Chemical and physical characteristics of lakes in the northeastern United States

The chemical status of 768 lakes in the northeastern United States was determined as part of the Eastern Lake Survey. The largest number of acidic lakes in the Northeast was estimated for the Adirondack area of New York, whereas the fewest acidic lakes were estimated to occur in Maine. Sulfate concentrations were lowest in Maine and highest in the Poconos/Catskills, corresponding to the pattern in sulfate deposition. Acidic lakes were associated with low levels of base cations (calcium and magnesium) and elevated sulfate levels. Clear water, acidic lakes also had elevated concentrations of aluminum. Acidic lakes were not uniformly distributed in the Northeast. The distribution of acidic lakes was influenced principally by concentrations of sulfate and base cations, among other factors such as lake type and hydrologic flow path.