Contamination of Fish and Shellfish Following Oil Spill Incidents

Abstract

ABSTRACT• Accidents and spillages are an inevitable consequence of the worldwide transport of crude oil and refined petroleum products by sea. The number of major spills occurring each year has decreased since the 1970s, but spillages and operational discharges from tankers nonetheless constitute a significant input of oil to the marine environment. The rapid uptake of oil and polycyclic aromatic hydrocarbons (PAHs) by exposed fish and shellfish, resulting from large oil spillages in coastal waters, poses a potential threat to human consumers of fish and shellfish and also affects the marketability of catches. In this article, the processes influencing uptake and retention of PAHs in fish and shellfish are outlined by drawing on the experience gained from previous incidents. This includes particular reference to three recent major oil spills from tankers in the United Kingdom and the United States, those involving the Exxon Valdez, Braer, and Sea Empress, and to the resulting contamination of local stocks. A more uniform approach to oil spill monitoring would aid comparisons between spills and would help interpret the kinetics and dynamics of released hydrocarbons in future cases. Currently, no statutory limits or guideline values have been established for PAHs in edible tissues of fish or shellfish, whether derived from oil or combustion sources.

Polycyclic Aromatic Hydrocarbons in Various Species of Fishes from Mumbai Harbour, India, and Their Dietary Intake Concentration to Human

“…Pollution by persistent chemicals is potentially harmful to the organisms at higher tropic levels in the food chain. The marine organisms like fish are able to accumulate severalfold higher concentration of PAHs than the surrounding water [8][9][10]. Fish is a major source of proteins and healthy lipids for people.…”

Post-incident monitoring to evaluate environmental damage from shipping incidents: Chemical and biological assessments

“…Some of the reasons that make this group suitable for these types of studies are that, as filter feeders, they accumulate both organic and inorganic pollutants in their tissues, they present a low rate of regulatory mechanisms for the internal concentrations of chemicals, have widespread distribution, and contaminated shellfish offer a threat to human consumers (Law and Hellou, 1999). In particular, mussels (Mytilus spp.)…”

“…Biota samples, in the form of fish, shellfish and plants can provide detailed information on which oil components the organisms have been exposed to. The techniques used for analyzing oil components in biota are generally very similar, involving extraction of petroleum hydrocarbons from the biota sample, a clean-up step to remove interfering endogenous material, followed by analysis that is typically performed by gas chromatography coupled to mass spectroscopy (GCeMS) (Bartolomé et al, 2007;Law and Hellou, 1999).…”

Toxic equivalency factors for PAH and their applicability in shellfish pollution monitoring studies©British Crown copyright 2002.

“…PAH are also readily accumulated by fish and shellfish, 8 and particularly by bivalve molluscs. As an example, following the Braer oil spill, the concentration of PAH (2-to 6-ring, parent and alkylated) in queen scallop gonad was found to be in excess of 26,000 mg kg 21 wet weight; 9 and following the Sea Empress oil spill the concentration of a similar range of PAH was around 100,000 mg kg 21 wet weight in one sample of mussels (Kelly, unpublished data).…”