis, greatly limiting the rapid detection of water organic pollutants. In this study, we designed a robot experimenter combined with GC × GC-TOFMS. By configuring self-developed automated analysis software, we established a fully automated process from sample collection to data characterization, for the analysis of organic pollutants. We validated the method with 111 organic standards compounds. The robot performed 2577 actions covering the entire workflow, from water sample collection to sample pre-treatment. The integration of mass spectrometry and related software enabled the automatic analysis of emerging hazardous contaminants, from sampling to the output of detection results. The results showed the automated process could qualitatively identify all compounds and demonstrated good linearity, low detection limits, and excellent quantitative ability within the range of 0.04–0.4 mg/L. The average recoveries of 82.89 % of the samples ranged from 70 % to 120 % (relative standard deviation (RSD) <15 %) at different spiked concentrations. This indicated that the established method could be used for non-targeted analysis of emerging contaminants in environmental water samples. We applied the method to samples from wastewater treatment plants and river sections, identifying 1,902 compounds across 26 categories, including 6 known hazardous contaminants found in all samples. The relative content of these characteristic compounds will inform whether treated wastewater meets discharge standards and aid in tracing the sources of pollutants. Therefore, the development of this fully automated machine experimental method enables real-time and online automatic analysis of organic pollutants in environmental water. The establishment of characteristic fingerprints can provide technical support for early warning and traceability of water quality.

Evaluation of physico-chemical quality and occurrence of Salmonella in water from food retail outlets

Salmonella is one among the most important biological contaminants in drinking water that possess safety hazards to human life. Faecal contamination of the water, indirectly from the household sewage discharge, municipal sewage etc. attributes to the repeated detection of Salmonella in water. This study aimed to investigate the occurrence of Salmonella and physico- chemical quality evaluation of samples of water collected from food retail outlets of Thrissur and Kollam districts. A total of 50 water samples (25 each from Thrissur and Kollam districts) used for cooking purpose were collected over a period of six months, March to August 2023. Water samples were subjected to comparative evaluation of physico-chemical qualities viz., pH, turbidity, total dissolved solids (TDS) and hardness. Collected water samples were examined for Salmonella spp. by conventional culture method and PCR. Genus specific and virulence genes of the isolates were detected using polymerase chain reaction. The occurrence of Salmonella spp. in samples of water collected from Thrissur was 24 per cent whereas in Kollam district it was only four per cent. The overall occurrence of Salmonella spp. in samples of water collected from both districts was 14 per cent. Physico-chemical parameters of water samples viz., pH, turbidity, total dissolved solids and hardness were within the BIS prescribed standards. The molecular characterisation of Salmonella spp. detected 16S rRNA in all isolates but invA and spvA genes were detected only in 14.28 per cent of the isolates. Hence proper disinfection of water and food sanitation in the retail outlets will help to minimize the risk of foodborne pathogens Keywords: Salmonella, water, physico-chemical quality, food retail outlets

Are you filtering enough? Unveiling the impact of water sample volumes on eukaryotic microbial community in freshwater lakes

The appropriate volume of filtered water samples is crucial for accurately reflecting microbial community characteristics. Previous research has shown that changes in water sample volumes significantly affect bacterial diversity and the relative abundance of dominant taxa in marine environments. However, the specific impact on freshwater microbial diversity and community structure, particularly for eukaryotic microorganisms, remains unclear. To address this gap, we collected water samples from eutrophic Lake Taihu and mesotrophic Lake Bosten. We filtered the samples through 0.2 μm filters using volumes ranging from 0.1 to 2 L for Lake Taihu and 0.1 to 3.2 L for Lake Bosten. Analysis of 18S rRNA gene amplicons revealed that variations in filtered water sample volume significantly affected the diversity, community structure, and composition of eukaryotic microorganisms. In light of these findings, we recommend using a filtered water sample volume of approximately 0.2 L for eutrophic aquatic ecosystems and 0.8 L for mesotrophic aquatic ecosystems in microbial analyses. These recommendations underscore the importance of selecting the appropriate filtered water sample volume to ensure representative and reliable results in the study of eukaryotic microorganisms in freshwater ecosystems.

Analysis of the physico-chemical relationship between losses of water, soil and soil nutrients in the water of the Farinha River – MA

Brazil has a vast reserve of water resources, but pollution from various sources and the effects of climate change have triggered a crisis in this sector. The as-sessment of water quality indices plays a crucial role in monitoring and unders-tanding this issue, and the country has established its own standards and moni-toring requirements to guarantee water quality. In addition, the physical-chemical relationship plays a fundamental role in the conservation of both soil and water. In this context, a study was carried out in the Farinha river basin, located in Maranhão, in the Cerrado biome, over an area of 55,338.12 hecta-res. Data was collected at ten different points along the river during the rainy and dry seasons. A Van Dorn bottle was used to collect water samples at vari-ous depths, which were analysed for pH, dissolved oxygen, electrical conducti-vity and temperature. Nutrients such as potassium, calcium, magnesium, sodi-um, silicon, nitrate and total phosphorus were quantified using filtration and spectroscopy techniques. The data obtained was tabulated and subjected to analysis of variance, with the means analysed using the Tukey test. This study reveals significant seasonal variations in the physico-chemical parameters of the water in the Farinha River in Maranhão, impacting aquatic life and water quality. This highlights the importance of continuous monitoring and manage-ment of these resources.

Study Quality on Groundwater Consumtion for Households at Economic Development Zone, Saythany District, Vientiane Capital

Water is an important factor for economic-social development, which many countries in the world give importance to the drinking water supply of the people. Drilling underground water to bring water to various activities of households and small business units are many and have a tendency to increase in the future. This study aims to evaluate the quality of underground water by collecting water samples in both seasons at 10 points, 4 of which were analyzed in the field and 12 of which were analyzed in the laboratory. The results of the study found that: in the dry season, the (pH: Potential of Hydrogen Ion) value at points 1, 2, 5-7, 9 and 10 is lower than the standard threshold. (EC: Electrical Conductivity), (TDS: Total Dissolved Solids), Salinity, (TSS: Total Suspended Solids), Turbidity, (NH4-N: Ammonium), (Cl- Chloride), (NO3-N: Nitrate), (As: Arsenic), (Mn: Manganese), (Zn: Zinc), (T-H: Total Hardness as CaCO3), (Fe: Iron) and (F-: Fluoride) all 10 points are within the national environmental standards; (Coliform Bacteria) values ​​at points values ​​at points (2, 4-6 and 8-10) exceed the standard. In the rainy season, the (pH: Potential of Hydrogen Ion) value at point 6 lowers the standard threshold. Salinity, (TSS: Total Suspended Solids), Turbidity, (NH4-N: Ammonium), (NO3-N: Nitrate), (As: Arsenic), (Mn: Manganese), (Zn: Zinc), (Fe: Iron) and (F-: Fluoride) which are within the standard range; In which (Coliform Bacteria) all 10 points and (T-H: Total Hardness as CaCO3), (EC: Electrical Conductivity), (TDS: Total Dissolved Solids), (Cl- Chloride) in the 8th point have high values ​​beyond the national environmental standards.

Research Regarding the Autochthonous Dissolved Organic Carbon to Recalcitrant Dissolved Organic Carbon Transformation Mechanism in a Typical Surface Karst River

Autochthonic recalcitrant organic carbon is the most stable component in karst aquatic systems. Still, the processes of its generation and transformation remain unclear, which hinders the study of the mechanisms and quantitative calculations of carbon sinks in karst aquatic systems. This study collected water samples from the Li River, a typical surface karst river in Southwest China. Through in situ microbial cultivation and the chromophoric dissolved organic matter (CDOM) spectrum, changes in organic carbon components and their contents during the transformation of autochthonic dissolved organic carbon (Auto-DOC) to autochthonic dissolved recalcitrant organic carbon (Auto-RDOC) were analyzed to investigate the inert transformation processes of endogenous organic carbon. This study found that microbial carbon pumps (MCPs) promote the tyrosine-like component condensed into microbial-derived fulvic and humic components via heterotrophic bacteria metabolism, forming Auto-RDOC. During the dry season, the high level of Auto-DOC provides abundant organic substrates for heterotrophic bacteria, resulting in significantly higher Auto-RDOC production compared to the rainy season. This study provides fundamental information on the formation mechanisms of Auto-DOC in karst aquatic systems, which contributes to the assessment of carbon sinks in karst aquatic systems.

Revealing the impact of sample enrichment method on concentration and cytotoxicity of volatile disinfection byproducts in drinking water: A quantitative study for liquid-liquid extraction

Liquid-liquid extraction (LLE) combined with the N2 blow-down method is a promising tool for bioanalysis of drinking water. However, detailed information on which disinfection byproduct (DBP) classes are retained in LLE extracts is currently unavailable. In this study, the recovery of seven classes of volatile DBPs and total adsorbable organic halogens (TOX) during the LLE method, combined with three common N2 blow-down methods, for bioanalysis in real tap water was analyzed at a 2-L scale, along with their corresponding cytotoxicity. The total concentration of seven classes of volatile DBPs in drinking water in Suzhou ranged from 64.6 to 83.0 µg/L, with the majority contributed by trihalomethanes (THMs: 59.9 µg/L), haloaldehydes (HALs: 5.4 µg/L), haloacetamides (HAMs: 3.4 µg/L), and haloacetonitriles (HANs: 3.2 µg/L). During the LLE - N2 blow-down process for bioanalysis, about 69–85 % of targeted volatile DBPs and 64–75 % of TOX were lost, respectively. Seven classes of volatile DBPs accounted for 52.8–64.3 % and 23.8–61.3 % of TOX in tap water and LLE - N2 blow-down samples, respectively, suggesting that targeted aliphatic DBPs are the key contributors to TOX. Furthermore, although LLE - solvent exchange had a better recovery performance than other N2 blow-down methods, the recoveries of volatile DBPs using this method were still not ideal. For example, HALs and HAMs had a slightly better recovery (>50 %), while most volatile DBPs had a poor recovery, including iodo-trihalomethanes (I-THMs, 0 %), haloketones (28 %), THMs (26 %), halonitromethanes (33 %), and HANs (38 %). During LLE - solvent exchange, 31 % and 36 % of targeted DBPs and TOX, respectively, in real tap water can be retained, which shows better performance than non-ionic macroporous copolymers (XAD). More importantly, the water volume required in this method for cytotoxicity analysis is 2 L, which greatly reduces the burden of water sample collection, transport, and pre-treatment compared to XAD (which typically requires 5 or 10 L). In general, this paper reveals the fate of volatile DBPs during LLE - N2 blow-down and indicates that LLE - solvent exchange is a good substitute for the XAD method in bioanalysis.

Assessment of groundwater suitability using water quality index and health risk analysis in upper catchment area of Kangsabati river, India

In the upper catchment area of the Kangsabati river basin, local people are highly dependent on groundwater for drinking purpose. The objectives of the present study are to assess the status of groundwater quality in this area and to examine the appropriateness of groundwater resource for drinking purpose in this region based on geochemical analysis. In this study, 20 sites have been selected to collect water samples from the four Community Development (CD) blocks under the study area amid the pre- and post-monsoon seasons during 2018, 2019, and 2020. A total of 13 hydro-chemical parameters have been selected to examine the groundwater quality status. In this study, the Water Quality Index (WQI) and Health Risk Analysis (HRA) have been applied to examine the health of groundwater resources and assess the non-carcinogenic risk to human health through the intake of fluoride-contaminated drinking water individually. The result reflects that the concentration of the selective hydro-chemical parameters has been accentuated from 2018 to 2020. The concentration of a few parameters like TH, Mg2+, K+, NO3–, and HCO3– has exceeded the desirable limit as per BIS guidelines. According to the WQI analysis, maximum groundwater samples (total of 12 samples) are categorized as poor, very poor, and not suitable for drinking purpose category. The outcomes of the HRA analysis reflect that local women are more vulnerable to the threats of fluoride contamination compared with male and children. The toxic agricultural and domestic effluents are considered vital factors in case of groundwater health deterioration in the study area.