Elemental content to rice grain related to growing regions and soil microbiology
Rice is the staple food of many Asian countries including Sri Lanka. Arsenic and other micropollutants accumulation in rice grain is becoming a serious issue due to several reasons. Some of these micropollutants are highly carcinogenic even in trace amounts. Moreover, People who use rice as their staple food has a high per capita use and therefore there is a tendency to get accumulated those micropollutants in considerable amounts in consumer’s body and cause various health problems. On the Other hand, rice is the major source of essential micro elemental nutrients for those people. Mobility and the availability of those trace elements, uptake of trace elements by rice plants and transferring them into rice grain is not fully understood yet. This study was mainly focused on the variability of metal(loid)s in rice, based on the growing regions linking with edaphic and microbial factors that would regulates those variabilities. Paddy soils and associated paddy samples were collected from various geographical locations ana analyzed for trace elements and As species in those samples. Soil and porewater chemical parameters such as pH, Eh, SOC were measured and kinked with element concentrations in soil and porewater. Moreover, bacterial DNA was extracted from paddy soils and log2 copy number of 16S rRNA and arsM genes were detected using qPCR. Those results were linked with the soil chemical parameters. The results of this study suggested that edaphic factors such as pH and Eh control the availability and mobility of trace elements in paddy soil. Furthermore, this study revealed that 16S rRNA and arsM copy number depend on the edaphic factors as well as paddy management practices.
Rice, paddy soil, porewater, trace elements, ICP-MS, arsenic methylation
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