Otimização de metodologias de extração e análise de HPAs para determinação da distribuição ambiental e estimativa de fontes na cidade de Fortaleza

Abstract

Polycyclic aromatic hydrocarbons (PAHs) are considered persistent organic pollutants possessing mutagenic, carcinogenic and teratogenic properties, but there is lack of data about PAHs distribution in Brazilian urban centers. The present work was performed to generate data about PAHs in coastal ecosystems of Fortaleza city. The main objectives were: validation of methodologies for extraction and analysis of PAHs in water and sediment; atmospheric distribution of PAHs in rainy period; evaluation of the pollution caused by PAHs in the rivers of Fortaleza city and estimation of PAHs sources. The temperature program elaborated for PAHs separation and resolution was efficient, except acenaphthene and acenaphthylene. The ultrasound technique was more advantages for the extraction of PAHs from sediments using hexane/acetone as extraction solvent and hexane/ethyl acetate for the clean-up. The recovery from environmental aqueous matrices fortified with PAHs varied from 63.7 to 93.1% for atmospheric liquid precipitation, from 38.3 to 95.1% for superficial river water, and from 70.2 to 89.4% for marine water. PAHs spatial distribution showed that the highest concentration plume is intense in the zone with larger automobile flow and favorable topography for the concentration of emited pollutant. The molecular ratio of some PAHs in atmosphere (preliminary), showed emission from gasoline, diesel, wood and coal exhaustion. The total concentration of PAHs in sediment (∑PAHs) ranged from 3.04 to 2234.76 µg.kg-1 (Cocó river) and from 3.34 to 1859.21 µg.kg-1 (Ceará river). To the sediments cores ∑PAHs decrease towards the sediment deep layer, confirming that the pollution now days is larger. The data show that the sediments of the principal rivers of Fortaleza city have PAHs levels similar to other cities with a superior industrial development. The data also show that the burning product of fossil fuels and other sources of energy are responsible by the pollution of both rivers.