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Irreversible binding of biologically reduced 2,4,6‐trinitrotoluene to soil
Author(s) -
Achtnich Christof,
Sieglen Ute,
Knackmuss HansJoachim,
Lenke Hiltud
Publication year - 1999
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.5620181106
Subject(s) - trinitrotoluene , chemistry , mineralization (soil science) , environmental chemistry , soil water , chromatography , extraction (chemistry) , soil contamination , anaerobic exercise , desorption , organic chemistry , adsorption , biology , ecology , physiology , nitrogen , explosive material
Abstract To analyze the fate of 2,4,6‐trinitrotoluene (TNT) and its reduction products, a TNT‐contaminated soil (350 mg TNT/kg dry soil) was spiked with [ring‐UL −14 C]TNT and treated in a laboratory slurry reactor. During an anaerobic/aerobic treatment, the total radioactivity measured in the supernatant and methanolic soil extracts decreased to 2%. The decrease corresponded to an increase of strongly bound radioactivity to the soil. Throughout the whole treatment process, mineralization of TNT was not observed. During the reductive process, unidentified polar substances increased to a maximum amount of 23.2% of the total radioactivity on the day after the start of the experiment. After the end of the anaerobic phase, still 9.7% of the radioactivity was found in this fraction. Only during the aerobic phase did the polar substances disappear completely. The irreversible character of the binding of the reduced metabolites of TNT to the soil was indicated by the failure of desorption even under rigorous and longterm extraction conditions. A significant release of radioactivity could be measured only by using high concentrations of HCI (5 N) or EDTA (12.5% and 5.9%, respectively). However, in none of the extracts were TNT or any reduced metabolites detected by HPLC and 14 C‐radiocounting. Size‐exclusion chromatography of humic acids extracted from the treated soil indicated that the metabolites of TNT were evenly bound to the complete range of molecular size of the humic acids.