Groundwater Quality beneath an Asian Megacity on a Delta: Kolkata’s (Calcutta’s) Disappearing Arsenic and Present Manganese

McArthur, J. M.; Sikdar, P. K.; Leng, Melanie J.; Ghosal, Utsab; Sen, Indra Sekhar

doi:10.1021/acs.est.7b04996

Cited by 28 publications

(29 citation statements)

References 66 publications

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“…Elevated As and Mn concentrations are frequently correlated in groundwater [22,[27][28][29][30][31][32]. Concentrations of As and Mn in these studies were as high as 1340 µg/L [28] and 4000 µg/L [27], respectively.…”

Section: Introductionmentioning

confidence: 58%

Arsenite Depletion by Manganese Oxides: A Case Study on the Limitations of Observed First Order Rate Constants

Schacht

Ginder‐Vogel

2018

Soil Systems

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Arsenic (As) contamination of drinking water is a threat to global health. Manganese(III/IV) (Mn) oxides control As in groundwater by oxidizing more mobile As III to less mobile As V. Both As species sorb to the Mn oxide. The rates and mechanisms of this process are the subject of extensive research; however, as a group, study results are inconclusive and often contradictory. Here, the existing body of literature describing As III oxidation by Mn oxides is examined, and several potential reasons for inconsistent kinetic data are discussed. The oxidation of As III by Mn(III/IV) oxides is generally biphasic, with reported first order rate constants ranging seven orders of magnitude. Reanalysis of existing datasets from batch reactions of As III with δ-MnO 2 reveal that the first order rate constants reported for As depletion are time-dependent, and are not well described by pure kinetic rate models. This finding emphasizes the importance of mechanistic modeling that accounts for differences in reactivity between Mn III and Mn IV , and the sorption and desorption of As III , As V , and Mn II. A thorough understanding of the reaction is crucial to predicting As fate in groundwater and removing As via water treatment with Mn oxides, thus ensuring worldwide access to safe drinking water.

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Section: Introductionmentioning

confidence: 58%

Arsenite Depletion by Manganese Oxides: A Case Study on the Limitations of Observed First Order Rate Constants

Schacht

Ginder‐Vogel

2018

Soil Systems

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“…In S/SE Asia, As impacts the health of millions of people and has been well documented in areas of Bangladesh [5][6][7][8][9][10][11][12][13][14][15], Cambodia [16][17][18][19][20][21][22][23][24][25][26][27][28][29], Vietnam [30][31][32][33][34][35][36][37][38][39][40][41], Pakistan [42][43][44][45] and more recently, Myanmar [46][47][48][49]. In India, groundwater As, particularly in the Ganga Basin, has been widely reported in West Bengal (noting that a reduced As hazard as compared with previous estimates has recently been postulated in a Kolkata-based study [71]), Uttar Pradesh [72][73]…”

Section: Introductionmentioning

confidence: 99%

Distribution and Geochemical Controls of Arsenic and Uranium in Groundwater-Derived Drinking Water in Bihar, India

Richards

Kumar

Shankar

et al. 2020

IJERPH

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Chronic exposure to groundwater containing elevated concentrations of geogenic contaminants such as arsenic (As) and uranium (U) can lead to detrimental health impacts. In this study, we have undertaken a groundwater survey of representative sites across all districts of the State of Bihar, in the Middle Gangetic Plain of north-eastern India. The aim is to characterize the inorganic major and trace element aqueous geochemistry in groundwater sources widely used for drinking in Bihar, with a particular focus on the spatial distribution and associated geochemical controls on groundwater As and U. Concentrations of As and U are highly heterogeneous across Bihar, exceeding (provisional) guideline values in~16% and 7% of samples (n = 273), respectively. The strongly inverse correlation between As and U is consistent with the contrasting redox controls on As and U mobility. High As is associated with Fe, Mn, lower Eh and is depth-dependent; in contrast, high U is associated with HCO 3 − , NO 3 − and higher Eh. The improved understanding of the distribution and geochemical controls on As and U in Bihar has important implications on remediation priorities and selection, and may contribute to informing further monitoring and/or representative characterization efforts in Bihar and elsewhere in India.Vaishali, noting importantly that only sources within 10 km of the Ganga River were sampled) [77]. Most recently, it has been reported that 22 districts of Bihar are currently As-impacted, although no further details such as location, non-summarized data or the functional definition of "As-impacted" are included [78]. Further, wheat consumption has recently been identified as an emerging route of As exposure in Bihar [84]. Although thorough reviews of the status of As in the Gangetic Basin are published elsewhere [78,85], the estimated population at risk for As contamination in West Bengal is 26 million people, followed by Bihar (9 million), Uttar Pradesh (3 million), Assam (1.2 million), Manipur (1 million) and Jharkhand (0.4 million) [85]. Widespread in nature, U is a radionuclide which geogenically occurs in granite and other rock types. U in groundwater can occur due to natural mobilization processes under oxic conditions, and can also be associated with anthropogenic activities such as mining, coal and fuel combustion, emissions from the nuclear industry and the use of PO 4 -based fertilizers containing U [4]. As chronic exposure to U may lead to numerous adverse health impacts including bone toxicity and impaired renal function [86,87], WHO has set a provisional guideline value of 0.13 µM (30 µg.L −1 ), noting that Germany adopted a lower threshold of 0.04 µM (10 µg.L −1 ) in 2011 [88]. Elevated concentrations of U in groundwater have been identified across the globe, including in North America (e.g., Canada [89], the United States [90,91]), Europe (e.g., Finland [87], Sweden [92], Switzerland [93], the United Kingdom [94]) and Asia (e.g., Bangladesh [95], China [96,97], Korea [98], Mongolia [99], Pakistan [43] and in the...

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“…Under the Ramsar Convention, in August 2002, the East Kolkata Wetlands were designated as a "wetland of international importance" [18]. Details on geology, geomorphology, surface water and groundwater hydrology and ecology are given in the publications by McArthur et al [19], Sahu and Sikdar [20][21][22][23][24], Sahu et al [25], Sikdar et al [26,27], Sikdar [28,29], Sikdar and Dasgupta [30]. The research focuses on the KMC area, and the EKW stand for their support to contribute to ecosystem service valuations (ESVs).…”

Section: Study Areamentioning

confidence: 99%

“…The water quality variables with corresponding objectives (as per the existing Indian regulatory authorities) tested for the CCME WQI calculation are listed in Table 5. [19] and WBPCB [40]). Groundwater quality index was calculated using water quality data of 270 groundwater monitoring stations (Figure 2) obtained from McAuthur et al [19].…”

Section: Water Quality Indexmentioning

confidence: 99%

Assessment of Environmental Water Security of an Asian Deltaic Megacity and Its Peri-Urban Wetland Areas

et al. 2021

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Achieving urban water security requires sustaining the trade-offs between the exploitation of water/environmental resources and ecosystem services. This achievement not only reduces the pollution and contamination in the environment, level of water stress, but also secures good ambient water quality and future for people’s well-being and livelihoods. Changes in land use and land cover and growth of impervious structures can immediately generate severe ecological and social issues and increase the level of natural or manmade risks, affecting the condition of ecosystem services within and in the vicinity of an urban region. As a result of these transformations and further exploitation, due to the growing anthropogenic pressure, surface water and groundwater quality can be deteriorated compared to ambient water quality standards (for both chemical and biological pollutants). Based on land use and land cover (LULC) data retrieved from remote sensing interpretation, we computed the changes of the ecosystem service values (ESV) associated with the LULC dynamics, water quality and, finally, urban water security during the pre- and post-monsoon periods of 2009, 2014 and 2019 in Kolkata, an Asian deltaic megacity, and its peri-urban wetlands named East Kolkata Wetlands (EKW). The area under wetlands reduced comprehensively in 2009–2019 due to the conversion of wetlands into various other classes such as urban settlement, etc. The quality of surface water bodies (such as rivers, lakes, canals and inland wetlands) deteriorated. The groundwater quality is still under control, but the presence of arsenic, manganese and other metals are a clear indication of urban expansion and related activities in the area. As a result, there was a change in the ESV during this timeframe. In the pre-monsoon period, there was an increase in total ESV from US$53.14 million in 2009 to US$53.36 million and US$59.01 million in 2014 and 2019, respectively. In the post-monsoon period, the ESV decreased from US$67.42 million in 2009 to US$64.13 and US$61.89 million in 2014 and 2019, respectively. These changes can be attributed to the peri-urban wetlands and the benefits or services arising out of them that contribute more than 50% of the total ESV. This study found that the area under wetlands has reduced comprehensively in the past 10 years due to the conversion of wetlands for various other uses such as urban expansion of the Kolkata City, but still, this peri-urban wetland supports the urban water security by providing sufficient ecosystem services. In conclusion, the transformation in extent of the water-related ecosystem is a crucial indicator of urban water security, which also measures the quantity of water contained in various water-related ecosystems. Quantitative analysis of the LULC change, hence, is important for studying the corresponding impact on the ecosystem service value (ESV) and water quality that helps in decision-making in securing urban water future and ecosystem conservation.

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Groundwater Quality beneath an Asian Megacity on a Delta: Kolkata’s (Calcutta’s) Disappearing Arsenic and Present Manganese

Cited by 28 publications

References 66 publications

Arsenite Depletion by Manganese Oxides: A Case Study on the Limitations of Observed First Order Rate Constants

Arsenite Depletion by Manganese Oxides: A Case Study on the Limitations of Observed First Order Rate Constants

Distribution and Geochemical Controls of Arsenic and Uranium in Groundwater-Derived Drinking Water in Bihar, India

Assessment of Environmental Water Security of an Asian Deltaic Megacity and Its Peri-Urban Wetland Areas

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