Contamination and Human Health Risk Assessment of Polycyclic Aromatic Hydrocarbons (PAHs) in Oysters After the Wu Yi San Oil Spill in Korea

Abstract

After the collision of the Singapore-registered oil tanker M/V Wu Yi San into the oil terminal of Yeosu, Korea on January 31, 2014, approximately 900 m(3) of oil and oil mixture were released from the ruptured pipelines. The oil affected more than 10 km of coastline along Gwangyang Bay. Emergency oil spill responses recovered bulk oil at sea and cleaned up the stranded oil on shore. As part of an emergency environmental impact assessment, region-wide monitoring of oil contamination in oyster had been conducted for 2 months. Highly elevated concentrations of polycyclic aromatic hydrocarbons (PAHs) were detected at most of the spill affected sites. Four days after the spill, the levels of PAHs in oysters increased dramatically to 627-81,000 ng/g, the average of which was 20 times higher than those found before the spill (321-4040 ng/g). The level of PAHs in these oysters increased until 10 days after the spill and then decreased. Due to the strong tidal current and easterly winter winds, the eastern part of the Bay-the Namhae region-was heavily contaminated compared with other regions. The accumulation and depuration of spilled oil in oyster corresponded with the duration and intensity of the cleanup activities, which is the first field observation in oil spill cases. Human health risk assessments showed that benzo[a]pyrene equivalent concentrations exceeded levels of concern in the highly contaminated sites, even 60 days after the spill.