Biomineralisation of 1,2,4-trichlorobenzene in soils by an adapted microbial population

In laboratory experiments the mineralisation of ¹⁴C-labelled 1,2,4-trichlorobenzene (1,2,4-TCB) in soils was studied by direct measurement of the evolved ¹⁴CO₂. The degradation capacity of the indigenous microbial population was investigated in an agricultural soil and in a soil from a contaminated site. Very low mineralisation of 1% within 23 days was measured in the agricultural soil. Whereas in the soil from the contaminated site the mineralisation occurred very fast and in high rates; up to 62% of the initially applied amount of 1,2,4-TCB were mineralised within 23 days. The transfer of the adapted microbial population into the agricultural soil significantly enhanced the mineralisation of 1,2,4-TCB in this soil, reflecting, that the transferred microbial population survived and maintained its degradation ability in the new microbial ecosystem. Additional nutrition sources ((NH₄)₂HPO₄) increased the mineralisation rates in the first days significantly in the contaminated soil. In the soil from the contaminated site high amounts of non extractable ¹⁴C-residues were formed.