Suspended Sediment Metal and Metalloid Composition in the Danube River Basin, Croatia

The Water Framework Directive (WFD) 2000/60/EC established a framework for community action in the field of water policy. This Directive requires the monitoring of surface watercourses’ quality, which is undoubtedly influenced by the sediment composition. Their function can serve the living and transport purposes of numerous microorganisms and algae, but sediment may be a medium for transmitting dangerous toxic substances that are harmful to all living organisms in the environment as well. Many substances (including chemical substances, metals, and nutrients) can accumulate in sediment over time and be released in water or contaminate aquatic species, thus potentially negatively affecting the ecological or chemical status. Furthermore, flood events as well as human interventions can remobilise deposited sediment and thus result in the downstream and cross-border transport of sediment-associated contamination. The purpose of this investigation was to calculate the daily values of chemical elements in the transmission of suspended sediment and its accumulation in the suspended matter collected at some hydrological stations in the Danube River Basin during high flow events. The joint vision for the “Mura-Drava-Danube” area is to use the Transboundary Biosphere Reserve (TBR) concept to maintain a living river ecosystem for biodiversity and ecosystem services and to promote nature-friendly economic development for the local communities of this rural region. Therefore, this region requires a permanent sediment quality monitoring program.