Influence of discharge and temperature on the transport of tracer pollutants along an urban river (Zenne, Belgium)

Human activities profoundly modified natural water circulation as well as water quality of rivers, with increased hydrological risks and chemical hazards as consequence. An extreme example of strongly modified river system is the river Zenne crossing the city of Brussels. In and around the city, the river determines a small vertical urbanized area (800 km²) combining extreme land-use landscapes: intensive agricultural activities upstream, a dense cityscape including a forested area in the center, and a strong industrial influence downstream. In this context, we established a box-model representation of selected polluting chemicals mass budgets (N and P, biological oxygen demand, and a selection of metals, pesticides and PAHs) for variable discharge and temperature ranges. For this, we have assessed the distribution of water flows, and pollutant tracer concentrations at the boundaries of the studied water system, including wastewater treatment plants and industrial waters, from available institutional databases. We discuss pollution tracer budgets for a yearly average situation, for dry and wet, and for warm and wintry weather conditions in order to understand climate effects on the transport/transfer/retention of pollutants in a highly human-impacted modified stream. Results from this study were obtained in the framework of the OSIRIS research project (INNOVIRIS Anticipate 2015-2018).

Trefwoorden:discharge, mass balance, temperature, pollutant, urban river

Toegankelijkheid:Open