The Freiberg Mulde River, which drains part of the Freiberg mining district, has high levels of heavy metal, arsenic and sulfate pollution. The section between Berthelsdorf and Siebenlehn in particular is strongly influenced by historic mining as well as by non-ferrous and precious metal metallurgy. The aim of two large-scale monitoring campaigns was to identify all point sources in this area in order to identify the main emitters as well as possible diffuse (groundwater-borne) sources of arsenic, lead, cadmium, copper, iron, nickel, sulfate and zinc by means of load balances. Eight main emitters were identified, which are largely responsible for a corresponding increase in pollution in the study area. The pollution balances were carried out according to a simplified approach that allows conclusions to be drawn about possible diffuse influxes or losses due to, for example, retention, degradation and infiltration. In this context, a balance over the entire study area showed limited value. Only a section-by-section balance along the study area reveals that inflow and retention processes alternate and possibly overlap within the sections. This provides useful insights for further considerations of the causes of pollution and for the implementation of the Water Framework Directive in the catchment area of the Freiberg Mulde River.