The use of Conventional Bioassays, Microbiotests and Some Rapid Methods in the Selection of an optimal Test Battery for the Assessment of Pesticides Toxicity

Abstract:

Due to the increasing use of pesticides, as well as the introduction of new formulations of biologically active substances, there are significant effects of these preparations on the aquatic environment. The aim of this study was to select effective biotests for a test battery to assess the potential effects of pesticides on aquatic life. Thirteen widely used and registered pesticides in Poland, with potassium dichromate as a reference chemical, as well as seven different test species (ranging from protozoan to fish) were chosen for the study. Principal component analysis (PCA) and cluster analysis (CA) were used as helpful statistical methods for the selection of the test battery. PCA clearly isolated two components that explained almost 82 % of total variance. The first consists of all crustacean and fish tests while the second of all tests with algae and the protozoan Tetrahymena thermophila. In other words, PCA separated unicellular and multicellular organisms in regard to their sensitivity to pesticides. CA has confirmed the above results and has provided more detailed insight into the connections within the separated group of biotests. Regression analysis, PCA and CA allowed for the selection of the following test battery : Algaltoxkit F^TM (Raphidocelis subcapitata), Protoxkit F^TM (Tetrahymena thermophila), Daphnia magna (Fluotox) and an acute test with Oncorhynchus mykiss or, alternatively Thamnotoxkit F^TM (Thamnocephalus platyurus). This test battery is comprised of organisms that belong to four different phylogenic groups as well as three trophic levels of the aquatic ecosystem. Acute, sublethal, and chronic effects are taken into consideration.