Data for: Field observations to establish the impact of fluvial flooding on potentially toxic element (PTE) mobility in floodplain soils
These datasets support the publication Ponting, J., Verhoef, A., Watts, M.J. and Sizmur, T., 2021. Field observations to establish the impact of fluvial flooding on potentially toxic element (PTE) mobility in floodplain soils. Science of The Total Environment, p.151378. The site used in this study is a floodplain downstream of a lowland urban catchment in England and is located adjacent to the River Loddon, a tributary of the River Thames, to the south of Reading, in southeast England, United Kingdom (51º24’47.6” N, 0º55’10.6” W). The data used in this paper was collected through the period of December 2018 to March 2019; pre-flood, during the flood, and post-flood. The flood event occurred due to high groundwater levels and overbanking of the River Loddon. There were 5 sampling visits before the flood (pre-flood), one visit during the flood (towards the end of approximately a one-week flood) and 5 sampling visits after the flood (post-flood). The 12 soil sampling locations used throughout the sampling regime were selected by creating a Fishnet grid (5m x 5m) in ArcGIS and taking the centre of the grid as the sampling point. At each sampling location, 5 soil samples were collected from an approximately 1m2 area using a stainless-steel auger to consistently sample the top 30cm of floodplain soil. These 5 samples were combined into 1 composite sample and stored in a cool box before return to the laboratory. Homogenised (~100 g) samples were centrifuged at 5,000 rpm (RCF 3830 x g) for 1 hour to extract pore water samples. Analyses conducted on the pore water samples included elements using Inductively Coupled Plasma Mass Spectrometry (ICP-MS), anions using Ion Chromatography (IC), and dissolved organic carbon using the Non-Purgeable Dissolved Organic Carbon (NPOC) method. River water samples were collected with a Nalgene bottle on a pole from a bridge located upstream of the floodplain at two time points (8 am and noon) on each sampling day during the period between November 2018 and March 2019. Groundwater samples were collected from two boreholes located on the Loddon Meadow Floodplain on each sampling day during the period between December 2018 and March 2019. An acid-washed 1 m plastic tube with 60 ml syringe was used to create a vacuum to draw water up from the borehole. The first sample drawn up was used to wash the 500 ml Nalgene sample bottle and then discarded. The river water and groundwater samples collected were transported in a cool box back to the laboratory and then were filtered using a 0.45 µm cellulose nitrate syringe filter and acidified prior to storage in the fridge and further analyses for elements (ICP-MS), anions (IC) and dissolved organic carbon (NPOC).