Physiological and genotoxic responses of the earthworm Aporrectodea caliginosa exposed to sublethal concentrations of AgNPs

The purpose of the current study was to measure the ecotoxicity of silver nanoparticles (AgNPs) on Aporrectodea caliginosa earthworm. No adult earthworm mortality was observed at any treatment during the sub-chronic exposure period (28 d). Biomass and cellulase levels reduced in a concentration-dependent manner in the exposed earthworms compared to those of the control. The hatched cocoons from the contaminated substrates were significantly (p < 0.05) fewer than that of the control substrate. This finding provided further support for the conclusion that AgNPs may affect cocoon hatchability. Cocoon hatchability could therefore be a more reliable endpoint at a specific concentration than cocoon production. A significant increase in DNA damage was revealed in the earthworms treated with AgNPs compared to the untreated ones. The results denoted the effectiveness of measuring cellulase activity, biomass, reproduction and DNA damage and reinforced the application of the present methods in nanoparticles pollution biomonitoring studies.