Pesticide Degradation in Soils

Abstract

Historical Aspects: The Hormone Herbicides Biological Aspects of Pesticide Degradation in Soils Pesticide Degradation in Natural Environments

Estimation of atrazine-degrading genetic potential and activity in three French agricultural soils

“…This observation suggests that the expression of atrazine-degrading genetic potential is affected by soil physicochemical properties, which modify pesticide fate and biodisponibility as well as microbial diversity and activity [6,10,14]. The soil of Couhins and La Bouzule exhibited similar atrazine-degrading genetic potential ranging from 1.0 to 2.0 Â 10 4 atz copy number per gram of soil.…”

“…However, their atrazine-degrading activities were different; the soil of Couhins was characterized by a 20-day lag phase and a maximal percentage of atrazine mineralization reaching 60% over a 60-day incubation period, while the soil of La Bouzule did not show a lag phase but reached a maximal percentage of atrazine mineralization of only 40%. This observation suggests that the expression of atrazine-degrading genetic potential is affected by soil physicochemical properties, which modify pesticide fate and biodisponibility as well as microbial diversity and activity [6,10,14]. Indeed, for each atrazine-degrading microbe the expression of its degrading genetic potential depends on several levels of regulation (i.e., transcrip-tional, translational and post-translational regulations) influenced by the perception of biotic and abiotic factors specific for each soil environment [43].…”

“…Sorption of pesticide on organic matter determines pesticide bioavailability [6] and modification of soil organic matter through organic matter application has been shown to affect atrazine sorption and thus microbial catabolism of atrazine [39,40]. Modelling of atrazine mineralizing kinetics only revealed two significant differences: (i) the soil of Couhins amended with 100 tons of sewage sludge per hectare every two years mineralized atrazine more rapidly than the control soil with a 150% increase of atrazine mineralization rate and a 20% decrease of the ti parameter and (ii) the soils of Pierrelaye amended with either lightly and moderately polluted waste water mineralized atrazine more rapidly than soil amended with highly polluted waste water (i.e., 35% decrease of atrazine ti).…”

“…They also play a key role in the quality of agricultural soils which is usually defined as the sustained capacity of the soil to produce healthy and nourishing crops, resist erosion and reduce the impact of environmental stresses on plants [3]. Soil microbiota notably affects: (i) soil fertility (availability of plant nutrients) [4] and health (suppression of soil-borne plant disease) [5] and (ii) detoxifying ability (e.g., pesticides and xenobiotic compounds biodegradation) [6]. Soil microorganisms have long been regarded as ubiquitous, i.e., ''everything is everywhere'' [7].…”

Applied Microbial Ecology and Bioremediation

“…(Martin-Laurent et al 2006). To some extent, pesticidedegrading-microbial consortia might be considered more resilient than pure degrading strain, as they are hosting various metabolic pathways that may constitute a selective advantage favoring their survival in oligotrophic conditions found in the soil environment (Soulas 2003). However, despite their ecological interest, until now the recourse to the use of degrading-microbial consortia for the bioaugmentation is compromised by two yet unresolved questions.…”