engleski

Problems with High Concentrations of Mn and Fe at the Pumping Site Petruševac - Zagreb (Croatia)

The aquifer of the Zagreb area is the most important source of water supply for the city of Zagreb. Daily, from the aquifer is pumped about 5.5m3/s. Because of its great importance it has been intensively explored. The aquifer is made of Quaternary sediments, which are distinguished by horizontal and vertical exchange of various litholoical units. Mainly aquifer consists of gravel-sand sediments where the pebbles and grains of limestone and dolomite are prevailing. Also, the aquifer is interbeded with silt, fine sand and clay sediments which can contain the organic matter and metals. In the Zagreb area there are several pumping sites. Petruševec is one of the Zagreb’ s pumping site. On this site on some wells it was observed the high concentrations of Mn and Fe. The concentrations sometimes exceed the Croatian drinking limits which for Mn is 50 ppb and for Fe 200 ppb. Both Fe/Mn are essential nutrients for all life. High levels of Mn in drinking water may affect neurological and muscle function in humans. The Mn concentrations vary from 2.2 ppb to 420 ppb and the Fe concentrations vary from 8.1 ppb to 350 ppb. The amount of Mn and Fe in the water depend on where the well situated is and how deep it is. The Mn and Fe are geogenic and it is not anthropogenic. Also, certain bacteria thrive in the presence of Fe/Mn, clog strainers, pumps, and valves. Because of all these problems Mn is removed from water.

hydrogeology ; hydrogeochemistry ; Zagreb aquifer ; Mn ; Fe

nije evidentirano