Department Of Environmental Science And Technology

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Subject: search.filters.subject.Arsenic

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    Arsenic Contamination in Groundwater and Its Removal Strategies with Special Emphasis on Nano Zerovalent Iron
    (wiley, 2022-12-02T00:00:00) Thakur, Shivani; Singh, Harminder; Chaudhari, Umakant; Mittal, Sunil; Sahoo, Prafulla Kumar
    An occurrence of arsenic (As) in an aquatic ecosystem is a major concern because of its very toxic and carcinogenic nature. Groundwater arsenic pollution has been reported globally, notably along the large Indo-Gangetic flood plain and some major rivers of South Asia and South American nations. It comes in water both via natural and anthropogenic sources. Major processes that trigger the release of As in groundwater include reductive dissolution of Fe-oxyhydroxides, sulfide oxidation, and alkali desorption. Microbial metabolisms of arsenic also play a crucial role in its mobilization in aquifers. Ions such as HCO 3 ? and PO 4 3? also help in triggering arsenic mobility in water. Different methods are developed for As removal from water such as precipitation, coagulation, ion exchange, and membrane filtration, but none of the methods are as effective as nanomaterials. With the advancement in a study in nanotechnology during the past few years, an increase in usage of different nanomaterials as adsorbents for arsenic removal has also been observed. Among these, nano zerovalent iron (nZVI) has been proved quite effective for arsenic removal from the water by the adsorption technique. The nZVI has high reactivity, good efficiency, and fast action for As removal, and a low impact on the environment. Further, intensive research is going on to alter the properties of nZVI following specific applications as per the requirements. This chapter presents an overview of several geochemical processes aiding in As mobility from the aquifer sediments into groundwater, briefly describing its distribution pattern across global groundwater systems. It also aims to provide an overview of the effectiveness of different iron-based nanoparticles with particular reference to nZVI for the removal of different species of Arsenic from water. � 2023 John Wiley & Sons Ltd. Published 2023 by John Wiley & Sons Ltd. All rights reserved.
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    Geochemical relationship and translocation mechanism of arsenic in rice plants: A case study from health prone south west Punjab, India
    (Elsevier B.V., 2020) Sharma S.; Kumar R.; Sahoo P.K.; Mittal S.
    Rice is a recognised hyperaccumulator of arsenic (As) and is a serious concern for rice varieties grown in As contaminated soil-water systems. In this regard, groundwater, soil and rice-plant samples (two varieties: PR122 and PUSA1121) collected from 10 sites of district Bathinda were studied for their physicochemical characteristics and As concentration. In vitro studies were carried out to study the role of antioxidant enzymes in As uptake and translocation mechanism. The results showed that the As concentration in water and soil samples ranged from 54 to 132 ?g/L and 6.62–19.56 mg/kg, respectively. The As in rice roots, straw, husk and grains of PR122 ranged from 1.89 to 8.56, 0.20–5.3, 0.12–1.42, 0–0.12 mg/kg, respectively and 1.24–8.16, 0.54–5.11, 0.11–1.06 mg/kg and below detection limit (BDL), respectively for PUSA1121. Although a moderate correlation (r = 0.37) was observed between As in groundwater and soil, the higher As concentration found in both media in Behman and Teona areas indicates that we cannot ignore the role of groundwater in As contamination. Spearman correlation analysis indicates the positive impact of As from groundwater and soil in aerial parts of both rice varieties except grains. In vitro studies showed an increase in antioxidant enzyme activities with the increase in As toxicity (15–60 ?M), which indicates As tolerant behaviour in both rice varieties. The hazard quotient (HQ) for both rice varieties is < 1, which suggest no potential non-cancer health risk, however the cancer risk (CR) for PR122 variety exceeded (2.06 – 10?4) the acceptable limit of 1 × 10?4 (USEPA). Based on the present study, it can be concluded that both the rice varieties are tolerant to As and their grains are safe for human consumption.
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    Arsenic induced physiological changes in improved varieties of rice grown in Malwa region of Punjab
    (Society for Advancement of Human and Nature (SADHNA), 2015) Kamboj, Ritu; Sharma, S; Vishwakarma, G.S.; Mittal, Sunil
    Rice is a major staple food throughout the world. However metal contamination of rice has been recognized as a new disaster on large scale. Two rice cultivars viz PR 116 and PR 118 were grown in vitro to study the effect of increasing arsenic concentration (50, 100, 250 and 500 µM) on germination, root and shoot length, biomass dry weight, chlorophyll content and per cent cellular respiration. Results showed reduction in all these parameters thereby proving the toxic nature of arsenic. Arsenic accumulation in roots and shoots of both the varieties was monitored by atomic absorption spectrophotometer (AAS) and it was concluded that arsenic is translocated to above ground tissues and ultimately reaches the grain. The status of arsenic concentration of rice and its affect on human health need to be further investigated.
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    Arsenic Induced Alteration in Macromolecule Concentration and Antioxidant System in Two Improved Rice Varieties
    (Tamil Nadu Scientific Research Organization (TNSRO), 2016) Kamboj, Ritu; Vishwakarma, Gajendra Singh; Sharma, Shilpa; Mittal, Sunil
    Arsenic contamination of rice has been highlighted as major issue throughout the world as it is a staple food for millions. The aim of study was to analyze the effect of different concentration of arsenic on the germination, physiology, macromolecules concentration and antioxidant enzymes in improved varieties of rice. In vitro study indicates that the lower concentration of arsenate had a stimulating effect on germination, chlorophyll content as well as respiratory content while an inhibitory effect at higher concentration. Roots were more affected than shoots. Further, the content of macromolecules (carbohydrate and protein) was elevated while the activities of their hydrolyzing enzymes (α, β amylase and protease) were declined on arsenic stress. The significant elevation in the activity of superoxide dismutase and peroxidase enzymes also proved the generation of reactive oxygen species due to the arsenic toxicity