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(M/FF223) Sublethal toxicity of an organophosphorous pesticide on terrestrial isopod Porcellio scaber (Isopoda, Crustacea) . Gabrijelcic, Elizabeta1, Trebse, Polonca1, Drobne, Damjana2, 1 2 ABSTRACT- Organophosphorous pesticides are the most commonly used insecticides in Slovenia. Several studies have been carried out on the effects of organophosphorous pesticides on vertebrates, thus their mode of action in higher organisms is well known. In the last decade, these studies have been expanded also on nontarget invertebrates, but only few research has involved terrestrial arthropods. Organophosphorous pesticides inhibite Acetylcholinesterase (AChE). The absence of the enzyme in the synapse leads to the abnormal persistence and accumulation of the neurotransmitter, generating multiple postsinaptic impulses. The aim of our study was to asses the AChE activity in terrestrial isopod Porcellio scaber as a biomarker of organophosphorous pesticide pollution. In the first part of the study we measured the normal activity of AChE in organisms of different weight and sex to determine individual variability and sex or age dependence of AchE activity. In the second part, organisms have been exposed for three weeks to different concentrations of diazinon added in the food (50, 100, 150, 300 Key words: isopoda, organophosphates, acetylcholinesterase, pesticide |
g/g of food). During the exposure, we measured weight of the animals, food consumption, faecal production and survival. At the end of exposure, the AChE activity has been determined. Results show a considerable reduction of weight, faeces production, mortality and a significant depression of AChE activity. On the basis of these data AChE activity is discussed as a suitable biomarker of diazinon pollution of terrestrial environment and as an aditional endpoint in toxicity test protokol with Porcellio scaber (Drobne D., Hopkin S. P. (1995). The Toxicity of Zinc to Terrestrial Isopods in a 'Standard' Laboratory Test. Ecotoxicol.Environ.Safe. 31:1-6.; Drobne D. (1997). Terrestrial isopods - a good choice for toxicity testing of pollutants in the terrestrial environment. Environ. Toxicol. Chem. 16, 6:1159-1164.)