TsengBPDisasterResearchAnnotation1

Schein, A., Scott, J., Mos, L., & Hodson, P.. (2009). OIL DISPERSION INCREASES THE APPARENT BIOAVAILABILITY AND TOXICITY OF DIESEL TO RAINBOW TROUT (ONCORHYNCHUS MYKISS). Environmental Toxicology and Chemistry, 28(3), 595-602. Retrieved March 2, 2011, from Research Library. (Document ID: 1654973391).


 * Abstract- ||
 * Diesel is a complex mixture containing polycyclic aromatic hydrocarbons, which persist after a spill, pass readily from water into tissues, and are toxic to early life stages of fish. The bioavailability and chronic toxicity of hydrocarbons dissolved into water from floating diesel (water-accommodated fraction) and chemically dispersed diesel (chemically enhanced water-accommodated fraction) were measured by the extent of ethoxyresorufin-O-deethylase (EROD) induction in juvenile rainbow trout (Oncorhynchus mykiss) and by the severity of blue sac disease in embryos. The water-accommodated fraction of floating diesel was virtually nontoxic to embryos at nominal concentrations up to 1,000 mg/L, causing only small weight changes. Liver EROD induction in juvenile trout was only observed at the highest nominal water-accommodated fraction concentration (10,000 mg/L). Chemical dispersion increased the bioavailability and toxicity of diesel to trout by 100-fold. Diesel chemically enhanced water-accommodated fraction induced EROD activity, caused blue sac disease, and impaired development and growth of embryonic trout at nominal concentrations as low as 10 mg/L; 88% mortality occurred at 100 mg/L. However, when total hydrocarbon concentrations were measured, differences between dispersed and undispersed diesel disappeared, with a median lethal concentration of 8 mg/L of total hydrocarbons and sublethal median effective concentrations ranging from 1.3 to 6.1 mg/L. Dispersion of diesel by high-energy mechanical mixing was recently reported to cause acute lethality to juvenile trout between 40 and 200 mg/L. Therefore, dispersion of oil by any means increases the bioavailability and apparent toxicity of diesel to fish embryos without changing the toxicity of its components. Nevertheless, in an actual spill, dispersion of diesel increases the effects of oil on fish populations. ||
 * Keywords-Oil spill Polycyclic aromatic hydrocarbons Fish Ethoxyresorufin-O-deethylase Blue sac disease. ||

Please see attach for full article.

The lead author, Dr. Peter Hodson, is a professor at School of Environmental Studies & Department of Biology of Queen’s University, Canada, He also serves as the editor of the scientific journal: Environmental Toxicology and Chemistry. In this article, Dr. Hodson pointed out that using dispersion may seem like a good idea on the surface, but the dispersed oil droplets then sink to the bottom of the ocean, affecting more fish, fish saplings, and eggs. He has demonstrated the test which focused on the lethality of diesel in water versus dispersant in water for the rainbow trout embryos. When compared to the diesel pollution, the toxicology of dispersant is far more complex and carries a long term effect on the fish and its offspring. Not only that the droplets of diesel does not disappear into the thin air, when they sink underneath the surface, it can be carried by the underwater current to a farther body of water. In the full article attached, there shows the testing results. The results can perhaps be used for legislation pushing towards the banning of dispersant usage. Like the professor said during the interview with MSNBC, “while you can see the risk on the surface, appreciating risk under the surface is much more difficult.”