Immunotoxic and cellular mechanisms of action of petrogenic compounds

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Our society is still largely dependent on fossil fuels. Accompanying that is an element of risk associated with the extraction, refining, transportation and use of petrochemicals. There are challenges in determining the cause of impacts on fish and wildlife when they are observed in the environment associated with petroleum substances. We are equally limited in our ability to predict those impacts when we attempt to determine the danger associated with activities such as pipelines. The reason for this is that petroleum mixtures are incredibly complex, containing tens of thousands of compounds and the hazard posed by most of those constituents remains unknown. When fishes are exposed to petrochemical substances, an increased incidence of infections has been observed. It is generally presumed that chemical agents in the mixtures cause immune suppression, allowing bacteria and viruses to infect the organism more easily. This research proposes to study two classes of compounds, naphthenic acids and polycyclic aromatic hydrocarbons found in petroleum mixtures, for their ability to impact the immune system of fishes. As it is prohibitively difficult and expensive to screen large numbers of compounds using live organisms, this research proposes to develop cellular methods using the immune tissue of fishes. This will be conducted by separating the major classes of white blood cells from the blood of rainbow trout and exposing the cells to chemicals. This will test the hypothesis that these groups of compounds influence the cell by a phenomenon known as programmed cell death. This is the cells way of recycling its contents when the damage to a cell has reached a point where it can no longer recover. The research will examine the mechanisms by which these two classes of compounds might cause toxicity to immune cells. Further to this, research will be conducted on waters and sediments from oil sands operations in order to identify substances that cause toxicity to cells isolated from the fish immune system. It is anticipated that from this research we will gain an understanding of the ability of specific compounds in petrochemical mixtures to cause immune suppression and determine mechanisms by which they do so. This is important, because if we want to diagnose impacts that are occurring in the environment, a chemically-induced disease state, we must know the symptoms of those impacts. When evaluating the hazard of such compounds in the environment it is also informative to know if there is a danger of immune suppression, leading to disease and or collapses of populations of organisms. Canada is heavily invested in fossil fuel exploitation and this research is directly applicable to current activities in this sector. Canada has also been an innovator in environmental monitoring and assessment, particularly with regards to aquatic systems, and new knowledge gained will be exported globally.