Bio-Use Form Spatial Distribution and Driven Factors of Heavy Metal Cadmium in the Surface Soil of Xiang´an Area, Xiamen, China

Five different kinds of bio-use form spatial distributions of heavy metal cadmium (Cd) in the surface soil of Xiang´an area in Amoy were quantitative analyzed by the method of a combination of geology statistical method and GIS. And it can be objectively reflected the spatial variation characteristic of the changes of each bio-use form content of the soil heavy metal Cd. Simultaneously, the pertinence of the bio-use form of heavy metal and the physical and chemical properties of soil were analyzed by the Gray correlation method. It also revealed the main internal factors which drove the bio-use form spatial distribution of the heavy metals Cd. The results showed that the contents of five different kinds of bio-use form spatial distribution of Cd are: 1 .oxidation state of manganese>2. Residue state> 3. Carbonate state> 4. Organic synthesis state> 5. Exchange state. The Cd organic synthesis state content had the stronger spatial correlation and its structural factors on the impact of spatial variability accounted for 79.9%. It was mainly concentrated in a northwest southeast direction with greater variability and its influence primary factors were coarse powder, pH and organic matter. The rest of the bio-use forms were all medium spatial correlation and the changes were mainly occurred in a southwest Northeast direction, whose primary factors were pH, bulk density, thin silt.