Does Activated Carbon Used for Soil Remediation Impact Eisenia fetida?

Abstract

Because granular activated carbon can sequester organic pollutants, a potential strategy for reducing the bioavailability of organic contaminants in soil is through its application to the soil's surface. It is well understood that activated carbon is effective in the remediation of air, water, sediment, and soil, but less information is available on the potential toxicity of activated carbon to native wildlife following in situ remedial applications. Several studies have evaluated the effects of activated carbon on aquatic species; however, less is known about its toxicity to terrestrial species. The present study aimed to evaluate the potential lethal and sublethal effects of activated carbon on adult and juvenile Eisenia fetida, which are earthworms in the family Lumbricidae. The percentage of mortality, initial weight, and pre-and postdepuration weights of the worms were observed following exposure to a range of activated carbon concentrations, from 0.5% to 10% based on the soil's wet weight. These concentrations exceeded the 2%-4% activated carbon typically applied in the field. Activated carbon had no statistically significant effects on E. fetida survival; however, significant although inconsistent effects were observed on earthworm biomass. Although some statistical significance in biomass was observed, the biological significance of these effects is unclear. Overall, the concentrations of activated carbon applied in the field for soil remediation are unlikely to impact earthworm survival, although further testing, specifically on potential sublethal toxic effects, is required.