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

The anthropogenic Gd (Gd_ant) 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 Gd_ant 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 Gd_ant 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 (6d-DTPA), gadobenic acid, and other compounds in Prague's hospitals (22 g-6_ant/d) exceeds the 6 days average of 15 g-Gd_ant/d in the effluent of the central sewage treatment plant. This strongly indicates uncontrolled losses of sewage from sewers to the groundwater.