Spatial distribution of soil heavy metal pollution estimated by different interpolation methods: accuracy and uncertainty analysis.
Mapping the spatial distribution of contaminants in soils is the basis of pollution evaluation and risk control. Interpolation methods are extensively applied in the mapping processes to estimate the heavy metal concentrations at unsampled sites. The performances of interpolation methods (inverse distance weighting, local polynomial, ordinary kriging and radial basis functions) were assessed and compared using the root mean square error for cross validation. The results indicated that all interpolation methods provided a high prediction accuracy of the mean concentration of soil heavy metals. However, the classic method based on percentages of polluted samples, gave a pollution area 23.54-41.92% larger than that estimated by interpolation methods. The difference in contaminated area estimation among the four methods reached 6.14%. According to the interpolation results, the spatial uncertainty of polluted areas was mainly located in three types of region: (a) the local maxima concentration region surrounded by low concentration (clean) sites, (b) the local minima concentration region surrounded with highly polluted samples; and (c) the boundaries of the contaminated areas.
Xie
Yunfeng
Y
Center for Environmental Remediation, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, PR China. sefeng@gmail.com
Chen
Tong-bin
TB
Lei
Mei
M
Yang
Jun
J
Guo
Qing-jun
QJ
Song
Bo
B
Zhou
Xiao-yong
XY
D004784:Environmental Monitoring / Q000379:methods*; D004787:Environmental Pollution / Q000706:statistics & numerical data; D019216:Metals, Heavy / Q000032:analysis*; D012989:Soil Pollutants / Q000032:analysis*; D013223:Statistics as Topic; D035501:Uncertainty
D019216:Metals, Heavy; D012989:Soil Pollutants