Distribution of polycyclic aromatic hydrocarbons in surface sediments and waters from Guanabara Bay, Rio de Janeiro, Brazil

Polycyclic aromatic hydrocarbons (PAHs) were identified and quantified in sediment and water samples from 12 sites in the north-northeast region of the Guanabara Bay. The samples were analyzed by GC-MS to assess the degree of contamination by monitoring the affected ecosystem after an oil spill that occurred in January 18, 2000. Total PAH concentrations ranged from 77 to 7,751 mu g kg(-1) dry weight in surficial sediment samples and from not detected to 1592 ng L-1 in water samples. The majority of sediment samples were classified as highly contaminated (total PAH > 500 mu g kg(-1)) while for water samples the concentration of PAHs was not sufficiently high to induce acute toxicity to aquatic organisms. In comparison with other coastal areas, PAH concentrations in Guanabara Bay are relatively high. The ratios of low molecular weight/high molecular weight (LMW/HMW) PAHs, phenanthrene/anthracene and benzo[a]anthracene/chrysene, are sensitive indicators of the origin of PAH pollution, which have shown to be mostly from fuel combustion in the Guanabara Bay.