Effects of Soil Properties on Crop Cd Uptake and Prediction of Cd Concentration in Grains

Soil Cd anomaly is ubiquitous in alluvial plains along rivers. Cereal produced in these areas is one of the major contributors to the dietary intake. A number of soil factors have been shown to affect the availability of soil Cd to crops. In order to determine the most notable factors affecting Cd concentration in crops, paired soil and paddy or wheat grain samples were collected from a large number of field sites that encompassed a wide range of soil types within the suburb of three cities in Jiangsu province. The statistic results showed that soil pH and total soil Cd content were the significant affecting factors (P0.01) though cation exchange capacity, salinity, organic carbon content and clay content also played some roles in controlling Cd concentration in the two crop grains. Using multiple regression analysis which included the factors of soil pH and total soil Cd content only, the best-fit predictive models for paddy and wheat were developed: log(rice Cd)=-0.369-0.068 pH+0.153 log(soil Cd), and log(wheat Cd)=0.624-0.164 pH+0.421 log(soil Cd). Compared with the measured Cd concentration in grains, the predicted Cd concentrations in paddy and wheat grain from the two models were well fitted.