Toxicity of exogenous hexavalent chromium to soil-dwelling springtail Folsomia candida in relation to soil properties and aging time.

作者：Lin Xianglong; Sun Zaijin; Zhao Long; Ma Jin; Li Xing; He Fei; Hou Hong^*

来源：Chemosphere, 2019, 224: 734-742.

DOI：10.1016/j.chemosphere.2019.02.196

• Aging time
• Folsomia candida
• Hexavalent chromium
• Soil properties
• Toxicity thresholds

Chromium (Cr) is a well-known toxic metal, but studies on Cr toxicity to soil-dwelling springtails are fairly limited, and did not consider the effects of various soil properties and long aging time. To address this, the chronic toxicity of Cr(VI) to survival and reproduction of model organism-Folsomia candida were evaluated in the laboratory studies. The results showed that compared to the soils aged only for 2 and 21d, the concentrations inhibiting 50% reproduction (EC50) significantly increased by 2.8-5.2 fold and 1.7-2.6 fold, the concentrations causing 50% mortality (LC50) were higher than the highest test concentration in four soils aged for 150d. Furthermore, the aging effects correlated significantly with soil amorphous Fe oxides. The EC50 values of Cr significantly differed in ten soils aged for 150d, ranging from 27 to 512mgkg(-1), which were associated with the variations in reduction and sorption capacity in different soils. Regression analysis indicated that soil clay was the most important single factor predicting soil Cr toxicity to reproduction, and the inclusion of cation exchange capacity in the clay regression could best explain the toxicity variance (87.2%). Additionally, soil pH, organic matter and amorphous Fe oxides could also well explain the toxicity variance (>55%).