Background Estimation and Distribution of Anthropogenic Input of Cadmium in Arable Land Soil

摘要

Obtaining accurate cadmium background concentrations in arable land soil is important because it can identify the anthropogenic Cd input distribution and realistically set the guiding level for remediation. In this study, four methods were applied, including the Iterative-2σ technique, 95 % upper confidence limit (UCL0.95), accumulative frequency plot and GM+2GSD (geometric mean + 2 x geometric standard) in order to estimate the Cd background concentrations in Hainan Island's arable land soil. In a comparative analysis, using the GM+2GSD method is ideal for estimating the background Cd concentrations since it does not consider the hypothetical distribution functions like UCL_(0.95). A concentration of 75 μg kg~(-1) was accepted as the Cd background concentration in arable land soils. The distribution of anthropogenic Cd inputs was obtained by subtracting the background concentrations from an existing spatial distribution of Cd. Rapid urbanization and excessive application of chemical fertilizers and pesticides have been attributed to the anthropogenic Cd input of Hainan's arable land soil.