Investigação ambiental em posto de abastecimento de combustiveis no municipio de Seropedica - RJ / Environmental survey of a Seropedica city gas station, Rio de Janeiro State, Brazil

AUTOR(ES)
DATA DE PUBLICAÇÃO

2006

RESUMO

Gas stations create a recognized potential threat of contamination to soil, groundwater and air. Brazilian environmental laws regulate the technical standards regarding the installation, equipaments and operation of gas stations in addition to requiring environrnental licenses. Accidents may expose the population to toxic and flammable substances. In Seropédica city (state of Rio de Janeiro), 11 gas stations (9 commercial and 2 non-commercial) were identified. The risk of the groundwater contamination was checked interacting the probably contaminant load created by those establishments with a vulnerability map of local aquifers. A case study was selected to allow a more detailed investigation of a non-commercial gas station that supplied a university in this city for more than 20 years. The gas station operated equipaments and a plant out of compliance with environmental laws. It is a contamination point source in the campus area. The research area is about 1300 m2 and is located under a rocky alteration mantle. The aquifer on residual soils in the city belongs to a local fractured aquifer system. First, a quantitative gas screening was performed on the soil with a portable monitor to identify optimum placement of boreholes. Samples were collected to ascertain soil properties. Later, six monitoring wells were installed to provide hidrodinamic characterization and to collect groundwater samples. On soil and groundwater samples was quantified the organic compounds that are used to identify the presence of fuels in the environrnent. The levels in the samples were compared with standards established by the Rio de Janeiro environrnental agency. Monitoring well number 5 revealed free phase (consequently, the area is contaminated). The source is a leaking diesel tank that is in operation. A residual gasoline phase was also observed (during the drilling of monitoring well number 2) which was associated with an old leaking tank (actually this tank is off operation). In other wells the organic compounds are in the acceptable limits of potability

ASSUNTO(S)

research aquiferos meio ambiente - pesquisa meio ambiente - rio de janeiro (rj) environment aquifers environment

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