Abstract: Preconcentration of transition trace ions by coprecipitation on iron-hydroxide has been combined with energy-dispersive X-ray fluorescence for environmental water analysis. The optimized preconcentration procedure implies adding 2 mg of iron to a 200 ml water sample, adding dilute NaOH up to pH 9, filtering off on a Nuclepore membrane after a 1 h equilibration time, and analyzing. Quantitative recoveries could then be obtained for Ni, Cu, Zn and Pb, e.g. at the 10 μg/l level in waters of varying salinity while Mn was partially collected. (In fact, for a given problem the iron carrier amount can be adjusted to obtain a satisfactory compromise between high recovery and low detection limit). The precision is 7-8% at the 10 μg/l level, and the detection limits are in the 0.5-1 μg/l range. Various environmental water samples are analysed by way of illustration.

Abstract: Few data are available on the inorganic atmospheric pollution in the rapidly expanding cities of South America, like Recife, on the Atlantic Coast of North-east Brazil. Therefore, the elemental composition of atmospheric aerosols was investigated for nine sites in the Recife conurbation and a fairly remote site in the area. Total aerosol samples were collected on cellulose filters for analysis by energy dispersive X-ray fluorescence and cascade impactors were used to collect the aerosols as a function of particle size for subsequent analysis by proton-induced X-ray emission. Local soil aliquots were also analysed. About eighteen elements were quantified in all cases. The average total atmospheric concentrations appeared to be well above natural levels but usually lower than, or comparable with, those of North American and European cities. Dispersal of sea spray and of local soil (often contaminated with, for example, Cu, Zn and Pb from industrial sources) contributes predominantly to the total atmospheric load in Recife. However, the particle size fraction results also indicated strong excesses in the small particle mode for S, K, V, Mn, Ni, Cu, Zn, Br and Pb, mainly in the downtown area. Again, the corresponding enrichment factors were only moderate in comparison with other published urban data.

Abstract: Two common procedures for wet destruction of biological materials for subsequent determination of selenium have been investigated. Rat organs and biological fluids were endogenously labelled with 75Se to monitor losses during the procedures. Addition of nitric and perchloric acids with gradual heating up to 210° seemed to be the best method: at this temperature the labelled selenium was still recovered quantitatively, and the destruction was fast and efficient.

Abstract: This article reviews the different methods used for the determination of selenium species in all types of environmental waters. Basic difficulties are discussed and the efficiency of the methods is explained in view of the sub-μg/1. concentration levels. Special attention is paid to preconcentration steps. Published data on speciation and concentration levels in various water samples are critically reviewed.