Estudo da contaminação e da toxicidade do solo do Aterro Metropolitano de Gramacho, Duque de Caxias RJ.

Abstract

The Gramacho Metropolitan Landfill, considered the largest in Latin America, had closed their waste disposal activities in mid 2012. The waste disposal was performed directly on the foundation soil since the beginning of its operation (1978). Considering that the contaminants present in the leachate can migrate by diffusion through the organo-saline clay of the landfill and reaches surroundings, an soil contamination investigation was made at the perimeter of the landfill. This research was conducted in the interstitial liquid of the soil and was based on two types of contaminants: ammoniacal nitrogen and organic recalcitrant compounds, parameter measured by total organic carbon (TOC). Moreover, acute toxicity assays was also performed with the species Vibrio fischeri to assess toxicity in the soil. Sorption and diffusion assays were performed to better understand the behavior of contaminants investigated. The results showed low levels of ammoniacal nitrogen and TOC in the soil. Ammoniacal nitrogen values are surprisingly low, because even in soil samples from the side barrier, which is situated adjacent to the drainage ditch leachate, these are less than 1% that found in leachate, indicating the soil adsorption. The acute toxicity assays showed the effect Hormesis in interstitial liquid samples, indicating the possibility of the presence of chronic toxicity.