Sorption of Chlorobenzenes to Cape Cod Aquifer Sediments

Abstract

Sorption of tetra- and pentachlorobenzene by sediment from a glacial outwash aquifer on Cape Cod, MA, was evaluated. Particle size and mineralogical fractions (separated based on paramagnetic susceptibility) were characterized with respect to sediment organic carbon (SOC), mineralogy, surface area, metal oxide coatings, and spatial variability. SOC increases by a factor of 10 as particle size decreases from 500–1000 to <63 μm. Magnetic mineral abundance is a function of particle size and increases from <5% in the 500–1000-μm fraction to>25% in the <63-μm fraction, and SOC is preferentially associated with the magnetic minerals. Sorption increases with decreasing particle size (increasing SOC, magnetic minerals, surface area, and metal oxyhydroxides), and the magnetic mineral fraction has greater sorption than the bulk or nonmagnetic fractions. Removal of SOC decreases sorption proportional to the decrease in SOC and results in a nonlinear isotherm. © 1994, American Chemical Society. All rights reserved.