Contamination assessment of soil and groundwater of a deactivated dumpsite in Brazil

The final disposal of solid waste in dumpsites can result in the migration of leachate components through the soil, contaminating it as well as the groundwater. The purpose of this manuscript was to analyze the contamination of a dumpsite along with three unlined leachate ponds that operated for approximately 25 years. Soil, surface water from three leachate lagoons, and groundwater samples were collected. Chemical analyses such as chloride, ammonia nitrogen, and total organic carbon were performed. The present work also aimed at elaborating the local flow pattern map and the assessment of subsoil. The results showed local subsoil mostly clayey, also occurring a region of sandy predominance, and great variation of rocky outcrops depth. The groundwater flow occurs from the waste towards one of the leachate lagoons. The leachate lagoon located closer to deposited area presented the highest concentration of all contaminants measured. Groundwater and soil showed low ammonia nitrogen with a maximum value of 2 mg.L^-1. Elevated chloride levels were detected in all matrices studied. In soil depth, the concentration varied ​​between 17 and 1270 mg.L^-1 and in groundwater between 843 and 3,252 mg.L^-1. Results suggest the migration of leachate components through the local soil. The concentration of total organic carbon measured in soil was of 10-982 mg.L^-1, suggesting its natural presence.