K. Kalliomäki

Lung retention and clearance of shipyard arc welders

SummaryThe amount of welding fume lung contaminants was measured in 42 shipyard arc welders. The subjects were divided into four groups according to the exposure time which varied from 1 to 40 years. A new measuring method, based on magnetic properties of fume iron retained in the lungs, was used to evaluate the amount of lung contaminants. The average alveolar deposition rate seemed to be from 20 to 40 mg per year, typical alveolar retention after 5 years of continuous exposure was 200 mg and the clearance rate ranged from 10 to 20 % per year.The interindividual variation in the amount of lung dust was high, the geometric standard deviation varying between 2 and 3. The results were compared with post mortem studies of coal miners. Retention rate of welding fumes seemed to be lower than that of coal mine dust but the clearance rate was about the same.

Lung-retained contaminants, urinary chromium and nickel among stainless steel welders.

SummaryThe magnetic method of measuring the amount of lung retained contaminants as well as urinary chromium and nickel determinations have been performed among 83 stainless steel (SS) welders who have used matural metal arc (MMA) and tungsten inert gas (TIG) welding techniques. The welders were divided into four groups according to the time percentage used for MMA welding. Only exposure to MMA/SS welding fumes resulted in clearly elevated chromium concentrations in the urine, the correlation coefficient between the values of urinary chromium and MMA/SS percentage being very significant (P < 0.001). Among the smokers the urinary chromium values were increased (P < 0.05) perhaps owing to contaminated cigarettes. In many workplaces the urinary chromium values of several welders exceeded the value of 30 μg/l which is the recommended reference value in Finland. Owing to the solubility properties of nickel compounds in SS welding fumes urinary nickel concentrations were only slightly elevated among MMA/SS welders, and therefore, the urinary nickel determinations do not reflect the level of exposure to nickel compounds. The measured average remanent magnetic field of the chest area correlated well (P < 0.01) with the use of the MMA technique. A very significant correlation (P < 0.001) existed between the average remanent magnetic fields of the chest and the urinary chromium values of MMA/SS welders.

Evaluation of biological monitoring among stainless steel welders

SummaryTen manual metal arc (MMA) high alloy stainless steel (SS) welders were studied during one week and the concentrations of chromium (Cr) and nickel (Ni) were determined in their urine and blood. Stationary and personal air samples were collected from the immediate work environment; they covered the entire work period. Spot urine samples were collected during the follow-up period. Whole blood and plasma samples were taken from the workers before and after one shift, and the retention rate of magnetic dust in the lungs was estimated with magnetopneumography. On the basis of the results, indices of short-term exposure to Cr and Ni were evaluated. Urinary Cr and Ni concentrations (corrected to creatinine) reflect both the body burden caused by long-term and short-term exposure to easily soluble fractions of these metals. The results indicated that the use of Cr and Ni urinary analyses as indices of short-term exposure is not as dependable as previously assumed. The Cr and Ni concentrations in whole blood and plasma did not correlate with the measured exposure, but the daily mean increase in the Cr concentration reflected exposure to total Cr and Cr (VI) very well. The large variation in the Cr concentration of the morning urine (0.01–2.7 μmol/l) and blood (0.05–1.43 μmol/l) indicated large personal variations of body burden among the exposed welders. The retention rate of magnetic dust in the lungs correlated well (P<0.01) with the daily mean increase of Cr in blood. Very good correlations (P<0.001) were found between the retention rate of magnetic dust and the personal air samples of Cr and Cr (VI).

Measurement of lung-retained contaminants in vivo among workers exposed to metal aerosols

In Finland the amount of lung-retained contaminants has been measured among welders, foundry workers, and iron and steel factory workers. About 300 subjects have so far been measured since 1976. The method of measuring is based on the magnetic properties of metal aerosols. At the very beginning the method resembled the one suggested by D. Cohen. The original method was too slow, and data processing was not suitable for clinical or hygienic work. Therefore, the automatic and computerized instrument for measuring lung-retained contaminants was developed in cooperation with Outokumpu Oy. The resolution of the magnetic measurement is better than 0.05 nT corresponding to a sensitivity of 0.5 mg of magnetic contaminants in the lung in the form of magnetite. These figures mean that, in practice, a shipyard welder has enough contamination for measurement after one months exposure. In addition, the present paper reviews the magnetic properties of metal aerosols briefly and summarizes the results of measuring different occupational groups.

Estimation of individual dust exposure by magnetopneumography in stainless steel production

The objectives of the study were to measure the magnetic dust lung burden of workers in stainless steel production by magnetopneumography (MPG) and to investigate the relationship of the results with air-borne concentrations of dust, total and hexavalent chromium as well as urinary excretion of chromium. There were 128 workers from the chromite mine, sintering plant, ferrochrome smelter, stainless steel smelting shop, cold rolling mill and welding shop in the exposed groups and five persons from the office staff in the control group. The remanent magnetic field (RMF) in the lungs was slightly elevated among workers in the ferrochromium and steel smelting shops; the levels were, however, lower than those reported for welders earlier and those observed in the welding/repair shop. Workers in the mine, concentrator and sintering plants and in the cold rolling mill exhibited remanent magnetic fields comparable to the referents. There was a relationship between the RMF and the actual urinary chromium concentration. Miners and concentrator and sintering plant workers showed retarded relaxation rate (ReR) of the remanent magnetic field. However, the RMF of the first two of these groups were low (< 0.1 nT) and this made it difficult to measure the ReR accurately. The duration of exposure correlated weakly but significantly with the relaxation rate, while smoking was not related to it.

Dusts in a steel-making plant

SummaryA magnetic method for measuring the amount of metal contaminants retained in the lungs was applied to workers in an iron- and steelmaking plant.Knowledge of properties of airborne particles is required for the calibration of the measuring method and for the estimation of the biological activities of the particles.In this study chemical composition, morphology of typical particles, and magnetic properties of dusts and fumes from different parts of the plant are presented. The amounts of contaminants retained in the lungs of 27 workers representing typical occupations in the production process were measured. The levels of lung contamination of the iron and steel workers were compared with those of manual metal arc steel welders and with those of foundry workers.In the sintering department, the dust is generated by mechanical handling of raw materials. Iron content of the dust is low, and iron is mainly in the form of magnetite.Blast furnace fumes contain mainly iron in the form of iron oxides condensed from pig iron. According to X-ray diffraction analysis, electron micrographs, and magnetic measurements, fume particles have a hematite/ magnetite shell structure. Similar iron fume particles are generated in the continuous casting process.The main part of the converter dust is glass-like slag where iron is dissolved in form of iron 11 oxides.Concentrations of toxic metals in metal fumes were low, e.g., the highest concentration of lead was 0.2%.The iron concentration of dusts and fumes was 25–59% Fe. Typical saturation magnetic moment was 42Am2/kg varying between 15 and 92 Am2/ kg. The equation between saturation magnetic moment and the iron content for dusts in the iron and steel production process was: Ms = 0.66 × Fe % + 11,r = 0.79.The mean magnetic moments of the dusts and fumes in different parts of the plant were equal so that the same calibration coefficient can be used for all dusts when measuring the amount of contaminants retained in the lungs.The approximate amount of lung-retained contaminants varied from 20–200 mg in blast furnace workers, from 10–40 mg in sintering plant workers, and from 2–20 mg in workers in continuous casting process. The mean remanent magnetic fields were in the same groups 1.4 nT, 0.47 nT, and 0.29 nT, respectively.Comparison between different occupational groups exposed to metal aerosols in different iron-based processes indicated that the level of lung contamination was lowest among iron and steel workers, next highest among foundry workers, and highest among stainless steel manual metal arc welders.

Retention of stainless steel manual metal arc welding fumes in rats

Twenty male Wistar rats were exposed to MMA/SS welding fumes. The exposure situation of the study simulated the features of the actual environment as closely as possible. The lung retention of the elements of interest present in MMA/SS welding fumes as well as their distribution in other organs of the rats were investigated. The rats were intermittently exposed to MMA/SS welding fumes maximally for 10 h, the fume concentration being 43 mg/m 3 . Atomic absorption spectrometry was used for the analyses of Cr and Ni concentrations in the blood, whereas instrumental neutron activation analysis was applied in the multielement analysis of organ samples of the rats. Exogenous lung iron was determined by means of the magnetic measuring technique. The concentrations of Cr, Ni, and exogenous Fe in the lungs and Cr in the blood, kidneys, and spleen increased linearly with increasing exposure time. The retention rates of these elements in the organs examined are also given. According to the lung retention and distrib...

Lung Retained Minerals Correlated with Smoking, Emphysema and Lung Cancer

The human lung is an effective filter for collecting airborne particles. For over 20 years it has been possible to analyze these particles, the main intrest having been focused on fibers. Mineral particles, metal dust and fume particles constitute an important fraction of the air pollutants to which everyone is exposed, but little information is available concerning the burden of such particles in the lungs (Churg and Wiggs 1985, Churg and Wiggs 1987, Paoletti et al. 1987). It is necessary to know the basic pulmonary level of inhaled particles in general population, when estimating lung particle burden from occupational exposure.

A microcomputer-controlled rotating-sample magnetometer

A microcomputer-controlled, automatic rotating-sample magnetometer is constructed for measuring the specific remanent magnetic moment and pulse coercive force of a ferro/ferrimagnetic dust sample. The sensor of the magnetometer consists of an iron-cored coil with an air gap in which the sample rotates inducing a voltage proportional to its magnetic moment. Another coil is used to magnetise or demagnetise the sample using a short pulse. All measurement steps are performed automatically and rapidly under computer control without any need to touch the sample holder. The construction and interface circuits of the magnetometer are described and some test results presented.

On the magnetic properties of some industrial metal aerosols

Abstract The magnetic properties of some dusts and fumes collected from different work environments are studied. The specific magnetic remanent and saturation moments, pulse coercive forces and iron contents of the dusts are given and regression equations for the relation between the results are calculated. Some examples of the remanent magnetization curves of the dust are illustrated. A change in the magnetizing time from 0.4 ms to 1 s was not found to affect the remanent moment of stearin embedded dust. When loaded filters were used as a sample, the specific remanent moment was not found to depend on the amount of dust. The variations of the remanent moments among magnetite samples mixed with viscose media is shown to be much higher than that of samples with stearin.