Diesel vs. Bitumen
Sophie McLean
Prince of Wales Secondary
Floor Location : J 143 V

In this experiment, the LC50 (lethal concentration for 50% of the organisms) of both bitumen and diesel was determined using red wriggler worms ("Eisena Fetida").The worms were placed in containers with increasing dilutions of bitumen and diesel for a seven day period. The toxicity of the substances was determined by counting mortality rates, calculating the worms' weight loss and observing the worms' general behavior. The results showed that the diesel-affected worms had lost much more weight, and had a higher mortality rate. The LC50 for diesel in the soil was 2.7%. The LC50 for bitumen was inconclusive, because only 40% of the worms died at the highest concentration. Additional observations included the fact that the diesel worms were not very active, and in some cases had developed deformities. Some of the worms were brighter in colour, and some were very bloated or very skinny. The main behavior that I observed was reaction time. The slowest reaction time observed was in container B-4, (5% bitumen) where it took a full two seconds for a worm to react to stimuli. My hypothesis is that this impact was likely a result of the effect of bitumen fumes, or lack of nutrition on the worm. Overall, my experiment shows that diesel was more toxic than bitumen on red wriggler worms in these experimental conditions.