title: An invisible soil acidification: Critical role of soil carbonate and its impact on heavy metal bioavailability.
abstract: It is well known that carbonates inhibit heavy metals transferring from soil to plants, yet the mechanism is poorly understood. Based on the Yangtze River delta area, we investigated bioaccumulation of Ni and Cd in winter wheat as affected by the presence of carbonates in soil. This study aimed to determine the mechanism through which soil carbonates restrict transport and plant uptake of heavy metals in the wheat cropping system. The results indicate that soil carbonates critically influenced heavy metal transfer from soil to plants and presented a tipping point. Wheat grains harvested from carbonates-depleted (due to severe leaching) soils showed Ni and Cd concentrations 2-3 times higher than those of the wheat grains from carbonates-containing soils. Correspondingly, the incidence of Ni or Cd contamination in the wheat grain samples increased by about three times. With the carbonate concentration >1% in soil, uptake and bioaccumulation of Ni and Cd by winter wheat was independent with the soil pH and carbonate content. The findings suggest that soil carbonates play a critical role in heavy metal transfer from soil to plants, implying that monitoring soil carbonate may be necessary in addition to soil pH for the evaluating soil quality and food safety.
authors.affiliation: Key Laboratory of Surficial Geochemistry, Ministry of Education, School of Earth Sciences and Engineering, Nanjing University, Nanjing 210093, China.
authors.forename: Cheng
authors.initials: C
authors.lastname: Wang
authors.affiliation: 1] Key Laboratory of Surficial Geochemistry, Ministry of Education, School of Earth Sciences and Engineering, Nanjing University, Nanjing 210093, China [2] Environmental Soil Chemistry Group, Delaware Environmental Institute and Department of Plant and Soil Sciences, University of Delaware, Newark, Delaware 19716, United States.
authors.forename: Wei
authors.initials: W
authors.lastname: Li
authors.affiliation: School of Earth Sciences and Resources, China University of Geosciences, Beijing 100083, China.
authors.forename: Zhongfang
authors.initials: Z
authors.lastname: Yang
authors.affiliation: Key Laboratory of Surficial Geochemistry, Ministry of Education, School of Earth Sciences and Engineering, Nanjing University, Nanjing 210093, China.
authors.forename: Yang
authors.initials: Y
authors.lastname: Chen
authors.affiliation: Key Laboratory of Surficial Geochemistry, Ministry of Education, School of Earth Sciences and Engineering, Nanjing University, Nanjing 210093, China.
authors.forename: Wenjing
authors.initials: W
authors.lastname: Shao
authors.affiliation: Key Laboratory of Surficial Geochemistry, Ministry of Education, School of Earth Sciences and Engineering, Nanjing University, Nanjing 210093, China.
authors.forename: Junfeng
authors.initials: J
authors.lastname: Ji
mesh_terms: D001682:Biological Availability; D002104:Cadmium / Q000737:chemistry / Q000493:pharmacokinetics; D002254:Carbonates / Q000737:chemistry; D002681:China; D006863:Hydrogen-Ion Concentration; D019216:Metals, Heavy / Q000737:chemistry / Q000493:pharmacokinetics*; D009532:Nickel / Q000737:chemistry / Q000493:pharmacokinetics; D012987:Soil / Q000737:chemistry*; D012989:Soil Pollutants / Q000737:chemistry / Q000493:pharmacokinetics*; D014908:Triticum / Q000187:drug effects / Q000378:metabolism
chemical_list: D002254:Carbonates; D019216:Metals, Heavy; D012987:Soil; D012989:Soil Pollutants; D002104:Cadmium; D009532:Nickel