Quality and mutagenicity of water and sediment of the streams impacted by the former uranium mine area Olsí-Drahonín (Czech Republic).

The water quality research performed in the years 2003-2010 demonstrated an impact of the mine water pumped from the closed Olsí uranium mine and discharged from the mine water treatment plant (MWTP) and groundwater from springs in the area on the water quality of the Haduvka stream. The water ecosystems of the lower part of the Haduvka stream are impacted mainly by water originated from the springs located in the stream valley and drained syenit subsoil, naturally rich in uranium. Those inflows caused a very high concentration of uranium measured in the water of the stream, which exceeds the given limit value. No negative impact on the water ecosystems of the receiving Bobruvka River was found. This reduction of impact is caused by five times higher average daily flow rate of the Bobruvka River in comparison with the Haduvka stream, which results in a sufficient dilution of pollution from the Haduvka.

International round-robin study on the Ames fluctuation test.

An international round-robin study on the Ames fluctuation test [ISO 11350, 2012], a microplate version of the classic plate-incorporation method for the detection of mutagenicity in water, wastewater and chemicals was performed by 18 laboratories from seven countries. Such a round-robin study is a precondition for both the finalization of the ISO standardization process and a possible regulatory implementation in water legislation. The laboratories tested four water samples (spiked/nonspiked) and two chemical mixtures with and without supplementation of a S9-mix. Validity criteria (acceptable spontaneous and positive control-induced mutation counts) were fulfilled by 92-100%, depending on the test conditions. A two-step method for statistical evaluation of the test results is proposed and assessed in terms of specificity and sensitivity. The data were first subjected to powerful analysis of variance (ANOVA) after an arcsine-square-root transformation to detect significant differences between the test samples and the negative control (NC). A threshold (TH) value based on a pooled NC was then calculated to exclude false positive test results. Statistically, positive effects observed by the William's test were considered negative, if the mean of all replicates of a sample did not exceed the calculated TH. By making use of this approach, the overall test sensitivity was 100%, and the test specificity ranged from 80 to 100%.