36 observation wells, varying from 2 to 5 meters in depth to water, were installed over a 20,000 m² area downgradient from the Taubate sanitary landílll as part of a project to monitor groundwater quality at the site. In 1984, the first year of the study, water leveis in the wells were measured monthly and water quality samples were collected and analyzed every 3 months. The chemical analyses results showed an increase in the overall mineralization of the groundwater in the vicinity of the landfill, particularly for chloride, soium bicarbonate, potassium, magnesium and ammonium ions. Good correlations were demonstrated between specific conductance and total dissolve d solids (TDS), which consiste d principally of chloride and sodium ions. For the geohydrologic environment studied, the best indicators of landfill pollution were: specific conductance, sodium, chloride and ammonium ions
