Submitted to: Fresenius Environmental Bulletin
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/1/2010
Publication Date: 10/10/2010
Citation: Zhu, Q., Zhou, S., Schmidt, J.P., Wu, S. 2010. Influence of plow pan on the enrichment and depletion of heavy metals in the surface soils. Fresenius Environmental Bulletin. 19:2176-2184. Interpretive Summary: Hydropedology is a new discipline that can be used to help understand soil water movement, and consequently soil contaminant movement within soils and across the landscape. This study investigated the influence of soil properties in the top soil horizons on the enrichment and depletion of heavy metals concentration at five agricultural/industrialized areas in Jiangsu, China. Heavy metals concentrations and physical soil characteristics were evaluated for 27 soil profiles. Greater enrichment of Cd and Hg in the Ap1 horizon was observed for soils with greater clay content in the Ap2 horizon. A thicker water-restrictive plow pan in the Ap2 horizon corresponded with greater heavy metals concentrations in the Ap1 horizon. Heterogeneous soil factors affected heavy metals concentrations differently. For example, organic matter content of the Ap1 horizon corresponded with enriched levels of Cd, Cr, Pb, Hg, and As, but not for Cu and Ni.
Technical Abstract: Hydropedology is a new discipline that uses pedological information to understand the soil water movement, and thus the storage, transformation, and transportation of heavy metals (HMs). However, limited studies have investigated how the hydropedological feature, for example the water-restrictive soil horizons, would affect the enrichment of HMs in soils. This study investigated the influence of soil properties on the enrichment and depletion of HMs using the data of 27 soil profiles opened in five study areas in Jiangsu, China. The enrichment or depletion of HMs in the Ap1 horizon was estimated using the concentration differences of HMs between surface Ap1 and subsurface B1 (or B) horizons. The high Ap1 sand content (SC) significantly (p less than 0.1) elevated the depletion of Pb in the Ap1 horizon (r2=0.13), while the high Ap1 clay content (CC) significantly (p less than 0.1) increased the enrichment of Cd and Hg (r2 less than or equal to 0.12) and the high Ap1 organic matter content (OMC) significantly (p less than 0.05) increased the enrichment of Cd, Cr, and As (r2 less than or equal to 0.15). The greater enrichment of Cd and Hg in Ap1 horizon was observed in areas with higher Ap2 CC (r2 less than or equal to 0.15), while greater enrichment of Hg and As was found in areas with higher Ap2 OMC (r2 less than or equal to 0.18). The Ap2 horizon (water-restrictive plow pan) thickness significantly (p less than 0.05) elevated the enrichment of all HMs in the Ap1 horizon. In study areas with thick Ap2 horizon (e.g., Taicang), less depletion of HMs in the Ap1 horizon was observed, while in study areas with thin Ap2 horizon (e.g., Baguazhou), depletion of HMs was expected.