Techniques for assessing the ecotoxicity of xenobiotic substances to soil microflora

Abstract

Because soil micro-organisms are mainly responsible for nutrient cycling they play a major role in plant nutrition and soil fertility. Soil is also the ultimate receptacle of a number of xenobiotic compounds and their degradation products which represent a potential threat due to their ecotoxicological impact. Soil micro-organisms are directly exposed. A desirable evolution towards sustainable agriculture requires taking into account these potentially damaging consequences. There are currently two main ways of monitoring side-effects of xenobiotic compounds on the soil microflora. For decades, size and activity descriptors of soil microbial communities were used. They have been criticised on the ground that they are the net outcome of complex physiological and structural rearrangements of the soil microflora and, for that reason, lack the necessary sensitivity. Recent progress in analysis of microbial diversity at the species, metabolic, physiological, and genetic levels offers new promising alternatives. Yet, some limitations in acquisition and interpretation of data are presented and discussed.