Ammonium Sulfate Case Study

It can not be determined that ammonium sulfate can be used to find the LC50 of Daphnia Magna. In every trial, there was no data that was consistent or logical to be used to determine an accurate LC50. The LC50 is the point at which the concentration of a pollutant is lethal to 50% of the organisms. Static toxicity tests occur when the aquatic organisms are exposed to the same pollutant concentration for the duration of the test. The data in the first two trials had mostly 100% death rates regardless of the ammonium sulfate solutions. These tests used Mr. Parent’s well water, which may have been the reason for the deaths. In trials three, four, and five, four of the 15 solutions had 100% death rates. Although there were less deaths than trials …show more content…
The mortality rate gradually decreased from 40%, 40%, 20%, 20%, to 0%. This supports the hypothesis because the greater dilutions had a higher mortality rate while the smaller dilutions had lower mortality rates. However, the upstream data was also convincing. The greatest dilution, 1:4, had a mortality rate of 80%, which is greater than on site. This could be considered an outlier because it seems random compared to the rest of the upstream dilution rates. However, the smaller dilutions, other than 40%, had mortality rates of 0%. This seems accurate because the toxins would mostly flow downstream with the current rather than up against the current. The downstream data stuck out from the rest due to its surprising data. The higher the dilutions, the lower the mortality rate. This is the opposite the hypothesis. Although the smaller dilutions had higher mortality rates, the dilution of 1:64 had a death rate of 20%, a significant drop from 60% in the 1:32 dilution. The drop in deaths occurred because Next time I do this project, I would be more careful while transferring the Daphnia from the culture tank to the experiment cups and beakers. I believe that sucking them into the pipettes so fast and releasing them into the cups rapidly may have put them into a state of shock. This may have resulted in deaths that were not directly due to the ammonium sulfate. It was extremely difficult to transfer the Daphnia into the cups and beakers because it would take multiple tries in order to get all five into the pipette. The constant threat of a pipette submerging into their tank and cups may have traumatized them right as they were introduced into the solutions. Next time this experiment is performed, the Daphnia will be collected into groups of five a day before being submerged in the