Food Safety and Environmental Stewardship Program

On April 20^th, 2010 a lethal explosion at the Deepwater Horizon oil drilling rig located 66 km southeast of the Louisiana coast in Mississippi Canyon Block 252, led to the largest marine oil spill in United States history. In the case of marine oil spills, such as the Deepwater Horizon spill, there is an initial, acute risk to organisms that can become covered in viscous crude as well as acute and chronic risks from exposure to toxic chemicals through air, water and food. Even after the oil is no longer visible, chemicals of concern can persist in the environment and affect exposed organisms . It is the freely dissolved fraction of chemicals in the water that is bioavailable to diffuse across biological membranes and enter organisms and the food web. The use of chemical dispersants during the Deepwater Horizon oil spill was a source of contention among scientists and the public, in part because the application of dispersants to crude oil makes PAHs and other hydrophobic compounds more soluble in water, increasing their bioavailability.

Passive sampling devices (PSDs) were developed to address the issue of quantifying the bioavailable fraction of hydrophobic compounds in environmental media. They sequester and accumulate the freely dissolved, and therefore bioavailable fraction of hydrophobic organic contaminants, such as PAHs; mimicking passive uptake and accumulation of these compounds by biomembranes and lipid tissues. PSDs provide a time integrated measure of the concentration of chemicals in the environment and, by effectively sampling a large volume of water, allow for the detection of chemicals that are present at low concentrations. This objectives of this study are to assess the impact of the Deepwater Horizon oil spill on bioavailable PAHs, OPAHs and other spill contaminants at coastal sites in the Gulf of Mexico