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Journal of Contaminant Hydrology Feb 2024Groundwater, a vital global resource, is essential for sustaining life and various human activities. However, its quality and availability face increasing threats from... (Review)
Review
Groundwater, a vital global resource, is essential for sustaining life and various human activities. However, its quality and availability face increasing threats from both natural and human-induced factors. Widespread contamination, arising from both natural origins and human activities such as agriculture, industry, mining, improper waste disposal, and wastewater release, poses significant risks to human health and water security. India, known for its dense population and pronounced groundwater challenges, serves as a prominent case study. Notably, in most of its regions, groundwater resources have been found to be severely contaminated by various chemical, biological, and radioactive contaminants. This review presents an examination of contamination disparities across various states of semi-arid and cold regions, encompassing diverse assessment methods. The studies conducted in semi-arid regions of North, South, West, and East India highlight the consistent presence of fluorides and nitrates majorly, as well as heavy metals in some areas, with values exceeding the permissible limits recommended by both the Bureau of Indian Standards (BIS) and the World Health Organization (WHO). These contaminants pose skeletal and dental threats, methemoglobinemia, and even cancer. Similarly, in cold regions, nitrate exposure and pesticide residues, reportedly exceeding BIS and WHO parameters, pose gastrointestinal and other waterborne health concerns. The findings also indicated that the recommended limits of several quality parameters, including pH, electrical conductivity, total dissolved solids (TDS), total hardness, and total alkalinity majorly surpassed. Emphasising the reported values of the various contaminant levels simultaneously with addressing the challenges and future perspectives, the review unravels the complex landscape of groundwater contamination and its health-related implications in semi-arid and cold regions of India.
Topics: Humans; Environmental Monitoring; Water Pollutants, Chemical; Groundwater; Water Quality; Nitrates; Organic Chemicals; Fluorides; India; Risk Assessment
PubMed: 38244426
DOI: 10.1016/j.jconhyd.2024.104303 -
Environmental Science & Technology Jul 2023Photochemical transformation is an important process that involves trace organic contaminants (TrOCs) in sunlit surface waters. However, the environmental implications...
Photochemical transformation is an important process that involves trace organic contaminants (TrOCs) in sunlit surface waters. However, the environmental implications of their self-photosensitization pathway have been largely overlooked. Here, we selected 1-nitronaphthalene (1NN), a representative nitrated polycyclic aromatic hydrocarbon, to study the self-photosensitization process. We investigated the excited-state properties and relaxation kinetics of 1NN after sunlight absorption. The intrinsic decay rate constants of triplet (1NN*) and singlet (1NN*) excited states were estimated to be 1.5 × 10 and 2.5 × 10 s, respectively. Our results provided quantitative evidence for the environmental relevance of 1NN* in waters. Possible reactions of 1NN* with various water components were evaluated. With the reduction and oxidation potentials of -0.37 and 1.95 V, 1NN* can be either oxidized or reduced by dissolved organic matter isolates and surrogates. We also showed that hydroxyl (OH) and sulfate (SO) radicals can be generated via the 1NN*-induced oxidation of inorganic ions (OH and SO, respectively). We further investigated the reaction kinetics of 1NN* and OH forming OH, an important photoinduced reactive intermediate, through complementary experimental and theoretical approaches. The rate constants for the reactions of 1NN* with OH and 1NN with OH were determined to be 4.22 × 10 and 3.95 ± 0.01 × 10 M s, respectively. These findings yield new insights into self-photosensitization as a pathway for TrOC attenuation and provide more mechanistic details into their environmental fate.
Topics: Polycyclic Aromatic Hydrocarbons; Nitrates; Photolysis; Organic Chemicals; Hydroxyl Radical; Kinetics; Water Pollutants, Chemical
PubMed: 37327199
DOI: 10.1021/acs.est.3c02276 -
Environmental Research Aug 2023Chemicals have been identified as a potential risk factor of renal dysfunction. However, studies that consider both multiple chemicals and non-chemical risk factors,...
Chemicals have been identified as a potential risk factor of renal dysfunction. However, studies that consider both multiple chemicals and non-chemical risk factors, such as hypertension, are rare. In this study, we assessed the associations between exposure to several chemicals, including major metals, phthalates, and phenolic compounds, and the albumin-to-creatinine ratio (ACR). A group of Korean adult women in reproductive age (n = 438, aged between 20 and 49 years), who had previously been studied for association of several organic chemicals, was chosen for this purpose. We constructed multivariable linear regression models for individual chemicals and weighted-quantile sum (WQS) mixtures, by hypertension status. Among the study population, approximately 8.5% of the participants exhibited micro/macro-albuminuria (ACR ≥30 mg/g), and 18.5% and 3.9% exhibited prehypertension and hypertension, respectively. Blood cadmium and lead levels showed a stronger association with ACR only among women with prehypertension or hypertension. Among organic chemicals, depending on the statistial model, benzophenone-1 (BP-1) and mono(2-ethyl-5-hydroxyhexyl) phthalate (MEHHP) showed a significant association regardless of hypertension status, but most associations disappeared in the (pre)hypertensive group. These findings clearly indicate that hypertension status can modify and may potentiate the association of environmental chemicals with ACR. Our observations suggest that low-level environmental pollutant exposure may have potential adverse effects on kidney function among general adult women. Considering the prevalence of prehypertension in the general population, efforts to reduce exposure to cadmium and lead are necessary among adult women to minimize the risk of adverse kidney function.
Topics: Adult; Humans; Female; Young Adult; Middle Aged; Lead; Creatinine; Cadmium; Prehypertension; Environmental Exposure; Environmental Pollutants; Phthalic Acids; Hypertension; Albumins
PubMed: 37236389
DOI: 10.1016/j.envres.2023.116234 -
The Science of the Total Environment Dec 2023This study aimed to develop machine learning based quantitative structure biodegradability relationship (QSBR) models for predicting primary and ultimate biodegradation...
This study aimed to develop machine learning based quantitative structure biodegradability relationship (QSBR) models for predicting primary and ultimate biodegradation rates of organic chemicals, which are essential parameters for environmental risk assessment. For this purpose, experimental primary and ultimate biodegradation rates of high consistency were compiled for 173 organic compounds. A significant number of descriptors were calculated with a collection of quantum/computational chemistry software and tools to achieve comprehensive representation and interpretability. Following a pre-screening process, multiple QSBR models were developed for both primary and ultimate endpoints using three algorithms: extreme gradient boosting (XGBoost), support vector machine (SVM), and multiple linear regression (MLR). Furthermore, a unified QSBR model was constructed using the knowledge transfer technique and XGBoost. Results demonstrated that all QSBR models developed in this study had good performance. Particularly, SVM models exhibited high level of goodness of fit (coefficient of determination on the training set of 0.973 for primary and 0.980 for ultimate), robustness (leave-one-out cross-validated coefficient of 0.953 for primary and 0.967 for ultimate), and external predictive ability (external explained variance of 0.947 for primary and 0.958 for ultimate). The knowledge transfer technique enhanced model performance by learning from properties of two biodegradation endpoints. Williams plots were used to visualize the application domains of the models. Through SHapley Additive exPlanations (SHAP) analysis, this study identified key features affecting biodegradation rates. Notably, MDEO-12, APC2D1_C_O, and other features contributed to primary biodegradation, while AATS0v, AATS2v, and others inhibited it. For ultimate biodegradation, features like No. of Rotatable Bonds, APC2D1_C_O, and minHBa were contributors, while C1SP3, Halogen Ratio, GGI4, and others hindered the process. Also, the study quantified the contributions of each feature in predictions for individual chemicals. This research provides valuable tools for predicting both primary and ultimate biodegradation rates while offering insights into the mechanisms.
Topics: Algorithms; Linear Models; Biodegradation, Environmental; Machine Learning; Software; Organic Chemicals
PubMed: 37652371
DOI: 10.1016/j.scitotenv.2023.166623 -
Journal of Water and Health Nov 2023The yield of three disinfection byproduct formation potentials (DBPFPs), including trichloromethane, dichloroacetic acid and trichloroacetic acid formation potential...
The yield of three disinfection byproduct formation potentials (DBPFPs), including trichloromethane, dichloroacetic acid and trichloroacetic acid formation potential (TCMFP, DCAAFP and TCAAFP), by Microcystis aeruginosa under the nitrate and phosphate inhibition conditions was investigated. The results showed that excessive nitrate could inhibit the growth of M. aeruginosa, but the concentration of DBPFPs in the five fractions of algal metabolites, including hydrophilic extracellular organic matter (EOM), hydrophobic EOM, hydrophilic intracellular organic matter, hydrophobic intracellular organic matter and cell debris, only decreased slightly. Accordingly, the productivity of DBPFPs by M. aeruginosa increased by approximately 40% under the nitrate inhibition condition and the increased productivity of DBPFPs mainly came from EOM. The phosphate inhibition also performed a similar pattern with a lesser extent. The nutrient inhibition did not change the proportion of these three DPBFPs, and TCMFP accounted for approximately 87% of the total DBPFPs. The inhibition could promote M. aeruginosa to secrete more metabolites. However, the cyanobacteria tended to secrete more DBPFPs under the nitrate inhibition condition, which resulted in an increased specific DBPFP, while they tended to secrete more non-DBPFPs under the phosphate inhibition condition, which resulted in a decreased specific DBPFP.
Topics: Disinfection; Microcystis; Nitrates; Organic Chemicals; Nutrients; Phosphates
PubMed: 38017598
DOI: 10.2166/wh.2023.391 -
The Science of the Total Environment Aug 2023Sulfamerazine (SM) is a commonly used antibiotic and have been widely used to control various bacterial infectious diseases. The structural composition of colored...
Sulfamerazine (SM) is a commonly used antibiotic and have been widely used to control various bacterial infectious diseases. The structural composition of colored dissolved organic matter (CDOM) is known to be a major factor that influences the indirect photodegradation of SM, yet the influence mechanism remains unknown. In order to understand this mechanism, CDOM from different sources was fractionated using ultrafiltration and XAD resin, and characterized using UV-vis absorption and fluorescence spectroscopy. The indirect photodegradation of SM in these CDOM fractions was then investigated. Humic acid (JKHA) and Suwannee River natural organic matter (SRNOM) were used in this study. The results showed that CDOM could be divided into four components (three humic-like components and one protein-like component), and terrestrial humic-like components C1 and C2 were found to be the main components that promote SM indirect photodegradation due to their high aromaticity. The indirect photodegradation of SM was much faster in low molecular weight (MW) solutions, whose structures were dominated by greater aromaticity and terrestrial fluorophores in JKHA and higher terrestrial fluorophores in SRNOM. The HIA and HIB fractions of SRNOM contained large aromaticity and high fluorescence intensities of C1 and C2, resulting in a greater indirect photodegradation rate of SM. The HOA and HIB fractions of JKHA had abundant terrestrial humic-like components and contributed more to SM indirect photodegradation.
Topics: Sulfamerazine; Dissolved Organic Matter; Organic Chemicals; Photolysis; Anti-Bacterial Agents; Rivers; Spectrometry, Fluorescence; China
PubMed: 37201832
DOI: 10.1016/j.scitotenv.2023.164231 -
Water Research Aug 2023Dissolved organic matters (DOM) are widely present in different water sources, causing significant effects on water treatment processes. Herein, the molecular...
Dissolved organic matters (DOM) are widely present in different water sources, causing significant effects on water treatment processes. Herein, the molecular transformation behavior of DOM during peroxymonosulfate (PMS) activation by biochar for organic degradation in a secondary effluent were comprehensively analyzed. Evolution of DOM was identified and inhibition mechanisms to organic degradation were elucidated. DOM underwent oxidative decarbonization (e.g., -CHO, -CH, -CH and -CO), dehydrogenation (-2H) and dehydration reactions by OH and SO. N and S containing compounds witnessed deheteroatomisation (e.g., -NH, -NO+H, -SO, -SO, -SH), hydration (+HO) and N/S oxidation reactions. Among DOM, CHO-, CHON-, CHOS-, CHOP- and CHONP-containing molecules showed moderate inhibition while condensed aromatic compounds and aminosugars exhibited strong and moderate inhibition effects on contaminant degradation. The fundamental information could provide references for the rational regulation of ROS composition and DOM conversion process in a PMS system. This in turn offered theoretical guidance to minimize the interference of DOM conversion intermediates on PMS activation and degradation of target pollutants.
Topics: Dissolved Organic Matter; Environmental Pollutants; Peroxides; Organic Chemicals
PubMed: 37290196
DOI: 10.1016/j.watres.2023.120166 -
Volatile organic compounds emitted by conventional and "green" cleaning products in the U.S. market.Chemosphere Nov 2023Exposure to cleaning products has been associated with harm to the respiratory system, neurotoxicity, harm to the reproductive system, and elevated risk of cancer, with...
Exposure to cleaning products has been associated with harm to the respiratory system, neurotoxicity, harm to the reproductive system, and elevated risk of cancer, with greatest adverse impacts for workers exposed in an occupational setting. Social and consumer interest in cleaning products that are safer for health created a market category of "green" products defined here as products advertised as healthier, non-toxic, or free from harmful chemicals as well as products with a third-party certification for safety or environmental features. In the present study we examined the air quality impacts of cleaning products and air fresheners, measuring the number, concentrations, and emission factors of volatile organic compounds (VOCs) in an air chamber following product application. Across seven common product categories, 30 products were tested overall including 14 conventional, 9 identified as "green" with fragrance, and 7 identified as "green" and fragrance-free. A total of 530 unique VOCs were quantified with 205 additional VOCs detected below the limits of quantification. Of the quantifiable VOCs, 193 were considered hazardous according to either the California's Department of Toxic Substances Control Candidate Chemicals List or the European Chemical Agency's Classification and Labeling Inventory. The total concentration of VOCs and total emission factors across all products with detections ranged from below limits of detection to 18,708 μg/m, 38,035 μg/g product and 3803 μg/application. Greater total concentration, total emission factors, and numbers of VOCs were generally observed in conventional cleaning products compared to products identified as "green", particularly compared to fragrance-free products. A hazard index approach was utilized to assess relative risk from measured VOC emissions. The five products with the highest hazard indices were conventional products with emissions of 2-butoxyethanol, isopropanol, toluene and chloroform. Overall, this analysis suggests that the use of "green" cleaning products, especially fragrance-free products, may reduce exposure to VOC emissions.
Topics: Humans; Volatile Organic Compounds; 2-Propanol; Certification; Chloroform; Genitalia; Perfume
PubMed: 37709066
DOI: 10.1016/j.chemosphere.2023.139570 -
Natural Product Research 2024A new alkaloid, identified as 1-benzyl-2-nitroso-1,2,3,4-tetrahydroisoquinoline-6,7-diol, named oleraisoquinoline (), and five organic acids and two esters, identified...
A new alkaloid, identified as 1-benzyl-2-nitroso-1,2,3,4-tetrahydroisoquinoline-6,7-diol, named oleraisoquinoline (), and five organic acids and two esters, identified as 5-(hydroxymethyl)furan-2-carboxylic acid (), 1-pyrrole-2,5-dicarboxylic acid (), (7,10)-octadeca-7,10-dienoic acid (), (10,13)-octadeca-10,13-dienoic acid (), (7,10)-hexadeca-7,10-dienoic acid (), methyl tridecanoate () and methyl (9,12)-octadeca-9,12-dienoate (), were isolated from L., among which compounds and ‒ were isolated for the first time. Moreover, the anti-inflammatory activities of compounds ‒ were studied, especially, compound presented good inhibitory effects on the production of inflammatory factors IL-1 and TNF-.
Topics: Portulaca; Alkaloids; Plant Extracts; Organic Chemicals; Anti-Inflammatory Agents
PubMed: 35876167
DOI: 10.1080/14786419.2022.2103696 -
Journal of Environmental Management Sep 2023This present investigation is carried out to study the effect of algal and bacterial inoculum concentrations on the removal of organic pollutants and nutrients from the...
This present investigation is carried out to study the effect of algal and bacterial inoculum concentrations on the removal of organic pollutants and nutrients from the tannery effluent by the combined symbiotic treatment process. The bacterial and microalgal consortia was developed in laboratory setup and mixed together to perform this study. The Influence of algae and bacteria inoculum concentrations on the removal of pollutants such as Chemical Oxygen Demand (COD) and Total Kjeldahl Nitrogen (TKN) were studied using statistical optimization through Response surface methodology. For the design of experimental set up and optimization, full factorial Central composite design was used. The profiles of pH, Dissolved Oxygen (DO) and nitrate were also monitored and studied. The inoculum concentrations of microalgae and bacteria showed significant effect on Co-culturing on COD, TKN and nitrate removals as major response. The linear effect of bacterial inoculum has positive dominant influence on COD and TKN removal efficiencies. Nitrate utilization by microalgae increases with the increase in microalgal inoculum concentration. The maximum removal efficiencies of COD and TKN with 89.9% and 80.9% were obtained at optimum bacterial and algal inoculum concentrations of 6.7 g/L and 8.0 g/L respectively. These outcomes of this study are immensely favorable for maximizing the COD and nitrogen (nutrients) removal capabilities of microalgae-bacterial consortia in tannery effluent.
Topics: Wastewater; Microalgae; Nitrates; Organic Chemicals; Bacteria; Nitrogen; Environmental Pollutants; Biomass
PubMed: 37146488
DOI: 10.1016/j.jenvman.2023.118008