Biomonitors to evaluate the toxic potential of urban solid waste landfill leachate

Abstract

The accentuated increase in the production of solid urban waste (SUW) and the consequent accumulation of leachate in landfills increase the risk of environmental contamination. Biomonitors are used to assess the toxicity of pollutants on living organisms. In this study, the pollutant potential of leachate from SUW from a deactivated landfill was evaluated by bioassays with Lactuca sativa L. and Lycopersicon esculentum Mill., and the relationship between chemical characteristics of the effluent and biological parameters was analyzed. The effluent was tested in its raw form and diluted in distilled water at concentrations of 75 and 50%. The percentage of germination, root growth (RG), mitotic index (MI), chromosomal abnormalities index (CAI), and micronuclei frequency (MCN) were analyzed. In the presence of effluent, germination and MI decreased, while RG, CAI and MCN frequencies increased in relation to the negative control (distilled water) for both species. Lead, iron and zinc presented negative relation with seed germination for both species, with RG of L. sativa and MI of L. esculentum, as well as a positive relation with MCN frequency in the studied species. Because of its larger chromosomes, L. sativa is a more suitable biomonitor of SUW leachate toxicity than L. esculentum. Even though the landfill is deactivated, it is necessary to treat this effluent, in order to minimize environmental impacts.