Characterisation of suspended matter in river systems: River Sava in Slovenia case study

δ13C and δ15N values in suspended matter were used to examine the seasonal (late summer 2004 and spring 2005) relationship with hydrological characteristics of the River Sava watershed in Slovenia. d13C values range from - 29.2 to - 23.0 ‰ and δ15N values from 0.5 to 16.7 ‰ and indicate that the samples are a mixture of two end members: modern soils and plant litter. A simple mixing model was used to indicate that soil organic carbon prevails over plantlitter and contributes more than 50 % of suspended material. The total suspended solid flux (TSS) is estimated to be 1.3 × 1012 g/year. Anthropogenic impact was detected only in a tributary stream of the River Sava which is located in an agriculture-industrial area and is reflected in higher δ15N values in suspended matter in the late summer season.