[en] Ten days after an oil spill which occurred on January 18, 2000 at Guanabara Bay near Rio de Janeiro in Brazil, parent and alkylated polycyclic aromatic hydrocarbons (PAHs) were measured in sediment samples from intertidal and subtidal areas. This study examined two to six-ring PAHs of molecular mass 128 to 278 including perylene. The results indicated total concentrations of 38 PAHs varying from 559 to 34,048 nanogram per gram dry weight. The median value was 4,198 nanogram per gram. The range for 16 Environmental Protection Agency (EPA) priority PAHs covered 207 to 9,399 nanogram per gram with a median concentration of 866 nanogram per gram. PAH indexes were evaluated to determine where the hydrocarbons came from. Results indicated that Guanabara Bay received anthropogenic PAHs from various sources, since there was a mixed pattern of petrogenic and pyrolytic inputs. The main sources might have been as varied as oil released from ships, accidental spills, discharge from domestic and industrial wastes, urban runoff, and incomplete fuel oil combustion. 32 refs., 2 tabs., 7 figs