ASSESSING TOXICITY AND MOBILIZATION OF IMPREGNATION SALTS AT A CONTAMINATED SITE

Severe soil contamination is often encountered at wood-impregnation pl ants due to spills, dripping and deposition of sludge associated with dissolved salts of copper, chromium and arsenic (CCA). Soil samples fr om a CCA-plant in southern Norway were analysed via a factorial extrac tion design to investigate mobilisation of contaminated soils. Various concentrations of organic acids, sea-salts, and pH showed that contam inants were not stable, and could be mobilised to the aqueous phase. T o further investigate mobilisation of impregnation salts, soil solutio n collectors were installed at various depths at the site. Concentrati ons varied considerably. Hydrological changes revealed elevated levels of dissolved salts, which agree with the factorial experiment. Soil c hemical processes (not total solid-phase concentrations) dominated the mobilisation and subsequent leaching. Soil solutions were tested for changes in toxicity by chemical analysis and degree of inhibition of l uminescence in Vibrio fisheri (Microtox). Changes in toxicity correspo nded to changes in soil solution.