Enrichment characteristics of selenium and cadmium in farmland soil-rice system and their relationships in the Nandu River basin
Selenium(Se)and Cadmium(Cd)contents in 80 samples of farmland topsoil and rice in the Nandu River basin were deter-mined.The enrichment characteristics of Se and Cd in the soil-rice system were analyzed using bioenrichment coefficients,and the in-terrelationships among Se content,Cd content,pH value and organic carbon content of topsoil and rice were analyzed using Pearson coefficient analysis.The results showed that,the farmland soil of the study area met the standards for sufficient and rich selenium,and 40%of the rice samples met the Se rich rice standard.The Cd content in the soil did not exceed the national agricultural land pollution risk screening value(0.300 mg/kg),and the Cd content in rice was less than the national food safety standard value(0.200 mg/kg),indicating no Cd pollution in the study area.The Se content in the soil-rice system in the study area showed a normal distribution,with an obvious segmentation phenomenon.Cd content was strongly influenced by external interference and was unevenly distributed in space.Both Se and Cd elements were moderately enriched in rice,with rice having a stronger ability to enrich Cd than Se.The Se rich soil in the study area was closely related to the local acidic soil environment and high organic carbon content.In summary,the farm-land soil Se resources in the Nandu River basin were abundant,and there was no phenomenon of"se-rice and cd-unpvlluted rice".It could be developed and utilized to produce green Se rich agricultural products.
soil-rice systemSeCdenrichment characteristicsatomic fluorescence spectrometer(AFS)inductively coupled plasma mass spectrometer(ICP-MS)Nandu River basin
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