Sensitivity comparison of the ISO Daphnia and algal test procedures with Toxkit microbiotests

SUMMARY A short comparative study has been made on the sensitivity of 2 conventional bioassays (the ISO Daphnia magna immobilization test and the ISO algal growth inhibition test with Scenedesmus quadricauda) and 3 Toxkit microbiotests : the Daphtoxkit F™ magna, also with D. magna, the Thamnotoxkit F™ with the crustacean Thamnocephalus platyurus, and the Algaltoxkit F™ assay with Selenastrum capricornutum .(presently renamed Raphidocelis subcapitata). The tests were performed on the reference chemical potassium dichromate and areal world sampie : aleachate of fly ash. The results showed good correlation between the 2 algal test procedures for potassium dichromate, but not for the fly ash leachate, which may be due to the use of 2 different algal species in the test procedures ... The tests with both D. magna tests on fly ash leachate gave quite comparable results, but diverging results were found for potassium dichromate. The latter differences can be explained by the (unintentional) lower water hardness which was discovered in the Toxkit assay. The anostracan crustacean T.platyurus appeared to be more sensitive than the cladoceran D.magna for potassium dichromate, but not for the fly ash leachate. Despite some shortcomings, this short study shows that Toxkit microbiotests seem to be an attractive alternative to the (substantially more costly) conventional assays, especially when considering application in routine. The Geoanalytieal Laboratory in Spisska Nova Ves in Slovakia has been investigating the hazardous properties of wastes for the last 5 years. Ecotoxieologieal tests are used in this regard for the determination of the toxie properties of the wastes.