Formation of conversion products and of bound residues of chlorinated anilines in soil

4‐Chloroaniline‐¹⁴C, 3,4‐dichloroaniline‐¹⁴C, and 2,4,6‐trichloroaniline‐¹⁴C were incubated in soil for 20–25 weeks under outdoor conditions. Extractable ¹⁴C‐residues as well as unextractable ¹⁴C were determined. Bound ¹⁴C‐residues were higher for lower chlorinated anilines than for higher chlorinated ones. By fractionation of extracted soil, the binding sites of unextractable residues were established. The highest concentration of bound residues was in humic acids, the lowest in inorganic soil fractions. Biomineralization and photodegradation of bound ¹⁴C‐residues in different fractions were determined by ¹⁴CO₂‐counting. In general, degradation of bound residues was much slower than that of non‐bound ¹⁴C‐labeled reference compounds. Degradation of residues bound in humic acids was most slow, that of residues bound in fulvic acids most rapid. The uptake of bound ¹⁴C by barley plants was highest for residues bound in fulvic acids and lowest for those bound in humic acids. By model experiments with the humic acid precursor catechol and 4‐chloroaniline, the formation of covalent bonds was demonstrated.

Key words:

• Chloroanilines
• soil
• conversion products
• bound residues

Notes

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