A new technique for generating heavy metal fumes with high melting point.
There are many kinds of fumes containing heavy metals in the working area. They sometimes have bad effects on the living body. It is important to determine their particle size distribution for considering the effects of those metals on health, together with measuring their amounts. For this purpose, it is neces-sary to generate fumes which are suitable to use. However, effective methods for generating fumes of heavy metals with high melting points have not been developed.In this study we attempted to determine whether the plasma flame metal sprayer can be used as a fume generator. The size distribution, particle form and amounts of the generated fumes were determined for the iron fume which were generated with this instrument under the various conditions. The fume was to consist of coagulated fine particles and dispersed globular particles. Our attempt extended to the generation of fumes consisting not only of one kind of metal but also of two kinds of metal. It was also found that fumes having the required radio might be generated by controlling the ratio of the metals in the powder mixture.We conclude that this instrument might be suitable for generating fumes of heavy metals in the laboratory.
Determination of chromium speciation in fumes prepared by a plasma metal sprayer as a model of actual welding fumes.
Chromium in fumes generated in work environments including sites of welding work appears in various and complex states. Determination of chromium speciation in samples is useful for estimating the toxicity of such fumes. In the present study, determination of chromium speciation in chromium fumes prepared using a plasma metal sprayer, which are regarded as a model of actual fumes, was carried out. Fumes were treated with heated sodium carbonate solution, ammonium chloride-ammonia buffer solution at pH 9.5, Tris-HCl buffer solution at pH 7.5, hydrochloric acid, heated dilute sulfuric acid, distilled water, and a boiling mixture of sulfuric acid and perchloric acid in various series of the tests. The amounts of chromium (III) and chromium (VI) dissolved in each solution were determined, and the dissolution rates in those solutions were examined. The fumes were concluded to contain dichromium trioxide with a corundum structure (25%), chromium (III) oxide (45%) and chromium (VI) oxide (27%) mixed at random in a nonstoichiometric state, and chromium trioxide (3%). The procedure presented could be applied to the determination of chromium speciation in various types of fumes with a few modifications. In addition, the sodium carbonate leaching method has been demon-strated to be available for the determination of chromium (VI) in such samples.
Volatile hydrocarbons in the atmosphere of the Kiel Bight (Western Baltic)
Abstract Volatile hydrocarbons (VHCs) in the Kiel Bight atmosphere were collected by adsorption on silanized porous glass (PG). This material proved to have a good capacity to concentrate VHCs, and it is easy to clean and to maintain free of contaminants. VHC concentrations in the atmosphere of the Bight vary strongly, depending on the wind direction and the amount of precipitation. Southerly, southwesterly and westerly winds are responsible for the transportation of VHCs from the land to the Kiel Bight.