Emerging organic pollutants in the vadose zone of a soil aquifer treatment system: Pore water extraction using positive displacement. (January 2018)

• Record Type: Journal Article
• Authors: Sopilniak, Alexander; Elkayam, Roy; Rossin, Anna Voloshenko; Lev, Ovadia
• Is Part Of: Chemosphere. Volume 190(2018)
• Page Start: 383
• Page End: 392
• Publication Date: 2018-01
• Subjects: Emerging organic contaminants (EOCs) -- Pore water extraction -- Soil-aquifer treatment (SAT) -- Wastewater treatment -- Breakthrough curves; Pollution -- Periodicals; Pollution -- Physiological effect -- Periodicals; Environmental sciences -- Periodicals; Atmospheric chemistry -- Periodicals; 551.511
• DOI: 10.1016/j.chemosphere.2017.10.010
• Languages: English
• ISSNs: 0045-6535

Abstract

Abstract: Trace organic compounds in effluents, water streams and aquifers are amply reported. However, the mobile pool of Emerging Organic Contaminants (EOCs) in the deep parts of the vadose zone is hard to estimate, due to difficulties in extraction of sufficient quantity of pore water. Here, we present a new methodology for depth profiling of EOCs in pore water by Positive Displacement Extraction (PDE): Pore water extraction from unsaturated soil samples is carried out by withdrawal of soil cores by direct-push drilling and infiltrating the core by organics free water. We show that EOC concentrations in the water eluted in the plateau region of the inverse breakthrough curve is equal to their pore water concentrations. The method was previously validated for DOC extraction, and here the scope of the methodology is extended to pore water extraction for organic pollutants analysis. Method characteristics and validation were carried out with atrazine, simazine, carbamazepine, venlafaxine, O -desmethylvenlafaxine and caffeine in the concentration range of several ng to several μg/liter. Validation was carried out by laboratory experiments on three different soils (sandy, sandy-clayey and clayey). Field studies in the vadose zone of a SAT system provided 27 m deep EOC profiles with less than 1.5 m spatial resolution. During the percolation treatment, carbamazepine remained persistent, while the other studied EOCs were attenuated to the extent of 50–99%.The highest degradation rate of all studied EOCs was in the aerobic zone. EOC levels based on PDE and extraction by centrifugation were compared, showing a positive bias for centrifugation. Graphical abstract: Image 1 Highlights: A novel method for pore water extraction for analysis of micropollutants is introduced. Positive displacement extraction, PDE was proven superior to centrifuge extraction. First EOC depth profile of micropollutants in vadose zone of a water recharge system.