Abstract:

In 1986 and 1987 seven series of samples were taken at 36 to 47 sampling points on Babno, Loško and Cerkniško Polje and on Bloke and at Loški potok in order to find out their physico-chemical properties and their quality. Rainwater flows from the limestone and dolomite landscape around Babno, Loško and Cerkniško polje into springs feeding the sinking streams. The nitrate level at most of the springs was below 4 mg NO3-/l and chloride below 5 mg Cl-/l; the o-phosphate level varied around the value of 0.05 mg PO43-/l. The bacteriological analyses of the spring waters showed that they are not of drinking quality and only few springs were seasonally of good quality. Poorer quality was found in springs with populated catchments, such as are Pudobski Izvir, Podgorski and Mežnarjev Studenec and, obviously in all the sinking waters at swallow-holes where the nitrate and chloride level was up to 20 mg/l and phosphate up to 5 mg/l. Flowing over karst poljes this water receives pollution due to habitations and industry. As the water of these sinking streams reappears downstream in several lower-lying karst poljes this results in the transport and accumulation of pollution downstream even in springs that are captured for water supply.