Removal of landfill leachate toxicity and genotoxicity by two treatment methods

Abstract

Leachates from active and closed municipal solid waste landfills can be a major source of contamination to groundwater and surface waters. In the present study the toxic and genotoxic effects of leachate from an old sanitary landfill prior to and following chemical and electrochemical treatments were assessed by using Lemna, Allium and comet tests. Photosynthetic pigments, malondialdehyde (indicator of lipid peroxidation) and antioxidant enzyme activities were evaluated as additional indicators of toxicity in duckweed. Following duckweed exposure to landfill leachate, growth rate and photosynthetic pigments content decreased while enzyme activity, malondialdehyde content and DNA damage increased. Untreated leachate caused inhibition of Allium cepa cell division and induction of mitotic and chromosomal aberrations. Although both water treatments completely reduced genotoxicity of leachate, electrochemical method was found to be more efficient in removal of toxic substances present in landfill leachate and thus more suitable for treatment of such leachates prior to their discharge into environment. As landfill leachates pose a risk to human health and environment in general due to their geno(toxicity), the present study demonstrates that the toxicity/genotoxicity assays should be used in leachate risk assessment together with physicochemical analysis.