Effects of environmental pollutants (pesticides, pharmaceuticals, heavy metals) in the zebrafish (Danio rerio) and other freshwater fish

In dieser Arbeit werden Effekte verschiedener Schadstoffe und Schadstoffmischungen auf die Embryonalentwicklung und die Stressproteinantwort (Hsp70) des Zebrabärblings (Danio rerio) untersucht. Des weiteren werden cytologische Studien zur Veränderung der Ultrastruktur von Kiemen der Regenbogenforelle (Oncorhynchus mykiss) unter Schadstoffeinwirkung, Halbfreilandstudien zur Embryonalentwicklung des Zebrabärblings unter Belastung mit Industrieabwässern sowie Untersuchungen zur Stressproteinkonzentration in Lebern und Kiemen freilebender Nasen und Döbel präsentiert.In this study, effects of environmental pollutants and mixtures of pollutants on the embryonic development and the Hsp70 stress-protein response of zebrafish (Danio rerio) were investigated. Furthermore, ultrastructural changes in gills of rainbow trout (Oncorhynchus mykiss) after exposure to enviropnmental pollutants, embryonic development of zebrafish exposed to industrial wastewaters as well as stress protein levels of freshwater fish in an European stream were studied

Interactions between toxic chemicals and natural environmental factors - a meta-analysis and case studies

The paper addresses problems arising from effects of natural environmental factors on toxicity of pollutants to organisms. Most studies on interactions between toxicants and natural factors, including those completed in the EU project NoMiracle (Novel Methods for Integrated Risk Assessment of Cumulative Stressors in Europe) described herein, showed that effects of toxic chemicals on organisms can differ vastly depending purely on external conditions. We compiled data from 61 studies on effects of temperature, moisture and dissolved oxygen on toxicity of a range of chemicals representing pesticides, polycyclic aromatic hydrocarbons, plant protection products of bacterial origin and trace metals. In 62.3% cases significant interactions (p< or =0.05 or less) between natural factors and chemicals were found, reaching 100% for the effect of dissolved oxygen on toxicity of waterborne chemicals. The meta-analysis of the 61 studies showed that the null hypothesis assuming no interactions between toxic chemicals and natural environmental factors should be rejected at p=2.7 x 10(-82) (truncated product method probability). In a few cases of more complex experimental designs, also second-order interactions were found, indicating that natural factors can modify interactions among chemicals. Such data emphasize the necessity of including information on natural factors and their variation in time and across geographic regions in ecological risk assessment. This can be done only if appropriate ecotoxicological test designs are used, in which test organisms are exposed to toxicants at a range of environmental conditions. We advocate designing such tests for the second-tier ecological risk assessment procedures.publishe

Interactions between effects of environmental chemicals and natural stressors: a review.

Ecotoxicological effect studies often expose test organisms under optimal environmental conditions. However, organisms in their natural settings rarely experience optimal conditions. On the contrary, during most of their lifetime they are forced to cope with sub-optimal conditions and occasionally with severe environmental stress. Interactions between the effects of a natural stressor and a toxicant can sometimes result in greater effects than expected from either of the stress types alone. The aim of the present review is to provide a synthesis of existing knowledge on the interactions between effects of “natural” and chemical (anthropogenic) stressors. More than 150 studies were evaluated covering stressors including heat, cold, desiccation, oxygen depletion, pathogens and immunomodulatory factors combined with a variety of environmental pollutants. This evaluation revealed that synergistic interactions between the effects of various natural stressors and toxicants are not uncommon phenomena. Thus, synergistic interactions were reported in more than 50% of the available studies on these interactions. Antagonistic interactions were also detected, but in fewer cases. Interestingly, about 70% of the tested chemicals were found to compromise the immune system of humans as judged from studies on human cell lines. The challenge for future studies will therefore be to include aspects of combined stressors in effect and risk assessment of chemicals in the environmen