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| Study on ecotoxicity differences of Cr(Ⅵ)and Cr (Ⅲ)in soils |
| Received:July 22, 2018 Revised:October 26, 2018 |
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| KeyWord:soil Cr;valence;normalization;species sensitivity distribution;ecotoxicity |
| Author Name | Affiliation | E-mail | | YU Xiu-yue | School of Water Conservancy and Environment, University of Jinan, Jinan 250022, China | | | MA Yi-bing | School of Water Conservancy and Environment, University of Jinan, Jinan 250022, China
Institute of Agricultural Resources and Regional Planning, Chinese Academy of Agricultural Sciences, Beijing 100081, China | | | SUN Zong-quan | School of Water Conservancy and Environment, University of Jinan, Jinan 250022, China | | | LI He-lian | School of Water Conservancy and Environment, University of Jinan, Jinan 250022, China | | | LI Shi-wei | School of Water Conservancy and Environment, University of Jinan, Jinan 250022, China | | | HAN Xue-mei | School of Water Conservancy and Environment, University of Jinan, Jinan 250022, China | stu_hanxm@ujn.edu.cn |
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| Abstract: |
| The toxicity of soil chromium (Cr)is related to its valence states. The present study aims to compare the toxicity differences of various valence states of soil Cr to diverse biological indicators and ecological system, and provide a basis for ecological risk assessment of the Cr-contaminated soils. Based on the collected ecotoxicological data of Cr (Ⅵ)and Cr (Ⅲ)in Chinese soils, the prediction models reflecting the quantitative relationship between median effective concentration (EC50)or 10% effective concentration (EC10)of Cr (Ⅵ)or Cr (Ⅲ)and soil properties were developed, respectively. After interspecific extrapolation and normalization were processed using the prediction models, the species sensitivity distribution (SSD)curves of Cr (Ⅵ)and Cr (Ⅲ)for various biological indicators in neutral soil scenarios were fitted with Burr Ⅲ. According to the formula of potential affected fraction (PAF), the differences between the toxicities of Cr (Ⅵ)and Cr (Ⅲ)to soil ecosystem were further evaluated in the condition of various PAFs. The results showed that root elongation of pakchoi and soil dehydrogenase activity were the most sensitive indicators for soil Cr (Ⅵ)and Cr (Ⅲ)contamination, respectively.The toxicity difference of the two valence states of Cr varied with distinct biological indicators at the species level and changed depending on PAF at the ecosystem level. Cr (Ⅵ)has the higher toxicity to soil ecosystem than Cr (Ⅲ)in a large range of PAF (i.e. PAFs derived from EC50 and EC10 data were less than 84.4% and 87.3%, respectively)and under the common protection level (i.e.PAF was equal to 5%).These findings indicated that the ecotoxicities of soil Cr (Ⅵ)and Cr (Ⅲ)were obviously different, and the ecological risk of soil Cr contamination could be comprehensively reflected based on the valence states of Cr and their toxicities to ecosystem, which would help the restoration management of the soils contaminated with Cr. |
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