Landscape characteristics and spatial patterns of soil heavy metal contamination in Huizhou City

104 soil samples were taken in Huizhou City,and concentrations of 8 heavy metals(Cu,Zn,Ni,Cr,Pb,Cd,As and Hg) were tested with those samples.Based on landscape theory,geostatistics and geographic information system technology were used to analyze their statistic and spatial characteristics with single pollution index and comprehensive index.The arithmetic means of single indices and comprehensive index were lower than 0.5 besides indices of Cu and Pb.Normal distribution curves were fitted for all indices distribution.Coefficients of variation were higher than 0.6 except for that of Cu and Pb.Spatial distribution of all heavy metals was heterogeneity,and the concentrations of those metals in northeast part were basically lower than that in south part where many industrials enterprisers existed.The index PLAND was great different,and the ratios of five classes(from class 1 to class 5) of index LSI was descending for metals Cu,Zn,Ni,Pb and Cd.The landscape index COHESION of each class for single and comprehensive concentration indices was higher than 90.The landscape indices of comprehensive concentration index revealed that landscape of heavy metal contamination in Huizhou City was fragmentation,and the connexity of landscape was relatively weakness.But the landscape of single indices showed the base was low concentration,and the area ratios of patches of high concentration were small and their shapes were regular.