Understanding the Leaching Dynamics of Lead (Pb+2) in Artificial Soils under Different Conditions

Abstract

Lead (Pb) is a heavy metal present in many agricultural fields, posing significant risks to the environment and public health. The mobility and leaching of Pb(II) in soils depend on soil characteristics. In agricultural soils, organic matter (OM) content has been reported as a crucial parameter influencing the leaching behavior of Pb(II). However, modeling the leaching behavior of Pb(II) in soils remains challenging, primarily due to the difficulty in obtaining soils that vary solely in OM content. In this study, the behavior of Pb(II) in artificial soils (ASs) was investigated, evaluating the effects of ionic strength, pH, and OM content. Additionally, the spatiotemporal distribution of the metal was explored using a multilevel factorial experimental design and column leaching experiments. The results indicate that lead retention capacity decreases with increasing ionic strength due to the increased leaching of OM, which forms complexes with Pb(II). The lead retention capacity of the soil is also affected by pH, with pH 7 inducing the highest retention. This modified the spatiotemporal distribution of the metal, which was analyzed using response surface methodology. A second-order polynomial model was obtained, allowing for the tracking of Pb(II) leaching in soils with 10% OM content.