HYDROGEOCHEMICAL CHARACTERIZATION OF AREA IMPACTED BY A DISABLED WASTE DEPOSIT IN A GUARANI AQUIFER RECHARGE ZONE

Abstract

The disposal of solid waste without a proper planning can impact the surroundings for decades or centuries after the activities ended. The impact of the leached contaminants in the surroundings depends on the characteristics of the geological formation, as well as of the occurrence of transport and attenuation processes. This study aimed at studying the contaminants found in the surroundings of an old landfill located in a Guarani Aquifer recharge zone, as well as their seasonal variations. Samples from 14 monitoring wells were collected in July and December 2017 and different parameters were analyzed, such as pH, electrical conductivity, alkalinity, COD, chloride, nitrate, ammoniacal nitrogen, iron, manganese, calcium and metals. High contaminants concentrations were found inside the waste deposit, but a considerable decrease was observed downstream. Even so, a visible influence of the deposit in its surroundings was verified, with the possible occurrence of redox reactions and seasonal quality fluctuations in the sampled wells. Researches focusing on the monitoring and mapping of contaminant plumes in Brazilian territory – whose geological and climatic conditions, as well as landfilled contents, are unique – are still imperative, so as to contribute to the establishment of guidelines for the management of these areas.