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1.
Environ Monit Assess ; 193(1): 24, 2021 Jan 03.
Artículo en Inglés | MEDLINE | ID: mdl-33389182

RESUMEN

The increasing trend of population growth along with the rapid groundwater-based agricultural expansion and decreasing trend of mean annual rainfall in the Northwest region of Bangladesh has been exacerbating the declination of groundwater for further expansion. Therefore, the present study attempts to demarcate the potential groundwater abstraction zones from the assessment of potential recharge and available recharge. Potential recharge was obtained with commonly used geospatial-based weighted linear combination (WLC) technique. Here, WLC analysis was based on eight factors related to physiographic (e.g. drainage density, lineament density, slope), geomorphologic (e.g. geomorphology, lithology, soil), land use and land cover (LULC) and hydrology (i.e. rainfall). Available net recharge was assessed for the period 1993-2017 by employing the water table fluctuation method. Finally, the resultant map on potential abstraction was characterized into five different classes, viz. 'very low', 'low', 'moderate', 'high' and 'very high'. The derived map reveals that 'very high' potential zone is distributed along the Teesta river floodplain, especially the northeastern part. In contrast, the Barind Tract (i.e. the southwestern and the southcentral parts) area shows 'very low' groundwater prospect. Such fused interpretations are expected to contribute to the planning of integrated management of water resources.


Asunto(s)
Sistemas de Información Geográfica , Agua Subterránea , Bangladesh , Monitoreo del Ambiente , Agua
2.
Environ Monit Assess ; 193(1): 25, 2021 Jan 03.
Artículo en Inglés | MEDLINE | ID: mdl-33389229

RESUMEN

Vulnerability assessment and mapping is a significant tool for sustainable management of the precious natural groundwater resources. DRASTIC is an extensively used index model to map groundwater vulnerable zones. However, the original DRASTIC model rates and weights used in most of the research depict the poor correlation between nitrate concentration and groundwater vulnerability index. Wilcoxon test and five population-based metaheuristic (MH) algorithms, namely, firefly algorithm (FA), invasive weed optimization (IWO), teaching learning-based optimization (TLBO), shuffled frog leaping algorithm (SFLA), and particle swarm optimization (PSO), were used to optimize the rates and weights of the DRASTIC model to improve its accuracy. The performance of all the employed metaheuristic algorithms converges to a global optimal solution at different iterations, and to choose the best algorithm for DRASTIC weights optimization, a ranking methodology was proposed. The algorithms were ranked by calculating the relative closeness of alternatives with computational speed and the number of iterations as attributes in the TOPSIS method. This study identifies FA as the outperforming algorithm among the employed for this specified weight optimization problem based on ranking. The result of the optimization model proposed depicts significant improvement in the correlation coefficient between the groundwater vulnerability index and nitrate concentration from 0.0545 for the original DRASTIC model to 0.7247 for the Wilcoxon-MH- DRASTIC. Hence, this ranking approach can be adopted when global optimal solution is found by all employed algorithms in DRASTIC weight optimization.


Asunto(s)
Monitoreo del Ambiente , Agua Subterránea , Algoritmos , Modelos Teóricos , Nitratos/análisis
3.
Ecotoxicol Environ Saf ; 208: 111779, 2021 Jan 15.
Artículo en Inglés | MEDLINE | ID: mdl-33396090

RESUMEN

High levels of ammonium in groundwater is a potential threat to drinking water security and ecological status. The role of dissolved organic matter (DOM) in mobilization of natural ammonium in groundwater is crucial but the intrinsic link between them has still been poorly understood. This study used high-pressure size exclusion chromatography (HPSEC) and fluorescence excitataion-emission-matrix spectra (EEMs) with parallel factor analysis (PARAFAC) to elucidate the influence of DOM characteristics in groundwater systems having contrastive ammonium levels in Dongting Plain, central Yangtze River. The results indicate that NH4+-N concentration in groundwater of western plain (0-16.75 mg/L) are much higher compared with southern plain (0-1.5 mg/L). The groundwater in western plain is in a more reductive environment and characterized by larger molecular weight (MW) of DOM and lower polydispersity (ρ), whereas DOM with relatively small molecular weight and high polydispersity is detected in the south with a more oxidative condition. The groundwater in western plain is characterized by lower fluorescence index (f450/500) and biological index (BIX), and dominated by the high molecular weight terrestrial humic-like component and larger amounts of microbial humic-like components. Protein-like is the main component in groundwater of southern plain with higher f450/500 and BIX. The ammonium concentration in groundwater correlates well with molecular weight and increases significantly with the content of high molecular weight terrestrial humic-like component, indicating that mobilization of ammonium is more closely associated with the terrestrial organic matter of high molecular weight. This study further enriches the theory on mobilization of ammonium in Quaternary alluvial-lacustrine aquifer systems and provides theoretical basis for the local water supply security.


Asunto(s)
Compuestos de Amonio/análisis , Agua Subterránea/química , Ríos/química , China , Monitoreo del Ambiente , Análisis Factorial , Fluorescencia , Espectrometría de Fluorescencia
4.
Ecotoxicol Environ Saf ; 208: 111548, 2021 Jan 15.
Artículo en Inglés | MEDLINE | ID: mdl-33396092

RESUMEN

In order to understand the pollution status of groundwater with geochemical evolution and appraisal of its probable public health risk due to nitrate (NO3-) and fluoride (F-), a total of 93 groundwater samples were collected during pre-monsoon (May) period from Wardha sub-basin, central India. By employing Piper plot, transition from Ca-HCO3 type water (recharge waters) to Na-Cl (saline water) type water through mixed Ca-Na-HCO3, mixed Ca-Mg-Cl (reverse ion exchange waters) and Ca-Cl types (leachate waters), were observed. The Geogenic processes such as silicate, dolomite, halite and carbonate weathering along with calcite precipitation and ion exchange process were identified as major controlling factors for evolution and alteration of groundwater chemistry. The Saturation index highlighted that the groundwater in the area is oversaturated with respect to the mineral calcite and dolomite, and under saturated with gypsum, fluorite and halite. The high NO3- and F- concentration overpassing the permissible limit were found in 54.8% and 18.5% of samples. The plot of F- with Na+/Ca2+, Na+/Mg2+ and F-/Cl- established fluoride bearing rock weathering is responsible for F- contamination. Based on the cluster analysis, the groundwater was grouped into Cluster-I Ca-Na-HCO3 type (61.3%) and Cluster-II Na-Ca-HCO3-Cl type (30.1%). The total hazard index (HI) based on human health risk assessment (HHRA) model for cumulative NO3- and F- toxicity through oral and dermal pathways were computed as 100%, 97.85% and 96.77% for children, female and male populations respectively. The HQ(nitrate) > 1 through ingestion pathway were in 84.95%, 68.82% and 62.37%, and HQ(fluoride) > 1 in 83.87%, 62.37% and 43.01% of the groundwater samples were recorded for children, female and male population respectively. The risk assessment study highlighted very high toxicity and severe health impact of ingestion of contaminated groundwater on public health.


Asunto(s)
Monitoreo del Ambiente , Fluoruros/toxicidad , Nitratos/toxicidad , Contaminantes Químicos del Agua/toxicidad , Carbonato de Calcio , Carbonatos , Niño , Femenino , Fluoruros/análisis , Agua Subterránea/análisis , Agua Subterránea/química , Humanos , India , Intercambio Iónico , Magnesio , Nitratos/análisis , Medición de Riesgo , Contaminantes Químicos del Agua/análisis
5.
J Environ Manage ; 278(Pt 2): 111486, 2021 Jan 15.
Artículo en Inglés | MEDLINE | ID: mdl-33157463

RESUMEN

Increased flooding, droughts, and sediment transport are watershed-scale problems negatively impacting agriculture and ecosystems in drylands worldwide. Vegetation loss in upland watersheds is leading to scouring floods, which in turn decreases infiltration, soil moisture levels, and downstream groundwater recharge. Management to confront these intractable problems has been hindered by a lack of accessible decision support tools for both land and water managers that synthesize the watershed processes that buffer against dryland disturbances. Flood flow connectivities across the landscape create buffer zones through replenishing soil moisture and reducing flood energy, which in turn support multiple functions. This study developed a decision support tool, the Flood Flow Connectivity to the Landscape (FlowCon) framework that quantifies the most efficient management efforts to increase the key watershed buffering functions of increasing infiltration and reducing flow energy. FlowCon links three spatially explicit, process-based, and predictive models to answer two critical management questions: what key processes acting in what optimal areas are drivers of infiltration dynamics and what roles do peak flows of differing scales of energy play. The spatial models delineated the buffer zone to characterize the heterogeneous and optimal infiltration dynamics across the landscape. The hydrologic process model, using a curve number technique, identified the key ecohydrologic processes that affect infiltration and characterized peak flows and flow regime variability. The predictive flood routing model quantified the potential management benefits. We calibrated the models with measured runoff and the corresponding rainfall events for a six-year period, which included thirty-six flow events. The synthesized ecohydrologic indicators provided critical calibrations, improving the relationship between the hydrologic modeling results and observed data by 12% for the linear regression R2 and 69% for the root mean square error (RMSE). Implementation of prioritized management is estimated to reduce peak flow by half, with interventions focused on 24% of floodplains that infiltrate three times the flow volume per area than the floodplain average. FlowCon provides an efficient assessment framework that integrates watershed process understanding in an accessible decision support tool to achieve tangible improvements in dryland watershed management.


Asunto(s)
Inundaciones , Agua Subterránea , Ecosistema , Hidrología , Suelo
6.
Sci Total Environ ; 751: 142161, 2021 Jan 10.
Artículo en Inglés | MEDLINE | ID: mdl-33182013

RESUMEN

Bioremediation of vanadium (V) (V(V)) for polluted groundwater is an emerging topic globally. With this study, microbial removal of V(V) was investigated by sawdust of pine used as a sole carbon source. The removal efficiency of V(V) reached up to 90.3% with anaerobic sludge as inocula and sawdust as the carbon source in nutrient solution. Microbial removal of V(V) could be enhanced by adding medical stone and phosphate rock, from 53.2% up to 82.6% in real groundwater. Microbiological analysis revealed such microbes as Thauera accumulated, which could contribute to V(V) reduction. Such functional species as Bacteroidetes vadinHA17 norank and Anaerolineaceae norank helped degradation of sawdust. In column experiments with domesticated sludge or indigenous microbes from soils, microbial V(V) removal efficiencies (on 26 d) with sawdust were around 58.7% (BS), 54.8% (BP) and 38.4% (BU), respectively. The study can offer a potential approach to microbially removing V(V) for contaminated groundwater and even for disposal of agricultural and forestry wastes.


Asunto(s)
Agua Subterránea , Vanadio , Biodegradación Ambiental , Carbono , Suelo , Vanadio/análisis
7.
J Environ Manage ; 279: 111760, 2021 Feb 01.
Artículo en Inglés | MEDLINE | ID: mdl-33316644

RESUMEN

This study examines the risks of seawater intrusion (SWI) in data scarce aquifers along the Eastern Mediterranean by quantifying the interaction of the main natural, anthropogenic and climatic drivers, while also considering varying abilities of implementing adaptation and mitigation measures. For this purpose, we conducted a semi-quantitative Strengths, Weaknesses, Opportunities and Threats (SWOT) analysis representing a first attempt at integrating a complex physical process with multi layered influences in a SWOT analysis model that was tested at 26 coastal aquifers with varying levels of SWI severity. The analysis results showed alarming signs of SWI at several eastern and southeastern aquifers, particularly those underlying densely populated centers (i.e. Beirut, Lebanon; Magoza, Cyprus; Gaza, Palestine and the Nile Delta, Egypt). The analysis also highlighted adaptive capabilities that appear to be strong in Cyprus, Israel and Turkey, emerging in Egypt, and weak in Lebanon, Syria, and Palestine. The risks exhibited a strong and statistically significant positive relationship with the reported status of SWI at the tested aquifers thus providing an effective decision-making tool towards the preliminary assessment of SWI in regions with data scarcity. The study concludes with proposing a framework for sustainable aquifer management in the East Med region with emphasis on controlling SWI risks.


Asunto(s)
Agua Subterránea , Chipre , Egipto , Israel , Líbano , Medición de Riesgo , Siria , Turquia
8.
Environ Pollut ; 269: 116110, 2021 Jan 15.
Artículo en Inglés | MEDLINE | ID: mdl-33310493

RESUMEN

Little is known about the fate of oil spills in rivers. Hyporheic flows of water through river sediments exchange surface and groundwater and create upwelling and downwelling zones that are important for fish spawning and embryo development. Risk assessments of oil spills to rivers do not consider the potential for hyporheic flows to carry oil droplets into sediments and the potential for prolonged exposure of fish to trapped oil. This project assessed whether oil droplets in water flowing through gravel will be trapped and whether hydrocarbons partitioning from trapped oil droplets are bioavailable to fish. Columns packed with gravel were injected with oil-in-water dispersions prepared with light crude, medium crude, diluted bitumens, and heavy fuel oil to generate a series of oil droplet loadings. The concentrations of oil trapped in the gravel increased with oil loading and viscosity. When the columns were perfused with clean water, oil concentrations in column effluents decreased to the detection limit within the first week of water flow, with sporadically higher concentrations associated with oil droplet release. Despite the low concentrations of hydrocarbons measured in column effluent, hydrocarbons were bioavailable to juvenile rainbow trout (Oncorhynchus mykiss) for more than three weeks of water flow, as indicated by strong induction of liver ethoxyresorufin-o-deethylase activity. These findings indicate that ecological risk assessments and spill response should identify and protect areas in rivers sensitive to contaminant trapping.


Asunto(s)
Aceites Combustibles , Agua Subterránea , Contaminantes Químicos del Agua , Animales , Disponibilidad Biológica , Citocromo P-450 CYP1A1/metabolismo , Ríos , Contaminantes Químicos del Agua/análisis
9.
Sci Total Environ ; 755(Pt 1): 142873, 2021 Feb 10.
Artículo en Inglés | MEDLINE | ID: mdl-33348482

RESUMEN

Groundwater discharge zones in streams are important habitats for aquatic organisms. The use of discharge zones for thermal refuge and spawning by fish and other biota renders them susceptible to potential focused discharge of groundwater contamination. Currently, there is a paucity of information about discharge zones as a potential exposure pathway of chemicals to stream ecosystems. Using thermal mapping technologies to locate groundwater discharges, shallow groundwater and surface water from three rivers in the Chesapeake Bay Watershed, USA were analyzed for phytoestrogens, pesticides and their degradates, steroid hormones, sterols and bisphenol A. A Bayesian censored regression model was used to compare groundwater and surface water chemical concentrations. The most frequently detected chemicals in both ground and surface water were the phytoestrogens genistein (79%) and formononetin (55%), the herbicides metolachlor (50%) and atrazine (74%), and the sterol cholesterol (88%). There was evidence suggesting groundwater discharge zones could be a unique exposure pathway of chemicals to surface water systems, in our case, metolachlor sulfonic acid (posterior mean concentration = 150 ng/L in groundwater and 4.6 ng/L in surface water). Our study also demonstrated heterogeneity of chemical concentration in groundwater discharge zones within a stream for the phytoestrogen formononetin, the herbicides metolachlor and atrazine, and cholesterol. Results support the hypothesis that discharge zones are an important source of exposure of phytoestrogens and herbicides to aquatic organisms. To manage critical resources within the Chesapeake Bay Watershed, more work is needed to characterize exposure in discharge zones more broadly across time and space.


Asunto(s)
Agua Subterránea , Contaminantes Químicos del Agua , Animales , Teorema de Bayes , Ecosistema , Monitoreo del Ambiente , Fitoestrógenos , Ríos , Contaminantes Químicos del Agua/análisis
10.
J Environ Radioact ; 226: 106354, 2021 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-33046265

RESUMEN

Tritium, the radioactive isotope of hydrogen, has been used to understand groundwater recharge processes for decades. The current variation of tritium in the atmosphere is largely attributed to stratospheric production and fall out rates as well as global circulation phenomena controlling the hydrological cycle. Global controls on the variability in atmospheric tritium activity are poorly suited to explain local variation and tritium activities in precipitation are often assumed to be uniform over both local and regional catchments and watersheds. This assumption can result in both over and under estimation of modern recharge within an aquifer when using tritium as the recharge proxy. In order to minimize the inherent prediction residuals associated with tritium based recharge investigations, the variability of tritium in precipitation was modelled from 127 spatial precipitation samples taken over a two year period, combined with a 76 precipitation sample group-set taken over a one year period in a single location. Precipitation events were traced backward in time, from the point of collection, using HYSPLIT modelling to ascertain the origins of moisture content as well as the altitudes of moisture origin reached along the particle track. Tritium activities, collected over a one year period in Paarl, range from 0.45 to 4.16 TU and have a mean of 1.59 TU. Spatial storm events in the Western Cape in 2017 and 2018 had a range from 0 to 2.2 and 0.37 to 3.27 TU, respectively, with mean activities of 1.18 (n = 34) and 1.25 TU (n = 32). Both storm events had similar tritium variability (σ = 0.5 n = 35 and 0.48 n = 32). Regional precipitation events had the largest range of tritium activities (0.55-12.2 TU). Although not all tritium activities can be explained by interrogating the water mass origin, this study suggests that approximately 90% of events can be completely or partially attributed to the origin of the water mass. The variability of tritium, both spatially and temporally, was higher than expected, confirming that when uniform tritium inputs are used, the groundwater system would provide inaccurate modern recharge estimates. Higher spatial resolution of tritium variation in precipitation for a particular region will improve our ability to relate tritium activities in groundwater to local precipitation.


Asunto(s)
Monitoreo de Radiación , Tritio/análisis , Agua Subterránea , Hidrología , Sudáfrica
11.
J Environ Radioact ; 226: 106368, 2021 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-33077303

RESUMEN

Radon mass balances in lakes can be used to trace transport processes along the sediment-water interface, such as groundwater discharge or pore water exchange. Understanding these transport processes is important, as they can affect the lake water budget, or biogeochemical cycles in lakes due to nutrient inputs. We present here a seasonal 222Rn mass balance of Lake Burullus (Northern Egypt), the second largest lake of Egypt. The Lake receives 222Rn from drainage water and the decay of 226Ra, and loses 222Rn via decay of 222Rn, atmospheric evasion and water discharge into the Mediterranean Sea. However, the mass balance reveals a significant surplus of 222Rn, which cannot be explained by the previously mentioned processes. The 222Rn surplus is especially high during the dry season, and might be explained by groundwater discharge and pore water exchange which transports 222Rn into the lake. Higher 222Rn fluxes into the lake during dry season might be explained by higher bioirrigation rates due to warmer temperatures, or higher groundwater discharge rates due to a higher hydraulic head on land caused by excessive irrigation in adjacent fields. Groundwater discharge and pore water exchange should be investigated in further detail in order to understand if they have effects on water budgets and biogeochemical cycles of Lake Burullus.


Asunto(s)
Monitoreo de Radiación , Radón/análisis , Contaminantes Radiactivos del Agua/análisis , Egipto , Monitoreo del Ambiente , Agua Subterránea , Lagos/química , Mar Mediterráneo , Estaciones del Año , Agua
12.
Ecotoxicol Environ Saf ; 207: 111512, 2021 Jan 01.
Artículo en Inglés | MEDLINE | ID: mdl-33254392

RESUMEN

This study investigated 324 groundwater samples collected from the southwest plain of Shandong Province during the dry and wet seasons. Groundwater fluoride in the study area and the influencing factors were characterized and discussed using statistical analysis, ion ratios, Piper diagrams, the saturation index (SI) and ArcGIS software. In addition, the risk posed by groundwater fluoride to human health was assessed. The results showed that groundwater in the study area had elevated fluoride concentrations, with average dry and wet season concentrations of 1.15 mg·L-1 and 1.08 mg·L-1, respectively. Groundwater fluoride showed consistent spatial variations during the dry and wet seasons, with a significant regionalization pattern of low concentrations in the east and high concentrations in the west. Groundwater F- was significantly negatively correlated with Ca2+ and positively correlated with pH, HCO3- and Na+. Important factors identified as having an effect on groundwater F- in the study area included the balance of dissolution of fluorite and calcite, the weakly alkaline environment and cation exchange. In addition, hydrochemical types of high-fluoride groundwater in the study area were identified as mainly HCO3-Na and SO4·Cl-Na. The assessment of the risk of high groundwater fluoride to human health showed that children are more at risk compared to adults, with the risk during the dry season exceeding that over the wet season. It is recommended that water quality management in the study area prioritize the formulation of measures to mitigate high concentrations of fluoride in groundwater .


Asunto(s)
Monitoreo del Ambiente , Fluoruros/análisis , Contaminantes Químicos del Agua/análisis , Adulto , Carbonato de Calcio/química , Niño , China , Agua Subterránea/química , Salud , Humanos , Minerales/análisis , Sodio/análisis , Calidad del Agua
13.
Chemosphere ; 263: 127946, 2021 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-33297017

RESUMEN

Although karst groundwater systems provide critical ecosystem services in many regions worldwide, anthropogenic contamination has seriously degraded groundwater quality. Properly elucidating geochemical processes, quantifying contributions of natural and anthropogenic end members, and then protecting karst aquifer systems remain challenging from scientific and engineering aspects. To identify the hydrochemical processes and quantifying contributions of end members (especially, contamination end members), 49 samples were collected from cave waters (CW), artesian springs (AS), and gravity springs (GS) in a karst watershed in Guiyang, China. With increased anthropogenic contamination, the CW, AS, and GS characterized by a Ca-Mg-SO42--HCO3- composition often had pH and SO42- concentrations exceeding USEPA secondary drinking water standards. That is attributed to the influence of water-rock interaction, rainfall, and anthropogenic sources (mainly, sewage and fertilizers), in agreement with the compositions of δ34SSO4, δ18OSO4, and 87Sr/86Sr as well as the results of principal component analysis and correlation coefficients. Based on an end-member mixing model, contributions of rainfall and anthropogenic sources were 47% and 33% of GS, 52% and 41% of CW, and 58% and 35% of AS, respectively. It suggests that the karst groundwater quality is predominantly controlled by rainfall and anthropogenic sources (especially, land use). Results may be applied to properly evaluate the impacts of natural and anthropogenic sources on karst aquifers, coupled with actions to efficiently control potential contamination end members.


Asunto(s)
Agua Subterránea , Contaminantes Químicos del Agua , China , Ecosistema , Monitoreo del Ambiente , Marcaje Isotópico , Contaminantes Químicos del Agua/análisis
14.
Chemosphere ; 263: 128096, 2021 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-33297092

RESUMEN

Studies on occurrence of radon in the environment are receiving growing attention worldwide due to its adverse impact on human health. Despite that, the dissolved radon in water is found to be a useful tracer in many hydrogeological studies. Although, several studies focused on the occurrence of high 222Rn in groundwater, the processes responsible for its variation is still not well understood. Hence, an attempt has been made in the present study to elucidate the underlying factors influencing the abundance 222Rn in hard rock (gneissic) aquifers of Karamana River Basin, southwest India. 222Rn in groundwater was analyzed in 71 dug wells during the pre-monsoon period of 2017. A large variability in 222Rn activities (170-68,350 Bq/m3) was noticed in groundwater and high activities were mainly seen in the khondalite formation. No significant dependencies between 222Rn activity and depth to water table, groundwater temperature and electrical conductivity were observed. However, majority of the presence of high 222Rn activity in groundwater matches with the location of lineaments. Furthermore, radium content in the host rock, degree of weathering and fracturing and the emanation coefficient of the rock were found to have an important bearing on the occurrence of radon in groundwater. The underlying factors influencing the abundance of radon in hard rock aquifers were also conceptualized. Thus, the study highlights the usefulness of 222Rn as a potential tool in delineating the macro-structural features like fractures/lineaments that are significant repositories of groundwater, which could be explored for groundwater development in hard rock terrains.


Asunto(s)
Agua Subterránea , Radón , Contaminantes Radiactivos del Agua , Humanos , India , Radón/análisis , Ríos , Contaminantes Radiactivos del Agua/análisis
15.
Chemosphere ; 263: 128124, 2021 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-33297113

RESUMEN

In this study, oxidants and nanomaterials were used to improve titanium dioxide based photocatalytic degradation of sulfolane. Hydrogen peroxide (H2O2), sodium persulfate (SPS) and ozone (O3) were the oxidants studied and carbon nanotubes (CNT) and nanosized zero valent iron (nZVI) were used as the nanomaterials. The impact of these oxidants and nanomaterials was evaluated at various dosages in both Milli-Q water and groundwater. The results indicate that with a suitable dose of oxidants or nanomaterials, photocatalytic degradation of sulfolane in Milli-Q water can be enhanced. The addition of ozone contributed to a significant increase in sulfolane degradation rate in Milli-Q water. The experiments conducted in groundwater showed that oxidants (H2O2, SPS and O3) increased the degradation of sulfolane while the nanomaterials (CNT and nZVI) impeded sulfolane degradation in groundwater.


Asunto(s)
Agua Subterránea , Nanotubos de Carbono , Contaminantes Químicos del Agua , Purificación del Agua , Peróxido de Hidrógeno , Oxidantes , Tiofenos , Contaminantes Químicos del Agua/análisis
16.
Chemosphere ; 263: 128145, 2021 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-33297132

RESUMEN

This publication presents a comparison of the content of pollutants in groundwater samples taken at 117 measurement points in four regions of Poland during a drought period and in the reference period without drought. Based on the chemical analyses of water, an assessment of the health risk resulting from the use of underground water for consumption was carried out. The study aimed to determine whether drought affects the increase in health risk exposure of the population. It was found that despite the occurrence of drought, the expected increase in the concentration of pollutants in water does not take place in all locations. This study found that in some cases the occurrence of drought did not cause an increase in the non-cancerogenic threat expressed by the hazard index. There were also no clear changes in excess lifetime cancer risk values except for selected measurement points. On the other hand, the statistical analysis of all data collected in the regions where the research was conducted showed a general trend of increasing environmental health risk caused by changes in groundwater pollution during drought.


Asunto(s)
Agua Potable , Agua Subterránea , Contaminantes Químicos del Agua , Agua Potable/análisis , Sequías , Salud Ambiental , Monitoreo del Ambiente , Polonia , Medición de Riesgo , Contaminantes Químicos del Agua/análisis
17.
Chemosphere ; 263: 128253, 2021 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-33297198

RESUMEN

Co-occurrence of arsenic and anions in groundwater causes a severe health problems and combine effects of these pollutants significantly affect performance of treatment process. Thus, this study has been conducted to examine the combine effects of anions on arsenic removal using aerated electrocoagulation (EC) reactor with 3D Al electrodes in groundwater. A 3-level, six factors Box-Behnken experimental design (BBD) was applied to investigate the individual and combine effect of anions and operating time: phosphate (x1: 1-10 mg L-1), silica (x2: 20-80 mg L-1), bicarbonate (x3: 130-670 mg L-1), fluoride (x4: 2-10 mg L-1), boron (x5: 5-10 mg L-1), and operating time (x6: 8-22 min) on desired responses. The specified responses were effluent arsenic concentration (Cf,As), removal efficiency of arsenic (Re), consumptions of energy and electrode (ENC and ELC), operational cost (OC), and adsorption capacity (qe). The optimum operating parameters predicted using BBD were found to be x1: 1.0 mg L-1, x2: 26.0 mg L-1, x3: 651.5 mg L-1, x4: 2.0 mg L-1, x5: 9.9 mg L-1, and x6: 10.5 min considering highest removal efficiency of arsenic and lowest operational cost. Under these operating conditions, the experimental values of Cf,As, Re, ENC, ELC, OC, and qe were found to be 2.82 µg L-1, 98.6%, 0.411 kWh m-3, 0.0124 kg m-3, 0.098 $ m-3, and 17.65 µg As (mg Al)-1, respectively. Furthermore, mathematical modelling was conducted using quadratic regression model and response surface analysis was performed to understand the relationship between independent parameters and responses.


Asunto(s)
Arsénico , Agua Subterránea , Contaminantes Químicos del Agua , Purificación del Agua , Electrocoagulación , Electrodos
18.
J Environ Sci (China) ; 101: 397-412, 2021 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-33334534

RESUMEN

In groundwater, deep soil layer, sediment, the widespread of xenobiotic organic contaminants (XOCs) have been leading to the concern of human health and eco-environment safety, which calls for a better understanding on the fate and remediation of XOCs in anoxic matrices. In the absence of oxygen, bacteria utilize various oxidized substances, e.g. nitrate, sulphate, metallic (hydr)oxides, humic substance, as terminal electron acceptors (TEAs) to fuel anaerobic XOCs degradation. Although there have been increasing anaerobic biodegradation studies focusing on species identification, degrading pathways, community dynamics, systematic reviews on the underlying mechanism of anaerobic contaminants removal from the perspective of electron flow are limited. In this review, we provide the insight on anaerobic biodegradation from electrons aspect - electron production, transport, and consumption. The mechanism of the coupling between TEAs reduction and pollutants degradation is deconstructed in the level of community, pure culture, and cellular biochemistry. Hereby, relevant strategies to promote anaerobic biodegradation are proposed for guiding to an efficient XOCs bioremediation.


Asunto(s)
Electrones , Agua Subterránea , Anaerobiosis , Biodegradación Ambiental , Humanos , Xenobióticos
19.
Chemosphere ; 262: 127853, 2021 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-32777616

RESUMEN

Green rusts (GRs) are redox active towards contaminants but they are not stable for long distance transport during the soil and groundwater remediation. In this study, green rust chloride (GR) was stabilized by selected regents, including silicate (Si), phosphate (P), fulvic acid (FA), carboxymethyl cellulose (CMC) and bone char (BC), then these stabilized GR, collectively named GR-X, would be further applied for Cr(VI) removal from aqueous solution. The stabilization experiment demonstrated that the release of Fe(II) from GR was effectively suppressed by above reagents, enabling at least 50% lower Fe(II) leaching from the stabilized GR-X than that from the pristine GR. The intact hexagonal GR plates and crystallinity were also confirmed by the SEM images and XRD patterns after storage for 7 days, indicating the stable structure of GR-X was remained. In the Cr(VI) removal tests, Cr(VI) was eliminated by GR-X in seconds with a Fe(II) utilization efficiency over 90%. The Cr species examination demonstrated that the GR-X was able to transfer Cr(VI) into stable Cr(III)-Fe(III) precipitates (Fe-Mn oxides fraction). After Cr(VI) removal tests, all reactors were exposed to the air for 1 week to monitor pH fluctuation and evaluated the risk of acidification. The results indicate that, except for GR-Si system, the other post-remediation systems are stable and the pH buffering ability of GR-X could avoid acidification and lower the Cr leaching risk.


Asunto(s)
Cromo/química , Contaminantes Químicos del Agua/química , Purificación del Agua/métodos , Carboximetilcelulosa de Sodio , Cromo/análisis , Agua Subterránea , Hierro/química , Cinética , Oxidación-Reducción , Óxidos , Suelo/química , Agua/química , Contaminantes Químicos del Agua/análisis
20.
Chemosphere ; 262: 127606, 2021 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-32805650

RESUMEN

PerFluoroOctane Sulfonate (PFOS), is a toxic anthropogenic chemical that has been produced and gradually released into the environment for the past seven decades. An accurate audit of global PFOS contamination and contaminated sites are yet to be published. The available technologies to remediate PFOS contaminated soil are limited and often basic strategies such as temporary soil containment are adopted as immediate measures to manage the contaminated sites. In this study, the in situ soil flushing technique is assessed for its capacity to remediate soil contaminated with PFOS. A complete treatment process with several operation units was proposed such as solvent flushing, ground water pumping, solvent recovery and water treatment for PFOS. Potential solvents were identified and it was observed that more than 98% PFOS removal could be attained by flushing with five bed volumes of 50% ethanol. In addition, the study investigated thirteen commercially available filter materials and identified PFA694E, K6362, MP 62, Amberlite IRA 67 and Dowexoptopore V493 as suitable to eliminate PFOS with competitive PFOS adsorption characteristics. The proposed method can be recommended to remediate PFOS in recognised contaminated soils, such as those at defence sites. Furthermore, a contaminated site with favourable characteristics to implement the suggested method was identified in Australia and described in this paper.


Asunto(s)
Ácidos Alcanesulfónicos/análisis , Restauración y Remediación Ambiental/métodos , Fluorocarburos/análisis , Contaminantes del Suelo/análisis , Adsorción , Australia , Contaminación Ambiental , Agua Subterránea , Suelo , Purificación del Agua
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