Geochemical relationship and translocation mechanism of arsenic in rice plants: A case study from health prone south west Punjab, India
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Date
2020
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Elsevier B.V.
Abstract
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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Keywords
Antioxidants, Arsenic, Oxidative stress, Rice, Translocation