Simulated annealing and kriging method for identifying the spatial patterns and variability of soil heavy metal

Environmental data, including information regarding soil heavy metals, may contain significant uncertainty and exhibit a skewed distribution with a co mplex and unexplainable spatial variation. This study identified the spatia l patterns and variations of soil heavy metals (Cu, Cd, Hg, and Pb) in the northern part of Changhua County in Taiwan to clarify the characteristics a nd pollution of soil heavy metals. The spatial maps of soil heavy metals we re also estimated and simulated using kriging and simulated annealing metho ds. Correlation analysis indicated that Pearson and Spearman correlation co efficients among these four heavy metals were significant; between Cd and C u, these two correlation coefficients were strongly significant. As expecte d, the spatial maps of estimation and simulation of soil heavy metals revea led high concentration areas of Cd, Cu along the main irrigation-ditch syst em and surrounding industrial plants in the area of study. In addition to r eproducing the spatial variation of the investigated Cd, Cu, Hg and Pb, sim ulated annealing could also identify the global spatial continuity and disc ontinuity patterns of soil heavy metals. Kriging and simulated annealing me thods can both be applied to identify pollution sources and patterns for mo nitoring and remedy.