leachate and pollution levels of heavy metals in the groundwater near municipal solid waste landfill site of mashhad, iran

background: the purpose of this study is to investigate the concentration of metals (lead, cadmium, chromium, copper, and nickel) in the landfill leachate and heavy metals in wells downstream of municipal solid waste landfill site in the city of mashhad. methods: in both winter and summer seasons in 2009 samples were collected from five wells that were in landfill downstream in mashhad. results: among heavy metals, nickel concentration in summer and lead concentration in winter had the highest levels. the results showed that the mean concentration of heavy metals in the studied wells was below the national standards of drinking water of iran, who, and the united states. pearson correlation coefficients also indicated that there was a significant correlation among the studied metals in the wells. conclusion: cd and cu concentrations in all of the wells (except pb in winter and ni in summer) did not pose any significant water quality problems since these concentrations were below the standards acceptable levels of drinking water.