Anthropogenic Gd in surface water, drainage system, and the water supply of the city of Prague, Czech Republic.

The anthropogenic Gd (Gdant) loads and fluxes of surface- and groundwaters, and of effluents from sewage treatment plants of Prague and its surroundings, have been determined. While passing Prague the Gdant load of the Vltava river increases from 4.5 to 19.2 nmol/m3, which is caused by the effluents of the central sewage treatment plant with a 6 day average of 250 nmol/m3. The Berounka river with its enhanced content doubles the Gdant flux of the Vltava river before entering Prague. All minor creeks draining Prague add less than 3% of the Gdant load in the Vltava river downstream of Prague. The 11-days average of the amount of the administered Gd complexes of the gadopentetic acid (Gd-DTPA), gadobenic acid, and other compounds in Prague's hospitals (22 g-Gdant/d) exceeds the 6 days average of 15 g-Gdant/d in the effluent of the central sewage treatment plant. This strongly indicates uncontrolled losses of sewage from sewers to the groundwater.