With Christmas just around the corner, it may be good that the carp Czechs are so fond of usually don't come from rivers. Scientists and environmentalists have been examining whether pollutants in the country's rivers are affecting the fish that make their way onto Czech tables. Although the findings in two recent studies are not alarming, they may give fish-eaters food for thought.
The Labe River splits the North Bohemian town of Decin on its way to Germany. This river is where scientists have been finding chemicals in fish that may prove harmful to people. Among them are brominated flame retardants.
"There is evidence about occurrence in our environment. Moreover we have identified localities with high pollution levels."
That's chemist Jana Hajslova, from Prague's Institute of Chemical Technology, talking about flame retardants used to make electronics and carpets.
"In general terms it's always downstream from big urban agglomerations like Pardubice or Prague. So these localities are most polluted from our data set."
Ms. Hajslova led the study, which tested fish in the Labe and Vltava rivers for the chemical. Brominated flame retardants make their way into rivers from factories, office buildings and garbage dumps.
The environmental group Arnika was also involved in the research. Jindrich Petrlik heads its toxics and waste program. He says the few studies on the flame retardants indicate they may affect people's mental functions.
He says the amount of the chemical in fish here is normal for industrial European countries.
"These levels are high and it is caused because in our country we use more computers which include these flame retardants compared to developing countries. That doesn't mean we have an advantage. In this case, it's a disadvantage."
Brominated flame retardants accumulate in the body. And they are passed down the food chain. Ms. Hajslova's study found the chemical in the breast milk of Czech mothers.
Another toxin that accumulates in the body is mercury. But back in Decin, an angler on the edge of the river seems undeterred. That's even though another group of researchers found the element mercury in fish very near this site. Among those involved was Jiri Drapal, of the State Veterinary Administration.
"The results of the research of mercury levels in the Labe showed that levels are around the hygienic limits. ... The highest levels were higher than this. It depends on the fish. Carnivorous fish like fatty dace contained higher levels than non-carnivorous fish."
Mr. Drapal says that the mercury levels are not dangerously high, but pregnant women should avoid eating fish with high fat content.