Matter nonextractable

Association with organic matter in soil to produce nonextractable residues (Thorn and Kennedy 2002). 

A residual CP concentration is often observed after soil bioremediation. The leveling-off of degradation is not due to decreased microbial activity, since freshly added CPs are rapidly degraded (Harmsen, 1993 Salkinoja-Salonen et al., 1989). The residual concentrations are explained by the gradual diffusion of pollutants deep into micropores, as well as by their adsorption onto soil organic matter (Harmsen, 1993). Lagas (1988) observed that the nonextractable fraction of CPs in sterile soil increased according to the square root of time as a consequence of diffusion into humic material. 

Tab. 2 0rganic contaminants identified in the nonextractable organic matter of Teltow Canal sediments after chemical degradation procedures... 

Samples Tla and Tib were higher contaminated by halogenated naphthalenes as compared to samples T2 and T3. With respect to the nonextractable particulate matter the occurrence of halogenated naphthalenes was limited to the extracts obtained after alkaline hydrolysis. 

Tab. 4 Specific contaminants quantified in the nonextractable fraction of Teltow Canal sediment samples after a separate application of different chemical degradation procedures (contents are given in pg/kg dry matter, nd = not determined).

Furthermore, a covalent linkage to the nonextractable organic matter can be excluded for numerous components according to the data on the release of different degradation techniques (see also Tab. 6). Consequently, the... 

With respect to the spatial distribution and the different selectivity of the degradation methods a second differentiation was observed. Most contaminants appeared frequently and independently of the kind of degradation procedure applied. Also a preferred occurrence at individual sampling locations was not observed for most of the substances. Considering additionally the specifity of the degradation reactions as well as the molecular structures of the contaminants investigated a weaker noncovalent association to the nonextractable particulate matter has to be stated for these compounds. 

In contrast the occurrence of only a few substances was spatially restricted. Also only few compounds were determined exclusively after application of one degradation method. For these contaminants a more specific interaction with the macromolecular organic matter of the nonextractable fraction has to be assumed. 

Additionally, the bound fraction of numerous further anthropogenic contaminants were investigated by quantitation of the extractable and nonextractable matter. The selection of the contaminants (including chlorinated and brominated naphthalenes, 2,4,6-tribromoaniline, mono-and dibrominated phenols, phthalates, tri-n-butylphosphate, 2,4,4-trimethylpentane-l,3-dioldi-Ao-butyrate, bisphenol A, butylated nitrophenols, 4-nitrobenzoic acid, galaxolide and tonalide) was based on the results of extended GC-MS-screening analyses applied to the extracts of the sediment samples as well to the extracts derived from selective chemical degradation procedures. 

Schwarzbauer J, Ricking M, Littke R (2003a) DDT-related compounds bound to the nonextractable particulate matter in sediments of the Teltow Canal, Germany. Environ Sci Technol 37, 488-495. 

Immunochemical methods have also been applied to the detection of bound pesticide residues in soil. These are formed by binding of pesticides to the organic matter of the soil, mainly humic and fulvic acids, and cannot be analyzed using common extraction and assay methods. Hahn et al. used Fab fragments labeled with a fluorescent dye to detect nonextractable residues of atrazine in soil from corn fields. The fluorescence signal obtained was related to the amount of bound atrazine in native soil samples determined by GC after supercritical methanol extraction. A noncompetitive sandwich lA for the analysis of bound residues based on HA-Ab and triazine Ab was developed by Ulrich et HA was extracted from soil, bound to the plates by the HA-Ab and the nonextractable triazine residues were detected by... 

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