The transboundary Mureş/Maros catchment : a review

Scattered and partly unpublished data are compiled and commented in this review of the transboundary (Romania/Hungary) Mures/Maros River Basin (catchment area 28,310 km 2 , river length 789 km, mean annual discharge 184 m 3 /s). Main characteristics of the Mures/Maros River are a conductivity mostly >100 μS/cm due to prevailing calcareous rocks, a nival hydrological regime (mean annual precipitation 520-1000 mm), and high pollution through mining (heavy metals), industry (toxicants, thermal), agriculture (fertilizers, pesticides) and domestic waste (organic C, N. P). Some 750 km or 33 % of monitored river course were in EU-WFD quality classes III-V. Pollution locally affects phytoplankton, periphyton, macroinvertebrates and fish communities. However, habitat heterogeneity and biodiversity are generally high due to mostly intact, near natural hydromorphological structures reflecting moderate human technical impacts, although gravel exploitation is considerable. This literature review is aimed at providing basic limnological information as the foundation of future scientific research into the catchment.