Assessment of the Hazard Potential of Environmental Chemicals by Quantifying Fish Behaviour

Abstract

Using the spontaneous locomotor behaviour of fi sh as a toxicological parameter, sublethal effects to the naturally occurring cyanotoxin microcystin-LR (MC-LR) and a characteristic man-made chemical 2.4.4′-trichlorobiphenyl (PCB 28) were investigated under laboratory conditions. Swimming activity of two fi sh species (Danio rerio and Leucaspius delineatus) was monitored continuously by using an automated video-monitoring and object-tracing system. For analysing cyclic aspects the basic behavioural analyses were combined with chronobiological procedures such as power spectral analysis. Using these methods it was shown that dissolved MC-LR concentrations between 0.5 and 50 μg l and PCB 28 concentrations at 100 and 150 μg l acted as stressors and caused signifi cant changes in the behaviour and circadian activity rhythms of Danio rerio as well as Leucaspius delineatus. For both species elevated concentrations of the stressors led to a reduction of their activity. It was proved that the basic behavioural analyses combined with chronobiological procedures could be valuable tools for the study of stressful or even harmful environmental factors in the fi eld of ecotoxicology as well as for biomonitoring. Some fi ndings of this study build the basis for the development of a new low-budget fi sh biomonitoring system for drinking water protection.