Assessment of thyroid,testes, kidney and autonomic nervous system function in lead-exposed workers

Summary The objective of the study was to assess whether moderate occupational exposure to lead may be associated with early changes in potential target organs (thyroid, testes, kidney, autonomic nervous system). Workers exposed to lead in a lead acid battery factory (n = 98; mean blood lead 51 g/dl, range 40–75 g/dl) and 85 control workers were examined. None of the indicators of kidney function (in urine: retinol-binding protein, ₂-microglobulin, albumin,N-acetyl--d-glucosaminidase; in serum: creatinine, ₂-microglobulin), endocrine function (follicle-stimulating hormone, luteinizing hormone, thyroid-stimulating hormone, thyroxine, triiodothyronine) and autonomic nervous system (R-R interval variations on the electrocardiogram) were correlated with lead exposure (blood lead or duration of exposure) or showed significantly different mean values between the exposed group and controls. These results and an assessment of the published data suggest that compliance with the Directive of the Council of the European Communities on lead exposure (health surveillance in workers whose lead in blood exceeds 40 g/dl and removal from exposure when blood lead exceeds 70–80 g/dl) would prevent the occurrence of significant biological changes in the majority of lead-exposed workers.     

Search for anti-laminin antibodies in the serum of workers exposed to cadmium,mercury vapour or lead

Summary Anti-laminin antibodies were sought for in the serum of workers exposed to mercury vapour (Hg, n = 58), lead (Pb, n = 38) or cadmium (Cd, n = 47). Thirty-one workers removed from Cd exposure for an average of eight years were also examined. Compared with control workers matched for age and socio-economic status, the prevalence of circulating anti-laminin antibodies was not increased in workers exposed to Hg (mean duration of exposure: 7.9 years and mean urinary excretion of Hg: 72 g/g creatinine) nor in those exposed to Pb (mean duration of exposure: 10.6 years and mean Pb levels in blood: 535 g/l). In contrast, anti-laminin antibodies were significantly more prevalent in Cd-exposed workers whose urinary Cd exceeded 20 g/g creatinine. This observation was made in both currently exposed workers and in workers removed from Cd exposure (mean duration of exposure: 9.4 and 24.6 years and mean urinary Cd: 7.8 and 13.4 g/g creatinine respectively). These autoantibodies were found in Cd workers with normal renal function as well as in those with increased proteinuria.     

Enzymuria in workers exposed to inorganic mercury

Summary Urinary excretion of beta-hexosaminidase (NAG = N-acetyl-beta-glucosaminidase) and albumin was examined in 41 chlor-alkali workers exposed to inorganic mercury and 41 age-matched controls. Either U-HG or B-Hg levels for these workers were available dating from the 1960s to the present. Increased U-NAG was seen in workers with a U-Hg today of more than 4g/mmol creat (about 50g/l; 35 g/g creat). Multiple linear regression analysis showed that U-NAG was correlated to U-Hg and integrated dose but not to the present B-Hg level. No albuminuria (detection limit 12.5 mg/1) was found in any of the subjects. In a longitudinal study, no decrease in UNAG levels was seen in 15 chlor-alkali workers after their vacation (x = 20 d). In five workers followed for ten months after a short exposure period, no definite time trend could be seen. The results show that there is a slight effect on renal tubules even at rather low levels of exposure to mercury vapour. The clinical significance of the enzymuria levels found here is, however, debatable.     

Organic and Inorganic Mercury in Neonatal Rat Brain after Prenatal Exposure to Methylmercury and Mercury Vapor

Background

Many populations are exposed to multiple species of mercury (Hg), predominantly organic Hg as methylmercury (MeHg) from fish, and inorganic Hg as Hg vapor from dental amalgams. Most of our knowledge of the neurotoxicity of Hg is based on research devoted to studying only one form at a time, mostly MeHg.

Objectives

In this study we investigated the effects of prenatal exposure to MeHg and Hg vapor on Hg concentrations in the brain of neonatal rats.

Methods

Female Long-Evans hooded rats were exposed to MeHg (0, 3, 6, or 9 ppm as drinking solution), Hg vapor (0, 300, or 1,000 μg/m³ for 2 hr/day), or the combination of both, from 30 days before breeding through gestational day 18. On postnatal day 4, whole brains were taken from one male and one female from each of four litters in each treatment group to assess organic and inorganic Hg in the brain by cold vapor atomic absorption spectrometry.

Results

Statistical analysis using linear mixed effects models showed that MeHg dose was the primary determinant of both organic and inorganic brain Hg levels. For both outcomes, we also found significant interactions between MeHg and Hg vapor exposure. These interactions were driven by the fact that among animals not exposed to MeHg, animals exposed to Hg vapor had significantly greater organic and inorganic brain Hg levels than did unexposed animals.

Conclusion

This interaction, heretofore not reported, suggests that coexposure to MeHg and Hg vapor at levels relevant to human exposure might elevate neurotoxic risks.     

The organic solvent syndrome

Summary A study was conducted to investigate the existence of a specific neurotoxic effect due to long-term exposure to organic solvents. A comparison was made regarding diagnoses, symptoms and other relevant medical data between persons receiving a disability pension on the basis of a neuropsychiatric disorder selected from an exposed (painters) and non-exposed (construction workers) trade organization. Information was collected from their medical files at the occupational health department. Concerning diagnoses and symptoms, no significant differences were found between exposed and non-exposed patients. No indications were found for the existence of a typical complex of symptoms associated with exposure to organic solvents among painters in The Netherlands. The number of reported symptoms was not related to the duration of exposure, thus lending no support for a dose-effect relationship. If a neurotoxic effect does exist among Dutch painters, it is of a non-specific type and not clearly distinguishable from other mental disorders.     

Cumulative biochemical effects of repeated subclinical hydrogen sulfide intoxication in mouse brain

Summary Adult female NMRI mice exposed four times to 100 ppm hydrogen sulfide vapour for 2 h at 4-day intervals showed increasing inhibition of the cerebral cytochrome oxidase activity. Cerebral RNA decreased significantly after the fourth exposure. This change was accompanied by the reduced orotic acid uptake in the RNA fraction. At the same time, 2,3-cyclic nucleotide 3-phosphohydrolase activity used as a marker for glia increased. Acetylcholine esterase activity remained unchanged. The initial exposures also caused an increase in the superoxide dismutase activity and an increase in the glutathione concentration. The latter effects were abolished in the third and fourth exposures. The present data seem to indicate that the biochemical effects of repeated subclinical hydrogen sulfide intoxications are cumulative.     

Comparison of renal function and psychomotor performance in workers exposed to elemental mercury

Summary Renal function and psychomotor performance (eye-hand coordination, arm-hand steadiness) of a group of 43 workers exposed to mercury vapor were examined. Their mean age and average duration of exposure to mercury were 38 and 5 years, respectively. The results were compared with those obtained in a matched group of 47 control workers. Increased proteinuria and albuminuria were found slightly more prevalent in the Hg-exposed group than in the control workers. These results are in agreement with those found during a previous study carried out in another group of workers also exposed to elemental mercury (Bucket et al. 1980). The scores of the psychomotor tests were less satisfactory in the Hg workers than in the control workers, the arm-hand steadiness test being more discriminative than the eye-hand coordination test. Preclinical changes in psychomotor function can be detected independently of the presence of signs of renal dysfunction. No clear-cut relationships were found between the prevalence of abnormal psychomotor scores and the level of mercury in blood (HgB) or in urine (HgU). Increased prevalences of abnormal psychomotor scores seem however to occur for HgB between 1 and 2 g/100 ml and for HgU between 50 and 100 g/g creatinine. Therefore, a biologic threshold limit value of 50 g/g creatinine is proposed for urinary mercury to prevent the development of preclinical effects on the central nervous system. A similar critical HgU level based on renal dysfunction prevalences has been suggested in a previous study.This study was supported by a grant from the Commission of the European Communities     

Behavioral effects of waterborne carbofuran in goldfish

The effects of concentration (1, 10, 100 g/L) and duration (4, 8, 12 h) of exposure to carbofuran were assessed on the swimming activity, social interactions, and behavioral responses of goldfish to a flow (0.1 L/min) of water, with or without chironomids. Observations were also made on the behavioral responses of unexposed goldfish to a flow (0.1 L/min) of carbofuran-contaminated water. A 4-h exposure of goldfish 1 g/L carbofuran produced a significant increase in sheltering, burst swimming, and nipping. Responses were enhanced at 100 g/L. After a 12-h exposure, the behavioral effects of 1 g/L carbofuran were less apparent. However, burst swimming at 10 g/L, and sheltering, nipping and burst swimming at 100 g/L, were still significantly increased after a 12-h exposure to carbofuran. Grouping was not consistently affected by exposure conditions. Chemical attraction to a filtrate of chironomids was significantly reduced after the 4-h exposure to 1 g/L carbofuran. Decreased attraction to the food extract was less apparent after the 12-h exposure, except at 100 g/L carbofuran. A significant decrease in attraction to a flow of uncontaminated water was also observed after a 4-h exposure to 10 and 100 g/L carbofuran. Unexposed goldfish did not show avoidance reaction to a flow of carbofuran-contaminated water, even at a concentration (10 mg/L) exceeding the mean 96-h LC-50 in cyprinids (0.5–1 mg/L). However, at all concentrations tested (0.1, 1, 10 mg/L), goldfish quickly reacted to the introduction of the solution of carbofuran by increased burst swimming and nipping. These results are discussed in the light of the data concerning behavioral and neurotoxic effects of carbamate and organophosphorous insecticides in fish.     

Biological assessment of exposure in factories with second degree usage of cadmium compounds

Summary Biological assessment of occupational exposure to cadmium in five different factories with low-level second degree usage of Cd-compounds has been carried out. In 124 exposed and control male workers the following measurements were performed: cadmium in blood (CdB) and urine (CdU), B₂-microglobulin (B2M), creatinin in urine (Great), hemoglobin (Hb) and hematocrit (Ht). Analysis of 34 pairs of workers matched according to age, smoking habits, ethnic origin and factory, established a significant difference only in CdU, the geometric means being 0.67 g/g Creat in the exposed group and 0.48 g/g Creat in the control group. Significant correlation was found between CdU x age and CdB x smoking habits. Multiple regression analysis showed that for each year increase in age CdU increased 3%, for each percent increase of CdB CdU increased 0.28%; for each cigarette smoked per day CdB increased 1.6%. It is concluded that in this type of work the low external cadmium exposure does not express itself in different CdB-levels, but only in different CdU-levels, indicating an increased body burden due to long term low level occupational cadmium exposure. In biological assessment of exposure to Cd, it is essential to take age and smoking habits fully into account.This study was supported by a grant from the Dutch Prevention Fund and the Ministry of Health and Environmental Protection     

Differences in heart rate variability associated with long-term exposure to NO2

Background

Heart rate variability (HRV), a measure of cardiac autonomic tone, has been associated with cardiovascular morbidity and mortality. Short-term studies have shown that subjects exposed to higher traffic-associated air pollutant levels have lower HRV.

Objective

Our objective was to investigate the effect of long-term exposure to nitrogen dioxide on HRV in the Swiss cohort Study on Air Pollution and Lung Diseases in Adults (SAPALDIA).

Methods

We recorded 24-hr electrocardiograms in randomly selected SAPALDIA participants ≥ 50 years of age. Other examinations included an interview investigating health status and measurements of blood pressure, body height, and weight. Annual exposure to NO₂ at the address of residence was predicted by hybrid models (i.e., a combination of dispersion predictions, land-use, and meteorologic parameters). We estimated the association between NO₂ and HRV in multivariable linear regression models. Complete data for analyses were available for 1,408 subjects.

Results

For women, but not for men, each 10-μg/m³ increment in 1-year averaged NO₂ level was associated with a decrement of 3% (95% CI, −4 to −1) for the standard deviation of all normal-to-normal RR intervals (SDNN), −6% (95% CI, −11 to −1) for nighttime low frequency (LF), and −5% (95% CI, −9 to 0) for nighttime LF/high-frequency (HF) ratio. We saw no significant effect for 24-hr total power (TP), HF, LF, or LF/HF or for nighttime SDNN, TP, or HF. In subjects with self-reported cardiovascular problems, SDNN decreased by 4% (95% CI, −8 to −1) per 10-μg/m³ increase in NO₂.

Conclusions

There is some evidence that long-term exposure to NO₂ is associated with cardiac autonomic dysfunction in elderly women and in subjects with cardiovascular disease.     

1H and13C NMR analysis of some trichothecenes

¹H and¹³C NMR chemical shifts were determined from the NMR spectra of low concentration solutions of T-2 toxin, T-2 triol, HT-2 toxin, diacetoxyscirpenol, and neosolaniol. Isomerization of neosolaniol was observed to occur in chloroform solution. 1D and 2D¹H and¹³C NMR techniques were used in order to determine the structure of the isomerization product, finally identified as 4,8-diacetoxy-3, 15-dihydroxy-12,13-epoxytrichothec-9-ene.     

Urinary 1-naphthol and 1-pyrenol as indicators of exposure to coal tar products

Chemical exposure of assemblers handling creosote-impregnated wood and of a single worker chiselling coal tar pitch layer was assessed by measuring airborne naphthalene and various polycyclic aromatic hydrocarbons (PAHs), and by measurement of urinary excretion of 1-naphthol and 1-pyrenol. The sum concentration of PAHs and of 4–6 aromatic ring-containing PAHs were high, 440 g/m³ and 290 g/m³, respectively, when chiselling. In the assembler's workplace, the PAH concentrations were about 1/50 of this value. Regarding airborne naphthalene concentrations the situation was reversed (assemblers, 1000 g/m³; chiseller, 160 g/m³). Correspondingly, the assemblers' urinary 1-napthol concentrations were 15–20 times higher than those of the chiseller. The urinary 1-pyrenol concentration of the chiseller was 2–4 times higher than among the assemblers. As the estimated pyrene inhalation doses among the assemblers could account for only about 2%–25% of the 24-h pyrenol excretion in urine, the skin was presumably the main route of uptake. For an assessment of the exposure to PAHs, air measurements, monitoring of metabolites in urine and preferably also data on the composition of the skin-contaminating product are needed.     

Individual and work-related risk factors associated with symptoms of musculoskeletal complaints

Summary Individual and work-related risk factors in the development of occupational musculoskeletal complaints were investigated in a cross-sectional study of 52 female production workers and 34 female office workers. The work tasks of the production workers were considered to generate shoulder muscle loads of low amplitude and high repetitiveness, and the work tasks of the office workers, muscle loads of low amplitude and low repetitiveness. The symptom scores were similar in the two groups, with the highest score for both groups in the shoulder-neck region. Previous pain symptoms were an important risk factor for musculoskeletal pain in all body regions, whereas psychosocial problems at work were a risk factor for complaints in the shoulder-neck region. For the office workers, 27% of the variance in shoulder-neck symptoms was explained by the variance in the parameters previous pain symptoms and psychosocial problems in a multilinear regression model. In three groups of workers with different physical loads on the shoulder muscles the symptom scores for workers without previous pain symptoms and psychosocial problems were related to the physical load. For workers with previous pain symptoms and psychosocial problems, the symptom scores were high and similar for all three groups.     

Elemental mercury in urine from workers exposed to mercury vapor

Summary Elemental mercury (Hg°) in urine samples from workers in thermometer manufacturing factories was determined. In a factory in which the mercury level in the ambient air averaged more than 0.1 mg Hg m^–3, the Hg° concentration in the workers' urine ranged between 0.05 and 1.7 g Hg 1^–1 and constituted less than 1% of the inorganic mercury (In-Hg) in urine. Higher amounts of Hg° could be detected in urine on the day of the filling operation when thermometer blanks were filled with metallic mercury and on the following day when compared with other days. During this operation, the workers were exposed to mercury vapor levels with as much as 0.47–0.67 mg Hg m^–3. Our findings suggest that Hg° appears in urine quite rapidly after the worker's exposure to unusually high mercury levels.     

Particulate Air Pollution,Metabolic Syndrome,and Heart Rate Variability: The Multi-Ethnic Study of Atherosclerosis (MESA)

Background

Cardiac autonomic dysfunction has been suggested as a possible biologic pathway for the association between fine particulate matter ≤ 2.5 μm in diameter (PM_2.5) and cardiovascular disease (CVD). We examined the associations of PM_2.5 with heart rate variability, a marker of autonomic function, and whether metabolic syndrome (MetS) modified these associations.

Methods

We used data from the Multi-Ethnic Study of Atherosclerosis to measure the standard deviation of normal-to-normal intervals (SDNN) and the root mean square of successive differences (rMSSD) of 5,465 participants 45–84 years old who were free of CVD at the baseline examination (2000–2002). Data from the U.S. regulatory monitor network were used to estimate ambient PM_2.5 concentrations at the participants’ residences. MetS was defined as having three or more of the following criteria: abdominal obesity, hypertriglyceridemia, low high-density lipoprotein cholesterol, high blood pressure, and high fasting glucose.

Results

After controlling for confounders, we found that an interquartile range (IQR) increase in 2-day average PM_2.5 (10.2 μg/m³) was associated with a 2.1% decrease in rMSSD [95% confidence interval (CI), −4.2 to 0.0] and nonsignificantly associated with a 1.8% decrease in SDNN (95% CI, −3.7 to 0.1). Associations were stronger among individuals with MetS than among those without MetS: an IQR elevation in 2-day PM_2.5 was associated with a 6.2% decrease in rMSSD (95% CI, −9.4 to −2.9) among participants with MetS, whereas almost no change was found among participants without MetS (p-interaction = 0.005). Similar effect modification was observed in SDNN (p-interaction = 0.011).

Conclusion

These findings suggest that autonomic dysfunction may be a mechanism through which PM exposure affects cardiovascular risk, especially among persons with MetS.     

Human exposure to styrene

Summary In order to estimate the importance of skin resorption of styrene, as compared to pulmonary absorption, nine male volunteers were exposed for 10 to 30 min by dipping one hand in liquid styrene. Urine and breath were sampled periodically for metabolites (mandelic and phenylglyoxylic acids) and styrene analyses respectively. The results obtained show that the rate of absorption of styrene through the skin is very low, averaging 1 ± 0.5 g/cm² · min. This rate seems to be affected by the duration of exposure. In conclusion, this study shows that skin resorption plays only a minor role in most practical situations.     

Occupational exposure to cadmium and kidney dysfunction

Summary Investigations were carried out in an alkaline battery factory. The study group consisted of 102 persons and the control group of 85 persons. Cadmium in blood (Cd-B) and cadmium in urine (Cd-U), as well as ₂-microglobulin (B₂-M), retinol binding protein (RBP), amino acids in urine were determined. Exposure to cadmium was high; Cd-B and Cd-U concentrations were higher than recommended, 10 gmg/l and 10 gmg/g creat. in 65% and 56% of workers, respectively. Excretion of B₂-M and RBP in urine was higher than the accepted upper limits of 380 and 130 I g/g creat. in about 20% of the workers. A significant correlation was observed between: log Cd-U log Cd-B (r = 0.85), log B₂-M log RBP (r = 0.66), log Cd-U · log B₂- M (r = 0.52), and log Cd-U · log RBP (r = 0.55). To evaluate the admissible period of occupational exposure to cadmium, an integrated exposure index (Cd-B × years of exposure) is proposed. According to the dose-response relationship, an increase of low molecular protein excretion in urine can be expected in 10% of the cases at Cd-U amounting to 10 to 15 g/g creat. and Cd-B × years of about 300 to 400.     

Beitrag zur Problematik der Elektroschwei\erpneumokoniose

Zusammenfassung In den Jahren 1951–1968 wurden an der Abteilung für Berufskrankheiten bei 40 Elektroschwei\ern koniotische LungenverÄnderungen festgestellt. Es handelte sich um 6 FÄlle der m-, n- und 34 der L- Form nach der Genfer Klassifikation. Bei 2 von diesen FÄllen wurde eine bioptische Lungenuntersuchung angestellt, und einer von diesen Elektroschwei\ern kam nach einer purulenten Peritonitis zur Sektion, so da\ wir die röntgenologischen und histologischen Befunde vergleichen konnten. Die Rekonstruktion der hygienischen VerhÄltnisse zeigte schlechte Arbeitsbedingungen mit einigen Hundert Milligramm Flugstaub im Kubikmeter Luft. Alle in der Kasuistik angeführten Schwei\er arbeiteten vorwiegend mit Rutil- oder basischen Elektroden. Der klinische Befund bei der Hospitalisation wies keine AbnormitÄten aus, au\er einer Atemnot bei Aussteigung und koniotische LungenverÄnderungen im Röntgenbild. Bei der Lungenfunktionsprüfung konnten wir Lungenkompliance-Werte an den unteren Grenzen der Norm finden. Die histologischen Befunde des bioptischen sowie auch des Sektionsmaterials zeigten eindeutig eine interstitielle Herd-Koniose mit Neubildung reticuliner und kollagener Fasern. Diese Feststellungen führten uns zu einer systematischen Studie der Elektroschwei\erarbeit. Wir untersuchten eine Gruppe von 65 Elektroschwei\ern und stellten auch eine hygienische Untersuchung ihrer ArbeitsatmosphÄre an. Weiter haben wir bei 15 Elektroschwei\ern, bei denen wir in den Jahren 1951–1968 koniotische LungenverÄnderungen fanden, eine Lungenfunktionsprüfung durchgeführt. Unsere Befunde bei den Elektroschwei\ern verglichen wir mit einer Kontrollgruppe nichtstaubexponierter Arbeiter und mit 380 Kohlenhauern.Unsere Ergebnisse zeigten, da\ man an sehr exponierten ArbeitsplÄtzen eine Flugstaubkonzentration bis 1364,5 mg/m³ finden kann, wobei Fluoridkonzentration von 0–3 mg/m³ vorkommt. Die Konzentration flüchtiger Noxen sind zwar unter den MAC-Werten, können aber in bezug zur Ätiologie der Bronchitis nicht vernachlÄssigt werden. Von den Lungenfunktionsbefunden sind die niedrigen Werte der dynamischen Lungencompliance mit den röntgenologischen und histologischen Befunden im Einklang. Im Tierexperiment an Wistar-Ratten mit dem Flugstaub der Elektrode E 4211 konnten wir den fibrogenen Charakter dieses Staubes bestÄtigen. Das Vorkommen der chronischen Bronchitis ist bei den Elektroschwei\ern hÄufiger als bei der Kontrollgruppe. Der Anteil der mucopurulenten chronischen Bronchitis ist bei den Elektroschwei\ern höher als bei den Kohlenhauern; das Vorkommen der chronischen obstruktiven Bronchitis ist bei den beiden letztgenannten Gruppen höher als bei der Kontrollgruppe. Im röntgenologischen Bild, sowie auch in den histologischen Befunden ist die Elektroschwei\erkoniose der Pneumokoniose der Kohlenhauer sehr Ähnlich. Schwerformen des Types ABC der Genfer Klassifikation haben wir nicht gefunden. Nach Aufgabe der Elektroschwei\erarbeit haben wir keinen Rückgang der koniotischen Röntgenbefunde gesehen.

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Contribution to the problem of electric-welders pneumoconiosis

Summary Fourty electric-welders' pneumoconiosis were recorded in 1951–1968 in the Department of Occupational Diseases. 6 cases were of the m, n and 34 of the L form of the International X-ray classification of pneumoconioses. The biopsy was performed in two cases and the post mortem examination in one case (an electric-welder who died because of a purulent peritonitis), and the authors were able to compare the X-rays and the histological results of their medical examination. A hygienic evaluation showed a bad state of the working place where high dust rates prevalled. This paper deals with a group of electric-welders who used rutil or basic types electrodes during the welding process. All of them were clinically examined and did not show any abnormalities except dyspnae and X-ray lung changes similar to pneumoconiosis. The examination of lung functioning was showed a low lung compliance. The histological examination of the biopsies and post-mortem material showed an interstitial focal coniosis with production of reticulin and collagen tissue. This finding led the authors to deal systematicaly with the evaluation of the electric-arc welding process. They examined a group of 65 electric-welders and the hygienic conditions of their working place. Furthermore they investigated ventilation in 15 electric-welders who developed pneumoconiotic changes in 1951–1968. A comparison of the examined group with a control group of workers from non-hazard work places and a group of 380 coal miners was performed. By estimating the dust in the atmosphere of working places, the dust rates reached 1364.5 mg/m³ in most hazard places, while the rates of fluorides varied from 0 to 3 mg/m³. The atmosphere was polluted by different toxic substances which did not exceed the MAC, but were considered one of the etiological factors in diseases of respiratory ways.With the help of examinations of lung functioning lungs low values of dynamic lung compliance were revealed which are in line with the histological and X-ray findings. The characteristic of the dust arising from arc-welding process with coated electrode E 4211 were studied in dusted rats lungs, which showed morphological changes similar to those in pneumoconiosis and confirmed the fibrogenic effect of this dust.Statistical tests showed that the syndrom of chronic bronchitis was more frequent in electric-welders than in the control group, that the mucopurulent chronic bronchitis existed in electric-welders at a higher rate than in coal miners, and that the rate of obstructional chronic bronchitis is higher in the two groups than in the control group. According to X-ray and histological findings, pneumoconiosis of electric-welders is very similar to that of coal miners. The authors did not find any severe forms of pneumoconiosis (A, B, C forms of the International Classification of Pneumoconiosis), neither did they observ any X-ray changes in electric welders which left the profession for less hazardous work.

     

Extent and conditions of exposure in the Swedish chrome plating industry

Summary The total air concentration of chromium and the concentration of Cr(VI) during hard and decorative chrome plating were measured with stationary and personal air samples at 13 chrome plating plants. Cr(VI) was determined by the Zephiramin method. The investigation covers nearly all Swedish work places where five or more platers are employed. The levels of exposure during hard plating at the different work places varied markedly. At one factory the daily mean values, recorded in the vicinity of three different baths, ranged between 20 and 46 Vg Cr(VI)/m³, while at another factory the exposure level at all baths was below 1 g/m³. In decorative chrome plating the exposure level was practically always below 0.5 g/m³. Near the baths and in fitting work, Cr(VI) accounted for about half of the total exposure to chromium; in polishing operations it only amounted to 10 to 20%. In order to elucidate variations in the level of exposure at the same work place, the exposure was measured every day for a whole week at four factories, comprising more than 100 test intervals. On about 90% of these occasions the values recorded differed less than 50% from the median for the same sampling site.     

Respiratory symptoms associated with sulfur dioxide exposure

Summary Exposures to sulfur dioxide (SO₂) have been associated with progressive, dose-dependent bronchoconstriction in sensitive individuals. The clinical significance of such changes remains poorly characterized. We studied subjective responses following exposure to low level concentrations of SO₂ (< 1 ppm) in a group of 10 healthy and 10 asthmatic subjects. The number and severity of complaints associated with SO₂ increased with concentrations in both healthy and asthmatic subjects. Asthmatics indicated progressive lower respiratory complaints, such as wheezing, chest tightness, dyspnea and cough with increasing levels of SO₂ while healthy subjects complained more frequently of upper airway complaints such as taste and odor with increasing levels of SO₂. Exercise increased the frequency of lower airway symptoms in asthmatics but led to no increases in symptoms in healthy subjects.From the Pulmonary Section, Yale University School of Medicine, P.O. Box 3333, 333 Cedar Street, and the John B. Pierce Foundation Laboratories, New Haven, CT 06510 (203) 785-4165Presented in part at the International Conference on Indoor Air Pollution August 10–24, 1984