engleski

spatial and temporal trends in pops sediment contamination in the Czech republic

The system of water quality monitoring in the Czech Republic is covered by Czech Hydrometeolorological Institute in the co-operation with Water Research Institute and some other institution such as River Basin Management companies or Agricultural Water Administration1. The present monitoring network has been developed since 1963. The basic moment was implementation and adoption of relevant EC Directives. In present 257 sampling profiles exist and cover the area of the Czech Republic. As far as POPs under Stockholm Convention they have been measured in surface waters for relatively long time - polychlorinated biphenyls since 1990, HCB and HCHs since 1993, DDT and driens since 1995 and PAHs since 1992. All these compounds have been also determined as a part of monitoring programme since 2000 in sediments and in suspended particles. In general, the level of contamination by organochlorinated pesticides such as DDTs, driens or HCHs is not high and is comparable with other countries. But still there are a few regional or local problems where higher levels of selected OCPs can be determined. The most important sites are the vicinities of former producers of these compounds such as Spolchemie Ústí n/L. (DDTs, HCB) or Spolana Neratovice (DDTs, HCHs, HCB). Higher amounts were also detected in some regions in the middle and south of Moravia (agricultural regions) (HCHs mainly). These Moravian regions are also highly contaminated with driens than other parts of the country, but in general absolute values of this contamination are very low. Probably the most important contamination of hydrosphere in the Czech Republic is given by PCBs. Among the main reasons there is a former production in Czechoslovakia and broad and intensive use of technical PCB mixtures in various industrial sectors. The determination of PCDDs/Fs contents in water is not included to the monitoring programme from the reason of low water solubility. The contamination of surface water is evaluated on the base of determination of PCDDs/Fs in sediments or particles after water filtration. But monitoring of PCDDs/Fs has still more sporadic than regular in the comparison with other POPs. In general, the lack of information concerning to the PCDDs/Fs contamination of Czech hydrosphere still exists with exception of few industrial sources such as area of chemical company Spolana Neratovice or region where the research projects were performed (region Zlín, Beroun). Time trends of PCBs a HCB in the Elbe sediment (sampling site Děčín - Hřensko) during the time period 1993 – 2000 were evaluated. Content of PCBs in these sediments are relatively stable during whole period with mean value between 100 and 200 ng.g-1. It can be considered as evidence of continuous contamination form still unidentified sources. Decreasing time trend of HCB contents from the same sampling site and the same time period is promising, but it is necessary noted that this decreasing is given by the changes of technologies and construction by new, more effective wastewater treatment plant in Spolchemie Ústí n/L. It is a decreasing from extremely high values and these levels are still higher than country mean value.

POPs, Czech Republic

nije evidentirano