Addie Schlussel is a biology and environmental studies major and over the last two semesters has been working on her biology St. Mary’s Project (SMP) looking at the effects of neonicotinoids (a class of insecticides) and an antidepressant (specifically Prozac) on Daphnia (Common Water Flea) survival. The two chemicals investigated are commonly found in the environment as water pollution due to runoff and other contaminants entering the environment.
Schlussel’s work investigated if the neonicotinoid insecticides and antidepressants were able to work conjunctively with one another in order to become more toxic and harmful to macroinvertebrates than they would have been able to alone. This is a problem which needs to be understood if both of these chemicals as pollutants in the environment would have more harmful effects on nature and the environment than one of them would have had alone. She hypothesized that the two would combining effects and would cause a “synergistic toxicity” to the Daphnia she said. Schlussel used Daphnia, to test this relationship. Daphnia are a “common ecotoxicology model organism” Schlussel explained.
Neonicotinoids function as insecticides by causing paralysis and death in the insects they come in contact with by impacting the insect’s central nervous systems. Since this is a relatively new class of insecticides, there is some concern about their long-term effects on the environment and other organisms within the environment. Their use has already been restricted in a few European countries because of these concerns.
The antidepressant Prozac specifically is understood to inhibit enzymes which are used by organisms to detoxify their bodies. Macroinvertebrates such as Daphnia specifically have several crucial enzymes they use for detoxifying impacted with this antidepressant.
Surprisingly, Schlussel found that when the Daphnia were exposed to the two chemicals, she did not see a synergistic relationship as she had expected. Rather than combining and becoming even more toxic and harmful to the organism’s, exposure to both chemicals was actually seen to be less toxic for the Daphnia. Schlussel explained that “the neonicotinoid insecticides may have inhibited [the Daphnia’s] feeding, so less antidepressant was taken up” by the organisms. In this way, the results she expected to see would not have been likely if the organisms were not actually ingesting as much of the insecticide and antidepressant as Schlussel thought that they would.
Schlussel will be presenting her SMP on Tuesday, May 2 at 2:20 if anyone is interested in hearing a more thorough explanation of her research and results.