Two Dimensional Heavy Metal Transport Model for Natural Watercourses

Abstract

This work presents the development and calibration of a two-dimensional (depth-averaged) river flow, sediment transport and heavy metal transport model in natural watercourses. Because heavy metals occur in dissolved and adsorbed phases, implementing the active-layer concept for sediment transport computation enabled the development of a heavy metal transport model that accounts for pollutant moving in dissolved phase, adsorbed on suspended sediment, adsorbed on bed-load, deposited in the active-layer of the river bed or adsorbed on sediment in deeper strata. The proposed concept also enables the modelling of pollutant exchange processes using accessible sediment particle surface area for suspended and bed sediment separately. The presented heavy metal transport model is able to manage sediment mixtures found in natural watercourses using an arbitrary number of sediment size-classes, distinguishing in this way smaller size-classes that engage in interaction with the pollutant. Using field measurements for a reach of the Danube River, simulations were conducted for water flow, sediment transport and heavy metal transport. While some discrepancies between measured and computed values for pollutant concentrations were observed, the model reproduced the water and sediment contamination quite reasonably with acceptable mass conservation errors. The simulations also gave an insight in the general behaviour of the monitored heavy metals in the considered river reach. Therefore, it can be concluded that the developed model is suitable for simulating complex flow, sediment transport and heavy metal transport conditions in natural watercourses.

Phytohormonal Roles in Plant Responses to Heavy Metal Stress: Implications for Using Macrophytes in Phytoremediation of Aquatic Ecosystems

“…The persistence of heavy metals in aquatic ecosystems represents an acute challenge for remediation because heavy metals exist in various physical states, including dissolved forms (e.g., free ions, complex ions, and/or chelated with inorganic/organic ligands) and particulate forms (e.g., colloids, aggregates, precipitates, and nanoparticles (NPs); Reed and Gadd 1990; Lead et al 2018). Moreover, heavy metals in aquatic systems are not easily contained because they can disperse with the water flow (Horvat and Horvat 2016) and can change their state at the sediment–water interphase, depending on the physiochemical properties of the system (He et al 2017; Li et al 2020). Several methods can be used to remediate heavy metals, such as replacement or washing of soil (Khalid et al 2017), metal precipitation, ion exchange, or adsorption in water (Akpor and Muchie 2010; Vardhan et al 2019).…”

Development, Calibration and Verification of a 1-D Flow Model for a Looped River Network

“…Other applications of one-dimensional open-channel flow models include longterm simulations [16], river network modeling [10], flood predictions and similar hydraulic engineering problems. Despite the fact that these models are widespread, their proper calibration still presents a major challenge [8,9,25]. Castellarin et al [3] discussed useful guidelines for identification of the geometric description of natural rivers [3].…”

Lattice-Boltzmann-Method-Based Numerical Simulation for Heavy Metal Migration Process during Deep-Sea Mining

“…Based on the Lattice Boltzmann method (LBM), a numerical model of heavy metals released into overlying water under hydrodynamic conditions is established. Horvat et al [11] developed a two-dimensional-numerical-model-suiting approach to simulate the complex flow, sediment transport, and heavy metal transport conditions in natural watercourses. By assessing the performance of the distributed hydrological model for simulating the transport of various heavy metals in rivers, Bouragba et al [12] utilized a hydrological model to numerically calculate the migration of multiple heavy metals, i.e., Pb, Hg, Cr, and Zn, in the Harrach Rivera.…”