Water Samples Research Articles

Vortex-assisted dispersive low-density liquid–liquid microextraction of xanthydrol derivatized acrylamide in processed chips and water samples for gas chromatographic analysis

Acrylamide, a probable human carcinogen present in heat-processed foods and environmental contaminants, requires sample extraction and preconcentration before chromatographic analysis. The method developed in this study employed derivatization with xanthydrol and dispersive liquid–liquid microextraction utilizing low-density anisole. Durian or potato chips were combined with deionized water, defatted with hexane, and subjected to precipitation of soluble carbohydrates and proteins using clarification reagents. Water samples were filtered through a membrane filter. Acrylamide was derivatized by introducing an acidic methanolic solution of xanthydrol at 50 °C. The derivatized acrylamide was extracted with 70 µL of anisole and vortexed, with the methanol from the xanthydrol solution serving as the disperser solvent. The anisole layer was analyzed using gas chromatography with both flame ionization and mass spectrometric detection. Linear calibration plots exhibited coefficients of determination >0.9997. The precision was measured at <10% RSD, and recoveries ranged from 84% to 107%. The quantitation limit varied from 2 to 10 µg kg−1 for processed chips and from 0.05 to 0.10 µg L−1 for water samples. Acrylamide was detected in all processed chip samples, with some concentrations exceeding the benchmark value of 750 μg kg−1. However, no acrylamide was identified in any of the water samples.

Assessing suitability of surface water from Oued El Gourzi for irrigation east of Alger

The study was conducted to determine the suitability of surface water from Oued El Gourzi for irrigation in the Fesdis area, Algeria, during irrigation season of July 2022. The suitability was assessed by analysing eight water samples collected from various sites along the Oued. A range of physicochemical parameters were examined, including EC, pH, Mg2+, Na+, Ca2+, K+, HCO3– and Cl–, alongside other indices such as sodium absorption ratio (SAR), soluble sodium percentage (SSP), residual sodium carbonate (RSC), permeability index (PI) and magnesium adsorption ratio (MAR) using standard procedures. The Richards classification shows that these waters are characterised by high salinity and low alkalinity hazard (C3–S1). According to the Wilcox classification, the majority of these waters are of doubtful quality, with only 25% exhibiting good quality for irrigation. Based on the RSC and MAR, all water samples are deemed safe and suitable for irrigation. However, PI values suggest that all sampling sites are of marginal quality for irrigation (class II). In terms of sodium and chloride concentration, all water samples were deemed unsuitable for irrigation. Based on these results, the waters pose risks for irrigation, particularly due to salinity, necessitating the implementation of special management practices and the selection of salt-tolerant crops.

Relationships between fecal indicator abundance in water and sand and the presence of pathogenic genes in sand of recreational beaches.

For decades, the risk of exposure to infectious diseases in recreational beaches has been evaluated through the quantification of fecal indicator bacteria in water samples using culture methods. The analyses of sand samples have recently been developed as a complement to the monitoring of recreational waters in beach quality assessments. The growing use of molecular techniques for environmental monitoring allows for the rapid detection of pathogenic genes, thus providing more accurate information regarding the health risk of exposure to contaminated sand. The aim of this work was to determine the relationship between the fecal indicators abundance in water and sand and the presence of Shiga toxin-producer Escherichia coli (STEC) in sand by analyzing samples from touristic beaches using culture-dependent (fecal coliforms assay) and culture-independent (real-time PCR of stx1, stx2, and eae genes) techniques. We found a high concentration of coliform bacteria in water and sand in several beaches in eastern Uruguay, with different levels of sanitation networks and levels of urbanization. The presence of STEC virulence genes (mainly stx1) was confirmed in 8 out of 20 sand samples. The recreational use of sandy beaches may imply a risk to the health of its users, especially near streams and creek outflows, thus highlighting the need of monitoring sand bacteriological quality and pathogens using molecular tools.

Selective Chromogenic Chemosensors for Arsenite Anion: A Facile Approach to Analyzing Arsenite in Honey, Milk, and Water Samples.

In this study, two chemosensors, N5R1 and N5R2, based on 5-(4-nitrophenyl)-2-furaldehyde, with varying electron-withdrawing groups, were synthesized and effectively employed for the colorimetric selective detection of arsenite anions in a DMSO/H2O solvent mixture (8 : 2, v/v). Chemosensors N5R1 and N5R2 exhibited a distinct color change upon binding with arsenite, accompanied by a spectral shift toward the near-infrared region (Δλmax exceeding 200 nm). These chemosensors established stability between a pH range 6-12. Among them, N5R2 displayed the lowest detection limit of 17.63 ppb with a high binding constant of 2.6163×105 M-1 for arsenite. The binding mechanism involved initial hydrogen bonding between the NH binding site and the arsenite anion, followed by deprotonation and an intramolecular charge transfer (ICT) mechanism. The mechanism was confirmed through UV and 1H NMR titrations, cyclic voltammetric studies, and theoretical calculations. The interactions between the sensor and arsenite anions were further analyzed using global reactivity parameters (GRPs). Practical applications were demonstrated through the utilization of test strips and molecular logic gates. Real water samples, honey, and milk samples were successfully analyzed by both chemosensors for the sensing of arsenite.

Seasonal Rise in the Contents of Microcystin-LR and Odorous Substances Due to Cyanobacterial Blooms in a Drinking Water Reservoir Supplying Xinyang City, China.

Cyanobacterial blooms have become a serious water pollution problem in many parts of the world, and the monitoring and study of the impacts of biotoxins on human health are of vital importance. In this study, the contents of microcystin-LR, 2-methylisoborneol, and geosmin were measured in water and sediment samples from Nanwan Reservoir, China, by means of bimonthly sampling between February and December 2023. The physicochemical and hydrochemical factors and phytoplankton dynamics in the reservoir were also investigated. The results showed that the overall mean concentration of microcystin-LR (0.729 μg/L) in summer approached the guiding standard (1 μg/L) set by the WHO for drinking water. Furthermore, the content of 2-methylisoborneol (143.5 ng/L) was 14 times higher than the national standard (10 ng/L). The results of laboratory cultures showed that lower light levels and medium temperatures were suitable for the growth of Microcystis and Planktothricoides but higher temperatures promoted the synthesis and release of microcystin-LR and 2-methylisoborneol. In addition, the results of co-cultures showed that the growth of Planktothricoides was inhibited by Microcystis. Our results suggest that cyanobacterial bloom and the presence of the metabolites 2-methylisoborneol and microcystin-LR can decrease the drinking water quality of Nanwan Reservoir.

Source apportionment and influencing factors of surface water pollution through a combination of multiple receptor models and geodetector

In line with sustainable development goals (SDGs), precise quantification of water pollution and analysis of environmental interactions are crucial for effectively safeguarding water resources. In this study, Nemerow's pollution index was used to evaluate water quality, three receptor models were used to identify pollution sources, and Geodetector analysis was applied to explore environmental interactions in the North Shangyu Plain, Southeast China. Using 5207 surface water samples from September 2023 with 11 physicochemical parameters, the results showed that surface rivers in the North Shangyu Plain exhibited varying degrees of pollution: slight pollution upstream, moderate pollution in midstream and downstream, and concentrated high pollution in certain areas, with TN, CODCr, and TP as the primary pollutants. Multimethod source apportionment significantly improved the accuracy of pollution source attribution and identified five main sources: domestic sewage (1.42%–3.54%) characterized by NO3-N, phytoplankton source (38.43%–50.05%) indicated by chl and PC, agricultural cultivation (16.1%–17.63%) marked by TP and CODMn, industrial wastewater (17.64%–25.1%) primarily associated with TN, and natural source (10.32%–13.26%) characterized by DO, NH3-N, and CODCr. Influencing factor analysis validated the source identification. Natural factors had minor impacts on water parameters, while pollution control from agricultural activities was suggested to diversify fertilizer types rather than merely reduce quantities. The combined effects of industrial and aquaculture activities intensified pollution from TN, chl, and PC, underscoring the need for targeted management practices. This study showed the objectivity and reliability of using a combined approach of multiple receptor models and Geodetector to evaluate the river water quality status, which helps assist decision-makers in formulating more effective water resource protection strategies.

Phytoplankton community structure in Tunda Island waters, Banten Indonesia as a bioindicator to measure water quality

Mining of sea sand in the water area of Tunda Island can result in changes in the quality of the aquatic environment. Phytoplankton may indicate changes due to their rapid reaction to external influences in water. This study aims to determine the water quality condition in Tunda Island waters using phytoplankton communities. The sample collection included 20 observation stations in Tunda Island waters, Banten province. The analyzed water samples had parameters of depth, temperature, pH, dissolved oxygen, total dissolved solids, salinity, nitrates, and phytoplankton communities. The results obtained by several quality water parameters still meet the quality standards except for nitrates. The composition of phytoplankton consists of 3 classes: Cyanophyceae, Bacillariophyceae, and Dinophyceae. Eight phytoplankton genera of the Bacillariophyceae class dominated during observation: Bacteriastrum sp., Chaetoceros sp., Hemiaulus sp., Lauderia sp., Nitzschia sp., Rhizosolenia sp., Skeletonema sp., Thalassiosira sp., and Thalassiotrix sp. The phytoplankton biological index describes the phytoplankton diversity index as moderate diversity, phytoplankton evenness is classified as unstable communities, and phytoplankton dominance is at a moderate condition. Variations within a phytoplankton group can reflect seasonal dynamics and the impact of changes in the aquatic environment.

Mandarin Peels-Derived Carbon Dots: A Multifaceted Fluorescent Probe for Cu(II) Detection in Tap and Drinking Water Samples.

Carbon dots (CDs) derived from mandarin peel biochar (MBC) at different pyrolysis temperatures (200, 400, 600, and 800 °C) have been synthesized and characterized. This high-value transformation of waste materials into fluorescent nanoprobes for environmental monitoring represents a step forward towards a circular economy. In this itinerary, CDs produced via one-pot hydrothermal synthesis were utilized for the detection of copper (II) ions. The study looked at the spectroscopic features of biochar-derived CDs. The selectivity of CDs obtained from biochar following carbonization at 400 °C (MBC400-CDs towards various heavy metal ions resulted in considerable fluorescence quenching with copper (II) ions, showcasing their potential as selective detectors. Transmission electron microscopic (TEM) analysis validated the MBC-CDs' consistent spherical shape, with a particle size of <3 nm. The Plackett-Burman Design (PBD) was used to study three elements that influence the F0/F ratio, with the best ratio obtained with a pH of 10, for 10 min, and an aqueous reaction medium. Cu (II) was detected over a dynamic range of 4.9-197.5 μM and limit of detection (LOD) of 0.01 μM. Validation testing proved the accuracy and precision for evaluating tap and mountain waters with great selectivity and no interference from coexisting metal ions.

Utilizing Iron Oxidizing Bacteria (IOB) in the Bio-remediation of Subsurface Drinking Water from Haridwar, Uttarakhand, India

Background and Aim: Iron-oxidizing bacteria (IOB) are harmless, chemotrophic organisms that use oxygen to dissolve iron in wastewater contaminated with heavy metals. They thrive in water with iron concentrations as low as 0.1 mg/L, offering a cost-effective, eco-friendly solution for water treatment. In Uttarakhand, widespread iron contamination continues to limit access to safe drinking water despite efforts to address the issue. This study aimed to explore the use of bioremediation and microbial consortia to reduce and eliminate iron contamination in drinking water sources. Methods: The study employed a biosorption process, where the iron-oxidizing bacteria and microbial consortia were immobilized on a solid carrier (coarser sand) to facilitate contact with the contaminated water. The bacteria and consortia adsorbed iron ions from the water onto the surface of the carrier material through various mechanisms, including ion exchange, chelation, and surface complexation. The biosorption experiments were conducted in a batch mode, where the contaminated water was mixed with the carrier material containing the microbial consortium. The mixture was agitated under controlled conditions to promote iron removal. Results: The study assessed the iron removal efficiency of various carriers (gravel, sand, coarse sand, bentonite, and lignite) and iron-oxidizing bacteria (IOB-1 to IOB-6) from 100 water samples collected in Uttarakhand. The key findings are: Carrier Performance: Coarse sand consistently demonstrated the highest iron removal efficiency among all carriers, with an average removal rate of 84.67% ± 0.02%. Microbial Isolate Performance: Among the IOB strains, IOB-1 exhibited the best iron removal efficiency, achieving an average of 46.67% ± 0.08%. Microbial Consortium: The microbial consortium formed using IOB-1 in combination with coarse sand achieved the highest overall iron removal efficiency of 89.33% ± 0.05. These results underscore the effectiveness of bioremediation techniques, particularly using microbial consortia, for addressing iron contamination in water resources. Discussion: The present study demonstrates the efficacy of bioremediation techniques, specifically utilizing iron-oxidizing bacteria and microbial consortia, in addressing iron contamination in water resources. The results indicate that the selected carriers, particularly coarse sand, and the microbial isolate IOB-1 exhibited significant potential for iron removal. Conclusion: The combination of iron-oxidizing bacteria and suitable carriers offers a promising approach for water treatment in regions affected by iron pollution. The microbial consortia entrapped in coarse sand demonstrated superior performance compared to individual strains, suggesting the synergistic effects of microbial interactions.

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

Simultaneous and High-Throughput Analytical Strategy of 30 Fluorinated Emerging Pollutants Using UHPLC-MS/MS in the Shrimp Aquaculture System.

This study established novel and high-throughput strategies for the simultaneous analysis of 30 fluorinated emerging pollutants in different matrices from the shrimp aquaculture system in eastern China using UHPLC-MS/MS. The parameters of SPE for analysis of water samples and of QuEChERS methods for sediment and shrimp samples were optimized to allow the simultaneous detection and quantitation of 17 per- and polyfluoroalkyl substances (PFASs) and 13 fluoroquinolones (FQs). Under the optimal conditions, the limits of detection of 30 pollutants for water, sediment, and shrimp samples were 0.01-0.30 ng/L, 0.01-0.22 μg/kg, and 0.01-0.23 μg/kg, respectively, while the limits of quantification were 0.04-1.00 ng/L, 0.03-0.73 μg/kg, and 0.03-0.76 μg/kg, with satisfactory recoveries and intra-day precision. The developed methods were successfully applied to the analysis of multiple samples collected from aquaculture ponds in eastern China. PFASs were detected in all samples with concentration ranges of 0.18-0.77 μg/L in water, 0.13-1.41 μg/kg (dry weight) in sediment, and 0.09-0.96 μg/kg (wet weight) in shrimp, respectively. Only two FQs, ciprofloxacin and enrofloxacin, were found in the sediment and shrimp. In general, this study provides valuable insights into the prevalence of fluorinated emerging contaminants, assisting in the monitoring and control of emerging contaminants in aquatic foods.

Preparation of grafted starch‐based cationic flocculants and its removal of reactive and disperse dyes

AbstractIn this paper, a starch‐based flocculant (ADSt) with medium and low temperature solubility and enhanced flocculation effect was synthesized using corn starch, acrylamide, and dimethyldiallyl ammonium chloride as main materials by the ethanol‐alkali method and grafting method. The main mechanism of ADSt's flocculation was electrical neutralization and bridging. The flocculation performance of ADSt was verified by using it along with polymeric aluminum chloride (PAC) as coagulant/flocculant, dispersible dye (dispersible yellow RGFL), and reactive dye (active trimeric blue KN‐G) to simulate dye wastewater. For the dispersed yellow water sample and active emerald blue water sample, the dosage of PAC was 40 and 35 mg/L respectively. When the dosage of ADSt was 10 mg/L with a dye content of 100 mg/L, the decolorization rates for both dyes reached up to 96.2% and 94.4% respectively. The properties of the flocs such as size and two‐dimensional fractal structure were described. The prepared ADSt maintained a good flocculation effect in the pH range of 5–9 due to its excellent water solubility achieved through the ethanol‐alkali preparation process, where its solubility reached 86.7% at 30°C. Overall, the preparation process for ADSt is simple, cost‐effective, while providing an effective solution for treating printing and dyeing wastewater.

Legionella in Primary School Hot Water Systems from Two Municipalities in the Danish Capital Region.

Legionella contamination in public water systems poses significant health risks, particularly in schools where vulnerable populations, including children, regularly use these facilities. This study investigates the presence of Legionella in the hot water systems from 49 primary schools across two municipalities in the Danish capital region. Water samples were collected from taps in each school, and both first-flush and stabile temperature samples were analysed for Legionella contents. The findings revealed that 97% of schools in Municipality 1 and 100% in Municipality 2 had Legionella in their hot water systems. The content of Legionella colonies was significantly higher in schools in Municipality 1, which was probably because of overall lower water temperatures. At stabile temperatures, 76% and 50% of the schools in the two municipalities exceeded the European Union's recommended limit of 1000 CFU/L. Stabile peripheral water temperatures were achieved after 3 min. Tap water temperatures above 54 °C and central tank temperatures above 59 °C were associated with Legionella contents below 1000 CFU/L. This study highlights the need for more stringent Legionella control procedures in schools, including higher water temperatures and refining Legionella reducing interventions with the addition of regular flow and draining procedures.

Simultaneous treatment and enrichment of total phosphorus from livestock sewage using hydrate technology

The presence of phosphorus in livestock sewage is a key factor that causes eutrophication and the degradation of ecological water quality. Cyclopentane (CP) hydrate-based water treatment technique was utilized for the efficient total removal of phosphorus in effluents. This study assesses the treatment effectiveness and enrichment potential of hydrate technology when applied to real-world samples, specifically livestock wastewater. The treatment process was applied under atmospheric pressure and optimized appropriate conditions comprising the CP-to-sample volume ratio of 1:4, reaction duration of 3 h, and temperature of 2 °C because of the high subcooling and ability to enhance the number of hydrate crystals formed along with water. In addition, various methods, such as vacuum filtration, cold centrifugation, and washing, were employed for the effective and comprehensive removal of phosphorus from water samples with the efficiency exhibited from approximately 30 % to 80 %. The structure and composition of the CPHs formed in wastewater were analyzed via Raman spectroscopy and the phosphorus content was determined according to ISO 6878:2004. After a single-stage hydrate process without pretreatment and posttreatment, the water recovered from the extracted hydrates showed that the phosphorus removal efficiency in livestock sewage was approximately 85 % with a remarkable water recovery above 25 %. The study findings provide insights into the development of hydrate-based treatment technology for the removal of phosphorus and explore opportunities for resource enrichment and recovery from sewage.

Department-specific patterns of bacterial communities and antibiotic resistance in hospital indoor environments

The hospital indoor environment has a crucial impact on the microbial exposures that humans encounter. Resistance to antibiotics is a mechanism used by bacteria to develop resilience in indoor environments, and the widespread use of antibiotics has led to changes in the ecological function of resistance genes and their acquisition by pathogens. By integrating the 16S rRNA Illumina sequencing and high-throughput-quantitative PCR approaches with water and air dust samples across seven departments in Peking University Shenzhen Hospital, China, this study yields intriguing findings regarding the department-specific variations, correlations and source tracing of bacteria, antibiotic resistance genes (ARGs) and mobile genetic elements (MGEs) within the hospital indoor environment. A notable observation was the pivotal role played by seasonal variations in shaping the bacterial composition across the entire hospital indoor environment. Another department-specific finding was the correlation between ARGs and MGEs abundance, which was evident in the overall hospital indoor environment, but not found in the blood test room, ophthalmology, and gynecology departments. Notably, as an important source of bacteria and ARGs/MGEs for the blood test room, the gynecology department also presented a close link between bacterial communities and the presence of ARGs/MGEs. Additionally, the results reiterate the importance of surveillance and monitoring of antibiotic resistance, specifically in Legionella spp. in man-made water systems, and highlight the significance of understanding genetic elements like Tp614 involved in gene transfer and recombination, and their impact on antimicrobial treatment efficacy. Key points•The department-specific variations, correlations and source tracing of bacteria, ARGs, and MGEs were uncovered in the hospital’s indoor environment.•Although each department exhibited consistent seasonal impacts on bacterial compositions, the co-occurrence between the presence of ARGs and MGEs was exclusively evident in the emergency, surgery, pneumology and otolaryngology departments.•The gynecology department emerged as a crucial source of bacteria, ARGs and MGEs within the hospital. Additionally, it was found to exhibit a significant correlation between bacterial communities and the presence of ARGs and MGEs.

Hydrochemical variation characteristics and driving factors of surface water in arid Areas—a case study of Beichuan River in Northwest China

Examining the chemical properties of river water and the controlling factors is crucial for devising efficacious strategies in water resources management and ecological conservation. This study investigates the hydrochemical characteristics and driving factors of the Beichuan River in the arid region of Northwest China. Surface water samples were collected during wet and dry seasons, and analyzed using hydrochemical diagrams, mathematical statistics, and principal component analysis (PCA). The results show that the pH value of Beichuan River is generally weakly alkaline, the main hydrochemical types are HCO3-Ca, and the average TDS are 224 mg/L and 236 mg/L respectively, which are higher than the world average level (115 mg/L). The seasonal variation of hydrochemical components is mainly controlled by rainfall, showing that the concentrations of Na+, Cl− and NO3− in the wet season are higher than those in the dry season, while the concentrations of other chemical components show an opposite trend, while the spatial variation is mainly controlled by human activities, and the concentrations of hydrochemical components show a gradual increasing trend from upstream to downstream, especially Na+, Mg2+, Cl− and NO3−. Rock weathering is the key natural factor controlling the Hydrochemical Composition of Beichuan River. Na+ and Cl− are mainly from the dissolution of silicate, Ca2+ and Mg2+ are mainly from the weathering of carbonate rocks and silicate, and SO42- is mainly from the dissolution of evaporite. It is noted that human activities, especially domestic sewage and agricultural runoff, contribute significantly to NO3− in the water body. PCA identified rock weathering and agricultural runoff as major wet-season factors, while domestic sewage predominantly affects the dry season. This study can provide a scientific basis for the rational development of water resources and ecological environment protection in arid areas.

Application of Sentinel-2 imagery for total suspended solids mapping off the Bodri River, Kendal Regency, Indonesia

Total suspended solids (TSS) is one of the key parameters in water quality monitoring. TSS dynamics off the seas of Bodri River can be observed using Sentinel-2. This research validates Wirasatriya and Laili's algorithm and redevelops a TSS retrieval algorithm based on in situ TSS and Sentinel-2 reflectance (Rrs). During the satellite's passing time, water sampling for TSS was conducted at 64 stations at a depth of 0.5m in October 2023. Bottom of Atmosphere (BoA) Rrs data were obtained from SNAP software, which had previously performed image cropping and resampling. Rrs data from all bands were initially correlated with in situ TSS. The validation results of Wirasatriya and Laili's algorithms obtained very high of RMSE values reaching 272.23 mg/L and 33.08 mg//L. While the results of generating the algorithm produced better the performance of the algorithmic model with RMSE = 7.34 mg/L, MAPE = 14.24%, and bias = 0.99. The development of the algorithms in the study based on the green band (B3) resulted in the equation: TSS (mg/L) = 4.6698exp10.609∗B3, which was further used for temporal mapping. High TSS was found in nearshore areas and river mouths influenced by shallow waters. Temporally, high TSS was found in October (55.65 mg/L) and low in May (11 mg/L). The temporal variation pattern is influenced by precipitation and tides. The findings of this algorithm are very important for analyzing the evolution of land accretion in the Bodri River estuary and as a review for land management in upland areas and can be used to monitor other shallow areas.

Laboratory Planning for Emergency Response to Water Contamination Investigations

Key TakeawaysWhile sample collection to monitor drinking water quality is a routine practice, water utilities must be prepared to address emergencies stemming from contamination.Having a plan for collecting and analyzing water samples during emergency response or other unusual circumstances better ensures actionable results.Guidance is available to help laboratories prepare to support a utility's emergency response.

Distributions of Fecal Indicators at Aquaculture Areas in a Bay of Republic of Korea.

Aquaculture products, such as clams, scallops, and oysters, are major vectors of fecal-derived pathogens. Male-specific and somatic coliphages are strongly correlated with human noroviruses, the major enteric viruses worldwide. Geographic information system with local land-use patterns can also provide valuable information for tracking sources of fecal-derived pathogens. We examined distributions of four fecal indicator microorganisms, i.e., male-specific and somatic coliphage, total coliform, and Escherichia coli (E. coli) in three river and seawater sampling sites located on the coast of Gomso Bay in the Republic of Korea during the sampling period (from March 2015 to January 2016). Geospatial analyses of fecal indicators and correlation between environmental parameters and fecal indicators or among fecal indicators were also performed. Overall, river water samples showed highest concentrations of both types of coliphage in summer (July 2015). High concentrations of both total coliform and E. coli were detected in river water during the period from July to September 2015. High concentrations of all fecal indicators were found at site GL02, located in the innermost part of Gomso Bay, which has high-density agriculture and residential areas. Environmental factors related to precipitation-cumulative precipitation on and from 3 days before the sampling day (Prep-0 and Prep-3, respectively)-and salinity were strongly correlated with concentrations of all fecal indicators. The present results suggest that investigations of multiple fecal indicators with a systemic geospatial information are necessary for precisely tracking fecal contaminations of aquaculture products.

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.