Assessing the chemical contamination dynamics in a mixed land use stream system

摘要: Traditionally, the monitoring of streams for chemical and ecological status has been limited to surface water concentrations, where dominant focus on general quality risk eutrophication. Mixed land use stream systems, comprising urban areas agricultural production, are challenging assess with multiple stressors impacting corridors. New approaches urgently needed identifying relevant sources, pathways potential impacts implementation suitable source management remedial measures. We developed a method assessing in these systems applied approach 16-km groundwater-fed corridor (Grindsted, Denmark). Three methods were combined: (i) in-stream contaminant mass discharge quantification, (ii) Toxic Units (iii) environmental standards. An evaluation all three compartments - water, hyporheic zone, streambed sediment made it possible link their respective sources obtain new knowledge about composition origin. Moreover, toxic unit estimation comparison standards revealed was substantially impaired by both geogenic diffuse anthropogenic metals along entire corridor, while less impacted. Quantification originating from former pharmaceutical factory that several 100 kgs chlorinated ethenes compounds into every year. The strongly reduced redox conditions plume result high concentrations dissolved iron additionally release arsenic, generating complex mixture found narrow zone. fingerprint observed km downgradient, nutrients, inorganics pesticides played minor role health. results emphasize future investigations should include compartments, highlight need holistic when dynamic systems.