The goal of collecting DNA samples of freshwater snails in different areas of Van Cortlandt Park is to determine the species richness of aquatic snails in the park. The DNA of at most 30 samples will be collected, and the DNA sequence will be determined. Additional data to determine water quality will be collected: amount of dissolved oxygen, phosphate, nitrate, pH, coliform, and turbidity. Collecting information about these environmental factors will determine the species richness of aquatic snails in habitats of certain water quality.