Performance characteristics of sequential separation and quantification of lead-210 and polonium-210 by ion exchange chromatography and nuclear spectrometric measurements

• Published in: Journal of environmental quality 2006-03, Vol.35 (2), p.568-574
• Main Authors: El Afifi, E.M, Borai, E.H
• Format: Article
• Language: English
• Subjects: Agronomy. Soil science and plant productions; Applied sciences; Biological and medical sciences; Calcium Sulfate - chemistry; chemical analysis; Chromatography; Chromatography, Ion Exchange; Comparative studies; Deposition; Digestion; Disks; Dissolution; Earth sciences; Earth, ocean, space; Engineering and environment geology. Geothermics; Environmental Monitoring - methods; Exact sciences and technology; Fundamental and applied biological sciences. Psychology; Gamma rays; gamma-ray spectrometry; Inorganic acids; Ion chromatography; Ion exchange; Lead; Lead Radioisotopes - analysis; liquid scintillation counting; Liquids; Mathematical analysis; Matrices; nondestructive methods; Oxalates; Phosphates; Phosphates - chemistry; phosphogypsum; Phosphorus - chemistry; Polished; Pollution; Pollution, environment geology; Polonium; Polonium - analysis; Quality control; radionuclides; Recovery; Reproducibility of Results; rock phosphate; Scintillation; Scintillation Counting - methods; Separation; Silver; soil; Soil (material); soil chemistry; Soil Pollutants, Radioactive - analysis; Spectrometry; Spectroscopy; Spectrum analysis; Spectrum Analysis - methods
• ISSN: 0047-2425; 1537-2537
• DOI: 10.2134/jeq2005.0223

A selective separation and quantitative determination procedure for 210Pb and 210Po in various environmental matrices from different sources such as IAEA-326 soil, phosphate rocks (PR), and phosphogypsum (PG) was developed. The tested samples were digested sequentially using concentrated mineral acids (HF, HNO3) by a programmable high-pressure microwave digestion system. The sample solution was loaded onto a preconditioned ion exchange column (Sr-resin) for chromatographic separation. Polonium-210 was eluted by 6 M HNO3 then spontaneously deposited onto polished silver discs to be measured using low-background alpha spectrometry. Lead-210 was sequentially eluted using 6 M HCl solution, precipitated as lead oxalate, dissolved in HNO3 solution, and mixed with scintillation cocktail to be measured by liquid scintillation counting (LSC). Performance of the developed procedure was tested using a reference soil (IAEA-326), with recommended isotope values, that was used as a quality control to assess separation and quantification efficiency (recovery %). The minimum detectable activities of 210Pb and 210Po were found to be 24 and 0.28 Bq kg(-1) for the measurements using LSC and alpha spectrometry, respectively. The recoveries (%) of 210Pb and 210Po were found to be 80 and 60%, respectively. To test the validity of the proposed LSC method, a comparative study was performed by measuring 210Pb activity concentration in test samples by nondestructive gamma-ray spectrometry.