A Perspective on the Toxicity of Petrogenic PAHs to Developing Fish Embryos Related to Environmental Chemistry

Abstract

Numerous studies demonstrate polynuclear aromatic hydrocarbons (PAHs) dissolved from weathered crude oil adversely affect fish embryos at 0.5 to 23 µg/l. This conclusion has been challenged by studies that claim (1) much lower toxicity of weathered aqueous PAHs; (2) direct contact with dispersed oil droplets plays a significant role or is required for toxicity; (3) that uncontrolled factors (oxygen, ammonia, and sulfides) contribute substantively to toxicity; (4) polar compounds produced by microbial metabolism are the major cause of observed toxicity; and (5) that based on equilibrium models and toxic potential, water contaminated with weathered oil cannot be more toxic per unit mass than effluent contaminated with fresh oil. In contrast, several studies demonstrate high toxicity of weathered oil; shifts in PAH composition were consistent with dissolution (not particle ablation), embryos accumulated dissolved PAHs at low concentrations and were damaged, and assumed confounding factors were inconsequential. Consistent with previous empirical observations of mortality and weathering, temporal shifts in PAH composition (oil weathering) indicate that PAHs dissolved in water should (and do) become more toxic per unit mass with weathering because high molecular weight PAHs are more persistent and toxic than the more abundant low molecular weight PAHs in whole oil.

Variations of transcript profiles between sea otters Enhydra lutris from Prince William Sound, Alaska, and clinically normal reference otters

“…Seventeen blood samples from 17 captive sea otters were obtained from the Monterey Bay Aquarium (Monterey, California), Shedd Aquarium (Chicago, Illinois), Oregon Coast Aquarium (Newport, Oregon), and the Vancouver Aquarium ( Vancouver, Bri tish Columbia) in 2008, 2009, and included both northern and southern subspecies (Bowen et al 2011). These animals were identified as clinically normal by staff veterinarians at these aquaria during the time interval of blood collection.…”

“…Crude petroleum oil has multiple aromatic and ali phatic hydrocarbon constituents, and the toxic effects of exposure and ingestion can be diverse and extensive (Rebar et al 1995, Mazet et al 2000, Mazet et al 2001, Quintana et al 2008, Veldhoen et al 2008, Carls & Meador 2009). Under these circumstances, molecular investigation of subtle alterations of expressed genes indicative of multiple physiological processes at the cellular level is particularly useful and can elucidate the mechanisms by which oil may have deleterious effects over a long period, including increased tumor formation or disease susceptibility.…”

An evaluation of background levels and sources of polycyclic aromatic hydrocarbons in naturally spawned embryos of Pacific herring (Clupea pallasii) from Puget Sound, Washington, USA

“…Other PAH-embryo field studies to date have focused on oil spill exposures in embryos of salmon (Carls et al, 1996) and herring (Incardona et al, 2012a(Incardona et al, , 2012b, and the physiological effects of exposure to low aqueous PAH concentrations (Carls et al, 2002;Carls and Meador, 2009;Incardona et al, 2004;Incardona et al, 2009). Incardona et al (2012a) illustrated the difficulty in interpreting postoil-spill tissue PAH concentrations and effects on developing herring embryos in an urban setting (San Francisco Bay), without knowledge of pre-spill background PAH conditions in embryos.…”

Bayesian inference-based environmental decision support systems for oil spill response strategy selection

“…PAED typically arises from pollutant-biota contact such as physical smothering or toxicological effects arising from fish exposure to naturally dispersed spilled oil (Carls and Meador, 2009;Claireaux et al, 2013;IPIECA, 1991) or from pollutant-environment contact e.g. through oil penetrating substrate (Jonker et al, 2006) and reducing the ability of affected habitat to support the pre-exposure ecology.…”