Predictive and estimation model of Cd, Ni, and Zn bioaccumulations in maize based on diffusive gradients in thin films

Assessing soil remediation effect of Cr and Pb based on bioavailability using DGT, BCR and standardized determination method

In the field of soil remediation, the importance of bioavailability of pollutants has not received adequate attention, leading to the excessive application of remediation measures. Therefore, to ensure the safe use of farmland soil, a scientific method is needed to assess labile contaminants and their translocation in plants. To evaluate soil remediation effect based on bioavailability, the concentrations of these heavy metals in soil were analyzed using by the method for total metal content, the Community Bureau of Reference (BCR) extraction, and the diffusive gradients in thin films (DGT) technique. The results reveal that the correlation coefficients between metal concentrations measured by DGT and those accumulated in rice grains are the highest (Cr-R2 = 0.8966, Pb-R2 = 0.9045). However, the capability of method for total metal content to evaluate the remediation effect of heavy metals is very limited. In contrast, although Cr and Pb measured by BCR show a high correlation with HMs in rice plants, the method still falls short in precisely assessing bioavailability. Significantly, DGT proves to be more effective, successfully distinguishing the remediation effects of different treatments. Generally, DGT offers a more accurate and simpler assessment method, underscoring its practical significance for monitoring soil remediation and environmental management.

Principles, applications, and limitations of diffusive gradients in thin films induced fluxed in soils and sediments

The diffusive gradients in thin films (DGT) technique serves as a passive sampling method, inducing analyte transport and concentration. Its application is widespread in assessing labile components of metals, organic matter, and nutrients across various environmental media such as water, sediments, and saturated soils. The DGT devices effectively reduce the porewater concentration through irreversible binding of solutes, consequently promoting the release of labile species from the soil/sediment solid phase. However, the precise quantification of simultaneous adsorption and desorption of labile species using DGT devices alone remains a challenge. To address this challenge, the DGT-Induced Fluxes in Soils and Sediments (DIFS) model was developed. This model simulates analyte kinetics in solid phases, solutions, and binding resins by incorporating factors such as soil properties, resupply parameters, and kinetic principles. While the DIFS model has been iteratively improved to increase its accuracy in portraying kinetic behavior in soil/sediment, researchers' incomplete comprehension of it still results in unrealistic fitting outcomes and an oversight of the profound implications posed by kinetic parameters during implementation. This review provides a comprehensive overview of the optimization and utilization of DIFS models, encompassing fundamental concepts behind DGT devices and DIFS models, the kinetic interpretation of DIFS parameters, and instances where the model has been applied to study soils and sediments. It also highlights preexisting limitations of the DIFS model and offers suggestions for more precise modeling in real-world environments.