Cholinesterase activity as a biomarker of pesticide exposure inAllolobophora chloroticaearthworms living in apple orchards under different management strategies

Abstract

The present study used cholinesterase (ChE) activity in earthworms as a biomarker of pesticide exposure at 17 apple orchards using different pest protection strategies (organic, integrated pest management [IPM], conventional, and abandoned) located within a 300-km(2) subregion near Avignon in southeastern France). The most common earthworm species in the 17 orchards was Allolobophora chlorotica. We examined inherent variability in ChE activity that might be attributable to soil characteristics and found that differences in soil structure or type did not significantly influence ChE activity. Furthermore, there was no relation between ChE specific activity and earthworm weight, and thus activity does not require correction for weight. Ten earthworms were collected in two successive months (April and May 2003) from each of the 17 orchards. Compared to the activity in worms from the control abandoned orchards, ChE activity was significantly decreased in earthworms from half the IPM and conventional orchards in April and all these orchards in May. Notably, ChE activity was also lower in earthworms from three organic orchards during May. No relation was observed between ChE decrease and the number of treatments (total or only organophosphorous and carbamate pesticides). Cholinesterase activity in earthworms from abandoned orchards varied between the two collecting periods, illustrating the difficulty in obtaining reference values for the use of ChE as a biomarker in field studies.

Ecological and physiological effects of soil management practices on earthworm communities in French vineyards

“…In contrast, Denoyelle et al [30] showed a significant inhibition of cholinesterase activity under pesticide exposure working in orchard field experiments, with variations due to the different pest protection strategies. These differences in ChE inhibition could be explained by different factors, including the nature of the sprayed pesticides, the quantities applied, the period of pesticide spraying [41], the earthworm species [71] and the soil properties [7].…”

“…Using the same pesticide mixture (chlorpyrifos-ethyl and lcyhalothrin as insecticides and folpet, metalaxyl-M, fosetyl-Al and myclobutanil as fungicides) in controlled experiments, Schreck et al [24] concluded that there was an inhibition of ChE activity in exposed earthworms. The limitations of the extrapolation of ecotoxicity results from laboratory conditions to field experiments was previously highlighted by Denoyelle et al [30] and Laszczyca et al [67]. However, numerous studies in microcosms are still performed to assess the impact of pollutants on earthworms [19e24] and only few investigations are carried out under field conditions [32].…”

“…In field experiments rather than soil management practices, several basic phenomena such as pesticide transfer processes (leaching) or interference with various environmental parameters could mitigate earthworm biochemical responses [30,41,71] differently according to the enzymes studied.…”

“…However, the indirect impact of farming practices, such as protection against predators, environmental conditions and the availability of pesticide and nutriments, on earthworm physiology in field conditions was still poorly described [30], especially in the vineyards.…”

Enzymes of Earthworm as Indicators of Pesticide Pollution in Soil

“…The biochemical biomarkers are being utilized these days for the analysis of pollutant toxicity, metabolization and detoxification in earthworm [13] [14] which later can be used for the detection and assessment of contaminant that influence the environmental modifications [15].…”