Prediction of Arsenic Uptake by Rice in the Paddy Fields Vulnerable to Arsenic Contamination

초록

There is an increasing concern over arsenic (As) contamination in rice. This study was conducted to develope aprediction model for As uptake by rice based on the physico-chemical properties of soil. Soil and brown ricesamples were collected from 46 sites in paddy fields near three different areas of closed mines and industrialcomplexes. Total As concentration, soil pH, Al oxide, available phosphorus (avail-P), organic matter (OM)content, and clay content in the soil samples were determined. Also, 1.0 N HCl, 1.0 M NH4NO3, 0.01 MCa(NO3)2, and Mehlich 3 extractable-As in the soils were measured as phytoavailable As concentration in soil. Total As concentration in brown rice samples was also determined. Relationships among As concentrations inbrown rice, total As concentrations in soils, and selected soil properties were as follows: As concentration inbrown rice was negatively correlated with soil pH value, where as it was positively correlated with Al oxideconcentration, avail-P concentration, and OM content in soil. In addition, the concentration of As in brown ricewas statistically correlated only with 1.0 N HCl-extractable As in soil. Also, using multiple stepwise regressionanalysis, a modelling equation was created to predict As concentration in brown rice as affected by selected soilproperties including soil As concentration. Prediction of As uptake by rice was delineated by the model [As inbrown rice = 0.352 + 0.00109 * HCl extractable As in soil + 0.00002 * Al oxide + 0.0097 * OM + 0.00061 *avail-P – 0.0332 * soil pH] (R = 0.714***). The concentrations of As in brown rice estimated by the modellingequation were statistically acceptable because normalized mean error (NME) and normalized root mean squareerror (NRMSE) values were -0.055 and 0.2229, respectively, when compared with measured As concentration inthe plant.

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