Determination of DDT and its metabolites in cattle dip soil available in aqueous phase after remediation

Soil taken from a former cattle tick dip site in NSW Australia, was remedia ted with a chemical leaching technology. The pre- and post-remediated soil (20g) was dispersed in water (100mL) and subjected to passive diffusion usi ng polymeric membranes. The remediation reduced tDDT from 1174.3 mug/g to 1 02.9ug/g (ash weight basis), which was further reduced to 43.2 mug/g with c omposting. The membranes accumulated 41.3 mug tDDT/g from the dip soil, 49. 2 mug tDDT/g from the chemically leached soil and 3.1 mug tDDT/g from the l eached composted soil. The chemical leaching removed over 90% of the tDDT, but released soil bound DDT, which was converted to DDE, while 2.99 mug/g w as accumulated by the membranes from dip soil, 37.52 mug/g was accumulated from remediated soil. Composting, however, almost eliminated the availabili ty for passive diffusion by the membranes from 50-60 mug/g in remediated so il to 3-3.5 mug/g in composted soil. Variability studies of the membranes u sing eight replicates demonstrated that the accumulation by the membranes w as reproducible with an average relative error of 20.3% for p,p'-DDT in soi l type two, whilst the lowest average relative error for p,p'-DDE was 4.3%, suggesting that triplicate analyses will achieve acceptable accuracy.