In the Armenian part of the sub-basin, the river is exposed to background contamination as a result of hydrochemical processes. The increased concentrations of heavy metals (vanadium — V, Mn, Cu, Fe) already exceed the MACs for the fish in the upper part of the sub-basin. The concentrations of, for example, zinc (Zn), Fe and sulphate, decrease from upstream to the monitoring station just upstream from the border of Armenia and Azerbaijan, indicating reduced potential for transboundary impact.