Measurements and vegetational impact of chemical drift from mechanical draft cooling towers

Collection and analyses of precipitation prior to and after cooling tower operation at the Palisades Plant in southwestern Michigan resulted in high deposition rates of sulfate and calcium up to 92 m from the towers. Sulfate deposition rates during operation averaged up to 9. 0 g m** minus **2 month** minus **1 in areas within 50 m of the cooling towers and decreased to 0. 61 g m** minus **2 month** minus **1 between 700 and 1609 m. Calcium deposition rates during operation averaged up to 4. 5 g m** minus **2 month** minus **1 in areas within 50 m of the cooling towers and decreased to 0. 57 g m** minus **2 month** minus **1 between 700 and 1609 m. The high sulfate deposition rates were assumed to be responsible for severe vegetation damage within 92 m of the cooling towers.