processes were investigated as part of a study on the biological effect of welding fumes. Welding fume particles from different stainless steel welding processes were compared with fume particles from mild steel welding processes. The contribution of Cr 6+ to the effect of welding fumes has been investigated by testing Cr 6+ (from K2CrO4). The following welding processes were applied: MMA/SS, M M A / M S , M M A / C I , M I G / S S and MIG/MS * The in vitro tests applied were the Ames test, chromosome aberration test, H G P R T test, and cytotoxicity test with bovine alveolar macrophages. The stainless steel welding fume particles induced genotoxic effects in all test systems, with the exception of the H G P R T test. The effects of M M A / S S (containing soluble Cr) were more pronounced than those of M I G / S S (containing Cr mainly as insoluble Cr). The M M A / M S was only slightly positive, the M I G / M S was negative, in the different test systems. M M A / C I was only positive in the SCE test. Cr 6+ was strongly positive in all test systems with the exception of the H G P R T test. It seems that Cr 6+ plays an important role in the genotoxicity and cytotoxicity of welding fumes, a contribution from other substances to the effects cannot be excluded. The results of these investigations indicate that the Ames test, the SCE test, the chromosome aberration test and the test with alveolar macrophages, but not the H G P R T test, are sensitive systems for the in vitro study of welding fumes. (These investigations have been supported by the Commission of the European Communities D G XIX 1A-5 (contract 7248/22/020) and by the Directorate General for Environmental Hygiene of the Dutch Ministry of Housing, Physical Planning and Environment.) * MMA, manual metal arc welding process; MIG, metal inert gas welding process; MS, mild steel (not containing Cr and Ni); SS, stainless steel (containing Cr and Ni); Ci = cast iron (containing Ni).
Trabucchi", University of Milan, and 2 Agusta S.p.A., Safety Department (Italy)
Cytogenetic study of a new resin composite for aerospace use
The evaluation of the potential health risk of a new resin composite (199-45), used in the aerospace industry was carried out by genotoxicity test with human lymphocytes "in vitro". The resin composite was made up of a mixture of tetraglycidyl-methyl-dianiline, epoxy novolac, urea compounds and diaminodiphenylsulfone as catalyst. Blood from 2 male and 2 female donors, nonsmokers, free from pharmacological treatment for at least 6 months, without chromosome fragility and recent viral infections (M.A. Stenchever et al., 1976), was incubated for 4 h with increasing doses of the resin composite for determination of cytotoxicity. A dose of 300 /~g/ml was found to produce approx. 30% toxicity. The lymphocytes of the donors were therefore treated for 4 h at the following doses: 10, 100, 150 and 300/~g/mi (bleomycin was utilized as positive control). The cultures were incubated for 72 h at 37 ° C to obtain chromosome preparations. A chromosome analysis carried out with an image computerized analyzer (IBAS II-ZEISSK O N T R O N ) , of 100 s a m p l e s / d o n o r showed a high number of chromosome aberrations of serious biological significance, such as breaks, chromosome fragments, rings, dicentrics, similar in type and frequency to those obtained with the known mutagen bleomycin. A reduction in the total number of cells was also observed. (This work was carried out within the oriented project "Medicina Preventiva e Riabilitativa", SP5 "Rischio Tossicologico" of the National Research Council.)
Rizzi, R. 1, E. Piatti 1, E. Chiesara 1, G.L. Marasi 2 and G. Zanon 2, 1 Dept. of Pharmacology, Chemotherapy and Medical Toxicology "E.
Mtiller, L., S. Madle and R. Bass, Federal Health Office, Institute for Drugs, Seestr. 10, D-1000 Berlin 65 (F.R.G.)