title: Novel DGT method with tri-metal oxide adsorbent for in situ spatiotemporal flux measurement of fluoride in waters and sediments.
abstract: Natural mineral-water interface reactions drive ecosystem/global fluoride (F(-)) cycling. These small-scale processes prove challenging to monitoring due to mobilization being highly localized and variable; influenced by changing climate, hydrology, dissolution chemistries and pedogenosis. These release events could be captured in situ by the passive sampling technique, diffusive gradients in thin-films (DGT), providing a cost-effective and time-integrated measurement of F(-) mobilization. However, attempts to develop the method for F(-) have been unsuccessful due to the very restrictive operational ranges that most F(-)-absorbents function within. A new hybrid-DGT technique for F(-) quantification containing a three-phase fine particle composite (FeAlCe, FAC) adsorbent was developed and evaluated. Sampler response was validated in laboratory and field deployments, passing solution chemistry QC within ionic strength and pH ranges of 0-200 mmol L(-1) and 4.3-9.1, respectively, and exhibiting high sorption capacities (98 ± 8 μg cm(-2)). FAC-DGT measurements adequately predicted up to weeklong averaged in situ F(-) fluvial fluxes in a freshwater river and F(-) concentrations in a wastewater treatment flume determined by high frequency active sampling. While, millimetre-scale diffusive fluxes across the sediment-water interface were modeled for three contrasting lake bed sediments from a F(-)-enriched lake using the new FAC-DGT platform.
authors.affiliation: State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing, 210023, People's Republic of China.
authors.forename: Chun-Yang
authors.initials: CY
authors.lastname: Zhou
authors.affiliation: State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing, 210023, People's Republic of China.
authors.forename: Dong-Xing
authors.initials: DX
authors.lastname: Guan
authors.affiliation: Institute for Global Food Security, School of Biological Sciences, Queen's University Belfast, Belfast, BT9 7BL, United Kingdom.
authors.forename: Paul N
authors.initials: PN
authors.lastname: Williams
authors.affiliation: State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing, 210023, People's Republic of China. Electronic address: esluojun@nju.edu.cn.
authors.forename: Jun
authors.initials: J
authors.lastname: Luo
authors.affiliation: State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing, 210023, People's Republic of China; Soil and Water Science Department, University of Florida, Gainesville, FL, 32611, USA.
authors.forename: Lena Q
authors.initials: LQ
authors.lastname: Ma
mesh_terms: D005459:Fluorides; D006863:Hydrogen-Ion Concentration; D008670:Metals; D009994:Osmolar Concentration; D014867:Water
chemical_list: D008670:Metals; D014867:Water; D005459:Fluorides
keywords: Diffusive gradients in thin-films; Fluoride; Sediment; Surface water