Biliary Polycyclic Aromatic Hydrocarbon Metabolite Equivalents Measured in Fish and Subtidal Invertebrates Following the Refugio Beach Oil Spill.

Monterey formation crude oil spilled from an onshore pipeline and entered the surf zone near Refugio State Beach, Santa Barbara County, CA, USA on 19 May 2015. Exposure to nearshore fish was evaluated by measuring biliary polycyclic aromatic hydrocarbon (PAH) metabolite concentrations in surfperch (Embiotocidae), collected near the release point, at a lesser oiled area, Gaviota State Beach, and near the Coal Oil Point oil seep, Campus Point, at both four days and approximately one year after the oil spill. Three to four weeks after the spill, fish, invertebrates, and kelp were collected near the same three sites for PAH analysis of edible tissues to support the fishery closure assessment. Additionally, thirteen days after the spill, vegetation, and invertebrate tissue samples from the seafloor near Refugio State Beach were analyzed for PAHs. In surfperch bile, mean naphthalene, phenanthrene and benzo(a)pyrene metabolite equivalents were significantly higher at Refugio State Beach, compared to Gaviota State Beach or Campus Point in 2015. One year later, there was no significant difference between the three sites. Spatial and depth zone patterns of PAH tissue concentrations from composited invertebrate, vegetation and fish showed highest concentrations were measured in invertebrates collected near Refugio State Beach. Overall, results show elevated PAH levels in nearshore organisms and provide a useful reference for potential PAH exposures in fish and subtidal invertebrates following a large nearshore oil spill.