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1.
Environ Geochem Health ; 45(5): 1555-1572, 2023 May.
Artículo en Inglés | MEDLINE | ID: mdl-35532837

RESUMEN

Metal contamination from upstream river water is a threat to coastal and estuarine ecosystem. The present study was undertaken to unveil sedimentation processes and patterns of heavy metal deposition along the salinity gradient of a tropical estuary and its mangrove ecosystem. Sediment columns from three representative sites of differential salinity, anthropogenic interference, and sediment deposition pattern were sampled and analyzed for grain size distribution and metal concentrations as a function of depth. Sediments were dominantly of silty-medium sand texture. A suite of fluvial and alluvial processes, and marine depositional forcing control the sediment deposition and associated heavy metal loading in this estuary. The depth profile revealed a gradual increase in heavy metal accumulation in recent top layer sediments and smaller fractions (silt + clay), irrespective of tidal regimes. Alluvial processes and long tidal retention favor accumulation of heavy metals. Enrichment factor (0.52-15), geo-accumulation index (1.4-5.8), and average pollution load index (PLI = 2.0) indicated moderate to higher heavy metal contamination status of this estuary. This study showed that alluvial processes acted as dominant drivers for the accumulation of metals in sediments, which prevailed over the influence of marine processes. Longer tidal retention of the water column favored more accumulation of heavy metals. Metal accumulation in the sediments entails a potential risk of bioaccumulation and biomagnification through the food web, and may increasingly impact estuarine ecology, economy, and ultimately human health.


Asunto(s)
Metales Pesados , Contaminantes Químicos del Agua , Humanos , Ecosistema , Sedimentos Geológicos , Ríos , Monitoreo del Ambiente , Contaminantes Químicos del Agua/análisis , Metales Pesados/análisis , Estuarios , Agua , Medición de Riesgo
2.
Environ Res ; 204(Pt B): 112067, 2022 03.
Artículo en Inglés | MEDLINE | ID: mdl-34543636

RESUMEN

COVID-19 positive patients can egest live SARS-CoV-2 virus and viral genome fragments through faecal matter and urine, raising concerns about viral transmission through the faecal-oral route and/or contaminated aerosolized water. These concerns are amplified in many low- and middle-income countries, where raw sewage is often discharged into surface waterways and open defecation is common. Nonetheless, there has been no evidence of COVID-19 transmission via ambient urban water, and the virus viability in such aquatic matrices is believed to be minimal and not a matter of concern. In this manuscript, we attempt to discern the presence of SARS-CoV-2 genetic material (ORF-1ab, N and S genes) in the urban water (lakes, rivers, and drains) of the two Indian cities viz., Ahmedabad (AMD), in western India with 9 wastewater treatment plants (WWTPs) and Guwahati (GHY), in the north-east of the country with no such treatment facilities. The present study was carried out to establish the applicability of environmental water surveillance (E-wat-Surveillance) of COVID-19 as a potential tool for public health monitoring at the community level. 25.8% and 20% of the urban water samples had detectable SARS-CoV-2 RNA load in AMD and GHY, respectively. N-gene > S-gene > ORF-1ab-gene were readily detected in the urban surface water of AMD, whereas no such observable trend was noticed in the case of GHY. The high concentrations of SARS-CoV-2 genes (e.g., ORF-1ab; 800 copies/L for Sabarmati River, AMD and S-gene; 565 copies/L for Bharalu urban river, GHY) found in urban waters suggest that WWTPs do not always completely remove the virus genetic material and that E-wat-Surveillance of COVID-19 in cities/rural areas with poor sanitation is possible.


Asunto(s)
COVID-19 , SARS-CoV-2 , Ciudades , Humanos , ARN Viral , Saneamiento , Aguas Residuales
3.
Ecotoxicol Environ Saf ; 229: 113075, 2022 Jan 01.
Artículo en Inglés | MEDLINE | ID: mdl-34923327

RESUMEN

The present research reports the level of nitrate (NO3-), associated health risks and possible sources of contamination in groundwater from south India. Many samples (32%) are above or approaching the recommended level of NO3- for safe drinking water. The correlation analysis indicates different sources of NO3- contamination in different regions rather than a common origin. The isotopic measurements provide information about potential nitrogen sources contributing NO3- to the groundwater. Based on isotope analysis, the sources of NO3- in the groundwater of this region are likely to be from (a) septic sewage (b) organic nitrogen (animal and livestock excreta) (c) sewage (domestic & chemical fertilizers). Among the sample analyzed sewage, manure and septic sewage contribute 46%, 23% and 31% NO3- to groundwater. The HQ > 1 indicates non-carcinogenic health risk due to consumption of high NO3- in drinking water. Among the studied age groups, infants are exposed to higher risk than children and adults. Results indicate that groundwater of this region is polluted with NO3- due to anthropogenic activities. Continuous consumption of such water may pose serious health risk to the residents.


Asunto(s)
Agua Subterránea , Contaminantes Químicos del Agua , Animales , Efectos Antropogénicos , Monitoreo del Ambiente , Humanos , Nitratos/análisis , Isótopos de Nitrógeno/análisis , Medición de Riesgo , Contaminantes Químicos del Agua/análisis
4.
Environ Res ; 202: 111780, 2021 11.
Artículo en Inglés | MEDLINE | ID: mdl-34329638

RESUMEN

The present study aims at the assessment of environmental quality of the most polluted stretch of river Yamuna along the megacity of Delhi. The study was conducted in order to examine toxicity and health hazards associated with persistent pollutants present in the fluvial ecosystem. Eighty four sediment and 56 vegetable samples from same locations were collected from the Delhi segment of river Yamuna flood plain in order to examine 20 organochlorine pesticides (OCPs) and 9 heavy metals (Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb and Zn). Both the organic and inorganic groups of persistent toxic substances were monitored and analysed for the extent of eco-toxicological as well as dietary health risks posed to the local population. Eco-toxicological assessment was done based on sediment quality guidelines, enrichment factor, geo-accumulation index, degree of contamination and Pollution Load Index. The dietary-risk was assessed with the help of translocation factors (TF) of these pollutants in vegetables. Carcinogenic and non-carcinogenic health risks from consumption of vegetables were also investigated. The level of concern for heavy metals was greater than that of OCPs as per the sediment quality guidelines. DDT, Cd, Pb and Zn had maximum concentrations corresponding to level 3 of concern, while Cr and Ni reached up to the highest i.e., 4th level of concern. Sediment samples were found to be enriched and contaminated significantly with Cd and moderately with Pb, as represented respectively by enrichment factors and contamination factors (CF). CF for metals lied in order Zn > Cd > CrNi > PbCu. Pollution load index was highest at the location lying on the exit point of Yamuna in Delhi. TF values greater than 1 were observed in majority of samples analysed for Ni, Cr, Cu and Zn. Spinach topped among vegetables in terms of metal contamination. Cd, Ni and Pb accumulated more in the roots, as against Mn, Zn, Cu and Cr which had higher accumulation in the shoots. Translocation factors were substantially high in vegetables for most of the OCPs, clearly indicating bioaccumulation and potential health risk to the consumers. Health risk to humans was assessed for non-carcinogenic and carcinogenic potentials from ingestion of vegetables. Hazard Quotient (HQ) > 1 due to radish (roots and leaves) and cauliflower consumption in children indicated non-carcinogenic risk. Hazard Index (HI) beyond 1 for all the vegetables (except onion leaves) confirmed substantial cumulative risk. Lifetime cancer risk (LCR) revealed moderate (spinach, radish, beet root and cauliflower) to low (all the others) levels of carcinogenic risk to humans. Cancer risks from γ-HCH, ß- HCH, Hept, Hept Ep, Ald, p,p'-DDT, and Cr exposure through the food chain could be well established.


Asunto(s)
Metales Pesados , Plaguicidas , Contaminantes del Suelo , Niño , China , Ecosistema , Monitoreo del Ambiente , Humanos , India , Metales Pesados/análisis , Metales Pesados/toxicidad , Plaguicidas/toxicidad , Medición de Riesgo , Ríos , Contaminantes del Suelo/análisis
5.
J Environ Manage ; 298: 113413, 2021 Nov 15.
Artículo en Inglés | MEDLINE | ID: mdl-34352482

RESUMEN

The Sutlej River basin of the western Himalaya (study area), owing to its unique geographical disposition, receives precipitation from both the Indian summer monsoon (ISM) and the Westerlies. The characteristic timing and intensity of the ISM and Westerlies, leaves a distinct footprint on the sediment load of the River. Analysis with the last forty years data, shows an increasing trend for temperature. While for precipitation during the same period, the Spiti watershed on the west has highest monthly accumulated precipitation with long term declining trend, in contrast to the other areas where an increasing trend has been observed. Thus, to probe the hydrological variability and the seasonal attributes, governed by the Westerlies and ISM in the study area, we analyzed precipitation, temperature, snow cover area (in %), discharge, suspended sediment concentration (SSC) and suspended sediment load (SSL) for the period 2004 - 2008. To accomplish the task, we used the available data of five hydrological stations located in the study area. Inter-annual shift in peak discharge during the monsoon period is controlled by the variation in precipitation, snow melt, glacier melt and temperature. Besides seasonal variability has been observed in generation of the sediments and its delivery to the river. Our analysis indicates, dominance of the Westerlies footprints in the hydrological parameters of the Spiti region, towards western part of the study area. While, it is observed that the hydrology of the Khab towards eastern part of the study area shows dominance of ISM. Further downstream, the hydrology of Nathpa station also shows dominance of ISM. It also emerged out that the snowmelt contribution to the River flow is mostly during the initial part, at the onset of the monsoon, while for rest and major part of the summer monsoon season, the River flow is augmented by the precipitation, glacial melt and some snow melt. We observed, that the SSC increases exponentially in response to increase in temperature and correlates positively with River discharge. The average daily SSL in the summer monsoon is many times more than that in the winter monsoon. The downstream decrease in steepness of the sediment rating curve is attributed to either a change in the River-sediment dynamics or on account of the anthropogenic forcing. The top 1% of the extreme summer monsoon events (only 4 events) in our study area contribute up to 45% of SSL to the total sediment load budget. It has also been observed that the River-sediment dynamics in the upstream catchments are more vulnerable and sensitive to the extreme events in comparison to the downstream catchments. The present study for the first time gives a holistic insight in to the complex dynamics of the hydrological processes operational in the study area. The research findings would be crucial for managing the water resources of the region and the linked water and food security.


Asunto(s)
Cambio Climático , Agua , Monitoreo del Ambiente , Hidrología , Ríos , Nieve
6.
Environ Geochem Health ; 41(1): 53-70, 2019 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-29744698

RESUMEN

Hooghly-Matla estuarine system along with the Sundarbans mangroves forms one of the most diverse and vulnerable ecosystems in the world. We have investigated the distribution of Co, Cr, Cu, Fe and Zn along with sediment properties at six locations [Shamshernagar (S1), Kumirmari (S2 and S3), Petuaghat (S4), Tapoban (S5) and Chemaguri (S6)] in the Hooghly estuary and reclaimed islands of the Sundarbans for assessing the degree of contamination and potential ecological risks. Enrichment factor values (0.9-21.6) show enrichment of Co, Cu and Zn in the intertidal sediments considering all sampling locations and depth profiles. Geo-accumulation index values irrespective of sampling locations and depth revealed that Co and Cu are under class II and class III level indicating a moderate contamination of sediments. The pollution load index was higher than unity (1.6-2.1), and Co and Cu were the major contributors to the sediment pollution followed by Zn, Cr and Fe with the minimum values at S1 and the maximum values at S5. The sediments of the Hooghly-Matla estuarine region (S4, S5 and S6) showed considerable ecological risks, when compared with effect range low/effect range median and threshold effect level/probable effect level values. The variation in the distribution of the studied elements may be due to variation in discharge pattern and exposure to industrial effluent and domestic sewage, storm water and agricultural run-off and fluvial dynamics of the region. The study illuminates the necessity for the proper management of vulnerable coastal estuarine ecosystem by stringent pollution control measures along with regular monitoring and checking program.


Asunto(s)
Monitoreo del Ambiente , Estuarios , Sedimentos Geológicos/química , Metales Pesados/análisis , Contaminantes Químicos del Agua/análisis , Ecosistema , India , Medición de Riesgo , Humedales
7.
Environ Technol ; 34(17-20): 2701-8, 2013.
Artículo en Inglés | MEDLINE | ID: mdl-24527632

RESUMEN

In this study we investigated the role of arsenic-resistant bacteria Arthrobacter sp. biomass for removal of arsenite as well as arsenate from aqueous solution. The biomass sorption characteristics were studied as a function of biomass dose, contact time and pH. Langmuir, Freundlich and Dubinin-Radushkevich (D-R) models were applied to describe the biosorption isotherm. The Langmuir model fitted the equilibrium data better than the Freundlich isotherm. The biosorption capacity of the biomass for As(+3) and As(+5) was found to be 74.91 mg/g (pH 7.0) and 81.63 mg/g (pH 3.0), respectively using 1 g/L biomass with a contact time of 30 min at 28 degrees C. The mean sorption energy values calculated from the D-R model indicated that the biosorption of As(+3) and As(+5) onto Arthrobacter sp. biomass took place by chemical ion-exchange. The thermodynamic parameters showed that the biosorption of As(+3) and As(+5) ions onto Arthrobacter sp. biomass was feasible, spontaneous and exothermic in nature. Kinetic evaluation of experimental data showed that biosorption of As(+3) and As(+5) followed pseudo-second-order kinetics. Fourier transform infrared spectroscopy (FT-IR) analysis indicated the involvement of possible functional groups (-OH, -C=O and -NH) in the As(+3) and As(+5) biosorption process. Bacterial cell biomass can be used as a biosorbent for removal of arsenic from arsenic-contaminated water.


Asunto(s)
Arseniatos/aislamiento & purificación , Arsenitos/aislamiento & purificación , Arthrobacter/química , Biomasa , Contaminantes Químicos del Agua/aislamiento & purificación , Adsorción , Arthrobacter/citología , Termodinámica
8.
Environ Sci Pollut Res Int ; 30(8): 20631-20649, 2023 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-36255575

RESUMEN

Recent studies have endorsed that surface water chemical composition in the Himalayas is impacted by climate change-induced accelerated melting of glaciers. Chemical weathering dynamics in the Ladakh region is poorly understood, due to unavailability of in situ dataset. The aim of the present study is to investigate how the two distinct catchments (Lato and Stok) drive the meltwater chemistry of the Indus River and its tributary, in the Western Himalayas. Water samples were collected from two glaciated catchments (Lato and Stok), Chabe Nama (tributary) and the Indus River in Ladakh. The mildly alkaline pH (range 7.3-8.5) and fluctuating ionic trend of the meltwater samples reflected the distinct geology and weathering patterns of the Upper Indus Basin (UIB). Gibbs plot and mixing diagram revealed rock weathering outweighed evaporation and precipitation. The strong associations between Ca2+-HCO3-, Mg2+-HCO3-, Ca2+-Mg2+, Na+-HCO3-, and Mg2+-Na+ demonstrated carbonate rock weathering contributed to the major ion influx. Principal component analysis (PCA) marked carbonate and silicates as the most abundant minerals respectively. Chemical weathering patterns were predominantly controlled by percentage of glacierized area and basin runoff. Thus, Lato with the larger glacierized area (~ 25%) and higher runoff contributed low TDS, HCO3-, Ca2+, and Na+ and exhibited higher chemical weathering, whereas lower chemical weathering was evinced at Stok with the smaller glacierized area (~ 5%). In contrast, the carbonate weathering rate (CWR) of larger glacierized catchments (Lato) exhibits higher average value of 15.7 t/km2/year as compared to smaller glacierized catchment (Stok) with lower average value 6.69 t/km2/year. However, CWR is high in both the catchments compared to silicate weathering rate (SWR). For the first time, in situ datasets for stream water chemical characteristics have been generated for Lato and Stok glaciated catchments in Ladakh, to facilitate healthy ecosystems and livelihoods in the UIB.


Asunto(s)
Monitoreo del Ambiente , Contaminantes Químicos del Agua , Ecosistema , Calidad del Agua , Ríos/química , Contaminantes Químicos del Agua/análisis , Agua/análisis , Carbonatos/análisis
9.
Environ Monit Assess ; 184(5): 3027-42, 2012 May.
Artículo en Inglés | MEDLINE | ID: mdl-21717202

RESUMEN

The pollution of aquifer sediments by heavy metals has assumed serious concern due to their toxicity and accumulative behavior. Changes in environmental conditions can strongly influence the behavior of both essential and toxic elements by altering the forms in which they occur and therefore quantification of the different forms of metal is more meaningful than total metal concentrations. In this study, fractionation of metal ions in aquifer sediments of Semria Ojhapatti area, Bhojpur district, Bihar has been studied to determine the ecotoxic potential of metal ions. The investigations suggest that iron, copper, and arsenic have a tendency to remain associated in the following order residual > reducible > acid-soluble > oxidizable; manganese and zinc have tendency to be associated as residual > acid-soluble > reducible > oxidizable. The risk assessment code reveals that manganese and zinc occur in significant concentration in acid-soluble fraction and therefore comes under the high risk category and can easily enter the food chain. Most of the iron, copper, and arsenic occur as immobile fraction (i.e. residual) followed by its presence in reducible fraction and would pose threat to the water quality due to changing redox conditions. The metal enrichment factor in the study area shows moderate to significant metal enrichment in the aquifer sediments which may pose a real threat in near future. The geo-accumulation index of metals also shows that the metals lie in the range of strongly contaminated (for iron at shallow depths) to moderately contaminated to uncontaminated values.


Asunto(s)
Sedimentos Geológicos/química , Agua Subterránea/química , Metales/análisis , Contaminantes Químicos del Agua/análisis , Monitoreo del Ambiente , India , Modelos Químicos , Medición de Riesgo , Contaminación Química del Agua/estadística & datos numéricos
10.
Mar Pollut Bull ; 174: 113273, 2022 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-35090268

RESUMEN

The dynamics of the coastal aquifers are well-expressed by geochemical and isotopic signatures. Coastal regions often exhibit complex groundwater recharge pattern due to the influence of depression in the Bay of Bengal, tidal variations on surface waters, saline water intrusion and agricultural return flows. In this research, groundwater recharge processes occurring in coastal Tamil Nadu, South India were evaluated using major ion chemistry and environmental isotopes. A total of 170 groundwater samples were collected from shallow and deep aquifers during both post-monsoon (POM) and pre-monsoon (PRM) seasons. The isotopic results showed a wide variation in the shallow groundwater, suggesting contribution from multiple recharge sources. But, the deeper groundwater recharge is mainly from precipitation. The northern part of the study area showed more depleted isotopic values, which rapidly changed towards south from -6.8 to -4.4‰. Alternatively, central and southern parts exhibited relatively enriched isotopic content with variation from -0.58 to -2.7‰. Groundwater was discerned to be brackish to saline with chloride content, 600-2060 mgL-1 and δ18O ranging from -5.8 to -4.5‰, suggesting influence of the saline water sources. A minor influence of anthropogenic activities was also observed in the deeper groundwater during PRM, which was confirmed by tritium and Cl- trends. The old groundwater with depleted isotopic content infer recharged by distant sources while modern groundwater with enriched isotopes points to the influence of evaporated recharge.


Asunto(s)
Efectos Antropogénicos , Agua Subterránea , Monitoreo del Ambiente , India , Isótopos/análisis
11.
Sci Rep ; 12(1): 2286, 2022 06 01.
Artículo en Inglés | MEDLINE | ID: mdl-35650242

RESUMEN

Water quality degradation and metal contamination in groundwater are serious concerns in an arid region with scanty water resources. This study aimed at evaluating the source of uranium (U) and potential health risk assessment in groundwater of the arid region of western Rajasthan and northern Gujarat. The probable source of vanadium (V) and fluorine (F) was also identified. U and trace metal concentration, along with physicochemical characteristics were determined for 265 groundwater samples collected from groundwater of duricrusts and palaeochannels of western Rajasthan and northern Gujarat. The U concentration ranged between 0.6 and 260 µg L-1 with a mean value of 24 µg L-1, and 30% of samples surpassed the World Health Organization's limit for U (30 µg L-1). Speciation results suggested that dissolution of primary U mineral, carnotite [K2(UO2)2(VO4)2·3H2O] governs the enrichment. Water-rock interaction and evaporation are found the major hydrogeochemical processes controlling U mineralization. Groundwater zones having high U concentrations are characterized by Na-Cl hydrogeochemical facies and high total dissolved solids. It is inferred from geochemical modelling and principal component analysis that silicate weathering, bicarbonate complexation, carnotite dissolution, and ion exchange are principal factors controlling major solute ion chemistry. The annual ingestion doses of U for all the age groups are found to be safe and below the permissible limit in all samples. The health risk assessment with trace elements manifested high carcinogenic risks for children.


Asunto(s)
Agua Subterránea , Uranio , Contaminantes Químicos del Agua , Niño , Monitoreo del Ambiente/métodos , Fluoruros/análisis , Agua Subterránea/química , Humanos , India , Medición de Riesgo , Uranio/análisis , Contaminantes Químicos del Agua/análisis
12.
Environ Geochem Health ; 32(2): 129-46, 2010 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-19551476

RESUMEN

Arsenic contamination in groundwater is of increasing concern because of its high toxicity and widespread occurrence. This study is an effort to trace the factors responsible for arsenic enrichment in groundwater of the middle Gangetic Plain of India through major ion chemistry, arsenic speciation, sediment grain-size analyses, and multivariate statistical techniques. The study focuses on the distinction between the contributions of natural weathering and anthropogenic inputs of arsenic with its spatial distribution and seasonal variations in the plain of the state Bihar of India. Thirty-six groundwater and one sediment core samples were collected in the pre-monsoon and post-monsoon seasons. Various graphical plots and statistical analysis were carried out using chemical data to enable hydrochemical evaluation of the aquifer system based on the ionic constituents, water types, hydrochemical facies, and factors controlling groundwater quality. Results suggest that the groundwater is characterized by slightly alkaline pH with moderate to strong reducing nature. The general trend of various ions was found to be Ca(2+) > Na(+) > Mg(2+) > K(+) > NH(4) (+); and HCO(3) (-) > Cl(-) > SO(4) (2-) > NO(3) (-) > PO(4) (3-) > F(-) in both seasons. Spatial and temporal variations showed a slightly higher arsenic concentration in the pre-monsoon period (118 microg/L) than in the post-monsoon period (114 microg/L). Results of correlation analyses indicate that arsenic contamination is strongly associated with high concentrations of Fe, PO(4) (3-), and NH(4) (+) but relatively low Mn concentrations. Further, the enrichment of arsenic is more prevalent in the proximity of the Ganges River, indicating that fluvial input is the main source of arsenic. Grain size analyses of sediment core samples revealed clay (fine-grained) strata between 4.5 and 7.5 m deep that govern the vertical distribution of arsenic. The weathering of carbonate and silicate minerals along with surface-groundwater interactions, ion exchange, and anthropogenic activities seem to be the processes governing groundwater contamination, including with arsenic. Although the percentage of wells exceeding the permissible limit (50 microg/L) was less (47%) than that reported in Bangladesh and West Bengal, the percentage contribution of toxic As(III) to total arsenic concentration is quite high (66%). This study is vital considering that groundwater is the exclusive source of drinking water in the region and not only makes situation alarming but also calls for immediate attention.


Asunto(s)
Arsénico/análisis , Monitoreo del Ambiente , Agua Dulce/química , Contaminantes Químicos del Agua/análisis , Geografía , Sedimentos Geológicos/química , Fenómenos Geológicos , India , Cinética , Tamaño de la Partícula , Estaciones del Año , Contaminantes del Suelo/análisis
13.
Sci Rep ; 10(1): 15324, 2020 09 18.
Artículo en Inglés | MEDLINE | ID: mdl-32948802

RESUMEN

Two atmospheric circulation patterns, the Indian Summer Monsoon (ISM) and mid-latitude Westerlies control precipitation and thus glacier variability in the Himalaya. However, the role of the ISM and westerlies in controlling climate and thus past glacier variability in the Himalaya is poorly understood because of the paucity of the ice core records. In this article, we present a new Holocene paleorecord disentangling the presence of the ISM and mid-latitude westerlies and their effect on glacier fluctuations during the Holocene. Our new record is based on high-resolution multi-proxy analyses (δ18Oporewater, deuterium-excess, grain size analysis, permeability, and environmental magnetism) of lake sediments retrieved from Chandratal Lake, Western Himalaya. Our study provides new evidence that improves the current understanding of the forcing factor behind glacier advances and retreat in the Western Himalaya and identifies the 8.2 ka cold event using the aforementioned proxies. The results indicate that the ISM dominated precipitation ~ 21% of the time, whereas the mid-latitude westerlies dominated precipitation ~ 79% of the time during the last 11 ka cal BP. This is the first study that portrays the moisture sources by using the above proxies from the Himalayan region as an alternative of ice core records.

14.
Isotopes Environ Health Stud ; 55(3): 254-271, 2019 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-31012329

RESUMEN

Stable isotopes of water (δ2H, δ18O) and δ13CTIC were used as a tool to trace the recharge processes, natural carbon (organic and inorganic) source and dynamics in the aquifers of the central Gangetic basin, India. Stable isotope (δ2H, δ18O) record of groundwater (n = 105) revealed that the groundwater of Piedmont was recharged by meteoric origin before evaporation, while aquifers of the older and younger alluvium were recharged by water that had undergone evaporation loss. River Ganges and its tributaries passing through this area have very little contribution in recharging while ponds play no role in the recharging of adjacent aquifers. The connectivity of shallow aquifers of aquitard formation (comprised of clay/sandy clay with thin patches of fine grey sand), i.e. 25-60 m below ground level (bgl) with the main upper aquifer (at a depth of >120 m bgl) was found to be higher in older and younger alluvium. Negative values of δ13CTIC (median -9.6 ‰; range -13.2 to -5.4 ‰) and high TIC (median 35 mM; range 31-46 mM) coupled with low TOC (median 1.35 mg/L; range 0.99-1.77 mg/L) indicated acceleration in microbial activity in the younger alluvium, especially in the active floodplain of river Ganges and its proximity.


Asunto(s)
Isótopos de Carbono/análisis , Deuterio/análisis , Agua Subterránea/análisis , Isótopos de Oxígeno/análisis , Bicarbonatos/análisis , Calcio/análisis , Monitoreo del Ambiente , India , Estanques/química , Ríos/química
15.
Bioresour Technol ; 99(10): 4467-75, 2008 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-17904360

RESUMEN

A pot-culture experiment was conducted to observe the effects of acidic sludge addition to the soils on bioavailability and uptake of heavy metals in different parts of pea plant as well as its influence on the growth of that plant. It is observed from our result the abundances of total and bio-available heavy metals in sludge vary as follows: Fe>Mn>Cr>Ni>Cu>Pb>Zn>Cd and Fe>Ni>Mn>Cr>Cu>Zn>Pb>Cd. Sludge applications increased both the total metals, DTPA-extractable metals and total N in the soils. On the other hand lime application has decreased the bioavailability of heavy metals with no change in total N in sludge amended soils. Organic carbon showed positive correlation with all metals except Zn, Cr and Pb. CEC also showed a strong positive correlation (R(2)>0.7) with the low translocation efficiency of pea plants. The value of translocation factor from shoot to seed was found to be smaller than root to shoot of pea plants. Our study thus shows that pea plants were found to be well adapted to the soil amended with 10% sludge with 0.5% lime treatment, minimizing most of the all metal uptake in the shoot of that plant. So, on the basis of the present study, possible treatment may be recommended for the secure disposal of acidic electroplating sludge.


Asunto(s)
Biotecnología/métodos , Monitoreo del Ambiente/métodos , Carbono/química , Química Orgánica/métodos , Galvanoplastia , Concentración de Iones de Hidrógeno , Residuos Industriales , Metales Pesados/análisis , Compuestos Orgánicos/química , Pisum sativum/metabolismo , Plantas/metabolismo , Análisis de Regresión , Aguas del Alcantarillado , Suelo , Contaminantes del Suelo
16.
J Hazard Mater ; 160(1): 187-93, 2008 Dec 15.
Artículo en Inglés | MEDLINE | ID: mdl-18433999

RESUMEN

A pot experiment was carried out to assess the effect of different amendments of industrial sludge on the growth of Canna indica L. as well as the translocation potential of heavy metals of this plant. The accumulation of metals (Cr, Fe, Cd, Cu, Ni, Zn, Mn and Pb) in different parts of C. indica L. grown on industrial sludge-amended soil increased with time and increasing doses of sludge amendments. Sequential extraction method was followed to estimate the different fractions of heavy metals in sludge-amended soils collected from different periods of this study. The results showed that Mn, Zn, Cd, Cr and Pb were mostly associated with Fe-Mn oxide fraction in all amendments, whereas, Ni was mostly found in residual (RES) fraction. Cu and Fe were found to be higher in organically bounded form (OM) and RES fraction. The metal concentration in C. indica L. after 90 days of experiment started, was in the order of Fe>Cr>Mn>Zn>Ni>Cu>Cd>Pb and the metal translocation was found lesser in shoot. With the increasing percentage of sludge amendments in soil the metal concentrations increased in different parts of plants. Overall, the plant C. indica L. was found to be well adapted in industrial sludge amendments and it may be recommended that this plant was found suitable for phytoremediation of most of the studied metals.


Asunto(s)
Residuos Industriales/análisis , Metales Pesados/química , Plantas/metabolismo , Contaminantes del Suelo/análisis , Química Física , Restauración y Remediación Ambiental , Análisis de Componente Principal , Aguas del Alcantarillado/análisis
17.
Artículo en Inglés | MEDLINE | ID: mdl-29360767

RESUMEN

A geochemical and speciation study of As, Fe, Mn, Zn, and Cu was performed using sequential extraction and statistical approaches in the core sediments taken at two locations-Rigni Chhapra and Chaube Chhapra-of the central Gangetic basin (India). A gradual increase in the grain size (varying from clay to coarse sands) was observed in both the core profiles up to 30.5 m depth. The concentrations of analyzed elements ranged as follows: 6.9-14.2 mg/kg for As, 13,849-31,088 mg/kg for Fe, 267-711 mg/kg for Mn, 45-164 mg/kg for Cu for Rigni Chhapra while for Chaube Chhapra the range was 7.5-13.2 mg/kg for As, 10,936-37,052 mg/kg for Fe, 267-1052 mg/kg for Mn, 60-198 mg/kg for Zn and 60-108 mg/kg for Cu. Significant amounts (53-95%) of all the fractionated elemental concentrations were bound within the crystal structure of the minerals as a residual fraction. The reducible fraction was the second most dominant fraction for As (7% and 8%), Fe (3%), Mn (20% and 26%), and Cu (7% and 6%) respectively for both the cores. It may be released when aquifers subjected to changing redox conditions. The acid soluble fraction was of most interest because it could quickly mobilize into the water system which formed the third most dominating among all three fractions. Four color code of sediments showed an association with total As concentration and did not show a relation with any fraction of all elements analyzed. The core sediment was observed enriched with As and other elements (Cu, Fe, Mn, and Zn). However, it fell under uncontaminated to moderately contaminate which might exhibit a low risk in prevailing natural conditions. X-ray diffraction analyses indicated the availability of siderite and magnetite minerals in the core sediments in a section of dark grey with micaceous medium sand with organic matter (black).


Asunto(s)
Sedimentos Geológicos/análisis , Metales Pesados/análisis , Monitoreo del Ambiente , Sedimentos Geológicos/química , India , Metales Pesados/química
18.
Mar Pollut Bull ; 129(1): 329-335, 2018 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-29680555

RESUMEN

Spatiotemporal variations of dissolved nutrients were studied along Gautami-Godavari mangrove ecosystem to delineate their sources and fate. Average values of nitrate (NO3-), dissolved silica (DSi) and phosphate (PO43-) is 2.09 mg/l, 12.7 mg/l and 0.16 mg/l in wet season and 0.47 mg/l, 6.96 mg/l and 0.29 mg/l in dry season respectively. In wet season river discharge has significant influence on NO3- and DSi. In dry season, NO3- and PO43- are controlled by groundwater discharge, benthic exchange and various in situ processes owing to sediment redox condition. Mixing model shows net addition of phosphate in Coringa mangroves (95%) and Lower estuary (13%) and net removal of nitrate (24.79%) in Coringa mangrove and in estuary (58.9%). Thus present mangrove acts as net source for phosphate and net sink for nitrate and DSi. Nutrient ratio shows seasonal switching between potential Phosphorus and Nitrogen limitation in wet and dry season respectively.


Asunto(s)
Monitoreo del Ambiente/métodos , Estuarios , Nitrógeno/análisis , Fósforo/análisis , Estaciones del Año , Humedales , Agua Subterránea/química , India , Ríos/química
19.
Chemosphere ; 204: 501-513, 2018 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-29679871

RESUMEN

Groundwater chemistry of mining region of East Singhbhum district having complex contaminant sources were investigated based on heavy metals loads and other hydrochemical constituents. This study aimed to identify the degree of heavy metals exposure and their potential health risk to local population. The results of hydrochemical analysis showed that Na+, K+, and Ca2+ ions are the dominant cations in the groundwater, while HCO3-, F- and Cl- ions dominate the anionic part of the groundwater. The weathering process was considered the dominant factor to determine the major ionic composition in the study area. Compositional analysis for heavy metal has identified that groundwater of the study area is contaminated by Cd, Pb and Cr elements. Source of these metals have been identified as an anthropogenic inputs from mining activities and mineral processing units. Health risk analysis of individual heavy metal for chronic daily intake (CDI) and hazard quotient (HQ) was found in the order of Cr > As > Cd > Pb which is indicating high health risk for the population. In addition, Hazard Index (HI) analysis for heavy metals was found significantly high (>1) which is considered as a threat for human population because they have the tendency to accumulate in the body and cause variety of diseases like kidney problem, dysfunction of liver and renal cortex as well as cancer.


Asunto(s)
Monitoreo del Ambiente/métodos , Agua Subterránea/química , Metales Pesados/análisis , Minería , Contaminantes Químicos del Agua/análisis , Humanos , India , Medición de Riesgo
20.
Mar Pollut Bull ; 127: 541-547, 2018 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-29475695

RESUMEN

Comparative study of trace metals distribution in the surface sediment of Sundarban mangrove ecosystem in India and Bangladesh is one of the primary baseline study done so far. Trace metal distribution assessment covering lower salinity zone to higher salinity zone was done along Matla River (tidal river) in Indian side and freshwater zone to higher salinity zone along Passur River in Bangladesh side of Sundarban; representing anthropogenic influenced area, agricultural area, tourist site and pristine area. Trace metals distribution in the surface sediments of Sundarban mangrove ecosystem shows relatively higher value of trace metals, Co, Cr, Cu, Fe, Ni, Pb and Zn in Indian part when compared to Bangladesh. Enrichment factor shows the highest enrichment of Pb in both parts of Sundarban mangroves. Co, Cr, Cu, Pb and Zn show EF>1 indicates sediment contamination from anthropogenic activities. Cr, Ni and Pb were found to have moderate accumulation in geoaccumulation index with Fe showing high accumulation. Normalized data of trace metals shows 87.5% from Indian site and 80% of Bangladesh site as outlier, indicating anthropogenic influence. Out of total sampling site 50% of Indian and 40% of Bangladesh site show trace metal values enriched more than predicted value of trace metals indicating Indian part have more polluted sites than Bangladesh side of Sundarban, which is also confirmed by enrichment factor, I-geo and normalization values in both the sides.


Asunto(s)
Monitoreo del Ambiente/métodos , Sedimentos Geológicos/química , Metales Pesados/análisis , Oligoelementos/análisis , Contaminantes Químicos del Agua/análisis , Humedales , Bangladesh , India , Ríos/química
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