Earth Science Frontiers ›› 2024, Vol. 31 ›› Issue (2): 137-146.DOI: 10.13745/j.esf.sf.2023.11.40

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Derivation of ecotoxicity thresholds for Co in soils in China

ZHANG Jingyuan1(), WANG Xuedong1,*(), LIANG Lichuan1, DUAN Guilan2   

  1. 1. College of Resources Environment and Tourism, Capital Normal University, Beijing 100048, China
    2. Laboratory of Soil Environment, Research Center of Eco-Environment, Chinese Academy of Sciences, Beijing 100085, China
  • Received:2023-09-28 Revised:2023-11-10 Online:2024-03-25 Published:2024-04-18

Abstract:

With increasing cobalt (Co) uses cobalt contamination in soil has attracted increasing attention. However, the potential ecological risks of Co contamination in soil and related risk thresholds have not been well researched. This study aims to derive ecological risk thresholds of Co in soil in China, using Co ecotoxicity data collected and screened through literature research, combined with ecotoxicological experiments and species sensitivity distribution (SSD) method. According to results, the EC10 values of Co in soils with different properties ranged between 7 to 4696 mg/kg. The relationships between EC10 and soil properties (pH, CEC, OC, Clay) and sensitivity k value of species were established by stepped-linear regression for eight species. The k value of the eight species ranged between -0.21 to 1.458. The k value (-1.207 and 2.201) of the non-normalized ryegrass and maize residue mineralization(MR) were obtained by extrapolation of the interspecies correlation estimation (ICE) model.Finally, regression models, with soil properties and k value as independent variables, were obtained for 10 species, and the predicted EC10 values were normalized to four soil conditions. Using SSD method and adjusting for aging leaching factor,the ecological risk threshold (HC5) values for Co in soil were derived for acidic (7.3 mg/kg), neutral (44 mg/kg), alkaline (72.08 mg/kg) and calcareous (38.88 mg/kg) soil conditions. The results provide a scientific basis for the formulation of soil standards for Co and for risk management.

Key words: soil, cobalt, species sensitive distribution curve, interspecific transfer, ecological risk, threshold

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