Engineered nanomaterials (NMs) may enter the soil through various channels and pose potential harm to soil animals, especially those proactively applied for soil heavy metal remediation. Effects of nano-carbon black (CB) and surface modified carbon black (MCB) on catalase (CAT) activity and malondialdehyde (MDA) content in earthworms exposed on filter paper for 48 h were tested. Avoidance test was used to determine hazard of soil treated with 0.015% and 1.5% CB and MCB. Surface properties of NMs were also characterized. MCB has a significant effect on CAT activity at 70 and 1000 mg/L (1.1 and 15.7 µg/cm2), but has no impact on MDA content in earthworm. Strongly avoidance behavior of worms was also found in soil added 1.5% MCB. Negative charges and oxygen functional groups increased for MCB and its adverse effect on earthworm was higher than CB. The application of MCB in soil remediation warrants more attention.
Keywords: Earthworm; Nano-carbon black; Soil immobilization agents; Surface charge and functional group; Toxicity.