Estimation of In Situ Sediment-to-Water Fluxes of Polycyclic Aromatic Hydrocarbons, Polychlorobiphenyls and Polybrominated Diphenylethers

• Published in: Environmental science & technology Vol. 44; no. 8; pp. 3014 - 3020
• Main Authors: Koelmans, Albert A, Poot, Anton, Lange, Hendrika J. De, Velzeboer, Ilona, Harmsen, Joop, Noort, Paul C.M. van
• Format: Journal Article
• Language: English
• Published: Washington, DC American Chemical Society 15.04.2010
• Subjects: Applied sciences; black carbon; contaminated sediments; Continental surface waters; desorption; Environment; Environmental Processes; Environmental science; Exact sciences and technology; Geologic Sediments - chemistry; Halogenated Diphenyl Ethers - chemistry; hudson river; hydrophobic organic-compounds; Natural water pollution; Organic chemicals; PCB; Pollution; Polychlorinated biphenyls; Polychlorinated Biphenyls - chemistry; Polycyclic aromatic hydrocarbons; Polycyclic Compounds - chemistry; release; Sediments; soot; sorption; Surface water; Water Pollutants, Chemical - analysis; Water treatment and pollution; Modeling; Persistent organic pollutant; Transport process; Passive detection; Mass transfer coefficient; Health and environment; Chlorine Organic compounds; Chlorocarbon; Aromatic compound; Stream; Chemical properties; Public health; Organic compounds; Boundary layer; Concentration gradient; Sediment water interaction; Carbonaceous materials; Carbon black; Molecular diffusion; Polychlorobiphenyls; Hydrophobic compound; Desorption; Polycyclic aromatic compound; Sediments; Mass transfer; Sorption; Surface water
• ISSN: 0013-936X; 1520-5851
• DOI: 10.1021/es903938z

Sediment−-water fluxes of hydrophobic organic chemicals (HOC) may affect the quality of surface waters. Here, we present an approach to derive such fluxes from (a) in situ HOC concentration gradients measured with passive samplers and (b) mass transfer coefficients measured with a novel flux method using Empore disks. For eight undisturbed sediments, this method identified whether the sediment acted as a source or as a sink for HOCs. The analysis also identified which type of transport resistance governed sediment water exchange. For seven inland locations, exchange was limited by benthic boundary layer transport, showing no dependencies on sediment or chemical properties other than concentration. For one river mouth location, exchange was limited by slow in-bed intraparticle diffusion. A biphasic dual compartment radial diffusion model adequately described the data for this location. Fast desorption was interpreted as molecular diffusion retarded by microscale dual domain sorption to amorphous as well as black carbon (BC). Slow desorption was invariant with LogK ow and consistent with intraorganic matter diffusion through BC particles. Finally, it is discussed how these findings can be translated into a general framework for flux based exposure assessment.