Comparison of insecticide toxicity research results performed using induct-test and microcosm
1Josip Milas, 2Branimir K- Hackenberger, 2Davorka Jarić, 2Enrih Merdić
1Public Health Institute of the Osijek-Baranja County, Osijek, Croatia
2Josip Juraj Strossmayer University, Department of Biology, Osijek, Croatia
Abstract:
Induct-test is a standard procedure for testing toxicity of various chemicals for experimental organisms after intraperitoneal (i.p.) administration of tested compound and “incubation” period of 4-12 days, while a microcosm as a procedure for toxicity testing
relies on imitating natural conditions and routes of exposure. Tested insecticides were malathion, temephos and carbofuran. Experimental organisms used were common carp (Cyprinus carpio) in both experiments and, additionally, prussian carp (Carrasius
auratus gibelio) in the induct-test.
Measured enzyme biomarkers in both experiments were: Ethoxyresorufin-O-deethylase (EROD), Total Glutathione (GT), Glutathione-S-transferase (GST), Thiobarbituric Acid
Reactive Substances (TBARS), Acetylcholinesterase activity (AChE) and Catalase activity (CAT). The microcosms contained 150 L of water, 35 specimens of common carp, artificial soil as sediment and 10 specimens of swan mussel (Anodonta cygnea) as a
filter-feeding organism. The pollutants were administered in realistically expected concentrations and 7 fish were sampled every 5 days, with a total of 5 samplings.
The results showed expected differences in biomarker change between induct-test and microcosm experiment (40- to 100-fold). The concentrations used in the induct-test are hardly expected in the environment even if species bioaccumulation potential is taken
into account. On the other hand, the microcosm experiment showed that all biomarkers used in the experiment can detect changes obtained by environmentally realistic concentrations and, therefore, microcosm test has a far more realistic and significant role
in ecological risk assessment of insecticides.