Interaction dynamics between a contaminated dredged sediment and extracting solutions of different nature
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SEDIMENTS AS A DYNAMIC NATURAL RESOURCE – FROM CATCHMENT TO OPEN SEA
Interaction dynamics between a contaminated dredged sediment and extracting solutions of different nature Nieves Garcia-Blas 1,2 & Eva Jimenez-Relinque 1 & Roman Nevshupa 1 & Marta Castellote 1 Received: 7 June 2019 / Accepted: 13 September 2019 # Springer-Verlag GmbH Germany, part of Springer Nature 2019
Abstract Purpose The purpose of this work is to study the dynamics between the matrix of a contaminated marine sediment, its contaminants and various desorbing solutions by means of equilibrium tests, sedimentation trials and zeta potential, with the focus on assessing optimum enhancing solutions for decontamination purposes. Materials and methods The sediment samples were analysed to determine their physico-chemical characteristics: particle size distribution, solids concentration, total organic carbon (TOC), content of heavy metals, organic contaminants, mineralogical phases, zeta potential and buffer capacity. Twelve extracting solutions of different nature were used for equilibrium tests, in which the dynamic behaviour of the sediment was evaluated. Elemental analysis was carried out for the sediment samples and the solutions before and after the tests. Results and discussion The sediment was mainly composed of clay and lime, with a high content of iron, which has a strong influence on sorption-desorption processes. The sediment had a considerable buffer capacity at low and high pH values. The desorption of the metals was not proportional to pH. The highest decrease in the concentration of metals from the sediment was obtained with 0.2 M ethylenediaminetetra-acetic acid (EDTA) and 1 M nitric acid, while the lowest degree of metal extraction occurred in pure water and potassium iodide (KI). Conclusions The most important parameters for contaminant release were complexation ability of the solution for the sediment components and pH of the solution. A promising design for the remediation treatment for the investigated sediment includes complexation and strong acid agents. Keywords Dredged sediment chemistry . Extracting solutions . Sediment decontamination . Sedimentation rate . Zeta potential
1 Introduction Marine sediments dredged from harbours are usually heavily contaminated with a wide variety of pollutants, such as heavy metals and organic compounds. Contamination has a profound impact on the reutilization of marine sediments and contributes to a loss of biodiversity, degradation of the ecosystems and a risk for humans (Eggleton and Thomas 2004; Zhang et al. 2014). Therefore, proper management of
Responsible editor: Elena Romano * Marta Castellote [email protected] 1
Institute of Construction Science Eduardo Torroja (IETcc-CSIC), Serrano Galvache 4 28033 Madrid Spain
2
National Distance Education University (UNED), Madrid Spain
sediments is needed in order to implement the EU Water Framework Directive (Den Besten et al. 2003). Despite several decades of research, an efficient technology for sediment decontamination has not yet
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