Embryotoxic and proteotoxic effects of water and sediment from the neckar river (southern germany) to zebrafish (danio rerio) embryos

Background: The Neckar River (Southern Germany) represents an aquatic system strongly affected by numerous anthropogenic activities. Thus, it is an excellent model for ecotoxicological investigations. The present study aims to assess time and spatial variations of embryo- and proteotoxic effects in surface water and sediment. For this end, embryos of zebrafish (Danio rerio) were exposed to Neckar River samples collected in the Tübingen region in different seasons over 2 years. Additionally, quantification of the heat shock (stress) protein Hsp70 was carried out in newly hatched larvae; furthermore, physico-chemical water parameters were measured in order to gain baseline information about the limnologic conditions. Results: Nearly all of the investigated Neckar River sites caused elevated mortality, developmental retardation and failures, modified heart rate and reduced hatching success in zebrafish embryos and larvae. Additionally, exposure to Neckar River water and sediment led to changes in larval Hsp70 level. During the 2 years of investigation, seasonal differences of embryo- and proteotoxic effects occurred. Along these lines, physico-chemical measurements delivered basic information for the interpretation of in vivo test data. Conclusions: Our study suggests a changing toxic burden in the whole investigated study area. Consequently, for ecotoxicological field studies, time and spatial variations on small scale must be dealt with. The lethal and sublethal endpoints of the fish embryo test combined with Hsp70 level measurements proved to be effective tools for toxicity assessment of environmental samples. © 2014 Vincze et al.