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.

Toxicity of Refugio Beach Oil to Sand Crabs (Emerita analoga), Blue Mussels (Mytilus sp.), and Inland Silversides (Menidia beryllina).

Monterey formation crude oil spilled from an onshore pipeline and entered the surf zone near Refugio State Beach, Santa Barbara County, California (USA) on 19 May 2015. During this season, early life stages of many marine fish and invertebrates were present. Surf zone water and beach porewater samples were collected during the 4 mo after the spill and 2 yr later for chemical analyses. Elevated polycyclic aromatic hydrocarbon (PAH) and total petroleum hydrocarbon concentrations were observed in surf zone water and porewater near the release point, declining with distance and time. Early life stage toxicity was investigated by conducting 6- and 7-d static renewal bioassays with sand crab (Emerita analoga) post larvae (megalopae) and inland silverside larvae (Menidia beryllina), respectively, and a 48-h blue mussel (Mytilus sp.) embryo development bioassay. Dilutions of a high-energy water accommodated fraction of the Refugio Beach oil and a seawater control were prepared to simulate surf zone PAH concentrations (nominal PAH45 ; 0, 0.5, 1, 5, 10, 50, 100, and 500 µg/L). The PAH45 median lethal concentrations (LC50s), based on measured concentrations, were 381 µg/L for Mytilus sp., 75.6 µg/L for Menidia, and 40.9 µg/L for Emerita. Our results suggest that PAH concentrations in coastal waters of the spill-affected area were potentially lethal to early life stages of fish and invertebrates. Environ Toxicol Chem 2021;40:2578-2586. © 2021 SETAC.