Rates of hydroxyapatite formation and dissolution in a sandstone aquifer: implications for understanding dynamic phosphate behaviour within an agricultural catchment
Bingham, Sam T.; Buss, Heather L.; Mouchos, Evangelos M.; Johnes, Penny J.; Gooddy, Daren C.; Bagnall, John P.. 2020 Rates of hydroxyapatite formation and dissolution in a sandstone aquifer: implications for understanding dynamic phosphate behaviour within an agricultural catchment. Applied Geochemistry, 115, 104534. https://doi.org/10.1016/j.apgeochem.2020.104534
Full text not available from this repository. (Request a copy)Abstract/Summary
Eutrophication, caused by excessive nutrient concentrations, is a major environmental issue and has significant impacts on both aquatic ecosystems and human health. Phosphorus (P) is a key element that contributes to this eutrophication response. As such, P concentrations are regulated under both the European Union Water Framework Directive (EU WFD) and Habitats Directive (EU HD). While P export to rivers from point sources is well-understood, diffuse sources, particularly that route through connected aquifer systems are less well-characterised. Based on data from a catchment in southern England where an Upper Greensand aquifer controls river baseflow, we hypothesise that dynamic precipitation and dissolution of phosphorus in the form of hydroxyapatite occurs along the groundwater flow path, affecting P storage and export. In addition, P may also occur as the less-reactive mineral fluorapatite or sorb onto, or substitute into, Fe-oxides, which also occur in the aquifer. To investigate hydroxyapatite kinetics in this context, batch experiments were conducted to precipitate the mineral onto sand grains, and then dissolved in a continuous-flow reactor under various pH and concentration conditions. The reactive transport of PO43- along a 1D flow path was modelled to simulate hydroxyapatite precipitation and dissolution. Fe-oxides were modelled as sorbing surfaces for phosphate under chemical conditions representative of the aquifer.
Item Type: | Publication - Article |
---|---|
Digital Object Identifier (DOI): | https://doi.org/10.1016/j.apgeochem.2020.104534 |
ISSN: | 08832927 |
Additional Keywords: | GroundwaterBGS, Groundwater |
Date made live: | 25 Aug 2020 14:44 +0 (UTC) |
URI: | https://nora.nerc.ac.uk/id/eprint/528376 |
Actions (login required)
View Item |
Document Downloads
Downloads for past 30 days
Downloads per month over past year