title: Heavy metal contents, distribution, and prediction in a regional soil-wheat system.
abstract: The entry of heavy metals into the food chain is of concern for potential health risks. To investigate the spatial relationships of heavy metals in a regional soil-wheat system, 99 pairs of surface soil (0-15 cm) and wheat grain samples were collected from Changshu, China, a typical county in the Yangtze Delta region. Both soil and wheat grain samples were analyzed for total Cd, Cu, Ni, Pb, and Zn. DTPA-extractable metals and major physico-chemical properties were also determined for soil samples. Moderate accumulation of heavy metals was found in soils and wheat grains, especially Cd. However, the levels were within the target hazard quotients (THQ) safe values with respect to non-carcinogenic risks, but more attention should be paid to Cd. Spatially, Cd, Cu, Ni, and Zn in wheat grains and soils had similar geographical patterns, whereas Pb showed opposite trends. Cross-correlograms further quantitatively confirmed the spatial relationships of heavy metals in wheat grains and soils. In addition, heavy metals in wheat grains were significantly spatially correlated with most soil physio-chemical properties. Particularly, a set of regression models for Cd in wheat grains were established with a maximum predictive success of 65%. These models can be used to predict Cd in wheat grains, and thus allows farmers to decrease the threat by certain framing practices such as ameliorating soil pH or growing a less metal-accumulating cultivar.
authors.affiliation: Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China; University of Chinese Academy of Sciences, Beijing 100049, China.
authors.forename: Jing
authors.initials: J
authors.lastname: Ran
authors.affiliation: Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China. Electronic address: djwang@issas.ac.cn.
authors.forename: Dejian
authors.initials: D
authors.lastname: Wang
authors.affiliation: Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China.
authors.forename: Can
authors.initials: C
authors.lastname: Wang
authors.affiliation: Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China.
authors.forename: Gang
authors.initials: G
authors.lastname: Zhang
authors.affiliation: Department of Plant and Soil Sciences, Oklahoma State University, Stillwater, OK 74078, USA.
authors.forename: Hailin
authors.initials: H
authors.lastname: Zhang
mesh_terms: D002681:China; D004784:Environmental Monitoring; D005506:Food Contamination / Q000032:analysis*; D019216:Metals, Heavy / Q000032:analysis*; D012987:Soil / Q000737:chemistry; D012989:Soil Pollutants / Q000032:analysis*; D014908:Triticum / Q000737:chemistry*
chemical_list: D019216:Metals, Heavy; D012987:Soil; D012989:Soil Pollutants
keywords: Heavy metals; Potential health risk; Prediction model; Spatial relationship; Surface soils; Wheat grains