Earth Science Frontiers ›› 2024, Vol. 31 ›› Issue (2): 196-203.DOI: 10.13745/j.esf.sf.2024.1.12

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Comparative study on soil remediation of slope-alluvial contaminated arable land in granite areas, northern Hebei Province

LIU Yongbing1,2(), SU Junjie3, GUO Wei2, WANG Yingnan1, YIN Yaqiu1   

  1. 1. The Land Consolidation and Rehabilitation Center, Ministry of Natural Resources, Beijing 100035, China
    2. National Research Center for Geoanalysis, Beijing 100037, China
    3. School of Water Resources and Environment, China University of Geosciences (Beijing), Beijing 100083, China
  • Received:2023-09-21 Revised:2024-01-10 Online:2024-03-25 Published:2024-04-18

Abstract:

Soil constitutes a crucial component of agricultural ecosystem, and heavy metal contamination in arable soil can adversely affect the quality and safety of agricultural products. This study focuses on weakly acidic farmland soils of colluvial and alluvial accumulation zones in the granite region of northern Hebei. Utilizing two remediation techniques—phytostabilization and phytoextraction (with maize and Solanum nigrum as the phytoremediation agents), this study explores the impacts of different parent material types and remediation methods on heavy metal remediation efficacy in cultivated soils. According to results, (1) significant differences existed in organic matter, readily available potassium, available phosphorus, and pH values between soils of colluvial and alluvial zones, with the former exhibiting substantially lower pH levels and both zones having high background levels of lead (Pb). (2) Following phytostabilization, the colluvial zone showed significant reduction in cadmium (Cd) and lead (Pb) concentrations in maize grains, with an increase in yield ranging from 19.10% to 33.00%, indicating superior remediation outcomes compared to its counterpart. (3) The colluvial zone, employing an intercropping system of Solanum nigrum and maize, demonstrated higher annual extraction of Cd, Pb, and copper (Cu) per mu (a traditional unit of area) of farmland, with respective extraction amounts of 167.25, 208.35, and 555.05 g, and removal rates of 2.727%, 0.043%, and 0.234%, showcasing more effective remediation compared to the alluvial zone. (4) The intercropping system of Solanum nigrum and maize outperformed single-crop cultivation by enhancing the bioavailability of heavy metals in the soil and improving the plants’ absorption efficiency. (5) When designing remediation strategies one should consider soil characteristics, parent material types, and the influence of different crops and choose appropriate remediation techniques and cultivation models. This study provides a reference for the safe utilization and remediation of farmland soils in geologically anomalous regions.

Key words: slope deposits, alluvial deposits, heavy metals, soil contamination, passivation remediation, phytoremediation

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