Silver toxicity to the earthworm Eisenia fetida is inconsistent in natural and artificial soils amended with wastewater biosolids

Abstract

Silver nanoparticles (AgNP) are present in biosolids from wastewater treatment facilities, a common soil amendment. Exposing earthworms (Eisenia fetida) to AgNP and AgNO3 in soil with 0 and 7.5 g biosolids kg-1 for 28 d showed AgNO3 was more lethal to earthworms in artificial soil (LC20 ≤ 325 mg Ag kg-1) than natural soil (LC20 ≥ 573 mg Ag kg-1). In contrast, AgNP were more lethal in natural soil (LC20 ≤ 425 mg Ag kg-1) than artificial soil (LC20 ≥ 653 mg Ag kg-1). Earthworm response to silver in artificial soil may not reflect toxicity in biosolids-amended natural soils.