Remediation and Restoration of a Wetland Contaminated by aCrude-Oil Spill, Paraná, Brazil

摘要

On July 16, 2000, an accidental release of medium crude oil occurred atthe refinery REPAR in the state of Paraná, Brazil. The majority of the spilled oil wasretained within Banhado 4, a 10-hectare wetland. The emergency response in Banhado 4consisted of water diversion and manual removal of oil, resulting in lowering of waterlevels, destruction of wetland vegetation and infiltration of oil into the wetland soil. Subsequently,Banhado 4 was converted into a treatment wetland, using a simple system ofdikes and control structures. Ecological recovery was achieved within less than one yearof the restoration of water levels. By 2007, concentrations of TPH, BTEX, and PAHswere below applicable criteria in groundwater, surface water and soil, with the exceptionof the thin surficial layer of organic-rich soil, which contains remnant oil in some areas ofthe wetland. Future efforts will attempt to determine the scope of this problem, andwhether remediation of this material (by manual removal) would cause more harm thangood.