Distribution Characteristics of Cadmium and Arsenic in the Typical Vegetable Soil and the Sediment of its Irrigation Sources in Xijiang River Basin at the End of the Farming Slack Period.

Abstract

We collected the farmland soil and the sediment, carried out sample speciation detection and distribution analyses, explored environmental self-purification on the distribution of Cd and As of agricultural sources. There were significant differences between total Cd and total As and between speciation distribution in the orders of magnitude. Total Cd (mean content was 1.74mgkg-1) and total As (mean content was 32.31mgkg-1) in all the samples were higher than the background contents. Cd distribution in the farmland soil was not significantly affected by geographical locations. As cumulative effect in riverside farmland soil was stronger, river irrigation and flooding may input more As, transformation mechanism of As may be exogenous input, binding and passive release. The bio-available proportions and risk assessment criteria of Cd were larger than As, the ecological risk of local Cd was higher than As, suggested to increase risk monitoring of Cd.