Divergent Responses of Earthworms (Eisenia Foetida) in Sandy Loam and Clay Soils to Cerium Dioxide Nanoparticles

Abstract

The reported biological effects of cerium dioxide nanoparticles (nCeO2) in soils range from toxic to protective. However, divergences of nCeO2 toxicity in soils of different textures are not known. In this study, the availability of nCeO2 on earthworms (Eisenia foetida) in sandy loam soils and clay soils were discussed, and the biological effects of nCeO2 (0-1000 mg/kg) on earthworms in two soils were investigated. The results showed the bioaccumulation and biological effects of Ce on earthworms in the two soils were inconsistent. The BCR sequential extraction revealed that the major portions of Ce in both soils were in the residual form (98%-99%), and the acid-soluble Ce fraction were greater in clay soils. However, compared with clay soils, nCeO2 was more toxic to earthworms in sandy loam soils as assesses by earthworm biomass, morphology, and antioxidative damage. Thus, the high ecological risk of nCeO2 in sandy loam soils with higher pH and lower clay contents needs to be avoided, being used in agriculture to improve both crop yield and quality.