Detection of bound nitroaromatic residues in soil by immunoassay

Bound nitroaromatic residues have been detected in three highly polluted soils of two former TNT production plants in Germany. Selectivity of the assay signal was proven by inhibition with TNT. The concentration of extractable TNT was 1.3 g/kg, 1.1 g/kg and 0.37 g/kg, determined by HPLC. After optimization of the immunoassay only the contaminated samples showed a distinct signal. High signal intensities correlated with high amounts of extractable TNT. It could be shown that the used monoclonal anti-TNT-antibody has no significant cross-reactivity to bound nitroaromatic structures of the 4-amino-2,6-dinitrotoluene type. Therefore one can assume that the signal is probably caused by other covalently bound nitroaromatic compounds.