Migration and Diffusion of Heavy Metal Cu from the Interior of Sediment during Wave-Induced Sediment Liquefaction Process

Abstract

Sediments are an important sink for heavy metal pollutants on account of their strong adsorption capacity. Elevated content of Cu was observed in the Chengdao area of the Yellow River Delta, where the surface sediment is mainly silt and is prone to be liquefied under hydrodynamic forces. The vertical transport of fine particles, along with pore water seepage, during the liquefaction process could promote the migration and diffusion of Cu from the interior of sediment. The present study involved a series of wave flume experiments to simulate the migration and diffusion of Cu from the interior of sediment in the subaqueous Yellow River Delta area under wave actions. The results indicated that sediment liquefaction significantly promoted the release of Cu from internal sediment to overlying water. The variations of Cu concentrations in the overlying water were opposite to the suspended sediment concentrations (SSCs). The sediment liquefaction caused high initial rises of SSCs, but led to a rapid decline of dissolved Cu concentration at the initial period of sediment liquefaction due to the adsorption by fine particles. Afterwards, the SSCs slightly increased and then gradually decreased. Meanwhile, the dissolved Cu concentration generally kept increasing under combined effects of intensively mix of sediment and overlying water, pore water seepage, and desorption. The dissolved Cu concentration in the overlying water during sediment liquefaction phase was 1.5–2.2 times that during the consolidation phase. Sediment liquefaction also caused vertical diffusion of Cu in sediment and the diffusion depth was in accordance with the liquefaction depth. The results of the present study may provide reference for the environmental management in the study area.

New Advances in Marine Engineering Geology

“…Lu et al [8] investigate the remobilization of heavy metal Cu under wave action, especially during sediment liquefaction. They conducted a series of controlled wave flume experiments using the sandy silts collected from the Yellow River Delta.…”

“…The issue collected 14 papers that cover different aspects of marine engineering geology and geotechnics using different approaches. Some of them used numerical simulations [1][2][3][4][5], some conducted laboratory experiments [6][7][8][9][10], and others acquired and analyzed field or laboratory tests to establish a theoretical modeling framework for predicting marine sediment properties and the potential hazards [11][12][13][14]. Moreover, with a timely and well-organized publication, it is believed that the state-of-the-art data, analyses, and methodologies presented in this Special Issue could be of great interest to all readers of Journal of Marine Science and Engineering.…”

Adsorption and migration of heavy metals between sediments and overlying water in the Xinhe River in central China

“…The heavy metals discharged in the water bodies through different sources would eventually be enriched in the sediments by adsorption, complexation, flocculation, and sedimentation (Zhang et al 2018). So, the sediments serve not only as a primarysettling accumulation field and a carrier of heavy metals, but they also reflect their contamination level (Tang et al 2014;Guan et al 2018;Lu et al 2019).…”

“…The power source resulting in changes of the sedimentary conditions is divided into natural factors and anthropogenic perturbations. The natural factors mainly include hydrodynamics (e.g., wind wave, storm, tide (Lin et al 2019;Lu et al 2019), and water flow), chemical processes, and bioturbation (Song et al 2015). The man-made factors mainly include ship transportation (Superville et al 2014), sand mining, dredging operations, fishing, and other human activities (Shi & Zhang 2018).…”

Release flux of heavy metals from river sediments at different flow rates

“…Many studies have targeted the release of heavy metals from sediments under different hydrodynamic conditions. However, most of them are focused on factors affecting the release of heavy metals from sediments, the different forms and levels of heavy metals in water after release, or the exploration of the migration and transformation rules of the different forms of heavy metals (Zheng et al 2013;Lu et al 2019). Few reports exist on the quantitative analysis of heavy metal release from sediments at different flow rates (Wen et al 2021;Yan et al 2021), and even fewer studies have been conducted on heavy metal release from river sediments (Liu et al 2018a;Cai et al 2021).…”