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Behavior of [ 14 C]‐4‐nitrophenol and [ 14 C]‐3,4‐dichloroaniline in laboratory sediment‐water systems: Part 2. Desorption experiments and identification of sorptive fraction
Author(s) -
Heim Kerstin,
Schuphan Ingolf,
Schmidt Burkhard
Publication year - 1995
Publication title -
environmental toxicology and chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.1
H-Index - 171
eISSN - 1552-8618
pISSN - 0730-7268
DOI - 10.1002/etc.5620140503
Subject(s) - sediment , environmental chemistry , chemistry , humin , sorption , fractionation , total organic carbon , desorption , chromatography , organic matter , humic acid , geology , adsorption , organic chemistry , paleontology , fertilizer
Both [ 14 C]‐4‐nitrophenol (4‐NP) and [ 14 C]‐3,4‐dichloroaniline (3,4‐DCA) were applied to laboratory sediment‐water systems; these were a sandy sediment (SED‐M), and a sediment with high clay/silt and organic carbon content (SED‐J). After sorption periods of 2 d (assay I) and 28 d (assay II) the water phases were replaced by fresh sample water. About 20/10% (3.9/3.9% of total applied 4‐NP in SED‐M/SED‐J) and 40/15% (8.5/6.2%; 3,4‐DCA) of the sediment‐associated radioactivity were initially (1 d of incubation) desorbed in assay I. The corresponding data of assay II amounted to 2/1% (0.9/0.7%; 4‐NP) and 3/2% (1.7/1.4%; 3,4‐DCA). No parent compounds were detected in the fresh‐water phases. The radioactivity released in assay I was readsorbed to the respective sediment. Remobilization distinctly reflected the preceding sorption process, and that regarding sediment properties and chemical features of 3,4‐DCA and 4‐NP. Fractionation of the nonextractable residues of 3,4‐DCA in SED‐J revealed that the xenobiotic was mainly attached to the insoluble humin fraction (55.8/53.8% after 7/28 d of incubation). Only minor amounts were associated with fulvic (14.3/12.7%) and humic acids (5.3/6.1%). Experiments using a clay fraction of SED‐J (< 0.063 μm; SED‐J‐C) and bentonite (CM) demonstrated that 3,4‐DCA was primarily bound to the organic matter of SED‐J‐C. Concerning sorption of 3,4‐DCA, both SED‐J and SED‐J‐C behaved very alike; in contrast, CM showed a strikingly different pattern. Regarding “outdoor” situations, it may be concluded that 4‐NP is not translocated very far from the site of contamination, whereas 3,4‐DCA shows considerable mobility.