WaterTox bioassay intercalibration network: Results from Argentina

Abstract

A series of blind samples were analyzed by our laboratory within the WaterTox Network using a battery of tests. These tests were selected according to sensitivity, easiness to perform, robustness, low cost, and representativeness of several trophic levels and consisted of acute and subchronic toxicity with the nematode Panagrellus redivivus (96 h) and the coelenterate Hydra attenuata (24, 48, 72, and 96 h), acute toxicity with the microcrustacean Daphnia magna (48 h) and the vascular plants Allium cepa (72 h) and Lactuca sativa (96 h), and genotoxic effects with a commercial kit based on the Ames Salmonella typhimurium test. Data from 30 blind samples (15 pure compounds, 2 types of mixtures and replicate samples) added with positive controls have been analyzed using the 6 selected bioassays and 12 endpoints. Results show that all assays provide relevant and complementary information. Regarding the nongenotoxic effects, within the tested concentration intervals all samples showed toxicity with at least one of the bioassays from the battery and only three samples were toxic to all. A relative toxicity rank shows that H. attenuata and D. magna are the most sensitive organisms for acute effects. H. attenuata and P. redivivus are more sensitive for sublethal effects than the vascular plants tested, except for 3 of the samples. From the 24 samples tested for genotoxic effects using the Fluctuation test 37% were mutagenic; however, serious difficulties were encountered when was run the kit for mutagenicity. The major difficulties with H. attenuata, P. redivivus, and D. magna were associated with the maintenance of stock organism cultures. The inclusion of the EC50 estimation of 6 blind samples tested with a core battery of bioassays (H. attenuata, D. magna, and L. sativa) selected in the first part of the exercise, improved the design of the experiment and data quality. © 2000 John Wiley & Sons, Inc. Environ Toxicol 15: 287–296, 2000