Parameters affecting the desorption of hydrophobic organic chemicals from suspended sediments

Journal Article · Sun Dec 01 04:00:00 EST 1996 · Environmental Toxicology and Chemistry

DOI:https://doi.org/10.1002/etc.5620151219· OSTI ID:483696

Borglin, S; Wilke, A; Jepsen, R; Lick, W ^[1]

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1. Univ. of California, Santa Barbara, CA (United States). Dept. of Mechanical and Environmental Engineering

Recent work has demonstrated that both the adsorption and desorption of hydrophobic organic chemicals to sediments and soils can be quite slow and that chemical equilibrium may not be a good approximation in many real situations. By means of long-term batch experiments, this has been recently and clearly shown for the adsorption of hexachlorobenzene and three poly-chlorinated biphenyls to suspended sediments. In the present study, long-term desorption experiments are performed with three hydrophobic organic chemicals (hexachlorobenzene and two polychlorinated biphenyls) and suspended sediments. Desorption times are on the order of a month to several years. It is shown that the desorption rates are dependent on the particle/floc size and density distributions, the type of water, the amount of organic carbon in the sediments, the time of adsorption before desorption, and the chemical partition coefficient. It is also shown that a simple chemical diffusion model with an effective diffusion coefficient dependent on the porosity of the particle/floc, the organic content of the sediments, and the chemical partition coefficient, along with proper consideration of particle/floc size and density distributions is sufficient to explain the experimental results.

• Sponsoring Organization: USDOE
• OSTI ID: 483696
• Journal Information: Environmental Toxicology and Chemistry, Journal Name: Environmental Toxicology and Chemistry Journal Issue: 12 Vol. 15; ISSN ETOCDK; ISSN 0730-7268
• Country of Publication: United States
• Language: English

Related Subjects

54 ENVIRONMENTAL SCIENCES
CHLORINATED AROMATIC HYDROCARBONS
DESORPTION
MATHEMATICAL MODELS
POLYCHLORINATED BIPHENYLS
SEDIMENTS
WATER CHEMISTRY
WATER POLLUTION