Although the effect of pH on As(V) adsorption varies considerably among soils, in general As is lessmobile in acidic soils due to adsorption onto iron oxide surfaces (Madejon and Lepp, 2007; Hartley et al., 2009).
Therefore, increasing fromacidic to neutral pH could explain the behavior of As.
For metals, significant differences in element availability were not observed between the beginning and the end of the assay despite the increase of pH.
However, As underwent an increase in soil availability with time corresponding to the rise of pH induced by earthworms.
This effectwasmore pronounced in themore diluted soils.
These results were important because they showed that available pollutants may be released into the environment due to significant changes in soil properties(Alexander, 2000).