CARBON PARTICLES IN DATED SEDIMENTS FROM LAKE-MICHIGAN, GREEN-BAY, AND TRIBUTARIES

Carbon particle analysis is carried out of four sediment cores from La ke Michigan (CLM-I), Green Bay (GB-D), and the Fox (FR-C) and Kinnicki nnic Rivers (KK-6) to explore the inputs of pollution from incomplete combustion of fossil fuels. Elemental carbon content is determined by CHN analyzer, and carbon particle type (from burning of coal, wood, an d petroleum), abundance, and size are determined through scanning elec tron microscopy. Carbon contents are between 0 and 1.0% except for cor e KK-6, where high values (3-33%) appear to be linked to a now defunct coke and coal gasification plant. Maxima are found in the 1950s (CLM- I) or during 1940-1962(FR-C). The abundance of coal particles is betwe en 40 and 95% in all four cores. The wood fraction is between 0 and 40 % with the highest value in the central Lake Michigan core (CLM-I), in dicating long-range transport of small diameter (18-22 mu m) wood part icles with a minimum during 1960-1970 in agreement with the U.S. consu mption record. The fraction of oil particles increases in the top laye rs of KK-6, FR-C, and CLM-I, reflecting increasing emissions from auto mobile traffic since 1920-1940. Core GB-D shows the opposite tend sinc e 1953, demonstrating reduced significance of Green Bay as a commercia l port. PAH data for these areas, obtained by others, generally suppor t our results.