Rapid metal extractability tests from polluted mining soils by ultrasound probe sonication and microwave-assisted extraction systems.
Ultrasonic probe sonication (UPS) and microwave-assisted extraction (MAE) were used for rapid single extraction of Cd, Cr, Cu, Ni, Pb, and Zn from soils polluted by former mining activities (Mónica Mine, Bustarviejo, NW Madrid, Spain), using 0.01 mol L-1calcium chloride (CaCl2), 0.43 mol L-1acetic acid (CH3COOH), and 0.05 mol L-1ethylenediaminetetraacetic acid (EDTA) at pH 7 as extracting agents. The optimum extraction conditions by UPS consisted of an extraction time of 2 min for both CaCl2and EDTA extractions and 15 min for CH3COOH extraction, at 30% ultrasound (US) amplitude, whereas in the case of MAE, they consisted of 5 min at 50 °C for both CaCl2and EDTA extractions and 15 min at 120 °C for CH3COOH extraction. Extractable concentrations were determined by inductively coupled plasma atomic emission spectrometry (ICP-AES). The proposed methods were compared with a reduced version of the corresponding single extraction procedures proposed by the Standards, Measurements and Testing Programme (SM&T). The results obtained showed a great variability on extraction percentages, depending on the metal, the total concentration level and the soil sample, reaching high values in some areas. However, the correlation analysis showed that total concentration is the most relevant factor for element extractability in these soil samples. From the results obtained, the application of the accelerated extraction procedures, such as MAE and UPS, could be considered a useful approach to evaluate rapidly the extractability of the metals studied.
Departamento de Ingeniería Civil: Hidráulica y Ordenación del Territorio, Escuela Técnica Superior de Ingeniería Civil, Universidad Politécnica de Madrid, C/ Alfonso XII, 3, 28014, Madrid, Spain. sara.garcia@upm.es.
Sara
S
García-Salgado
Departamento de Ingeniería Civil: Hidráulica y Ordenación del Territorio, Escuela Técnica Superior de Ingeniería Civil, Universidad Politécnica de Madrid, C/ Alfonso XII, 3, 28014, Madrid, Spain.
M Ángeles
MÁ
Quijano
D004492:Edetic Acid / Q000737:chemistry; D004784:Environmental Monitoring / Q000379:methods; D004787:Environmental Pollution / Q000032:analysis; D019220:High-Energy Shock Waves; D008670:Metals / Q000737:chemistry*; D008872:Microwaves; D008906:Mining; D012987:Soil / Q000737:chemistry*; D012989:Soil Pollutants / Q000737:chemistry*; D013010:Sonication; D013030:Spain; D014465:Ultrasonics
D008670:Metals; D012987:Soil; D012989:Soil Pollutants; D004492:Edetic Acid
ICP-AES; Metals; Microwave-assisted extraction; Polluted mining soils; Single extraction; Ultrasound probe sonication