Abstract:
In order to determine the toxicity threshold of phenanthrene (Phe) to Folsomia canadida in Chinese soils and to establish a prediction model for Phe toxicity, we investigated the effects of exogenous Phe on the survival and reproduction of the model organism Folsomia candida in 15 typical soils. The results showed that the sensitivity of survival to Phe toxicity was much lower than that of reproduction. The EC
50 (half effect concentration) of the reproduction rate derived from the Phe value of mixed organic solvent (1:1 volume mixture of n-hexane and acetone) extraction ranged from 21.09 mg/kg to 99.50 mg/kg with a difference of 4.72 times. The EC
50 of the reproduction rate derived from the Phe value of mild HPCD (Hydroxypropyl- β- Cyclodextrin) extraction ranged from 18.31 mg/kg to 48.26 mg/kg with a difference of 2.63 times. Furthermore, pearson correlation analysis revealed that the EC
50 values based on the Phe values of organic solvent extraction were significantly correlated with soil organic matter and soil clay, with the correlation coefficients of 0.923 and 0.656, respectively. The EC
50 values were significantly negatively correlated with soil pH, with the correlation coefficients of −0.590. For the Phe toxicity thresholds for reproduction, we developed a prediction model lg(EC
50)=1.436+0.012OM based on soil organic matter using multiple stepwise regression analysis. The toxicity prediction model shows that the content of Soil organic matter is the most important single factor affecting the difference in the toxicity of Phe to the EC
50 in different soils, which can explain 84.0% of the difference in the EC
50 value in different soils.