PAHs in sediments: Unmixing and CMB modeling of sources

A chemical mass balance (CMB) model, applied to polycyclic aromatic hydroca rbon (PAH) compounds, is used to apportion PAH sources in a group of seven sediment cores in the Milwaukee Basin of the central Lake Michigan area. PA H apportionment results indicate the dominance of coke oven emissions from 1925-1976, and of highway inputs from. 1983-1992 for most of the seven core s. This is consistent with results of carbon particle analysis from the sam e basin. Milwaukee and Port Washington appear to be primary contributors of point source inputs of PAHs from coke ovens and highway dust. Wood burning is a minor source (<13%). These findings are supported by an independent f actor analysis study. Historical PAH records are also determined for the se ven sediment cores. The records are unmixed and averaged over the basin. Th e resulting average record is then used as measured profile in a CMB model to determine PAH sources. Source profiles are historical records of the con sumption of coal, petroleum, and wood, including coal used for coke product ion. A cubic spline technique is developed and applied for the curve fittin g of original data points for all of the cores. Unmixed profiles reveal a n umber of features that are not seen in the original data. Wood burning, cok e oven emissions, and highway dust profiles are found to resemble the natio nal consumption records. Coal burning is a very small PAH source (<1%).