Trace metals Remobilization and Distributions in Aquatic Sediments and Agricultural Soils
Trace metals are of great importance in the biogeochemical circulation of terrestrial and aquatic environments. Trace metals in agricultural soils could be taken up by crops and further enter the food chain, while trace metals in sediments could be transferred into the water column and result in accumulation in marine or estuarine creatures. Hence, studying and monitoring the distribution and remobilization of trace metals in agricultural soils and aquatic sediments would improve the understanding of their biogeochemical cycle and further impact on the ecosystems.
A passive sampling technique which is so-called Diffusive Gradients in Thin-Films (DGT) allows the investigation of labile metal fractions in the soils and sediments. When deploying DGT devices, it continuously removes target compounds from the medium to its sink, the disequilibrium caused by DGT will lead to a re-distribution of trace metals between the porewater and solid phase, therefore, the remobilization of metal species in different phases may occur. The traditional treatment of DGT probes, i.e., slicing resin gels, gives us a vertical distribution of trace metals, whereas the horizontal distribution of trace metals is neglected. Since unperturbed soils and sediments are mostly heterogeneous systems, which means 2D profiles are essential to study localized remobilization of trace metals, e.g. microniches. Besides, the resolution of 1D-DGT profile (0.5cm) is not sufficient to observe the presence of microniches which are normally at mm or µm scale. One way to solve both of the two issues is to combine the DGT technique with the analysis of Laser Ablation (LA)-ICP-MS. Additionally, the corresponding model which is the so-called DGT-Induced Fluxes (DIFS) would also be applied in our study to describe the remobilization process between the solid phase and porewater.
Trace metals, DGT, DIFS, sediments, Soils, LA-ICP-MS
Chinese Scholarship Council