THE USE OF ENVIRONMENTAL FORENSIC TOOLS FOR THE IDENTIFICATION OF POLYCYCLIC AROMATIC HYDROCARBON SOURCES IN BRAZILIAN ECOSYSTEMS

摘要

Polycycllc aromatic hydrocarbons (PAH), present worldwide in the environmental ecosystems, may beintroduced by natural processes (natural fires, natural oil seepage, diagenetic processes) and anthropogenic inputs (releases/spills of petroleum and derivatives, sewage outfalls, river runoff, combustion of organic matter such as petroleum, coal, wood). These compounds tend to interact with the different types of environmental compartments and are subject to many processes that lead to geochemical fates such as physical-chemical transformation, biodegradation and photo-oxidation. So, the evaluation of PAH sources in any ecosystem had became a challenger nowadays and the forensic environmental chemistry has been played an important role to achieve this goal. In this paper, the sources of PAH have been investigated by applying diagnostic ratios and multivariate statistics based on principal component analysis (PCA) of the sediment data from 2 different ecosystems in Brazil: an estuary and a wetland. The estuarine area is Guanabara Bay, located in Rio de Janeiro, a highly urban ecosystem that receives an intense chronic anthropogenic pollution and was target by an oil spill of 1,300 m3 of marine fuel in January 2000. The other studied area is located closer to a refinery at Araucaria, Parana, south of the country, characterised by wetlands and rivers with a scattered activity of sand extraction. The area was also target by an accidental oil spill of about 4,000 m3 of a crude oil in June 2000, reaching the wetlands and Bangui and Iguassu rivers. Both PAH diagnostic ratios and Principal Component Analysis have proved to be helpful tools for PAH sources determination in environmental samples, exhibiting promising capacity of separating the samples into groups with different patterns of hydrocarbons introduction (petrogenic, pyrolytic and natural).