US EPA

2171574 

Journal Article 

Distribution of hydrophobic contaminants between sediment, water, and colloids in batch incubations 

Booij, K 

1993 

Yes 

Bulletin of Environmental Contamination and Toxicology
ISSN: 0007-4861
EISSN: 1432-0800 

50 

2 

205-211 

English 

7678522 

The sediment-water partition coefficient of hydrophobic contaminants is an important parameter for modelling the transport of these compounds in the aquatic environment. The most widely used procedure for determining partition coefficients is the batch method, which involves shaking of sediment, water, and an amount of contaminant in a flask for several days. After equilibrium is attained, the phases are separated by either filtration or centrifugation. The partition coefficient (Kd) is calculated from the concentrations in the water phase (Cw) and the sediment phase (Cs). The particles that remain in the water phase after phase separation are commonly referred to as colloids. A separation between the dissolved and bound fraction can be achieved by liquid-solid chromatography. Experiments were conducted for the determination of sediment-water partition coefficients using solid phase extraction with PFA teflon beads. Spike solutions in hexane contained alpha-, and gamma-, hexachlorocyclohexane, penta-, and hexachlorobenzene (1 microg/ml each), and the technical PCB mixtures Clophen A30 (8 microg/ml) and Clophen A60 (7 microg/ml). Differences between true and apparent Kd values were negligible for compounds with log (Kow) < 6, and were up to 1 log unit for more hydrophobic compounds. Freshwater sediments probably will yield different results due to their higher organic carbon contents and higher amounts of colloidal material. (White-Reimer-PTT) 

Hydrophobic compounds; Path of pollutants; Sediment-water interfaces; Solute transport; Colloids; Partition coefficient; Polychlorinated biphenyls; Sediment contamination; Separation techniques/