surface waters

Use of effect-based methods to assess surface water status

This article deals with the use of effect-based methods for the qualitative assessment of the state of surface waters in the context of Directive 2000/60/EC establishing the framework for Community activity in the field of water policy and the upcoming amendment to Directive 2008/105/EC on environmental quality standards. The implemented monitoring of priority substances and specific pollutants is not able to capture all sources of pollution that negatively affect surface water quality. Likewise, current practice does not allow a comprehensive assessment of mixtures, including emergent pollutants, metabolites, and transformation products of substances on water quality. Effect-based methods are a suitable tool for ecotoxi-cological evaluation of pollution, which considers all substances contained in the sample and possible effects of mixtures (synergistic effects). They thus provide important additional information for the results of the assessment of the state of surface water bodies.

Radioactive indicators in surface waters of the Ploučnice river basin

The Czech Hydrometeorological Institute (CHMI) is engaged in systematic monitoring and evaluation of radiological indicators in surface waters. The article describes changes in the values of radiological indicators in surface waters in the time series from 1967 to the present. The evolution of total volume alpha and beta activity, uranium concentration, and radium activity (226Ra) is described on characteristic profiles in the area of uranium-containing raw materials mining, in the vicinity of Stráž pod Ralskem, where the mining of radioactive raw materials has already been suppressed. The Ploučnice river flows through this mining area and flows into the Elbe river in Děčín near the Hřensko border crossing, where activities of radiological indicators are also monitored and documented. Following the cessation of uranium mining at the Stráž pod Ralskem deposit, uranium concentrations dropped by two orders of magnitude, and surface waters on the Ploučnice – Mimoň profile have been classified as Class I – unpolluted water for the last five years. The values of Kendall’s correlation coefficient τ for the profiles evaluated on the selected profiles during the mining period are characterized by an increasing trend (+0.7) for the indicator of total volume beta activity; after the end of mining, a decreasing trend is indicated (-0.5).