Lethal and long-term effects of landfill leachate on Eisenia andrei earthworms: Behavior, reproduction and risk assessment

Abstract

Leachate is difficult to biodegrade, and presents variable physical, chemical and biological characteristics, as well as high toxicological potential for soil, groundwater and water bodies. In this context, untreated leachate toxicity was evaluated through acute and chronic exposures in Eisenia andrei earthworms. Physico-chemical leachate characterizations indicate a complex composition, with high organic matter (COD – 10,634 mg L−1) and ammoniacal nitrogen (2388 mg L−1) concentrations. Metals with carcinogenic potential, such as Cr, As and Pb, were present at 0.60, 0.14 and 0.01 μg L−1, respectively and endocrine disrupting compounds were detected in estradiol equivalents of 660 ± 50 ng L−1. Acute tests with Eisenia andrei indicated an LC50 (72 h) of 1.3 ± 0.1 μL cm−2 in a filter paper contact test and 53.9 ± 1.3 mL kg−1 in natural soil (14 days). The EC50 in a behavioral test was estimated as 31.6 ± 6.8 mL kg−1, indicating an escape effect for concentrations ranging from 35.0 to 70.0 mL kg−1 and habitat loss from 87.5 mL kg−1 of leachate exposure. Chronic exposure (56 days) led to reproduction effects, resulting in a 4-fold decreased cocoon production and 7-fold juvenile decrease. This effect was mainly attributed to the possible presence of endocrine disrupting compounds. An estimated NOAEL of 1.7 mL L−1 and LOAEL of 3.5 mL L−1 were estimated for earthworms exposed to the assessed effluent. Extremely high-risk quotients (RQ ≥ 1) were estimated based on leachate application in irrigation. Thus, adequate municipal solid waste management is paramount, especially with regard to generated by-products, which can result in high toxicological risks for terrestrial organisms.