Source Water Samples Research Articles

Rapid determination and health risk assessment of neonicotinoids in source water and tap water of the tropical Hainan Island, China.

Neonicotinoids (NEOs) pesticides are widely used around the world, especially in the tropics with greater frequency and intensity. However, little is known about NEOs residue in drinking water of tropics. In this study, a highly efficient method using ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) was established for determining eight NEOs in source water and tap water of Hainan Island, China. The method adopted a high-throughput direct aqueous injection without sample concentration steps, with a rapid analyzing period of 5.0min, method detection limits (MDLs) in the range of 0.84-1.82ng/L and the average recoveries ranged from 83% to 116%. NEOs were detected in all source water samples and at an upper level as compared with other parts of China. The most frequently detected NEO was imidacloprid with a detection frequency of 94%, followed by clothianidin (88%) and thiamethoxam (78%), with maximum concentrations of 86.4, 164, and 188ng/L, respectively. Moreover, seasonal and spatial variations had remarkable impacts on NEO contamination in source water. Drinking water treatment processes removed approximately 20% of NEOs from surface water. However, 90% of tap water samples contained at least one NEO, With 3 samples' concentration of single NEO exceeding the acceptable value recommended by the European Union (100ng/L). Therefore, the risk of human exposure through drinking water was evaluated for 4 age group and 2 genders. Young children aged 9months to 3years old were found to have the highest risk, with the median exposure up to 4 times greater than teenagers and adults. Next, water intake is likely only a small part of the daily intake of these individuals, thus the potential health problems caused by NEOs present in the tap water of Hainan should not be ignored.

RANCANG BANGUN ALAT FILTRASI PENYEDIA AIR SIAP MINUM DENGAN SISTEM REVERSE OSMOSIS

Drinking water is a very basic basic need, and cannot be replaced by other elements. The needs of living things for drinking water are very many, not only needed by humans but also needed by animals and plants. To produce good and quality drinking water in accordance with health standards that have been set by the Regulation of the Minister of Health of the Republic of Indonesia No. 492 / MENKES / PER / IV2010, a proper water treatment process is needed. This research activity is aimed at designing a filtration device that is able to process dirty water into clean ready-to-drink water using reverse osmosis (RO) technology. The parameters tested are biological, physical, and chemical parameters in accordance with the requirements for good drinking water set by Permenkes No. 492 of 2010. This study used 3 water source samples to be tested, namely: the first sample was a relatively clear and odorless water sample but the bacteria content was above the standard, the second sample was turbid but odorless water, while the third sample was odorous water. After going through the filtration process with the tool made, ready-to-drink water is able to be produced with the condition that the bacterial level (total coliform) drops from 200/100ml to 0/100ml. In addition, the turbidity level also dropped from 8 NTU to 0 NTU, and the water condition also changed from smelly to odorless. So it can be concluded that the filtration device made and tested is able to produce readyto-drink water according to the standards of Permenkes No. 492 of 2010.

Pollution Characteristics and Risk Assessment of Antibiotics and Resistance Genes in Different Water Sources in the Wuhan Section of the Yangtze River

The distribution characteristics, correlations, and potential ecological risks of 13 antibiotics and 10 antibiotic resistance genes (ARGs) in 16 water sources in Wuhan were analyzed using solid-phase extraction-ultra-high performance liquid chromatography-tandem mass spectrometry (SPE-UPLC-MS/MS) and real-time quantitative PCR technology. The distribution characteristics and correlations and potential ecological risks of antibiotics and resistance genes in this region were analyzed. The results showed that a total of nine antibiotics were detected in the 16 water source samples, and the concentration range was ND-177.36 ng·L-1. The concentration distribution presented as follows:Tributary Jushui River<lower reaches of the main stream of the Yangtze River<upstream of the main stream of the Yangtze River<Tributary Hanjiang River<Tributary Sheshui River. The total absolute abundance of ARGs after the Yangtze River and Hanjiang River confluence was significantly higher than that before the confluence, and the average abundance of sulfa ARGs was significantly higher than that of the other three ARGs resistance genes (P<0.05). There was a significant positive correlation between sul1 and sul2, ermB, qnrS, tetW, and intI1 in ARGs (P<0.01), and the correlation coefficients were 0.768, 0.648, 0.824, 0.678, and 0.790, respectively. The correlation within the sulfonamide ARGs group was weak. Correlation of ARGs between groups. Four antibiotics, sulfamethoxazole, aureomycin, roxithromycin, and enrofloxacin, had a medium risk to aquatic sensitive organisms, and the proportion of each risk area in the ecological risk map was 9.0% (medium risk), 30.6% (low risk), and 60.4% (no risk). The combined ecological risk assessment (RQsum) of the 16 water sources indicated medium risk, and the RQsum (mean) of the rivers involved was 0.222 (Tributary Hanjiang River)<0.267 (main stream of the Yangtze River)<0.299 (other tributaries).

The status of microbiological contamination of water using to produce bottled drinking water in Khanh Hoa province in 2022

Ninety-three samples of source water, used to produce bottled drinking water at&amp;nbsp;bottled drinking water producers in Khanh Hoa province in 2022, were examined for&amp;nbsp;microbiological criteria such as coliform, Escherichia coli, Pseudomonas aeruginosa, and&amp;nbsp;HPC (Heterotrophic Plate Count). Results indicated that 19/93 (20.4%) of samples did not&amp;nbsp;meet the microbiological requirements according to QCVN 01-1:2018/BYT. In which, the&amp;nbsp;percentage of microbiological unsatisfactory well water (42.9%, 6/14) was higher than that&amp;nbsp;of tap water (16.5%, 13/79). The proportion of source water samples of bottled drinking&amp;nbsp;water facilities that did not meet the microbiological requirements in Cam Lam district&amp;nbsp;(83.3%) was higher than those of Cam Ranh (33.3%), Dien Khanh (30%), Ninh Hoa&amp;nbsp;(13.6%), Nha Trang (8%), and Van Ninh (7.7%). Unsatisfactory microbiological criteria&amp;nbsp;included coliform (16.1%), P. aeruginosa (15.1%), and E. coli (1.1%). In addition, there&amp;nbsp;were 8/93 (8.6%) samples with HPC higher than the recommended limit (500 CFU/mL) of&amp;nbsp;the Environmental Protection Agency (EPA). The means of HPC, coliform, and P.&amp;nbsp;aeruginosa were 4,2 &amp;times; 102, 6,2 &amp;times; 101, and 1,1 &amp;times; 102 CFU/100 mL, respectively.&amp;nbsp;Contaminated source water is one of the risks of microbiological contamination in finished&amp;nbsp;bottled drinking water. Therefore, bottled drinking water producers in Khanh Hoa need to&amp;nbsp;maintain good infection control and minimize the risk of microbial contamination from&amp;nbsp;source water to finished bottled drinking water. &amp;nbsp;

Organophosphate esters in source, finished, and tap water in Wuhan, China

As important plasticizers and flame retardants, organophosphate esters (OPEs) have resulted in the contamination of various water bodies worldwide. However, their removal efficiency by different tap water treatment processes and seasonal variations in drinking water in China are not fully understood. In this study, source (n = 20), finished (n = 20), and tap (n = 165) water samples sourced from the Hanshui and the Yangtze River were collected in Wuhan, central China from July 2018 to April 2019 to measure selected OPE concentrations. The OPE concentrations in the source water samples ranged 10.5–113 ng/L (median: 64.6 ng/L). Most OPEs were not removed effectively by conventional tap water treatment, except for tris(2-chloroisopropyl) phosphate (TCIPP). Interestingly, trimethyl phosphate content was found to increase significantly during chlorination for water sourced from the Yangtze River. The OPEs could be removed more effectively by advanced processes with ozone and activated carbon (maximum removal efficiency of specific OPE was 91.0%). Similar cumulative OPE concentrations (ΣOPEs) values were found for the finished water and tap water in February rather than in July. The ΣOPEs (ng/L) in the tap water ranged 21.2–365 (median: 45.1). TCIPP and tris(2-chloroethyl) phosphate were the predominant OPEs in the studied water samples. Significant seasonal variations in the OPE residues in tap water were observed in this study. OPE exposure via tap water ingestion posed low health risks to human beings. This is the first study reporting the removal efficiencies of OPEs and the seasonal variations in tap water from central China. This is also the first study documenting the occurrence of cresyl diphenyl phosphate and 2,2-bis(chloromethyl)propane-1,3-diyltetrakis (2-chloroethyl) bisphosphate in tap water. Based on currently available data, the contamination of tap water by OPEs is in the order of Korea > eastern China > central China > New York State, the United States. Additionally, this study provides a method involving a trap column, to eliminate OPE contamination from the liquid chromatography system.

Comparison of three cyclodextrins to optimize bisphenol A extraction from source water: Computational, spectroscopic, and analytical studies.

Computationally and spectroscopically assisted analytical comparative investigation into the extraction of bisphenol A using three cyclodextrins, that is, α, β, and γ respectively, were performed. A simple, self-tailored μ-solid-phase extraction podium was used to extract bisphenol A from water samples, and high-performance liquid chromatography-ultraviolet was used for the qualitative and quantitative analysis of bisphenol A. Density functional theory first principle calculations, attenuated total reflectance Fourier-transform infrared spectroscopy and Fourier-transform Raman spectroscopy data supports the analytical selection of β-cyclodextrin as the adsorbent for bisphenol A extraction. Analytical optimization of various parameters including sample volume, sample pH, eluting solvent and its volume was performed to discover the most proper conditions for maximum extraction. Under the optimized conditions, a limit of detection value of 0.70ng/ml and a limit of quantification value of 2.31ng/ml was achieved with β-cyclodextrin, with recovery (%) values over 98.40-102.50 in real source water samples. Overall, well assisted by comprehensive computational and spectroscopic studies, a novel, simple, sensitive and economic analytical method was developed for the extraction of bisphenol A from source water using cyclodextrin.

Occurrence, fate, seasonal variability, and risk assessment of twelve triazine herbicides and eight related derivatives in source, treated, and tap water of Wuhan, Central China

Triazine herbicides have been widely used, are frequently detected in aqueous environments and soils, and can cause acute or chronic toxicity to living organisms. We collected source water samples (n = 20) originating from the Hanshui River and the Yangtze River of Wuhan section, treated water samples (n = 20), and tap water samples (n = 169) in Wuhan, Central China during 2019 for determination of twelve triazine herbicides and their eight derivatives (collectively defined as TZs) and characterizing their fate during water treatment. Eighteen of the twenty TZs were detected in the source water. Atrazine (ATZ) had the highest concentrations (median: 22.4 ng/L) in the source water samples while DACT had the highest concentrations (median: 31.4 ng/L) in the treated water. “Tryns” (ametryn, prometryn, simetryn, terbutryn) were efficiently removed by conventional water treatment, while other target analytes were not; interestingly, hydroxypropazine and prometon increased significantly accompanied by prometryn disappearance, which implicated potential transformation pathways. In addition, “tryns” might be transformed into “tons” (atraton, prometon, secbumeton, terbumeton) by ozonation. In the tap water samples, diaminochlorotriazine had the highest concentrations (median: 34.9 ng/L) among the target analytes, followed by ATZ (18.3 ng/L), hydroxyatrazine (5.17 ng/L), deethylatrazine (5.00 ng/L), hydroxypropazine (3.20 ng/L), deisopropylatrazine (2.05 ng/L), hydroxydesethylatrazine (1.68 ng/L), and others. The TZs had the highest cumulative concentration in July in the tap water samples (median: 89.7 ng/L). This study found that ozonation in combination with activated carbon was more efficient in removing triazine herbicides, although “tryns” could also be transformed during conventional treatment. Ecological risk assessment showed moderate risks posed by hydroxyterbuthylazine, prometryn, and simetryn; the Hanshui River had higher risks than the Yangtze River, and July had higher risks than February. Human exposure to the TZs via water ingestion was low compared to the reference doses. This study characterized the occurrence of some new emerging TZs in the source water, their fate during drinking water treatment, and their seasonal variability in the tap water.

Glacier contribution to lowland streamflow: A multi-year, daily geochemical hydrograph separation study in subarctic Alaska

Glacier melt water is a critical fresh water contribution of stream discharge for many regions and in high latitudes glacier extent is decreasing with climate warming. However, characteristics of glacierized contributions to subarctic watershed-scale geochemistry and runoff have attracted limited attention. Tracer studies of glacier dominated watersheds are also commonly limited to a few days. We conducted a six-year geochemical hydrograph separation study of melt season daily streamflow in a glacierized watershed in Interior Alaska to estimate glacier, rain, snow, and baseflow contributions. Bulk streamflow water samples were collected daily from the lowlands of Jarvis Creek (634 km2, 3.3% glacier cover) throughout the flow season (late April through September) during 2011–2016. Synoptic sampling of source waters included rain, snow, headwater late-winter streamflow and late-summer glacier terminus discharge. All 1227 source water and bulk streamflow samples were analyzed for stable water isotopes (δ18O and δD) and dissolved ion concentrations (SO42−:Cl− ratio). Bulk streamflow water samples exhibited large seasonal and inter-annual geochemical variation. Considerable inter-annual differences in stable water isotopes within each source water (δ18O values of −15.8 to −20.9‰ for rain, for example) emphasize the importance of informing the mixing model with source waters sampled during the same season as bulk streamflow collection. We estimated glacier discharge to be the largest seasonal contributor to total warm season lowland streamflow (average 35%, ranging from 20% in year 2016 to 44% in 2012) with daily variability from 2 (June 2, 2011) to 80% (September 10, 2013). If the glacier contribution were to cease completely, total warm season bulk stream discharge would be reduced by between 22 and 48% during an above or below average total seasonal rainfall, respectively, with up to an 80% reduction in peak flows. Results from this study suggest that high variability in source contribution of glacierized watersheds, extending across intra- and interannual timescales, challenge any generalization of hydrologic function derived from short-term studies.

How CAFOs affect Escherichia coli contents in surrounding water sources

Commercial Concentrated Animal Feeding Operations (CAFOs) produce large quantities of waste material from the animals being housed in them. These feedlots found across the United States contain livestock that produce waste that results in hazardous runoff. Water sources surrounding CAFOs become contaminated making the water unusable for humans, livestock, and uninhabitable for aquatic life. This study examines how CAFOs affect water sources by testing for Escherichia Coli (E. coli) content in bodies of water near CAFOs. We hypothesized that the level of E. coli content in water samples near CAFO sites will be higher than in water samples not near CAFOs sites. To test our hypothesis, private drinking water bacteriological tests were performed on water samples sourced within one mile of a CAFO and then compared to water samples sourced more than five miles from the nearest CAFO. We found an increase in the E. coli concentration in water source samples closer to CAFOs. This research is crucial to understanding the impact that CAFOs have on the environment. It also provides important information for those living near CAFOs so that they can make informed decisions regarding their use of nearby water sources.

Hydro-Chemical Facies Water Sources. The Region Rabat-Sale-Zemmour-Zaer of Morocco

A sampling network of fifty-one (51) samples of water sources has been chosen as a geographic and habitat significant enough to afford to acquire representative data on the spatial variability of groundwater quality of the Rabat-Salé-Zemmour-Zaer. This network consists of three groups of water areas and covers almost the entire study site. With the help of the method of Piper diagram, the waters of different origins are easily differentiated.

Source water microorganism assessment in three cities in China: A comparative study

Reservoirs, rivers and groundwater are the top three sources of drinking water supplies in China. As microbial contamination of drinking water is still a prominent water quality problem in rural areas, understanding the microbial quality of these sources is important to the public’s health and economic prosperity of communities. In this study, three types of source water samples were collected from three cities in China. Bacterial contamination indicators testing showed that: total coliforms (TCs) and potential E. coli were not detected in groundwater, but both were detected in river and reservoir water. Total bacteria (TB) of rivers and Res-Ⅰ (sampling site Ⅰ of reservoir water) were greater than 100 CFU/ml, while less than 100 CFU/ml from Res-Ⅱ (sampling site Ⅱ of reservoir water) and groundwater. Salmonella spp. were isolated from river water and no pathogenic microorganisms were isolated from the other two types of water sources by selective culture. Microbial communities testing by 16S rRNA gene amplicon sequencing indicated that, there were 14,114 operational taxonomic unit (OTU) of microbial abundance from all 30 samples, and most OTUs were only present in river water (15.17%), reservoir water (10.46%) or groundwater (43.91%), while 1540 OTUs (10.91%) were shared by all three types of water sources. There were significant differences in the microbial communities of the three types of source water (p &amp;lt; 0.05). Based on the Ace, Chao, and Shannon-Weaver, and Simpson indexes, the species diversity of bacteria in groundwater was higher than in river water or reservoir water (p &amp;lt; 0.05), with the reservoir water having the lowest diversity of bacteria. More than seven potential pathogenic bacteria were detected in 30 water samples, for example, E. coli, Staphylococcus aureus, Clostridioides difficile and Bacteroides fragilis were present in all three types of water sources, while other pathogenic bacteria occurred only in some of the water samples. Clostridium perfringens were detected in river water and groundwater. This study adds information on the microbial communities of various drinking water sources in rural China, which is valuable to water treatment and waterborne pathogen studies. In addition, this study supports the idea that 16S rRNA gene amplicon sequencing could be used as a supplementary tool for sources water quality monitoring.

A novel ion-imprinted polymer based on pyrrole as functional monomer for the voltammetric determination of Hg(II) in water samples

A novel selective ion-imprinted polymer (IIP) was synthesized, characterized, and used as part of a carbon paste electrode (CPE) for the electrochemical analysis of Hg(II) in real water samples by differential pulse anodic stripping voltammetric (DPASV). Hg-IIP (mercury-ion imprinted polymer) was synthesized using pyrrole for the first time as a functional monomer, ethylene glycol dimethacrylate (EGDMA) as a cross-linker agent, and sodium persulfate as initiator. The CPE was modified with IIP (CPE-IIP) with a composite mixture of Hg-IIP (10%), graphite (90%), and 0.08 g of paraffin oil. A notable difference in the Hg(II) Iap (anodic peak current) between a CPE, CPE-IIP and CPE-NIP (non-imprinted polymer) was observed when optimizing the differential pulse anodic stripping voltammetry (DPASV) parameters by a Box-Behnken design. When analyzing a 50 µmol l−1 Hg(II) solution, the optimal conditions (step potential: 0.11 V, amplitude: 0.15 s, modulation time: 0.005 s, and interval time: 0.15 s) allowed an Iap of 144 µA with a %RSD < 10% for the CPE-IIP response, in comparison to the Iap of 1.47 µA obtained with the CPE-NIP, Iap confirming the existence and performance of the recognition cavities in the IIP. The proposed methodology presents a limit of detection (LOD) of 0.02 mg l−1 within a linear range of 0.09 mg l−1 to 20.05 mg l−1. The inter-day and intra-day precision were measured in two concentration levels (1 mg l−1 and 10 mg l−1) with %RSD < 10%. The developed methodology was successfully applied to determine Hg(II) in three spiked samples (10 mg l−1) of natural water sources without acid digestion, obtaining percentage recoveries close to 99.74%, which demonstrates that digestion treatment is not required for this kind of samples.

Quantitative Assessment of First Nations Drinking Water Distribution Systems for Detection and Prevalence of Thermophilic Campylobacter Species.

Water is considered a major route for transmitting human-associated pathogens. Although microbial water quality indicators are used to test for the presence of waterborne pathogens in drinking water, the two are poorly correlated. The current study investigates the prevalence of thermophilic DNA markers specific for Campylobacter spp. (C. jejuni and C. coli) in source water and throughout the water distribution systems of two First Nations communities in Manitoba, Canada. A total of 220 water samples were collected from various points of the drinking water distribution system (DWDS) between 2016 and 2018. Target Campylobacter spp. were always (100%) detected in a home with a fiberglass (CF) cistern, as well as the community standpipe (SP). The target bacteria were also frequently detected in treated water at the Water Treatment Plant (WTP) (78%), homes with polyethylene (CP) (60%) and concrete (CC) (58%) cisterns, homes with piped (P) water (43%) and water truck (T) samples (20%), with a maximum concentration of 1.9 × 103 cells 100 mL−1 (C. jejuni) and 5.6 × 105 cells 100 mL−1 (C. coli). Similarly, target bacteria were detected in 68% of the source water samples with a maximum concentration of 4.9 × 103 cells 100 mL−1 (C. jejuni) and 8.4 × 105 cells 100 mL−1 (C. coli). Neither target Campylobacter spp. was significantly associated with free and total chlorine concentrations in water. The study results indicate that there is an immediate need to monitor Campylobacter spp. in small communities of Canada and, particularly, to improve the DWDS in First Nations communities to minimize the risk of Campylobacter infection from drinking water sources. Further research is warranted in improving/developing processes and technologies to eliminate microbial contaminants from water.

Trace determination of fifteen free amino acids in drinking source water via solid-phase extraction coupled with liquid chromatography tandem mass spectrometry.

Amino acids (AAs) are important nitrogen-containing organics in water, and a large number of reports have proven that they were the precursors of many nitrogen-containing disinfection by-products, some of which have cytotoxicity and carcinogenicity. However, little has been done on their occurrence in drinking source water. Therefore, a trace determination method via solid-phase extraction coupled with ultra-high pressure liquid chromatography tandem mass spectrometry (UPLC-MS/MS) for 15 free AAs (FAAs) was developed, which was successfully applied for drinking source water samples. For sample preparation, strong cation-exchange stationary solid-phase extraction (SPE) cartridge showed better extraction performance to that of reverse phase stationary oasis HLB SPE cartridge. The optimal water pH was determined to be 2.8 before extraction. Strong matrix effects for most FAAs were observed in this work; thus, sample extraction with SPE was recommended to eliminate the matrix effects. The developed method showed excellent linearity (R2 > 0.991), low limits of detection (LODs, 0.01-0.27nmol/L), and good recoveries of 69.8-117.9% in drinking source water with low relative standard deviations (RSDs, 0.3-13.2%). The developed method was finally applied to eight drinking source water samples, and the top five FAAs were found to be serine, glycine, leucine, alanine, and isoleucine.

Elucidate the Ground water Quality Parameters of Malpura Block (Tonk-Rajasthan-India)

This Paper deals with the Physico - chemical Parameters of various Sampling Sites of Malpura Block in Tonk District Rajasthan. Water samples of various water sources were analyzed for determination of degree of contamination w.r.t. to various physico-chemical parameters for investigations. The parameters analyzed included:-(1) general parameters (pH, EC, TDS and TH); (2) cations (Na+, K+, Ca2+and Mg2+); and (3) anions (Cl-, SO42-, F-, CO32-, HCO3- and NO3-) for a period of pre monsoon (March- June2011). The study will provide reliable water quality data, which can be involve for the assessment of precise health risks and for farming up of effective management and necessary water treatment required water sources.

Occurrence of dissolved black carbon in source water and disinfection byproducts formation during chlorination

Dissolved black carbon (DBC), the water-soluble component of black carbon, which is formed by incomplete combustion of fossil fuels or biochar, takes up about 10% of dissolved organic matter (DOM) in river water. However, the distribution of DBC in water environment especially in source water is not clear and as an important component of DOM, whether DBC can produce disinfection byproducts (DBPs) like other DOM during disinfection remains unknown. In this study, the DBC concentrations in seventeen source water samples from East China were measured. The concentrations of DBC in the source water samples ranged from 60 to 270 μg/L, which were positively correlated with UV254 absorbance and chemical oxygen demand. The levels of DBC in wet season were higher than that in dry season. The average concentrations of DBC in different types of source water samples followed the order of reservoir > canal > lake > river. DBC could only be removed by 20% during the simulated coagulation, and further generate different categories of DBPs during chlorination, among which the concentrations of haloacetic acids (HAA) were the highest. The results indicated that DBC widely distributes in source water and is an important precursor of HAAs and THMs during chlorination.

Integration of solid phase extraction with HILIC-MS/MS for analysis of free amino acids in source water

Amino acids (AAs) are prevalent in source water, particularly during spring run-off. Monitoring of amino acids in source water is desirable for water treatment plants (WTP) to indicate changes in source water quality. The objective of this study was to establish analytical procedures for reliable monitoring of amino acids in source water. Therefore, we examined two different methods, large volume inject (LVI) and solid phase extraction (SPE), for sample preparation prior to HILIC-MS/MS. The LVI-HILIC-MS/MS method can provide fast and sensitive detection for clean samples, but suffers from matrix effects, resulting in irreproducible separation and shortening column lifetime. We have demonstrated that SPE was necessary prior to HILIC-MS/MS to achieve reproducible and reliable quantification of AAs in source water. A natural heterocyclic amine 1-methyl-1,2,3,4-tetrahydro-β-carboline-3-carboxylic acid (MTCCA) was also included in the method to indicate changes in other natural nitrogenous compounds in source water. The SPE-HILIC-MS/MS method was able to achieve limits of detection from 2.6-3400 ng/L for the amino acids and MTCCA with RSDs (n=3) of 1.1%-4.8%. As well, retention times (RT) of the analytes were reproducible with variation less than 0.01 min (n=3) through the entire project. We further applied the SPE-HILIC-MS/MS method to determine AAs in authentic source water samples collected from two drinking water treatment plants (WTPs) during the 2021 spring run-off season. The results support that the SPE-HILIC-MS/MS method does not require derivatization and can provide reliable, accurate, and robust analysis of AAs and MTCCA in source water, supporting future monitoring of source water quality.

Precursor characteristics of mono-HAAs during chlorination and cytotoxicity of mono-HAAs on HEK-293T cells

Monohaloacetic acids (mono-HAAs), a class of disinfection by-products widely occurred in drinking water, receives significant attention due to their extremely high toxicity. Many studies on the biological toxicity of mono-HAAs have been reported, yet the toxic effects of mono-HAAs on human renal cells (kidney is one of the target organs for disinfection by-products) has not been involved. Studies on organic precursors for mono-HAAs formation were also very limited due to their lower levels as compared to di-HAAs and tri-HAAs. Based on this, the formation of mono-HAAs after chlorination of some typical source water samples and their relationship with water quality parameters were investigated. Meanwhile, the cytotoxicity of monochloroacetic acid (MCAA), monobromoacetic acid (MBAA), and monoiodoacetic acid (MIAA) were tested using human embryonic kidney cells (HEK-293 T cells). The results showed that the levels of mono-HAAs formed during chlorination of source water samples were between 0.44 and 0.87 μg/L. Formation of MBAA positively (p < 0.05) correlated with bromide ion and dissolved organic carbon, but negatively (p < 0.01) correlated with SUVA254 (specific UV absorbance at 254 nm), while formation of MCAA was only positively (p < 0.05) related with SUVA254. These results suggested that although MCAA and MBAA both belong to the mono-HAAs, the characteristics of their organic precursors differ significantly. MCAA precursors have high aromaticity and are more hydrophobic, yet MBAA precursors have low aromaticity and are more hydrophilic. The half-lethal concentrations (LC50) of MCAA, MBAA, and MIAA on HEK293T cells were 1196–1211 μM, 16.07–18.96 μM, and 6.08–6.17 μM, respectively. An in-depth analysis showed that the cytotoxicity of mono-HAAs on HEK 293 T cells could not be explained by the parameters concerning cellular uptake (e.g., logP and pKa), but the SN2 reaction of C-X bond with cellular molecules (e.g., glyceraldehyde-3-phosphate dehydrogenase, etc) may be the relevant cause for the cytotoxicity of mono-HAAs on HEK 293 T cells.

Fecal Contamination in Child Play Spaces and on Child Hands Are Associated with Subsequent Adverse Child Developmental Outcomes in Rural Democratic Republic of the Congo: REDUCE Prospective Cohort Study.

The objective of the Reducing Enteropathy, Undernutrition, and Contamination in the Environment (REDUCE) program is to identify exposure pathways to fecal pathogens that are significant contributors to morbidity among young children in the Democratic Republic of the Congo (DRC), and on developing and evaluating scalable interventions to reduce fecal contamination from these pathways. This prospective cohort study of 270 children under 5 years of age was conducted in rural South Kivu, DRC, to investigate the association between Escherichia coli in hand rinse, soil, food, object, surface, stored water, and water source samples and child developmental outcomes. Child developmental outcomes were assessed by communication, fine motor, gross motor, personal social, problem-solving, and combined scores measured by the Extended Ages and Stages Questionnaire (EASQ) at a 6-month follow-up. Children having E. coli present in the soil in their play spaces had significantly lower combined EASQ z scores (coefficient: -0.38 (95% CI: -0.73, -0.03)). E. coli on children's hands was associated with lower communication EASQ z scores (-0.37 (95% CI: -0.0.10, -0.01), and E. coli in stored drinking water was associated with lower gross motor EASQ z scores (-0.40 (95% CI: -0.68, -0.12). In the REDUCE cohort study, E. coli in child play spaces, on children's hands, and in stored drinking water was associated with lower developmental outcome scores (communication, gross motor, fine motor, and problem-solving skills). These results suggest the need for interventions to reduce fecal contamination in the household environment to protect the cognitive development of susceptible pediatric populations in rural DRC.

Determination of 42 antibiotic residues in seven categories in water using large volume direct injection by ultra high performance liquid chromatography-triple quadrupole mass spectrometry

抗生素作为新型有机污染物在自然水体中被频繁检出,检出种类多且含量水平低,为了实现更加快速、全面、准确的高通量分析,研究开发了一种利用大体积直接进样测定水中7大类(磺胺类、林可酰胺类、喹诺酮类、大环内酯类、四环素类、头孢类及氯霉素类)42种抗生素的超高效液相色谱-三重四极杆质谱法。水样经0.22 μm滤膜过滤,加入Na2EDTA并调节pH值至6.0~8.0,加入内标混匀后,采用Phenomenex Kinetex C18柱(50 mm×30 mm, 2.6 μm),以0.1%(v/v)甲酸水溶液-乙腈作为流动相进行梯度洗脱,质谱智能化分时间段-多反应选择离子监测(Schedule-MRM)模式进行检测。42种抗生素在相关线性范围内线性良好(r=0.9949~0.9995),回收率为80.1%~125%,相对标准偏差为0.8%~12.2%,方法检出限为0.015~3.561 ng/L。将该方法应用于10份水源水和5份末梢水的检测,结果显示在42种抗生素中,12种抗生素有检出,包括磺胺类、大环内酯类、林可酰胺类和氯霉素类,其在水源水中的检出率达100%;林可霉素和氯霉素是检出质量浓度最高的两种抗生素,它们的质量浓度范围分别为3.83~13.8和24.8~33.6 ng/L。该方法从检出限和回收率两方面与标准方法和文献报道进行了比较,检出限及回收率均满足要求。该方法与传统前处理方法相比具有简单、快速、绿色、精密度高、准确度高、消耗样品量小的优点,能用于地表水、地下水、末梢水等较为洁净水体中42种痕量水平的抗生素测定。