Strain difference in sensitivity to 3,4-dichloroaniline and insect growth regulator, fenoxycarb, in Daphnia magna.

Acute and reproductive toxicity tests were conducted on seven strains of Daphnia magna from six laboratories in five countries. 3,4-Dichloroaniline (DCA) and fenoxycarb were used as test chemicals. Acute toxicity tests revealed that estimated EC(50) (50% effective concentration) values for DCA varied by a factor of 2.

[Ecotoxicology and water quality].

Fundamental concepts of ecotoxicology are presented, making specific reference to the aquatic environment. As far as exposure to contaminants is concerned, the main properties of a substance that determine its presence in the various environmental compartments and matrices are illustrated and discussed. The crucial importance of the bioaccumulation potential is stressed, as it can be responsible for the level of substance reached in the biota, which can be much higher than that present in the external environment.

Aquatic effects assessment: needs and tools.

In the assessment of the adverse effects pollutants can produce on exposed ecosystems, different approaches can be followed depending on the quality and quantity of information available, whose advantages and limits are discussed with reference to the aquatic compartment. When experimental data are lacking, a predictive approach can be pursued by making use of validated quantitative structure-activity relationships (QSARs), which provide reliable ecotoxicity estimates only if appropriate models are applied. The experimental approach is central to any environmental hazard assessment procedure, although many uncertainties underlying the extrapolation from a limited set of single species laboratory data to the complexity of the ecosystem (e.