The chemical composition of atmospheric precipitation from selected stations in Michigan

Abstract

The pH and amount of rainfall from over 60 selected stations throughout northern and lower Michigan was determined from September 1972 to December 1974. Precipitation pH was determined for each station by calibrated electrode meters. The seasonal weighted average and median pH from all stations in the study was 5.0 and 6.3, respectively. Daily readings from stations throughout Michigan indicate that pH is dependent on the amount of rainfall and that variations in it are often locally controlled. Collectively the pH values suggest carbonic acid control for most of the state. Annual median pH varied from a high of 8.45 at Dimondale, a station located 1.5 km from a concrete tile plant in central Michigan to 4.65 at Vassar, a small town located east of several industrial centers in the thumb region of the state. A comparison of annual nutrient loading for NO₃^-1, SO₄^-2, Cl^-1, PO₄^-3, Ca⁺⁺, Mg⁺⁺, Na⁺, K⁺, and pH of rainwater from selected stations revealed that the eastern U.S. stations reporting pH's < 4.02 have similar loadings for no₃ but twice the SO₄ input found for rural areas of Michigan.

Parent Publication

• Proceedings of the first international symposium on acid precipitation and the forest ecosystem

Citation

Richardson, Curtis J.; Merva, George E. 1976. The chemical composition of atmospheric precipitation from selected stations in Michigan. In: Dochinger, L. S.; Seliga, T. A., eds. Proceedings of the first international symposium on acid precipitation and the forest ecosystem; Gen. Tech. Rep. NE-23. Upper Darby, PA: U.S. Department of Agriculture, Forest Service, Northeastern Forest Experiment Station. 321-332