Exploiting natural chemical heterogeneity within a sedimentary deposit to probe controls on nonlinear non-ionic organic pollutant sorption

Natural variability within sediments with respect to sorption and other physical and chemical characteristics was developed to better understand controls on pollutant retention. The sorption measurements for each depth-specific subsample were fit with two models, i.e., a Freundlich isotherm and an adsorption/partition two component model. The Freundlich isotherms indicated that both magnitude and nonlinear exponent are variable with depth in the aquifer. Consistent with the Freundlich isotherm results, the magnitude of the adsorbing component of the organic carbon content (f_oc((1-x)f_oc) was positively correlated to the carbonate content of the sediment. The partitioning component of the f_oc was not significantly correlated to any of the physical-chemical properties of the sediment that were measured. The strong correlation between the adsorbing component of the f_oc and the carbonate content implied a link between the carbonate grains and high surface area carbonaceous material.