Arsenic speciation dynamics in paddy rice soil-water environment: sources, physico-chemical, and biological factors - A review

Prasanna Kumarathilaka, Saman Seneweera, Andrew Meharg, Jochen Bundschuh

Research output: Contribution to journalReview article

52 Citations (Scopus)

Abstract

Rice is the main staple carbohydrate source for billions of people worldwide. Natural geogenic and anthropogenic sources has led to high arsenic (As) concentrations in rice grains. This is because As is highly bioavailable to rice roots under conditions in which rice is cultivated. A multifaceted and interdisciplinary understanding, both of short-term and long-term effects, are required to identify spatial and temporal changes in As contamination levels in paddy soil-water systems. During flooding, soil pore waters are elevated in inorganic As compared to dryland cultivation systems, as anaerobism results in poorly mobile As(V), being reduced to highly mobile As(III). The formation of iron (Fe) plaque on roots, availability of metal (hydro)oxides (Fe and Mn), organic matter, clay mineralogy and competing ions and compounds (PO43- and Si(OH)4) are all known to influence As(V) and As(III) mobility in paddy soil-water environments. Microorganisms play a key role in As transformation through oxidation/reduction, and methylation/volatilization reactions, but transformation kinetics are poorly understood. Scientific-based optimization of all biogeochemical parameters may help to significantly reduce the bioavailability of inorganic As.

Original languageEnglish
Pages (from-to)403-414
Number of pages12
JournalWater Research
Volume140
Early online date21 Apr 2018
DOIs
Publication statusPublished - 01 Sep 2018
Externally publishedYes

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