Spatial Distribution of Heavy Metals in Agricultural Soil in Wutan, China

Total of 120 soil samples from the topsoil (0-20 cm) at an approximate interval of 100 m were collected in Wutan, China, to determine the spatial variability of five heavy metals, Cd, As, Hg, Pb, and Cr, with classical statistical and geostatistical analyses. Ordinary kriging was utilized for estimating heavy metals determination. Classical statistical indicated that As, Pb, and Cr concentrations were correlated with organic matter (p < 0.05). The concentration of Pb was negatively correlated with pH (p < 0.05). Geostatistical analyses suggested that the coefficient variation of heavy metals in the study area were relatively small. The Nugget/Still ratio of all heavy metals were less than 75% except Cd, which indicated that the spatial variability of the heavy metals were influenced by both structure factors and human activities. Higher heavy metal concentrations were mainly located in paddy fields and residential areas. To some degree, human activities, such as fertilizer application, sewage irrigation, and vehicles, influenced the spatial distributions of the analyzed heavy metals.