The goal of this experiment is to determine the pollution levels of the water in Van Cortlandt Park by measuring the snail diversity. We plan to do this by first measuring the oxygen level in the bodies of water and then collecting multiple snail specimens from each location. Depending on the oxygen levels of each body of water and the diversity of the snails, we will be able to determine the water quality of the water. If there is a higher quantity of lunged snails in a body of water we will then determine that the oxygen levels in the water are extremely low. Low levels of dissolved oxygen are caused by increased levels of nitrogen and phosphorus. The increase in nitrogen and phosphorus levels in the water can be attributed to plant fertilizer.The lower levels of oxygen in the water proves that the fertilizer run off from the park has detrimental effects on the water quality.