DETERMINATION OF PAH SOURCES IN DATED SEDIMENTS FROM GREEN BAY, WISCONSIN, BY A CHEMICAL MASS-BALANCE MODEL

Six sediment cores were collected from Green Bay, Wisconsin, in order to identify possible sources of polycyclic aromatic hydrocarbons (PAHs ) by a chemical mass balance (CMB) model. The cores which were obtaine d in 1995 had total PAH concentrations between 8.04 and 0.460 ppm. Pb- 210 and Cs-137 dating was used to determine historical trends of PAH i nputs, and elemental carbon particle analysis was done to characterize particles from combustion of coal, wood and petroleum. The results sh ow that coke burning, highway dust, and wood burning are likely source s of PAHs to Green Bay. The contribution of coke oven emissions (CB) f or the Green Bay cores is in the range of 5 to 90%. The overall highwa y dust (HWY) contribution is between 5 and 70%. There is a maximum (si milar to 67%) contribution of HWY around 1988 which is in agreement wi th the historical US petroleum consumption. The wood burning (WB) cont ribution is between 1 to 30%, except in core GB-A where a maximum (sim ilar to 50%) is found around 1994. The average relative errors of meas urement for chi(2) equal to the number of degrees of freedom, are 52.5 , 56.2, 36.2, 52.3, and 42.8 (df = 3) for the Green Bay cores A, B, C, E, and F, respectively. The sums of the contribution factors are less than one, indicating gain of inert biological or other bulk material between source and receptor. The results of carbon particles for Green Bay core D show that coal, oil, and wood burning are consistent with the CMB modeling results. (C) 1998 Elsevier Science Ltd. All rights re served.