On January 22 2013, the SETAC Laurentian Chapter had the honour of hosti
ng Dr. Ulysses Klee of Stantec Consulting as a pub night speaker. A very sizable (50+) and enthusiastic crowd was in attendance at Shakespeare Arms Pub in Guelph, Ontario to hear Ulysses talk regarding the use of the Petrotox model to help set ecological standards for the Atlantic Provinces. Ulysses’ talk started with a very informative overview of what ecological standards are and the standards currently used by other agencies and jurisdictions. Canada’sAtlantic Provinceswere essentially the only group inCanadathat had not developed their own standards. As a result, an Eco Task Group consisting of representatives from private industry, academia and government was formed to work towards resolving this. Ulysses’ talk focused on the task group’s efforts to develop risk-based standards for Petroleum Hydrocarbons in sediment. T
he key behind any standard is toxicity data and Ulysses quickly pointed out that there is not a wealth of toxicity information on petroleum hydrocarbons. In addition, petroleum hydrocarbons consist of an extremely diverse group of products, each with different mixtures of hydrocarbons. In order to deal with these complexities, the task group elected to use the Petrotox model. This model mimics the conduct of aquatic toxicity studies, specific to petroleum hydrocarbons. It has data on 42 test species and is based on both quantitative structure-activity relationships (QSAR) to predict fate and behaviour and the target lipid model to predict toxicity. The acute-to-chronic ratio in the model is fixed at a set level. The model can be used to output chronic toxicity levels for multiple species which can then be used to create species sensitivity distributions. These, in turn, can be used to make inferences on the toxicity to populations. The model has undergone some preliminary validation using diesel fuel and bunker C oil with real toxicity tests and the results indicated that the model was very close at predicting the results of the laboratory tests. The evening ended with a number of questions for Ulysses as well as Ulysses indicating that this is still in an early stage of development and further validation is encouraged. - Submitted by Matthew Graham