Effect of The Oil Spill from the Presidente Getúlio Vargas Refinery, Brazil, in July of 2000, on the Populations of Fishes of the Rivers Saldanha, Barigüi, and Iguaçu

Abstract

ABSTRACT In July of 2000, an accident occurred in the Refinery Presidente Getúlio Vargas (REPAR), located in the Municipality of Araucaria, Southern Brazil, and involved a spill of about 4 million liters (25,160 barrels) of crude oil. This was considered the largest oil spill in the history of Brazil. Despite the use of containment barriers, the oil slick reached up to 45 km downstream of a small creek (Arroio Saldanha) and two important rivers of the region (Rio Barigüi and Rio Iguaçu). In this stretch, both of the latter rivers are highly polluted, having crossed the City of Curitiba, a city of about 2+ million inhabitants. The spatial and temporal distribution of fishes of these streams after the accident was analyzed in 10 collection sites (in a river stretch of 250 km) located upstream Rio Barigüi and Rio Iguaçu) or downstream (all streams) from the point of oil introduction. Fishes were captured monthly with cast nets, traps, hook and line, and/or gill nets. Immediately after the event, sites close to the point of introduction of oil presented a less diverse fish fauna. However, one year later, the fish fauna of the Arroio Saldanha, showed signals of recovery, while no fish were collected during the entire year from the sites located upstream in the Rio Barigüi and Rio Iguaçu. The results strongly suggests that the impact of the oil spill on the fish fauna of these streams was minimized due to the previous highly polluted state of the streams, as indicated by the absence of fish species in the upstream collection sites, which were never directly exposed to the oil spot.