(PDM staff with CTK) 17 August - The quality of surface as well as ground water slightly improved last year compared with previous years, but the pollution of some rivers still exceeds critical levels, according to a report the government will discuss today.

One of the most polluted rivers is Bilina in north Bohemia. Hydrologists ascribe this to the river's small flow and a big concentration of industrial companies on its banks, the biggest being Chemopetrol.

According to the report, the content of mercury has slightly decreased in the Bilina, but the quantity of chlorinated substances, boron and copper is still high.

The north Moravian rivers Olse and Ostravice are polluted with extremely dangerous substances, the report says.

In contrast, water in the main Czech rivers, the Elbe, Vltava, Moravia and Odra has been improving for over the last few years.

Hydrologists say this is due to the construction of modern water treatment plants, the closing down of many industrial companies, improved environmental restrictions on companies and the reduction of fertilizers used in farming.

Compared with 2003 the quality of ground water has also slightly improved, the report says.

The biggest pollutants are the same as in the past years, namely nitrogen substances, chlorides and metals.

The biggest concentration of nitrogen substances is in areas with big farming.

The Czech Environment Inspection office registered 306 cases of acute pollution or threat to the quality of waters last year, with oil substances being involved in almost a half of them.

The inspection office collected over CZK25 million crowns in fines.

The report also says that last year was average in terms of precipitation. The most rainy month was June when hydrologists measured 96 millimetres of precipitation. The driest was December when 24 millimetres of precipitation fell, which is a mere 48 percent of a long-term month average.