Toxicity of weathered Exxon Valdez crude oil to pink salmon embryos

Abstract

Abstract-Research was conducted at the University of Idaho

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

“…These low K ow compounds are also more likely to volatilize to the atmosphere compared to the more hydrophobic PAHs (e .g., phenanthrenes) leading to an increased percentage of high K ow compounds in solution. These physical processes explain the characteristic, time-dependent weathering pattern that emerges both in the natural environment (Bence and Burns 1995;Short and Heintz 1997;Carls et al 2001;Boehm et al 2004Boehm et al , 2005Neff et al 2006) and in laboratory studies (Marty et al 1997;Short and Heintz 1997;Heintz et al 1999Heintz et al , 2000Carls et al 1998Carls et al , 1999Carls et al , 2005Brannon et al 2006). To summarize, not only is the toxicity of dissolved PAHs important, the previously cited zebrafish study (Carls et al 2008) demonstrates toxicity of particulate oil is unimportant to fish embryos.…”

“…Paired comparisons of zebrafish embryos exposed to particulate-laden, water-accommodated fractions of crude oil and those isolated from particles by agarose sequestration demonstrate that fish embryos react predominantly to dissolved oil; physical contact did not enhance sensitivity (Carls et al 2008). Furthermore, the degree of response by fish embryos in contact with whole oil in oiled-rock column experiments and those isolated from it were the same (Heintz et al 1999;Brannon et al 2006). Induction of cytochrome P4501A (CYP1A) provided evidence of PAH exposure in pink salmon embryos without physical oil contact , confirming embryo exposure and biochemical response to dissolved PAHs.…”

“…A suggestion that direct contact with oil is required for PAHs to transfer to fish embryos (Brannon et al 2006) has no support because eggs and other life stages isolated from contact with whole oil or PAH mixtures consistently exhibit severe adverse effects (Carls et al 1998(Carls et al , 1999(Carls et al , 2008Heintz et al 1999;Incardona et al 2005;Rhodes et al 2005;Farwell et al 2006). Paired comparisons of zebrafish embryos exposed to particulate-laden, water-accommodated fractions of crude oil and those isolated from particles by agarose sequestration demonstrate that fish embryos react predominantly to dissolved oil; physical contact did not enhance sensitivity (Carls et al 2008).…”

“…Observations of high toxicity of weathered PAHs in water have been challenged by a series of studies that claim (1) much lower toxicity of weathered aqueous PAHs (Brannon et al 2006), (2) direct contact with dispersed oil droplets plays a significant toxic role or is required for toxicity (Pearson 2005;Brannon et al 2006), (3) uncontrolled factors (oxygen, ammonia, and sulfides) contributed substantively to toxicity (Pearson 2005), (4) polar compounds produced by microbial metabolism are the major cause of observed toxicity in the oiled-rock column assays we typically use (Neff et al 2000), and (5) that based on equilibrium models (where the toxic potential of a PAH is defined as the ratio of aqueous solubility to its toxicity), water contaminated by contact with weathered oil cannot be more toxic than effluent contaminated by fresh oil (Di Toro et al 2007).…”

An Experimental System to Assess Potential Biological Impact of Operational Response During an Oil Spill

“…wave action, promotes their formation. Moreover oil droplets are suggested as a determinant of toxicity [11]. On this basis, an experimental system adapted from Blackman et al [12] was proposed to measure the total petroleum hydrocarbons transferred in the water column and the toxicity following dispersant application.…”