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Transport of Naturally Occurring Dissolved Organic Carbon in Laboratory Columns Containing Aquifer Material
Author(s) -
Dunnivant F. M.,
Jardine P. M.,
Taylor D. L.,
McCarthy J. F.
Publication year - 1992
Publication title -
soil science society of america journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.836
H-Index - 168
eISSN - 1435-0661
pISSN - 0361-5995
DOI - 10.2136/sssaj1992.03615995005600020016x
Subject(s) - aquifer , dissolved organic carbon , adsorption , environmental chemistry , desorption , chemistry , absorbance , total organic carbon , groundwater , geology , chromatography , organic chemistry , geotechnical engineering
The subsurface transport of ionic and nonionic pollutants may be strongly impacted by the movement of naturally occurring dissolved organic carbon (DOC) in aquifers. Thus, the adsorption, desorption, and transport of DOC in laboratory columns containing well‐packed aquifer material was investigated. Data showed that the breakthrough of DOC from aquifer columns was the result of complex adsorption reactions between DOC and the aquifer material. Breakthrough curves (BTCs) of the DOC were characterized by an initial rapid concentration increase followed by extended tailing to long times. The extensive tailing of the BTCs was attributed primarily to the slow adsorption kinetics of DOC to the aquifer material and the nonlinear nature of the adsorption isotherm. Independent experiments suggested that the size exclusion of DOC from aquifer pores was negligible. The time required to saturate the aquifer material with organic C was dependent on the influent DOC concentration, with lower organic influent levels requiring longer pulse durations to fully saturate the aquifer sediment with organic C. Hydrophobic constituents of the DOC were preferentially adsorbed while hydrophilic components were rapidly transported through the aquifer columns. Spectral analysis (light absorbance at 260 nm) of the column effluents confirmed that the composition of the mobile organic C changed during the breakthrough of DOC. Data from this investigation demonstrate that DOC can be mobile in soil systems, and emphasizes the need to evaluate the cotransport of pollutants by DOC.