Slomberg D, Ollivier P., Radakovitch O., Baran N., Sani-Kast N., Miche H., Borschneck D., Grauby O., Bruchet B., Scheringer M., Labille J. Characterization of suspended particulate matter in the Rhône River: Insights into analogue selection. (2016) Environmental Chemistry, 13 (5) 804-815
The fate and behavior of pollutants such as pesticides, metals, and nanoparticles in natural waters will influence their impact on the environment and human health. Due to the complexity of natural waters and suspended particulate matter (SPM) that can interact with pollutants, as well as low pollutant concentrations, determination of pollutant fate and transport is non-trivial. Herein we report a characterization of the Rhone River chemistry to provide insight into selecting SPM analogues for experimental and modeling approaches.
Selection of realistic suspended particulate matter (SPM) analogues remains vital for realizing representative experimental and modeling approaches in predicting environmental fate of pollutants. Here, we present the characterization of dissolved ion and SPM compositions for 9 sampling sites over the length of the Rhone River. Dissolved ion concentrations remained stable, but SPM concentrations varied among sampling sites. Size fractionation and mineralogical characterization of the mineral SPM revealed that the same minerals (e.g., quartz, calcite, muscovite) constituted every size class from 0.5 to more than 50 µm, as is such with allochthonous and large scale systems. To gain insight into SPM analogue selection, aggregation kinetics of silica, calcite, muscovite, feldspars, and clays were monitored in the native filtrate and related to the respective zeta potential (ζ). An SPM mixture of calcite (49%), muscovite (14%), feldspar (23%), and chlorite (14%) proved the best match for the Rhone SPM, demonstrating that mineral surface chemistry, structure, and size are all important in selecting a realistic SPM analogue for a riverine system.