Body burden of aluminum in relation to central nervous system function among metal inert-gas welders

Abstract

ObjectivesThe relationship between elevated internal aluminum loads and central nervous system function was studied among aluminum welders, and the threshold level for adverse effect was defined.Methods For 65 aluminum welders and 25 current mild steel welders body burden was estimated, and the aluminum concentrations in serum (S-Al) and urine (U-A1) were analyzed with graphite furnace atomic absorption spectrometry with Zeeman background correction. Referents and low-exposure and high-exposure groups were defined according to an aggregated measure of aluminum body burden, the group median S-A1 levels being 0.08, 0.14, and 0.46 pmolll, respectively, and the corresponding values for U-A1 being 0.4, 1.8, and 7.1 pmolll. Central nervous system functions were assessed with a neuropsychological test battery, symptom and mood questionnaires, a visual and quantitative analysis of electroencephalography (EEG), and P3 event-related potentials with pitch and duration paradigms.Results Subjective symptoms showed exposure-related increases in fatigue, mild depression, and memory and concentration problems. Neuropsychological testing revealed a circumscribed effect of aluminum, mainly in tasks demanding complex attention and the processing of information in the working memory system and in the analysis and recall of abstract visual patterns. The visual EEG analysis revealed pathological findings only for aluminum welders. Mild, diffuse abnormalities were found in 17% of the low-exposure group and 27% of the high-exposure group, and mild to moderate epileptiform abnormalities at a frequency of 7% and 17%, respectively. C O~C~U S~O~S Both objective neurophysiological and neuropsychological measures and subjective symptomatology indicated mild but unequivocal findings dose-dependently associated with increased aluminum body burden. The study indicates that the body burden threshold for adverse effect approximates an U-A1 value of 4-6 pmol/l and an S-A1 value of 0.25-0.35 kmol/l among aluminum welders.

Behavior of aluminum in aluminum welders and manufacturers of aluminum sulfate—impact on biological monitoring

“…This study and many previous ones (2)(3)(4)(5)11,13,14) show that exposure to aluminum welding fumes can be Riihimäki et al of concern because the intake can lead to significant rapid systemic absorption of aluminum and, in the long term, to the development of a remarkable lung burden, as well as to an abnormally large body burden in the skeleton. The concern also applies to other processes involving the generation of vapor condensation fumes of aluminum (arc spraying, plasma cutting), as well as to the manufacture of finely divided aluminum powder (3,(15)(16)(17).…”

“…In a group of long-term aluminum welders, both the serum and urinary aluminum concentrations correlated directly with the duration of exposure; this finding demonstrates the development of the lung burden (11). Lung burden is a reservoir for systemic aluminum uptake for many years postexposure, and slow mobilization of the lung burden is presumably rate limiting for the urinary excretion of aluminum in the later postexposure phase.…”

“…In a previous study on 84 long-term welders of aluminum or mild steel, the serum and urinary aluminum concentrations were correlated in that, at a urinary aluminum concentration of 0.6 µmol/l, the ratio of urinary aluminum to serum aluminum was 6, while the corresponding ratios at urinary aluminum concentrations of 3 µmol/l and 10 mol/l, the corresponding ratios were 14 and 25 (11). Thus it appears that the clearance of aluminum in serum is concentration dependent.…”

Cognitive and Neurophysiological Outcome of Cardiac Arrest Survivors Treated With Therapeutic Hypothermia

“…The number of variables was reduced by calculating regional means from the original variables: frontal region (Fp1, Fp2, Fpz, F3, F4, Fz), temporal region (T3, T4, T5, T6), centroparietal region (C3, C4, Cz, P3, P4, Pz), and occipital region (O1, O2, Oz) by a method previously described. 22 After these calculations there were 36 EEG variables (16 for the absolute power, 16 for the relative power, and 4 for mean frequencies).…”

“…Latencies and amplitudes were measured afterward using a method previously described. 22 The neurophysiologist analyzing the Q-EEGs and P300 potentials was unaware of the treatment assignment.…”