Derivation of Soil Ecological Criteria for Copper in Chinese Soils

PLoS One. 2015 Jul 24;10(7):e0133941. doi: 10.1371/journal.pone.0133941. eCollection 2015.

Abstract

Considerable information on copper (Cu) ecotoxicity as affected by biological species and abiotic properties of soils has been collected from the last decade in the present study. The information on bioavailability/ecotoxicity, species sensitivity and differences in laboratory and field ecotoxicity of Cu in different soils was collated and integrated to derive soil ecological criteria for Cu in Chinese soils, which were expressed as predicted no effect concentrations (PNEC). First, all ecotoxicity data of Cu from bioassays based on Chinese soils were collected and screened with given criteria to compile a database. Second, the compiled data were corrected with leaching and aging factors to minimize the differences between laboratory and field conditions. Before Cu ecotoxicity data were entered into a species sensitivity distribution (SSD), they were normalized with Cu ecotoxicity predictive models to modify the effects of soil properties on Cu ecotoxicity. The PNEC value was set equal to the hazardous concentration for x% of the species (HCx), which could be calculated from the SSD curves, without an additional assessment factor. Finally, predictive models for HCx based on soil properties were developed. The soil properties had a significant effect on the magnitude of HCx, with HC5 varying from 13.1 mg/kg in acidic soils to 51.9 mg/kg in alkaline non-calcareous soils. The two-factor predictive models based on soil pH and cation exchange capacity could predict HCx with determination coefficients (R2) of 0.82-0.91. The three-factor predictive models--that took into account the effect of soil organic carbon--were more accurate than two-factor models, with R2 of 0.85-0.99. The predictive models obtained here could be used to calculate soil-specific criteria. All results obtained here could provide a scientific basis for revision of current Chinese soil environmental quality standards, and the approach adopted in this study could be used as a pragmatic framework for developing soil ecological criteria for other trace elements in soils.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • China
  • Copper / chemistry*
  • Ecology*
  • Soil / chemistry*
  • Soil Pollutants*

Substances

  • Soil
  • Soil Pollutants
  • Copper

Grants and funding

The authors are thankful for the financial support provided by the Special Fund for Environmental Protection Scientific Research in the Public Interest (Project no. 201509032), the International Copper Association and Rio Tinto Pty Ltd. There are no patents, products in development or marketed products to declare. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.