of water from these As-contaminated aquifers, mining activities and
arsenic-containing pesticides have led to an As buildup in paddy soils.
Arsenic chemistry in paddy soils is extremely complex, because soils
are subject to frequent redox cycles in both time and space (Chen
et al., 2008). Results obtained by the RDA are confirmed by analyzing
the PCA, which showed that As, Zn and Pb came from anthropogenic
activities, especially agriculture. However, there are no presences of significant
variations in dry croplands among sampling sites; dry croplands
had no significant effects on the variations of metal concentrations