Long-term elemental dry deposition fluxes measured around Lake Michigan with an automated dry deposition sampler

Long-term measurements of mass and elemental dry deposition (Mg, Al, V, Cr, Mn, Ni, Co, Cu, Zn, As, Sr, Mo, Cd, Sb, Ba, and Pb) were made with an auto mated dry deposition sampler (Eagle Il)containing knife-edge surrogate surf aces during the Lake Michigan Mass Balance/Mass Budget Study. Measurements were made over a roughly 700-day period in Chicago, IL; in South Haven and Sleeping Bear Dunes, MI; and over Lake Michigan on the 68th Street drinking water intake cribs from December 1993 to October 1995. Average mass fluxes in Chicago, South Haven, Sleeping Bear Dunes, and the 68th Street crib wer e 65, 10, 3.6, and 12 mg m(-2) day(-1), respectively. Primarily crustal ele mental fluxes were significantly smaller than the mass fluxes but higher th an primarily anthropogenic elemental fluxes. For example, the average eleme ntal flux of Al in Chicago, South Haven, Sleeping Bear Dunes, and the 68th Street crib were 1.0, 0.34, 0.074, and 0.34 mg m(-2) day(-1), respectively. The average Pb fluxes in Chicago, South Haven, Sleeping Bear Dunes, and th e 68th Street crib were 0.038, 0.023, 0.035, and 0.032 mg m(-2) day(-1) res pectively. The measured fluxes at the various sites were used to calculate the dry deposition loadings to the lake. These estimated fluxes were highes t for Mg (3800 t/yr) and lowest for Cd (7 t/yr).