Analytical laboratory comparison of major and minor constituents in an active crater lake

The crater lake water from Mary Semiachik volcano in Kamchatka was used for the international analytical laboratory comparison of major and minor elem ents, and hydrogen, sulfur, and oxygen isotope data. Eight institutions par ticipated in this program, giving analytical results of 9 major and 20 mino r elements mainly by using ICP-AES for cations and IC for anions. Among the major elements, Na, Mg and Si showed coefficients of variation (CV) of 10% or more, whereas B, Al, Fe, Mn had coefficients less than 7%. The CV% of t he minor elements Co, Cu, P, Cr, Pb was much greater (>30%) while the V ana lyses agreed well (<10%). Ti, Sr, Zn, and F were intermediate (between 10 a nd 20 CV%). The errors observed for these constituents are inherent to the methods applied: large dilutions and spectrometric interferences. Even the major anions such as Cl (>2000 ppm) and SO4 (>5000 ppm) gave considerable r anges (5.1 and 8.8 CV%, respectively) as did the obtained pH values (22 CV% ). The measured delta(18)O of the water samples and delta(34)S of sulfate a re in excellent agreement but the SD values had CV% of 8. Technical recomme ndations are presented to improve the analytical results for these elements with significant deviations from the mean values. (C) 2000 Elsevier Scienc e B.V. All rights reserved.