Application of ICP sector field MS and principal component analysis for studying interdependences among 23 trace elements in Polish beers.

Twenty-three metallic elements, including almost all essential and toxic metals such as lead, cadmium, mercury, arsenic, silver, and thallium, have been quantified in 35 types of bottled and canned Polish beer by using double-focusing sector field inductively coupled plasma mass spectrometry (ICP-MS) with ultrasonic nebulization. The samples were digested using concentrated HNO3 in closed PTFE vessels and applying microwave energy under pressure. The means and medians of the concentrations of Rb, Mn, and Fe were on the order of 200 ng/mL; Cu, Zn, V, Cr, Sn, As, Pb, and Ni were detected at 1-5 ng/mL; Ag, Ga, Cd, Co, Cs, Hg, U, and Sb were found at < 1 ng/mL; and In, Tl, Bi, and Th were present at < 0.1 ng/mL. The concentrations of Hg, Cd, As, Pb, and Zn were 1-3 orders of magnitude lower than proposed tolerance limits. The interdependences among determined trace elements were examined using the principal component analysis (PCA) method. The PCA model explained 74% of the total variance. The metals tend to cluster together (As, Tl, Cs, Sn, Th, Bi, and Hg; Cd and Co; Cs and Cr; Fe and Zn; Mn and V).     

Activity Disequilibrium between 234U and 238U Isotopes in Southern Baltic

The aim of the work was to determine the concentration of ²³⁴U and ²³⁸U and calculate the values of the ²³⁴U/²³⁸U activity ratio in samples of living organisms, bottom water, surface and interstitial water and also sediments from the various regions of southern Baltic Sea. The knowledge of ²³⁴U/²³⁸U activity ratio in ecosystem allows getting know about the mechanisms and processes of uranium transport and origin.The activities of the analyzed uranium radionuclides in samples were measured using alpha spectrometry. The results of researches revealed diversified concentrations of uranium in the sediments of the southern Baltic Sea (sea and coastal waters) and increase of uranium with sediment depth, suggesting the diffusion of uranium from sediments to water through interstitial water and diagenesis processes in sediment material. The nuclides of uranium ²³⁴U and ²³⁸U were radioactive state equilibrium in most of the sediments. The values of the ²³⁴U/²³⁸U activity ratio oscillate around one. In bottom, surface, interstitial water and living organisms mean values of the ²³⁴U/²³⁸U activity ratio are between 1.12 and 1.15. Higher uranium concentration was observed in samples of sediments and seawater after flood in 1997 and torrential rainfalls in 2000–2001. River waters are characterized by higher ²³⁴U/²³⁸U activity ratio. The values of the ²³⁴U/²³⁸U activity ratio equal 1.27 in sediments and 1.34–1.38 in seawater indicate the influence of fresh waters.