Fig. 2
![Fig. 2](http://media.springernature.com/full/springer-static/image/art%3A10.1186%2Fs12302-017-0108-y/MediaObjects/12302_2017_108_Fig2_HTML.gif)
Histopathological classification of gills, liver, and kidney in rainbow trout (a), barbel (b), loach (c), and European bullhead (d) from the investigated field sites on the Argen River. Results are presented as the frequency (%) of given evaluation classes for each fish species and organ. Likelihood ratio tests revealed no significant (*p < α = 0.05) differences between the sampling sites