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Objective-To conduct a field study to obtain information on the urinary concentrations of aluminium (Al) and fluoride (F-) depending on the different compounds exposed to in the aluminium industry. Methods-16 workers from one plant that produced aluminium fluoride (AIF,), and from two plants that produced alnium electrolytically by two different processes participated in the study for one working week. Pollutants were monitored by eight hour personal sampling every day, and urine samples were collected during the week. Al and F-were analysed in both atmospheric and urine samples by atomic absorption spectrometry and an ion selective electrode. Results-The principal results show different characteristics of kinetic curves of Al and F-excretion in workers with different exposures. Some characteristics of excretory peaks were linked to specific exposures-for instance, after exposure to AlF3 there was one delayed Al peak associated with one delayed F-peak about eight hours after the end of the daily shift, and after mixed exposure to HF and AIF3, two F-peaks were noted, one fast peak at the end of the shift and another delayed peak at 10 hours synchronised with an Al peak. In one of the electrolysis plants, the exposure to Al and F-compounds led to the simultaneous excretion of Al and Fpeaks, either as a single peak or two individual ones depending on the type of technology used on site (open or enclosed potlines). The average estimated half life of Al was 7 5 hours, and of F-about nine hours. Quantitative relations between excretion and exposure showed an association between the F-atmospheric limit value of 2-5 mg/m3 with a urinary F-concentration of 6-4 mg/g creatinine at the end of the shift, a peak of 7*4 mglg creatinine, and 7-4 mg excreted a day. For Al, the exposure to 136 mglm' during the shift Conclusion-Particular differences in the behaviour of Al and F-in urine depended upon the original molecular form in the pollutant. These results reinforce the principle that, in biological monitoring, the sampling strategy and the choice of limit value should be dependent on kinetic data that take the exposure compound of the element in question into account.(Occup Environ Med 1995;52:396-403)

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An epidemiological, cross-sectional study was conducted in order to assess non-neoplasic effects on the lung due to chronic exposure to arc welding fumes and gases. The study involved 346 arc welders and 214 control workers from a factory producing industrial vehicles. These workers (welders and controls) had never been exposed to asbestos. Respiratory impairments were evaluated by using a standardized questionnaire, a clinical examination, chest radiophotography and several lung function tests (spirometry, bronchial challenge test to acetylcholine, CO transfer tests according to the breath-holding and the steady-state methods, N2 washout test). The only significant differences between the welders overall compared to the controls were a slightly higher bronchial hyper-reactivity to acetylcholine and a lower lung diffusing capacity for CO in the welders. However, non-specific, radiologic abnormalities (reticulation, micronodulation) and obstructive signs were more frequent in the most exposed welders (welding inside tanks) than in welders working in well ventilated workplaces. The nature of the metal welded (mild-steel, stainless steel, aluminium) did not seem to have an influence on respiratory impairments. In the mild-steel welders, respiratory symptoms (dyspnoea, recurrent bronchitis) and obstructive signs were more frequent in the welders using a manual process than in the welders involved with the semi-automatic process (MIG). For all the workers (welders and controls), smoking had a markedly adverse effect on respiratory symptoms and lung function. Moreover, smoking seemed to interact with welding since CO lung transfer was more impaired in smoking welders than in smoking controls.

Air and biological monitoring were used for assessing external and internal chromium exposure among 116 stainless steel welders (SS welders) using manual metal arc (MMA), metal inert gas (MIG) and tungsten inert gas (TIG) welding processes (MMA: n = 57; MIG: n = 37; TIG: n = 22) and 30 mild steel welders (MS welders) using MMA and MIG welding processes (MMA: n = 14; MIG: n = 16). The levels of atmospheric total chromium were evaluated after personal air monitoring. The mean values for the different groups of SS welders were 201 micrograms/m3 (MMA) and 185 micrograms/m3 (MIG), 52 micrograms/m3 (TIG) and for MS welders 8.1 micrograms/m3 (MMA) and 7.3 micrograms/m3 (MIG). The curve of cumulative frequency distribution from biological monitoring among SS welders showed chromium geometric mean concentrations in whole blood of 3.6 micrograms/l (95th percentile = 19.9), in plasma of 3.3 micrograms/l (95th percentile = 21.0) and in urine samples of 6.2 micrograms/l (95th percentile = 58.0). Among MS welders, mean values in whole blood and plasma were rather more scattered (1.8 micrograms/l, 95th percentile = 9.3 and 1.3 micrograms/l, 95th percentile = 8.4, respectively) and in urine the value was 2.4 micrograms/l (95th percentile = 13.3). The analysis of variance of chromium concentrations in plasma previously showed a metal effect (F = 29.7, P < 0.001), a process effect (F = 22.2, P < 0.0001) but no metal-process interaction (F = 1.3, P = 0.25). Concerning urinary chromium concentration, the analysis of variance also showed a metal effect (F = 30, P < 0.0001), a process effect (F = 72, P < 0.0001) as well as a metal-process interaction (F = 13.2, P = 0.0004). Throughout the study we noted any significant differences between smokers and non-smokers among welders. Taking in account the relationships between chromium concentrations in whole, plasma or urine and the different welding process. MMA-SS is definitely different from other processes because the biological values are clearly higher. These higher levels are due to the very significant concentrations of total soluble chromium, mainly hexavalent chromium, in welding fumes.