RNA/DNA ratio as an indicator of the impact of long-term accumulative contamination for the assessment of river degradation — a pilot study

To improve our understanding of the hierarchy of human induced modifications of the natural environment, with particular regard to the controlling strength of the habitat or chemical impacts, it was found to be appropriate to employ indicators at a molecular level. This paper examines the potential use of the analysis of the RNA/DNA ratio for the evaluation of the ecological status of two rivers of Central Poland. The study confirmed that analysis of the RNA/DNA ratio has the potential to be a sensitive indicator of river degradation. It is also a useful screening method for the evaluation of the impact of prolonged sub-lethal contamination of freshwater ecosystems dominated by tolerant fish species such as the perch, Perca fluviatilis L.