Ecological Effects to Benthic Infauna from Lingering Oil 15 Years after the EXXON VALDEZ Oil Spill. EXXON VALDEZ Oil Spill Restoration Project Final Report. (Restoration Project 040772)

摘要

In 2001, Short et al. (2004) identified residual oil from the 1989 Exxon Valdez oil spill in intertidal sediments. In the current study, five pairs of intertidal stations, each composed of one oiled and one nearby unoiled station (as identified by concurrent National Marine Fisheries Service studies), were evaluated for potential ecological impacts due to subsurface lingering oil. Oiled sediments were not toxic in the larval mussel bioassay using Mytilus edulis gallopprovincialis, where development and survival in the 100% elutriate were equivalent to the unoiled stations and the controls. Significant toxicity was observed in the 28-day amphipod bioassay using Leptocheirus plumulosus, where survival at the oiled stations was 0% while survival in the unoiled stations ranged from 37 to 84%. Survival was inversely related to sediment PAH and positively related to percent fines (p < 0.05). However, decreased survival in the unoiled sediments suggests that this test may have been influenced by the predominance of very coarse sediments and a lack of fine-grained sediments. Benthic community structure was found to be similar between most oiled and unoiled stations; however, the power of statistical tests was low due to replicate variability. Study results indicate that residual oil sequestered in intertidal sediments is not causing community-wide effects though populations of sensitive species, such as amphipods, may be impaired.