DETERMINATION OF THE TOTAL AND LEACHABLE AMOUNTS OF ORGANOHALOGENS IN SOIL

Different pretreatments of soil samples were combined with incineration in oxygen atmosphere and microcoulometric titration of formed hydrogen halides to determine the total and leachable amounts of organically bound halogens (TOX and LOX, respectively). The results showed that the investigated procedures can be standardised to provide reproducible results. In general, inorganic chloride present in soil particles and microorganisms did not have any significant impact on measured LOX concentrations. The possible impact of chloride on the determination of TOX in soil is more uncertain. However, even though analytical artifacts cannot be completely ruled out, there was strong evidence that the TOX measurements resulted in adequate estimates of the true organohalogen content of the analysed soil samples. A substantial part of the TOX was recovered as LOX by leaching with NaOH, and there was a good agreement between TOX-to-l.o.i. ratios of dried and ground soil samples and AOX-to-TOC ratios of leachates of the same samples.