Joint recording of contamination status, multi-element dynamics, and source identification on a sub-catchment scale:...

Investigations on the enrichment level, binding dynamics, and source identification of contaminants are important objectives of environmental research into surface waters, but are often carried out independently of each other. To simultaneously address these issues an investigative approach is presented that combines multi-element analyses of water and suspended particulate matter (SPM) and is applied on the scale of a sub-catchment, using the Lahn River (Germany) as an example. Analyses of water and SPM comprised phosphorus (P), vanadium (V), chromium (Cr), manganese (Mn), iron (Fe), cobalt (Co), nickel (Ni), copper (Cu), zinc (Zn), arsenic (As), cadmium (Cd), lead (Pb), and uranium (U). For the dissolved phase, the investigations additionally included nitrogen compounds (NH₄, NO₃) and dissolved organic carbon (DOC). SPM of the Lahn showed increased average concentrations of Zn (2.13 g kg^-1), Cd (4.01 mg kg^-1), and Pb (160 mg kg^-1). The water phase sampled from points along the length of the Lahn showed significant spatial differences in the dissolved concentrations of Mn (15.7-98.4 μg l^-1), Co (0.08-0.66 μg l^-1), Ni (0.75-4.69 μg l^-1), Zn (19.9-187 μg l^-1), and Cd (0.01-0.18 μg l^-1), which could be attributed to the inflow of two tributaries draining historic mining areas. The study emphasizes the importance of mine waters during low water periods and proves that such sources can differently affect the SPM quality and the dissolved concentrations of their receiving waters.