Biogeochemical cycling of selenium in Chinese environments

The biogeochemical cycling and chemical transformation of Se in Chinese env ironments is reviewed, especially with regard to the formation of low-Se en vironments. The occurrence, distribution, concentration and flux of Se in C hinese environments are reported in comparison to those in the rest of the world. Low-Se regions in China can be classified into 4 categories. In the NE, organic matter in the soil affects bioavailability of Se in soil. In th e Huabei plain, the concentration of soil Se is strongly influenced by leac hing acid hydrological transport processes and Se deficient regions are mos tly located on the hill-slopes due to leaching. In the Loessial Plateau, lo w-Se soils have developed on the low-Se parent material with a very low flu x of Se between soil and plants. Low-Se regions in the SW have soils derive d from weathered materials of lower Se contents. Both the lowest and highes t concentrations and the Aux of Se in environments are reported For China. (C) 2001 Elsevier Science Ltd. All rights reserved.