Novel bioassay based on acetylcholinesterase and lactate dehydrogenase activities to evaluate the toxicity of chemicals to soil isopods

This study developed a bioassay with the isopod Porcellio dilatatus based o n the activity of the enzymes acetylcholinesterase (AChE) and lactate dehyd rogenase (LDH). The in vivo effects of the insecticides parathion-ethyl and endosulfan-sulfate on AChE and LDH activities of P. dilatatus under labora tory conditions were investigated. The route of uptake of the pesticides wa s through the food (alder leaves). Isopods were exposed to a wide range of concentrations of parathion or endosulfan (0.1, 1, 10, 25, 50, 100, 250, an d 500 mu g/g of food) for 21 days. After this period, the activity of AChE and LDH was determined. Parathion induced significant depression of both AC hE and LDH activities. Animals fed with endosulfan-contaminated food exhibi ted lower LDH activities than control animals, while AChE activity was simi lar in all treatments. The results of the present investigation suggest tha t the isopod. P. dilatatus is a suitable species for use in toxicity tests and indicate that the enzymes AChE and LDH could be used as effect criteria both in laboratory and in held studies with this species. (C) 1999 Academi c Press.