Improvements of existing and developments of new methods for sampling and analysis of phosphorus fractions in surface-, soil- and sediment water, in order to separate particulate/colloidal, low molecular and anionic/neutral/cationic phosphorus compounds.
The new and improved methods will be used for better system and process understanding in WP2 and as input to the improved models in WP3. The work will be performed in cooperation between NIVA and MSc students at UiO-Chem (Prof. Vogt), and focuses on:
i) Phosphorus fractions in river and surface water. Study the new DGT sampler for collection of free phosphate fraction as well as low molecular organic phosphorus compounds (AMP and similars). We have limited knowledge of the latter fraction, and will examine the potential for using DGT to sample this fraction. NIVAs Size Charge Fractionation (SCF) method will be further examined to separate particulate, low molecular and free anionic/neutral/cationic phosphorus compounds and compared with the results from the DGT samplers.
ii) Phosphorus fraction in sediment and soil pore water. For fluxes over sediment surfaces, new pore-water profiling tools of P fractions in top lake sediments are to be examined by use of DGT probes. DET-micropeeper probes (Diffusive Equilibrium in Thin films), as well as conventional peeper systems, are under development in cooperation with NIVA and UiO-Chem.
iii) New high sensitivity analytical tools for P measurements. SCF/FIA/SIA techniques with long path flow cells/molybdate blue chemistry as well as HRICPMS, are to be be examined.