RAPID METHOD FOR ASSESSING POLLUTION-INDUCED COMMUNITY TOLERANCE IN CONTAMINATED SOIL

Using the pollution-induced community tolerance (PICT) concept, this a rticle presents a rapid method for detecting toxic effects of contamin ated soil on soil microbial communities and for elucidating the causal relationship between exposure history and toxic effects in exposed mi crobial communities. The method is based on the use of multiwell plate s (Biolog(R)) for producing concentration versus effect relationships for (maximally) 95 different microbial metabolic activities. For this, artificial exposure in the multiwell plate is established to the cont aminant supposedly causing toxic effects in the field. The method was rested in a gradient of zinc-contaminated field plots by studying comm unity tolerance to zinc. For most substrates the metabolic activities showed an increased community tolerance for zinc with increased zinc c oncentration in the field. Consequently, PICT has evolved after 2.5 ye ars of zinc exposure under field conditions. The perspectives for futu re use of the PICT concept in combination with the multiwell technique for demonstrating ecotoxicological effects at contaminated sites is e xemplified by the comparison of Dutch soil quality criteria for zinc w ith the collected data. This comparison showed that the evolution of m icrobial-PICT for zinc has occurred at environmental concentrations ne ar the Dutch intervention value, a quality criterion linked to remedia tion urgency.