The standards consisted of two marine sediments, one of which is heavily contaminated by As, Cu, Pb and Zn, and three different splits of an overbank sediment sample with low to moderate concentrations of the elements of interest for this study.
The highest recorded concentrations for these elements were in soils influenced directly by tailing ponds.
Atomic concentrations for the detected elements are given in atomic percent, abbreviated by at%.
These ferromanganese concentrates were analysed by ICP-MS following acid digestion in accordance with the analytical procedure reported previously.[9] Based on the results thus obtained, six concentrate samples were selected, providing the widest possible concentration ranges for the elements studied.
Decreasing concentrations are observed for the elements Fe, Ca, P, Li, Cr, Co, Cs, Cu, U, Sb, and Mo.
A much larger range of concentrations was found for the elements, spanning almost 5 orders of magnitude, from < 0.003 ng/m for beryllium to 18 ng/m for nickel.
This accounts for the mean concentration of the element (0.02 mg/L) slightly higher than WHO recommended drinking water level (0.01 mg/L).
Analysis of variance of the measured elemental concentrations showed differences in the mean concentrations for several elements at the sampling sites.
For the samples collected in Piracicaba city, one sample presented highest concentrations for the majority of the elements when compared to the other four samples collected at the same place, exceeding the toxicity limits for: Cr, Ni, Cu, and Pb.
