Sources, lability and solubility of Pb in alluvial soils of the River Trent catchment, U.K.

Abstract

Alluvial soils are reservoirs of metal contaminants such as Pb that originate from many different sources and are integrated temporally and spatially through erosional and depositional processes. In this study the source, lability and solubility of Pb was examined in a range of alluvial soils from the middle and lower River Trent and its tributary the River Dove using Pb isotope apportionment and isotopic dilution. All samples were collected within 10 m of the river bank to represent the soil that is most likely to be remobilised during bank erosion. Paired samples were taken from the topsoil Pb ratios showed that the isotopic ratios of Pb in the total, labile and solution pools fitted along a mixing line between Broken Hill Type ('BHT') Pb, used as an additive in UK petrol, and the local coal/Sourthern Pennine ore Pb. Various anomalies were found in the Pb isotopes of the bankside alluvial soils which were explained by point source pollution. Statistically significant differences were found between (i) the isotopic composition of Pb in the total soil pool and the labile/solution pools and (ii) the isotopic composition of Pb in the labile and solution pools, suggesting an enrichment of recent non-Pennine sources of Pb entering the soils in the labile and solution pools.

Lability, solubility and speciation of Cd, Pb and Zn in alluvial soils of the River Trent catchment UK

“…However, using 0.0005M EDTA as suggested by Atkinson et al 24 , allowed more analytically robust Pb isotope measurements to be obtained for all soils (E-values with CV <0.4-7%), as previously reported by Izquierdo et al 2 . Thus, the final dataset for Pb modelling 15 ( Table S2) contains only E-values obtained using 0.0005M EDTA as the background electrolyte.…”

“…Loss on ignition (LOI) was undertaken at 450°C as a measure of soil organic matter. Particle size analysis was determined using a laser diffraction particle size analyser after organic matter had been destroyed using H 2 44 . The humic/fulvic acids were extracted by shaking soils with 0.1M NaOH.…”

“…In addition Pb concentrations have been enhanced from the diffuse deposition of tetra-ethyl Pb and its combustion products, used in 70 petrol and phased out in the year 2000. Previous work by Izquierdo et al 2 in the Trent catchment examined the sources and lability of Pb in these alluvial soils and whilst several point sources of contamination were identified, the diffuse enrichment of Pb from petrol Pb was found to be widespread.…”

“…Alluvial soils act as archives for fluvially dispersed metal contaminants from numerous sources [1][2][3][4][5] . These soils are often used in intensive agricultural systems.…”

Industrial mining heritage and the legacy of environmental pollution in the Derbyshire Derwent catchment: Quantifying contamination at a regional scale and developing integrated strategies for management of the wider historic environment

“…The geochemical evidence suggests that mining has provided much of the fluviallytransported Pb in the Derwent and Pb isotopic fingerprinting suggests that it may also be important on a wider regional scale. Lead isotopic data for sediments from the River Trent downstream of the Derwent confluence suggest both a mining-and industrially-derived source for Pb, in the latter case from a local power station and railway marshalling yard (Izquierdo et al, 2012). These data suggest that the Derwent catchment as a whole is a , 2004).…”