Representative Water Samples Research Articles

Spatial Variation of Physico-chemical and Microbial Parameters in Groundwater of Selected LGAs of Akwa-Ibom State, Nigeria

Physico-chemical and microbial parameters of groundwater are useful indicators in monitoring the progress of Goal 6.3 of Sustainable Development Goals (SDGs). The study evaluated the spatial variation of physico-chemical and microbial parameters in groundwater of selected LGAs of Akwa-Ibom State, Nigeria in line with SDGs. A total of twenty (20) groundwater samples were collected from boreholes at different locations within Uyo, Itu, Ibiono Ibom and Ibesikpo Asutan Local Government Areas of Akwa-Ibom State. The boreholes were selected at random. Sterilized and pre-labelled water sampling bottles were used in collecting representative water samples to prevent contamination. Physico-chemical parameters sensitive to environmental changes such as temperature, pH and electrical conductivity were measured in-situ. Sampling and analysis followed guidelines specified by the American Public Health Association, (2012). Chemical analysis was carried out at the Geospectra Laboratory in Port Harcourt, Rivers State of Nigeria. Results showed that the groundwater condition ranged from acidic and slightly weakly acidic in Uyo and Ibiono Ibom but slightly alkaline in Itu. All the heavy metals analysed were within the permissible limits specified by WHO (2018) and NSDWQ (2015) in drinking water. The average values of total dissolved solids (TDS), biochemical oxygen demand (BOD), chemical oxygen demand (COD), faecal coliform and total coliform in Uyo, Itu, Ibiono and Ibesikpo were 57.4 mg/L, 40.1 mg/L, 97.0 mg/L, 1032 and 1542.3 MPN/100ml, 54.3 mg/L, 51.6 mg/L, 110 and 47, 20.5 mg/L, 35.7 mg/L, 78.5 mg/L, 28.8 and 82.5 MPN/100ml, and 184 mg/L, 42.8 mg/L, 94.3 mg/L, 130 and 280 MPN/100ml respectively. The values of pH, BOD, COD, faecal and total coliforms were found to be above the permissible limits. Faecal and total coliforms, which indicate recent contamination, are high in Uyo and could be attributed to urbanisation with its consequent sewage management issues and increased animal droppings. There is a need for proper sewage management within the city.

Estimation of hydrochemical profile and trophic status of a coastal Ramsar site in south west coast of India

Coastal lakes are confronting a spectrum of threats arising from both natural processes and human activities. This study presents an investigation into the nutrient and trophic status of the Ramsar-designated (Ramsar site No. 1204) Ashtamudi Lake (ASL; area= 56 km2), situated along the southwest coast of India. To establish a comprehensive hydrochemical profile, 50 representative water samples comprising lake, surface and bottom layers were systematically collected from 25 distinct sites during the non-monsoon and monsoon seasons of 2017. Physcio-chemical characteristics were evaluated using standard protocols and procedures. The salinity observations consistently position the majority of the lake's area within the 'polyhaline' condition (18–30 PSU) throughout the year. The evaluation of nutrient ratios (DIN/DIP, DSi/DIN, and DSi/DIP) during the respective seasons highlights a prevalent phosphorus (P) and silicon (Si) limited scenario during non-monsoon period. This condition is marked by elevated dissolved inorganic nitrogen (DIN) concentrations juxtaposed with lower levels of dissolved inorganic phosphorus (DIP) and dissolved silicon (DSi). The computed Trophic Index (TRIX) unequivocally denotes a 'hypertrophic' state within the lake during the non-monsoon season. This characterization is upheld by TRIX values of 7.73±0.61 and 8.06±0.62 for surface and bottom water during non-monsoon. Further insight into the TRIX findings is derived from the supplementary Efficiency Coefficient (EF) index, which accentuates ASL's limited nutrient assimilation in conjunction with a substantial input of DIN. Overall, the sustained condition of occurrence of low dissolved oxygen and elevated DIN/DIP ratios exacerbates the hypertrophic state. This complex interplay heightens ecological strain, thereby imperiling aquatic organisms, particularly valuable fishery resources. Unfortunately, this situation invariably curtails the essential ecosystem services furnished by ASL. Therefore, the adoption of strategic interventions aimed at ameliorating nutrient influx and restoring a balanced trophic equilibrium stands imperative to mitigate ecological degradation and uphold the lake's pivotal contributions to its surrounding environment.

Detection of microplastics in zebrafish housing systems: Can microplastic background contamination affect the final results of microplastic-related toxicological tests?

Concentrations of microplastics (MPs) were determined in three commonly used zebrafish housing systems to see if their levels could affect the final results of laboratory microplastic-related toxicology tests.MPs have received notable attention in the last few years, and their toxicology tests have also come to the fore. Zebrafish (Danio rerio), kept in fish housing systems, are widely used as models for MPs studies. Most of these systems contain a significant number of parts made of different polymers. As usage and amortization can erode these parts, MPs might appear in the keeping water or the fish body, which may represent a background load and possibly influence the results of microplastic-related toxicological tests.To take representative water samples from systems, two in-situ filtration techniques, a newly developed peristaltic pump-, and a jet pump-driven method were applied. The collected MP particles were analyzed with a Fourier-transform infrared microscope (detection limit 50 μm), and their possible origin was also investigated.The newly developed technique was more sufficient for sampling as it had a higher MPs recovery, especially in the smaller size range. Polyester, polyethylene and polypropylene were the most frequently detected polymers in the examined fish housing systems, the highest detected concentration was 0.31±0.12 particles/liter (0.22±0.16 μg/liter). These values are negligible compared to the literature data reporting enormously high applied MPs concentrations (104 - 2.21 × 108 particles/liter) during toxicology tests. The results also show that some detected MPs did not originate from the systems, their origin was presumed to be external.

Haloketones: A class of unregulated priority DBPs with high contribution to drinking water cytotoxicity

Although unregulated aliphatic disinfection byproducts (DBPs) had a much higher concentration and cytotoxicity than known aromatic DBPs, a recent study indicated that seven classes of regulated and unregulated priority DBPs (one and two-carbon-atom DBPs) just accounted for 16.2% of disinfected water cytotoxicity in the U.S., meaning some of the highly toxic aliphatic DBPs may be overlooked. Haloketones (HKs) are an essential class of priority DBPs with a 1–100 µg/L concentration in drinking water but lack cytotoxicity data. This study investigated the cytotoxicity of seven HKs using Chinese hamster ovary (CHO) cells. The order for cytotoxicity of HKs from most to least toxic was: 1,3-dichloroacetone (LC50: 1.0 ± 0.20 μM) ≈ 1,3-dibromoacetone (1.5 ± 0.19 μM) ≈ bromoacetone (1.9 ± 0.49 μM) > chloroacetone (4.3 ± 0.22 μM) > 1,1,3-trichloropropanone (6.6 ± 0.46 μM) > 1,1,1-trichloroacetone (222 ± 7.7 μM) > hexachloroacetone (3269 ± 344 μM). The cytotoxicity of HKs was higher than most regulated and priority aliphatic DBPs in mono-halogenated, di-halogenated, and tri-halogenated categories. A prediction model of HK cytotoxicity was developed based on the quantitative structure-activity relationship (QSAR), optimizing structures and computing descriptors with Gaussian 09 W. The average concentrations of HKs in representative drinking water samples from South Carolina (U.S.) and Suzhou (China) were 12.4 and 0.9 μg/L, respectively, accounting for 18.8% and 1.7% of their specific total DBPs measured (i.e. not TOX). For South Carolina drinking water, their contributions to total calculated additive cytotoxicity of aliphatic DBPs and overall drinking water cytotoxicity were 86.7% and 14.0%, respectively, demonstrating that HKs are an essential class of overlooked DBPs with a high contribution to drinking water cytotoxicity. Our study can help to explain the conflict that why regulated and priority DBPs (except HKs) just accounted for 16% of chlorinated drinking water cytotoxicity even enough they had much higher concentration and cytotoxicity than known aromatic DBPs.

Evaluation of Physicochemical Parameters, Carbamazepine and Diclofenac as Emerging Pollutants in the Machángara River, Quito, Ecuador

This study evaluates the pollution of the Machángara River basin in Ecuador. For the assessment, water samples were pumped from the river for 1 to 4 h, with a representative water sample of 4 L collected. In the site and laboratory, the physicochemical parameters, carbamazepine (CBZ), and diclofenac (DIC) concentrations were measured using standardized analytical methods. On average, a temperature of 17.02 °C, pH of 7.06, electrical conductivity of 760.96 µS/cm, and turbidity of 83.43 NTU were found. Furthermore, the average solids content was 72.88, 495.47, and 568.35 mg/L for total suspended solids (TSS), total dissolved solids (TDS), and total solids (TS) in that order. The highest chloride concentration (Cl− = 87.97 mg/L) was below the maximum permissible limit (MPL) based on the Ecuadorian regulations for surface and underground water for human consumption and domestic use, which only require conventional treatment. In contrast, levels of nitrate (NO3− = 27.75–288.25 mg/L) and nitrite in five points (NO2− = 2.02–5.42 mg/L) were higher than the MPLs. Moreover, sulfate (SO42− = 34.75–110 mg/L) and phosphate (PO4−P = 4.15–16.58 mg/L) contents caused turbidity and eutrophication in the river water., Additionally, concentrations of copper (Cu2+ = 0.002–0.071 mg/L), zinc (Zn2+ = 0.001–0.011 mg/L) and iron (Fe3+ = 0.000–0.287 mg/L) were within the permissible limits. On the other hand, carbamazepine concentrations in the Machángara River basin were below the limit of detection (LOD) up to a value of 0.121 mg/L. At the same time, diclofenac levels ranged from 9.32 to 48.05 mg/L. The concentration discrepancy for both pharmaceuticals is linked with the trend of drug consumption by Quito’s inhabitants. As measured in this investigation, meaningful amounts of CBZ and DIC are released to the Machángara River. Accordingly, the two pharmaceuticals in the river water may be dangerous for aquatic species.

Investigation of radiogeology and environmental geochemistry of quarry ponds in post-tin mining areas of Phuket Island, southern Thailand

Increasing demand for water supply on Phuket Island for both the local consumption and hotel industry has led to overexploitation of ground- and surface water bodies; hence, it is unremittingly important to monitor the local hydrologic regime. Radiogeological and hydrogeochemical environments are investigated by representative water and surface sediment samples collected from the different quarry ponds located in post-tin mining areas on Phuket Island. The study assessed water quality, analyze the relationship between bedrock weathering and water quality, and identify radiogeological factors and natural radon concentrations, with insights into the local geology of the study areas. The representative quarry ponds of Phuket Island consist of a granite quarry pond (PKW1), a Quaternary sediment quarry pond (PKW2), a granitic-metamorphic quarry pond (PKW3), and the perturbation pond (PKW4), with the formation of a variety of geologic features. All collected water samples show total cation concentrations with Ca2+ > Na+ > K+ > Mg2+ and total anion concentrations with HCO3− > Cl− > NO3− > SO42−. However, Gibbs diagrams suggest that rock–water interactions and precipitation are major factors in geochemical processes controlling the water quality. Radon enrichments in the water samples are involved in the local geological structures and hydrogeological environments, as follows: PKW1 > PKW3 > PKW2 > PKW4. No significant correlation between the radon activity concentrations and major/minor ions is shown. Surface sediment samples are reported, and the activity concentrations of radium-228 and thorium-228 (radioactive decay series of thorium-232) are relatively higher than those of radium-226 (radioactive decay series of uranium-238). Therefore, the activity concentrations of natural radionuclides in the surface sediments could be directly influenced by physical weathering, particularly the depositional environments of granitic bedrock around the quarry ponds. Long-term monitoring is necessary to consider the behavior of quarry ponds, which is related to tourism planning and the overall development of Phuket Island.

Identification of Playa Lakes and tracking their evolution pathways using geochemical models in the Great Indian Thar desert

Playa Lakes of the great Indian Thar desert are unique and intricate systems with pronounced scientific and ecological significance. In this study, the combined use of geospatial and field data assisted in depicting and understanding the changes within these natural systems. The purpose of this study is to provide a comprehensive dataset of Playa Lakes, which can help with an overall understanding of playas from a geochemical, ecological, and economic perspective. The 1163 surface depressions were accounted for as possible playas considering the threshold area of >5 km2. A total of 42 representative surface water samples were collected from the selected playas (Sambhar, Didwana, Pachpadra, and Pokhran) and hydrochemical analysis was carried out to identify the geochemical evolution of these playas. The major water types were Na-Cl and Na-Cl-SO4 type. Hardie and Eugster's model was used to explain the possible sequence of evolutionary pathways and brine shifts in the selected playas. Simulated evaporation modeling suggests precipitation of major evaporites (chlorides, carbonates, and sulphates) during progressive evaporation. Surface sediment analysis (X-ray diffraction) confirmed the presence of calcite, halite, and dolomite minerals in the playa sediments. The greatest economic value of these playas may be mineral production and providing food and habitat for migratory birds, though conservation and policy intervention is required for their sustainable utilization.

Geological Trap Controlling the Residence Time of Groundwater in Assessment of Exploitation Zone for Its Sustainable Resources Case Study: The Slope of Karang Mount, Banten Province, Indonesia

The southern slope of Mount Karang is covered by complex volcanic deposits with complicated texture and structure. The study on zone or location of water resources which would be exploited required a comprehensive hydrogeological approach. Through detailed geological mapping, spring sampling, and well drilling were carried out. Representative spring water samples were taken to be analyzed in the laboratory, and to obtain the data of physical groundwater, chemical groundwater, stable isotopes 18O (oxygen-18), and deuterium contents, as well as the age of the groundwater. In general, the groundwater facies of the studied area showed Ca, Na, KHCO3 with several sites indicating changes to CaHCO3 during the dry and rainy seasons. The synthesis results of the stable isotope 18O (oxygen-18) and deuterium contents, verified by the physical and chemical groundwater controlled by geological setting in the groundwater subbasins, show the anomaly of residence time as trapped by the normal fault in the middle of the studied area. The existing normal fault might control this anomaly of residence time of groundwater surrounding site JH1, JH9, and JH20. However, the distribution of three different water source zones occurred. All group of groundwater indicated a complex flowing with geological setting controlling the physical, chemical content, and the age of the groundwater. At last, sites JH4, JH5, and JH9 show that the zones are proper to be developed as sustainability groundwater resources. Keywords: groundwater facies, stable isotope, groundwater flow, sustainable water

Chemical Characteristics-Based Evolution of Groundwater in Tailan River Basin, Xinjiang, China

Groundwater plays an important role in ecological environment protection in arid and semi-arid areas. Therefore, understanding the characteristics of hydrochemical evolution is of great significance for the sustainable use of groundwater in the area of the Tailan River Basin. The Tailan River Basin is located in an arid, ecologically sensitive area in western China. In this study, we collected 42 groups of representative water samples from the Tailan River Basin and analyzed the chemical distribution in the groundwater using mathematical statistics, Piper and Gibbs diagrams, ion ratio analysis, and hydrogeochemical simulation methods. We also discussed the water–rock interactions in the groundwater hydrochemical evolutionary process. The results were as follows: (1) The chemical types of groundwater changed from HCO3·SO4-Ca·Na to SO4·Cl-Na·Ca, Cl·SO4-Na, and Cl-Na, and the total dissolved solids content increased from less than 1 g/L to more than 40 g/L from the gravel plain to the fine soil plain. (2) The Gibbs diagram, the ion ratio analysis, and the saturation index showed that the groundwater chemical characteristics in the study area were mainly controlled by water–rock interactions, as well as evaporation and concentration. Along the runoff of groundwater, halite and gypsum were dissolved. Nevertheless, dolomite and calcite precipitated. The relationship between the chlor-alkali index and [(Na+ + K+)-Cl−] and [(Ca2+ + Mg2+)-(HCO3− + SO42−)] indicated that cation exchange also affects the chemical composition of groundwater in the area. (3) Through reverse hydrogeochemical simulation, the main water–rock effect of the groundwater runoff process revealed by qualitative analysis was quantitatively verified.

An integrated approach for water quality assessment in African catchments based on physico-chemical and biological indicators

Rapid urbanization, industrialization and population growth pose major threats to the ambient water quality, indicator 6.3.2 of the United Nations Sustainable Development Goal (SDG) 6, in African catchments. One example is the catchment of the Akaki Rivers that flow through Ethiopia's capital, Addis Ababa. The objective of this study was to demonstrate a monitoring approach for assessing the physico-chemical and ecological health status of African Rivers using locally available expertise and analytical capabilities. Representative water samples were collected from twenty-three different sampling locations in the Akaki catchment for various physico-chemical measurements. A biological assessment was conducted using the mini-stream assessment scoring system (miniSASS) tool. Principal component analysis (PCA) was applied to assess variations in water quality. The study revealed notable differences in water quality between the Little Akaki River, which flows through the city center of Addis Ababa, and the Big Akaki River, which flows mostly through the peri-urban fringe of Addis Ababa. PCA revealed higher levels of water quality parameters in the Little than in the Big Akaki River. For the Little Akaki River, except for pH, all of the measured parameters had significant seasonal variation. In contrast, for the Big Akaki River, no significant seasonal variation was observed in the measured parameters. Downstream of Addis Ababa, improvement in water quality was observed to most of the measured parameters and during all of the seasons where the Akaki Rivers pass through rural areas. There were no significant correlations between physico-chemical measurements and miniSASS scores. The study thus showed that monitoring physico-chemical parameters alone may be insufficient and biological monitoring should be included. Application of these methods and analysis of the results can help catchment scale monitoring of freshwater quality on the African continent.

Does microplastic analysis method affect our understanding of microplastics in the environment?

Two analytical methods – both in active use at different laboratories – were tested and compared against each other to investigate how the procedure influences microplastic (MP) detection with micro Fourier Transform Infrared Spectroscopy (μFTIR) imaging. A representative composite water sample collected from the Danube River was divided into 12 subsamples, and processed following two different methods, which differed in MP isolation procedures, the optical substrate utilized for the chemical imaging, and the detection limit of the spectroscopic instruments. The first instrument had a nominal pixel resolution of 5.5 μm, while the second had a nominal resolution of 25 μm. These two methods led to different MP abundance, MP mass estimates, but not MP characteristics. Only looking at MPs > 50 μm, the first method showed a higher MP abundance, namely 418–2571 MP m−3 with MP mass estimates of 703–1900 μg m−3, while the second method yielded 16.7–72.1 MP m−3 with mass estimates of 222–439 μg m−3. Looking deeper into the steps of the methods showed that the MP isolation procedure contributed slightly to the difference in the result. However, the variability between individual samples was larger than the difference caused by the methods. Somewhat sample-dependent, the use of two different substrates (zinc selenide windows versus Anodisc filters) caused a substantial difference between results. This was due to a higher tendency for particles to agglomerate on the Anodisc filters, and an ‘IR-halo’ around particles on ZnSe windows when scanning with μFTIR. Finally, the μFTIR settings and nominal resolution caused significant differences in identifying MP size and mass estimate, which showed that the smaller the pixel size, the more accurately the particle boundary can be defined. These findings contributed to explaining disagreements between studies and addressed the importance of harmonization of methods.

Evaluate the compliance of ballast water management system on various types of operational vessels based on the D-2 standard

The transfer of ship ballast water poses significant risks to the aquatic ecosystem and human health. To mitigate the influences of non-native species, ballast water management systems (BWMS) have been installed on international ships to ensure proper treatment of ballast water before discharge. This study investigates whether ballast water discharges managed by BWMS meet the requirements of the D-2 standard for organisms in different size classes. Representative ballast water samples were collected from 28 ships (a total of 20 different BWMS) arriving in Shanghai during the period 2020–2022. Results have shown that two samples (7.1 %) exceeded the D-2 Standard. The compliance rates varied among different vessel types, with cargo vessels achieving a compliance rate of 81.8 %, while LNG vessels and container vessels achieved 100 % compliance. The potential to achieve higher levels of ballast water management will increase as crews improve their skills in operating BWMS and BWMS is further developed.

Uncovering an Emerging Group of Halogenated Nucleobase-Derived Disinfection Byproducts in Drinking Water: Prioritization of the Highly Cytotoxic 2-Chloroadenine.

Constant efforts have been devoted to exploring new disinfection byproducts in drinking water causally related to adverse health outcomes. In this study, five halogenated nucleobases were identified as emerging disinfection byproducts in drinking water, including 5-chlorouracil, 6-chlorouracil, 2-chloroadenine, 6-chloroguanine, and 5-bromouracil. We developed a solid phase extraction-ultraperformance liquid chromatography-tandem mass spectrometry method with the limits of detection (LOD) and recoveries ranging between 0.04-0.86 ng/L and 54-93%, respectively. The detection frequency of the five halogenated nucleobases ranged from 73 to 100% with a maximum concentration of up to 65.3 ng/L in the representative drinking water samples. The cytotoxicity of the five identified halogenated nucleobases in Chinese hamster ovary (CHO-K1) cells varied with great disparity, in which the cytotoxicity of 2-chloroadenine (IC50 = 9.4 μM) is appropriately three times higher than emerging DBP 2,6-dichloro-1,4-benzoquinone (IC50 = 42.4 μM), indicating the significant toxicological risk of halogenated nucleobase-DBPs. To the best of our knowledge, this study reports the analytical method, occurrence, and toxicity of halogenated nucleobase-DBPs for the first time. These findings will provide a theoretical basis for further research on probing the relationship between its mutagenicity and human health risk.

Validation and implementation of principles of the Integrated Pest Management concept - sustainability and current challenges in pest endemic pulse bowl of India

Insect pests and vascular diseases are the major constraints to pigeonpea production in Karnataka and primarily responsible for lower productivity. There is no substantial host plant resistance to key insect pests in currently adopted cultivars, however effective utilization of other components of pest management led to development of various integrated pest management (IPM) to minimize yield losses and protect the environment. In present studies, it is a total “system approach” to sustainable pest management involving seed treatment with microbials, synchronized sowing, modification in landscape and application of need-based pesticide spray. Spray schedule was combined with online pest monitoring system for the plant protection related advisories for the target region. The resultant IPM package implemented through farmer-managed operational scale plots and compared with non-IPM (normal farmer practices) across 7 taluks of Gulbarga district for 4 years (2010–2013 seasons). A total of 2197 farmer-managed demonstrations were conducted, giving a 5–104% yield advantage (district means) of IPM over farmers’ practice. Pest incidence data in IPM vis-à-vis non-IPM clearly indicates that pest can be managed by adopting IPM technology. Number of spray of pesticides could be reduced from 6 to 4. Pesticide residue analysis for 102 chemical pesticides for representative soil, water and grain samples drawn from IPM as well as non-IPM (farmers’ practice) fields, indicates their presence within the prescribed limits. Grain yields in IPM plots were generally 15–20% higher than in FP. Even with all the available inputs, the production is subject to residual production risk due to abiotic constraints (rainfall), diseases and insect pests, which often large farmers are able to bear. Here in present studies it has been clearly demonstrated that strategies are friendly and adoptable by the small and marginal farmers. Effective implementation of IPM practices by participating farmers demonstrated that remunerative and reliable yields could be obtained in this pest-prone environment and helps mitigate climate induced threat to agricultural development having relevance to other pigeonpea growing regions prone to similar pest pests.

Pollution Characteristics and Risk Assessment of Typical Antibiotics and Persistent Organic Pollutants in Reservoir Water Sources

The major task of Chinese water governance has gradually shifted away from water environment protection to water ecology remediation, and the governance of trace organic pollutants, including persistent organic pollutants and antibiotics, has attracted growing concern. The present study examined the seasonal distribution and sources of typical persistent organic pollutants and antibiotics in six representative water sources in the lower reaches of the Yangtze River, as well as their ecological risk to the environment. Six representative surface water and surface sediment samples were collected at different time intervals, i.e., December 2018, March 2019, and June 2019, and the concentrations of nineteen organochlorine pesticides (OCPs), seventeen polychlorinated biphenyls (PCBs), and eight polybrominated diphenyl ethers (PBDEs) were analyzed by GC-MS. The major findings are listed below: ① Endosulfan sulfate, Beta-endosulfan, and methoxychlor were the major persistent organic pollutants (POPs) detected in the sediments from Gaoyou Lake, Gonghu Lake, and Gehu Lake, with concentrations ranging from 9.0 to 10.6 ng/g. ② The target antibiotics in water sources were at relatively low levels. Occurrences of sulfonamide antibiotics in water and surface sediments were NF~37.4 ng·L−1 and NF~47.3 ng·g−1. Concentrations of quinolone antibiotics in the two media were NF~5.3 ng·L−1, 0.4~32.5 ng·g−1. ③ The combined toxicity of antibiotics (risk quotient, RQ) in Lake Gehu was 0.18, which was at a moderate risk level. There was no obvious ecological risk in most water sources affected by POPs. However, there were certain ecological risks in the water sources of Gaoyou Lake, Gonghu Lake, and Sanjiangying, induced by OCPs and PCBs. This study provides a scientific basis for the treatment of antibiotics and organic pollutants in reservoir water sources.

A robust multi-residue method for the monitoring of 25 endocrine disruptors at ultra-trace levels in surface waters by SPE-LC-MS/MS.

Estrogenic endocrine disruptors are one of the biggest ecotoxicological threats in water that pose a significant ecological burden and health-risk for humans due to their high biological activity and proven additive effects. Therefore, we have developed and validated the most comprehensive and ultra-sensitive analytical method published to date, for reliable quantification of 25 high-risk endocrine disruptors at their ecologically relevant concentrations: naturally excreted hormones (estradiol, estrone, estriol, testosterone, corticosterone, and progesterone), synthetic hormones used for contraception and menopausal symptoms (ethinylestradiol, drospirenone, chlormadinone acetate, norgestrel, gestodene, tibolone, norethindrone, dienogest, and cyproterone) and bisphenols (BPS, BPA, BPF, BPE, BPAF, BPB, BPC, and BPZ). It is based on a solid-phase extraction of water samples, followed by a robust dansyl chloride derivatization with detection by liquid chromatography-tandem mass spectrometry with a single sample preparation and two analytical methods using the same analytical column and mobile phases. The achieved limits of quantitation are in the sub-ng L-1 range, and detection limits as low as 0.02 ng L-1, meeting the newest proposal for environmental quality standards (EQS) by the EU water framework directive for estradiol and ethinylestradiol. The method was extensively validated and applied to seven representative Slovenian water samples, where we detected 21 out of 25 analytes; 13 were quantified in at least one sample. Estrone and progesterone were quantified in all samples, reaching levels up to 50 ng L-1; ethinylestradiol was higher than the current EQS (0.035 ng L-1) in three samples, and estradiol was above its EQS (0.4 ng L-1) in one sample, proving the method's applicability and the necessity for monitoring these pollutants.

Sensing Trace-Level Metal Elements in Water Using Chirped Femtosecond Laser Pulses in the Filamentation Regime.

Femtosecond filament-induced breakdown spectroscopy (FIBS) is an efficient approach in remote and in situ detection of a variety of trace elements, but it was recently discovered that the FIBS of water is strongly dependent on the large-bandgap semiconductor property of water, making the FIBS signals sensitive to laser ionization mechanisms. Here, we show that the sensitivity of the FIBS technique in monitoring metal elements in water can be efficiently improved by using chirped femtosecond laser pulses, but an asymmetric enhancement of the FIBS intensity is observed for the negatively and positively chirped pulses. We attribute the asymmetric enhancement to their different ionization rates of water, in which the energy of the photons participating in the ionization process in the front part of the negatively chirped pulse is higher than that in the positively chirped pulse. By optimizing the pulse chirp, we show that the limit of detection of the FIBS technique for metal elements in water, e.g., aluminum, can reach to the sub-ppm level, which is about one order of magnitude better than that by the transform-limited pulse. We further examine the FIBS spectra of several representative water samples including commercial mineral water, tap water, and lake water taken from two different environmental zones, i.e., a national park and a downtown business district (Changchun, China), from which remarkably different concentrations of Ca, Na, and K elements of these samples are obtained. Our results provide a possibility of using FIBS for direct and fast metal elemental analysis of water in different field environments.

Evaluation, comparison and combination of molecularly imprinted polymer solid phase extraction and classical solid phase extraction for the preconcentration of endocrine disrupting chemicals from representative whole water samples

Estrogens are endocrine disrupting chemicals and of high concerns due to demonstrated harmful effects on the environment and low effect levels. For monitoring and risk assessment, several estrogens were included in the "watch list" of the EU Water Framework Directive which sets very low environmental quality standard (EQS) levels for Estrone (E1) and 17β-Estradiol (E2) of 0.4 ng L−1 and for 17α-Ethinylestradiol (EE2) of 0.035 ng L−1 requiring sensitive detection methods, as well as extensive sample preparation. A sensitive, derivatization-free, isotope dilution calibration HPLC-MS/MS method for a panel of 5 selected estrogens (including the 3 estrogens of the EU WFD watchlist), and a procedure for the reproducible preparation of a representative whole water matrix including mineral water, humic acids and solid particulate matter are presented. These are used in a diligent comparison of classical solid phase extraction (SPE) on hydrophilic-lipophilic balanced (HLB) phase to SPE on an estrogen-specific molecularly imprinted polymer phase (MISPE) for ultra-trace levels of the analytes (1–10 ng L−1). Additionally, a two-step procedure combining HLB SPE disks followed by MISPE is evaluated. The tow-step procedure provides superior enrichment, matrix removal and sample throughput while maintaining comparable recovery rates to simple cartridge SPE. Estimated method quantification limits (MQLs) range from 0.109–0.184 ng L−1 and thus meet EQS-levels for E1 and E2, but not EE2. The representative whole water matrix provides a reproducible comparison of sample preparation methods and lays the foundation for a certified reference material for estrogen analysis. The presented method will serve as the basis for an extended validation study to assess its use for estrogen monitoring in the environment.

Tracking anthropogenic nitrogen-compound sources of surface and groundwater in southwestern Nile Delta: hydrochemical, environmental isotopes, and modeling approach

This research aims to assign the specific and potential sources that control migration and transformation mechanisms of ammonium/nitrate contaminants of surface and groundwater systems in the southwestern Nile Delta, Egypt. To achieve that, an integration of hydrogeochemistry, multiple environmental stable isotopes (δ2H-H2O, δ18O-H2O, δ15N-NH4, and δ15N-NO3) coupled with three-dimensional nitrogen transport numerical model (MODFLOW-MT3D) was done. A set of representative water samples (20 canals and drainage water) and 14 groundwater samples were collected and analyzed for physical, chemical, and stable isotope analysis. NH4+ and NO3− concentrations in surface water samples varied from 0.29 to 124 mg/l and 0.52 to 39.67 mg/l, respectively. For groundwater samples, NH4+ and NO3− concentrations varied from 0.21 to 1.75 mg/l and 0.33 to 32.8 mg/l, respectively. Total risk quotient (THQ) level of nitrate (oral and dermal effects) from drinking water exceeds unity for all water samples indicating a potential noncancer risk for the southwestern Nile Delta residents. The potential sources of nitrogen compound pollution are water from sewage treatment plants used for irrigation, sludge and animal manure, septic tanks, soil nitrogen, and artificial fertilizers according to results of δ15N values. Results of ammonium/nitrate modeling in shallow groundwater aquifers are compared with observed concentrations and are found to be in good agreement. Some recommendations are given to decrease nitrogen loads in the study area through suggested a need for adoption of N-fertilizer management practices and treatment of sewage water before to application in agricultural activities.

Water quality assessment using optimized CWQII in Taihu Lake

To improve the rationality of weight allocation and weight proportion of different periods in the process of water quality assessment, the comprehensive water quality identification index (CWQII) model was optimized in this study. A new improved comprehensive water quality identification index (ICWQIIG) model based on game theory was established to combine subjective weight and objective weight. Based on ICWQIIG, an improved comprehensive water quality identification index (ICWQIIP) model with phased period combination weights was established to determine determined the weight proportion of phased periods was established. In this study, CWQII, ICWQIIG, and ICWQIIP were used to evaluate the water quality of seventeen sites in Taihu Lake in 2020. The models selected nine water quality parameters and six water quality indicators. The assessment results of water quality classification were between “slightly polluted” and “moderately polluted”. The pollution level on the east bank was lower than that on the west bank and north bank. Furthermore, it was also affected by seasonal change, water quality was worse in January and February but better in October and November. The mean value of Iwq calculated by CWQII, ICWQIIG, and ICWQIIP were 2.405, 2.833, and 3.000, respectively. The compared results showed that the ICWQIIG method can more representative identify the location of polluted water than CWQII. Moreover, the ICWQIIP method calculation results not only retained the representative polluted water samples in the ICWQIIG method but can also identify more pollution sites and worse polluted water bodies. Both ICWQIIG and ICWQIIP had high reliability and accuracy in assessment results, and ICWQIIP was more accurate under sufficient data conditions. This study can offer a scientific basis for local water resource management in Taihu Lake, while simultaneously proposing a science-based and valid methodology for the assessment of other similar water bodies.