The Effect of Insecticde Concentration on the Health and Survival Rate of Earthworms
2013 Fairfax County Regional Science and Engineering Fair
The abstract below was written by the student. The Northern Virginia Soil and Water Conservation District made no editorial changes.
The Effect of Insecticide Concentration on the Health and Survival Rate of Earthworms
By: Katherine R. Walton and Stephanie C. Halsted, South County High School
Supposedly, pesticides do not affect human health, or the health of organisms other than insects. By manipulating the concentration of Consero (an insecticide) an earthworm population is exposed to, then closely monitoring their health and survival, this experiment was designed to test the hypothesis that greater insecticide concentration will lead to a decreased survival and health rate in earthworms. Prior to our actual experiment, we conducted a pre-experiment to demonstrate what concentration of about 2% caused most of our population to die in only three days, while 0% concentration resulted in a little to no earthworm death. In our pre-experiment, we also measured that if earthworms received a solution that is only about 1% Consero (the recommended amount), significantly less than half of the population died within three days. After completing this, we extended our observations time to two weeks and only tested solutions with concentrations between one and two percent. This time, we used smaller intervals so we could study the effect of different concentrations more closely. In our observations, we saw that the lower concentrations of pesticide was to zero, the less drastic the difference in survival rates. As the concentration was increased, smaller intervals increased the death rate drastically. Our hypothesis was supported by the decreased survival rate when worms are exposed to higher concentrations, but raised questions about the uneven correlation between the two variables.