Review on the acuteDaphnia magnatoxicity test – Evaluation of the sensitivity and the precision of assays performed with organisms from laboratory cultures or hatched from dormant eggs

Abstract

EXECUTIVE SUMMARYOne of the most internationally used bioassays for toxicity screening of chemicals and for toxicity monitoring of effluents and contaminated waters is the acute toxicity test with daphnid crustaceans, and in particular that performed with Daphnia magna. Standard methods have been developed for this assay that were gradually endorsed by national and international organisations dealing with toxicity testing procedures, in view of its application within a regulatory framework. As for all toxicity tests, the organisms used for the acute D. magna assay have to be obtained from live stocks which are cultured in the laboratory on live food (micro-algae). Unsurprisingly the various standard protocols of this particular assay differ -at least to a certain extent -with regard to the test organism culturing conditions. In addition, some technical aspects of the toxicity test such as the effect criterion (mortality of immobility), the exposure time, the type of dilution water, etc., also vary from one standard to another. Although this particular assay is currently used in many countries, the technical and biological problems inherent in year-round culturing and availability of the biological material and the culturing/maintenance costs of live stocks restrict its application to a limited number of highly specialised laboratories. This fundamental bottleneck in toxicity testing triggered investigations which brought forward the concept of "microbiotests" or "small-scale" toxicity tests. "Culture/maintenance free" aquatic microbiotests with species of different phylogenetic groups were developed in the early 1990s at the Laboratory for Environmental Toxicology and Aquatic Ecology at the Ghent University in Belgium. These assays which were given the generic name "Toxkits", are unique in that they employ dormant stages ("cryptobiotic eggs") of the test species, which can be stored for long periods of time and "hatched" at the time of performance of the assays. One of these microbiotests is the Daphtoxkit F magna, which is currently used in many laboratories worldwide for research as well as for toxicity monitoring purposes. The microbiotest technology has several advantages in comparison to the "traditional" tests based on laboratory cultures, especially its independence of the stock culturing burden. However, the acceptance (or possible non-acceptance) of performing assays with test organisms obtained from "dormant eggs" should be clearly dictated by the "sensitivity" and "precision" criteria of the former assays in comparison to the latter. The first part of this review therefore thoroughly reviews the scientific literature and of data obtained from various laboratories for assays performed with either D. magna test organisms obtained from lab cultures or hatched from dormant eggs. Attention has focused on data of quality control tests performed on reference chemicals, and in particular on potassium dichromate (K 2 Cr 2 O 7 ) for which an acceptability range of 0.6-2.1 mg·L -1 has been set in ISO standard 6...

A Lymnaea stagnalis Embryo Test for Toxicity Bioindication of Acidification and Ammonia Pollution in Water

“…The Daphnia magna bioassay is one the most commonly used bioassays worldwide for acute toxicity testing of various chemical substances [56]. Moreover, toxicity values between Daphnia and many other aquatic organisms are known to be strongly correlated, especially in the case of fish.…”

Toxicity of Some Pesticides, Heavy Metals and Their Mixtures to Vibrio fischeri Bacteria and Daphnia magna: Comparative Study

“…So, the Microtox ® assay, based on Vibrio fischeri, has been widely applied as a rapid, economical monitoring tool for toxicity of environmental contaminants (McFeters et al, 1983). On the other hand, acute toxicity testing using daphnids, (e.g., Daphnia magna), is a common bioassay used internationally for screening toxicity of chemicals and monitoring of effluents and contaminated waters (Persoone et al, 2009). D. magna has been recommended as a standard test organism by many international organizations (e.g., ISO, 1996 andOECD, 2004) and has ISSN 2157-6076 2015 www.macrothink.org/jbls 230 been used routinely in toxicological studies (Biesinger and Christensen, 1972;Hermens et al, 1984;De Schamphelaere et al, 2004).…”

Adverse Effects of Herbicides on Freshwater Zooplankton

“…and copepods have also been used (Table 3). Some of these protocols have been recognized by International Standard Organizations (ISO), USEPA, OECD, ASTM, Standard Methods (Snell & Janssen, 1995;Persoone et al, 2009). …”