title: Cadmium availability in rice paddy fields from a mining area: The effects of soil properties highlighting iron fractions and pH value.
abstract: Cadmium (Cd) availability can be significantly affected by soil properties. The effect of pH value on Cd availability has been confirmed. Paddy soils in South China generally contain high contents of iron (Fe). Thus, it is hypothesized that Fe fractions, in addition to pH value, may play an important role in the Cd bioavailability in paddy soil and this requires further investigation. In this study, 73 paired soil and rice plant samples were collected from paddy fields those were contaminated by acid mine drainage containing Cd. The contents of Fe in the amorphous and DCB-extractable Fe oxides were significantly and negatively correlated with the Cd content in rice grain or straw (excluding DCB-extractable Fe vs Cd in straw). In addition, the concentration of HCl-extractable Fe(II) derived from Fe(III) reduction was positively correlated with the Cd content in rice grain or straw. These results suggest that soil Fe redox could affect the availability of Cd in rice plant. Contribution assessment of soil properties to Cd accumulation in rice grain based on random forest (RF) and stochastic gradient boosting (SGB) showed that pH value should be the most important factor and the content of Fe in the amorphous Fe oxides should be the second most important factor in affecting Cd content in rice grain. Overall, compared with the studies from temperate regions, such as Europe and northern China, Fe oxide exhibited its unique role in the bioavailability of Cd in the reddish paddy soil from our study area. The exploration of practical remediation strategies for Cd from the perspective of Fe oxide may be promising.
authors.affiliation: Guangdong Key Laboratory of Agricultural Environment Pollution Integrated Control, Guangdong Institute of Eco-Environmental and Soil Sciences, Guangzhou, China.
authors.forename: Huan-Yun
authors.initials: HY
authors.lastname: Yu
authors.affiliation: Guangdong Key Laboratory of Agricultural Environment Pollution Integrated Control, Guangdong Institute of Eco-Environmental and Soil Sciences, Guangzhou, China.
authors.forename: Chuanping
authors.initials: C
authors.lastname: Liu
authors.affiliation: Guangdong Key Laboratory of Agricultural Environment Pollution Integrated Control, Guangdong Institute of Eco-Environmental and Soil Sciences, Guangzhou, China.
authors.forename: Jishu
authors.initials: J
authors.lastname: Zhu
authors.affiliation: Guangdong Key Laboratory of Agricultural Environment Pollution Integrated Control, Guangdong Institute of Eco-Environmental and Soil Sciences, Guangzhou, China. Electronic address: cefbli@soil.gd.cn.
authors.forename: Fangbai
authors.initials: F
authors.lastname: Li
authors.affiliation: Guangxi University of Science and Technology, Liuzhou, 545006, China.
authors.forename: Dong-Mei
authors.initials: DM
authors.lastname: Deng
authors.affiliation: Guangdong Key Laboratory of Agricultural Environment Pollution Integrated Control, Guangdong Institute of Eco-Environmental and Soil Sciences, Guangzhou, China.
authors.forename: Qi
authors.initials: Q
authors.lastname: Wang
authors.affiliation: Guangdong Key Laboratory of Agricultural Environment Pollution Integrated Control, Guangdong Institute of Eco-Environmental and Soil Sciences, Guangzhou, China.
authors.forename: Chengshuai
authors.initials: C
authors.lastname: Liu
mesh_terms: D000143:Acids / Q000032:analysis; D001682:Biological Availability; D002104:Cadmium / Q000032:analysis*; D002681:China; D006863:Hydrogen-Ion Concentration; D007501:Iron / Q000032:analysis*; D008906:Mining; D012275:Oryza / Q000737:chemistry* / Q000254:growth & development; D010087:Oxides / Q000032:analysis; D012987:Soil / Q000737:chemistry*
chemical_list: D000143:Acids; D010087:Oxides; D012987:Soil; D002104:Cadmium; D007501:Iron
keywords: Cadmium bioavailability; Fe oxide; Paddy soils; Soil properties; pH