Avaliação de HPA e BTEX no solo e água subterrânea, em postos de revenda de combustíveis: estudo de caso na cidade de Natal -RN

Abstract

The retail fuel stations are partially or potentially polluters and generators of environmental accidents, potentially causing contamination of underground and surface water bodies, soil and air. Leaks in fuel retail stations´ underground storage systems are often detected in Brazil and around the world. Monoaromatic hydrocarbons, BTEX (benzene, toluene, ethylbenzene and xylenes) and polycyclic aromatic hydrocarbons (PAHs) are an indication of the presence of contamination due to its high toxicity. This paper presents a case study of contamination in a Fuel Retail Station by petroleum derivative products in the city of Natal. For identification and quantification of the hydrocarbons, EPA analytical methods were used. The values of benzene quantified by EPA method 8021b CG-PID/FID, ranged from 1.164 to 4.503 mg.Kg-1 in soil samples, and from 12.10 to 27,639 μg.L-1 in underground water samples. Among the PAHs, naphthalene and anthracene showed the most significant results in soil samples, 0.420 to 15.46 mg.Kg-1 and 0.110 to 0,970 mg.Kg-1, respectively. In underground water samples, the results for Naphthalene varied between 0.759 and 614.7 μg.L-1. PAHs were quantified by EPA Method 8270 for GCMS. All of the results for the chemical analysis were compared with the values for the CONAMA 420/2009 resolution. The results for benzene (27,639 μg.L-1) showed levels highly above the recommended by the CONAMA 420 resolution, wherein the maximum permissible for underground water is 5 μg.L-1. This is a worrying factor, since underground water makes up 70% of the city of Natal´s water supply