Mental disorders in workers exposed to chemicals at work

The article considers data on boundary psychic disorders in subjects exposed to chemicals of I-II jeopardy classes. Chemical factor appears to increase risk of psychiatric diseases. The authors suggest periodic psychiatric examination of workers engaged into hazardous chemical production for better occupational selection, early diagnosis and treatment of boundary psychic disorders.     

Effect of occupational and nonoccupational factors on the respiratory system of vinyl chloride and other workers

There are suggestions in the literature that vinyl chloride (VC) acts as a lung irritant. Respiratory questionnaires and lung function tests were administered to 174 chemical (VC) workers, 81 polyvinyl chloride (PVC) workers, 72 former VC workers, and 136 rubber workers, and 68 maintenance workers with exposure to VC, PVC, and rubber. Except for small airways obstruction associated with rubber, increased respiratory symptoms and decreased pulmonary function were not associated with working in chemicals, plastics, or rubber. Some increases in baseline pulmonary function were associated with VC exposure. Acute reductions in pulmonary function were observed in smokers working in chemicals, plastics, and rubber. Heavier cigarette smokers over 40 years of age had the most adversely affected respiratory system. Work was not associated with chronic respiratory effects, but all exposure groups experienced some acute respiratory insult.     

Surveillance of respirable crystalline silica dust using OSHA compliance data (1979-1995)

BACKGROUND: The objective of this work was to estimate the percentage of workers by industry that are exposed to defined concentrations of respirable crystalline silica dust. METHODS: An algorithm was used to estimate the percentage of total workers exposed to crystalline silica in 1993 at concentrations of at least 1, 2, 5, and 10 times the National Institute for Occupational Safety and Health (NIOSH) Recommended Exposure Limit (REL) of 0.05 mg/m3. Respirable crystalline silica air sampling data from regulatory compliance inspections performed by the Occupational Safety and Health Administration (OSHA), for the years 1979-1995, and recorded in the Integrated Management Information System (IMIS) were used to estimate exposures. Therefore, this work does not include industries such as mining and agriculture that are not covered by OSHA. The estimates are stratified by Standard Industrial Classification (SIC) codes. RESULTS: This work found that some of the highest respirable crystalline silica dust concentrations occurred in construction (masonry, heavy construction, and painting), iron and steel foundries (casting), and in metal services (sandblasting, grinding, or buffing of metal parts). It was found that 1.8% (13,800 workers) of the workers in SIC 174--Masonry, Stonework, Tile Setting, and Plastering--were exposed to at least 10 times the NIOSH REL. For SIC 162--Heavy Construction, Except Highway and Street Construction--this number is 1.3% (6,300 workers). SIC 172--Painting and Paper Hanging--which includes construction workers involved in sandblasting was found to have 1.9% (3,000 workers) exposed to at least 10 times the NIOSH REL. The industry that was found to have the highest percentage of workers (6%) exposed to at least the NIOSH REL was the cut stone and stone products industry. CONCLUSION: Not enough is being done to control exposure to respirable crystalline silica. Engineering controls should be instituted in the industries indicated by this work.     

The treatment problems of soft-tissue infections

The authors analysed retrospectively a reproductive function among female workers of chemical plant. The subjects were exposed to mutagenic and carcinogenic chemicals before pregnancy and during early term pregnancy. Occurrence of complications during pregnancy and delivery was significantly higher in the exposed group vs. the reference one. Incidence of congenital abnormalities among children in the exposed group tended to increase. Cytogenetic alterations were reliably more frequent in peripheral WBC and in embryonal tissues obtained during abortions in workers of the plant, if compared to the parameters of the reference group.     

The inhalation of low concentrations of manganese powders produces changes in respiratory mucociliary clearance

The aim of this study is to verify whether inhaling metallic dusts, containing a lower concentration of Mn (as Mn3O4) than current TLV can cause alterations in exposed workers tracheobronchial mucociliary clearance. We studied 20 grinders using an 11.5-13% Mn steel, and a control group of 21 standard steel grinders, employed in the same foundry. Environmental Mn dust was measured by personal samplers. All workers were administered a questionnaire about chronic bronchitis; the following examinations were also carried out: medical examination, spirometry, chest standard X-ray and urinary Mn dosage. Mucociliary clearance was measured by human respiratory mucus transportability on frog palate and expressed as normalized frog palate transport rate (NFPTR). Mucus was obtained through a sputum so protected as to avoid salivary contamination. Environmental measurements showed a Mn concentration from 0.1 to 1 mg/m3 with respect to a TLV of 5 mg/m3. Exposed workers and control group were homogeneous as far as age, working period, tobacco smoking habit and spirometric parameters are concerned. Chest X-ray examination showed no evidence of pneumoconiosis. Mn exposed workers showed a NFPTR reduction, if compared to normal level (0.70). NFPTR average value in exposed group has come out to be much lower than in control group. NFPTR alteration in Mn exposed group appears to be strictly linked to a longer than 15 years working seniority. Urinary Mn values resulted extremely low in each worker and their average was not significantly different between the groups.(ABSTRACT TRUNCATED AT 250 WORDS)     

Ocular effects of exposure to triethylamine in the sand core cold box of a foundry

OBJECTIVES: To assess the acute and chronic ophthalmological effects of triethylamine exposure among foundry workers. METHODS: Ocular effects on people currently, previously, and never exposed to triethylamine in a foundry cold box were studied at two points in time. The initial phase included an ocular examination with a slit lamp to assess corneal health, a visual acuity test, and a questionnaire to assess vision symptoms. The follow up included measurements of corneal thickness with an ultrasonic pachymeter and the vision symptoms questionnaire before and after the shift and at the beginning and end of the week. Personal air measurements for triethylamine were also obtained during the follow up. RESULTS: The vision symptoms of blurriness, halos around lights, and blue hazy vision occurred more often in currently exposed workers than those previously or never exposed to triethylamine. Air concentrations of triethylamine ranged from < 0.33 mg/m3 to 20.3 mg/m3. Among currently exposed workers, symptoms were more common among those with exposure to > 10 mg/m3 of triethylamine (odds ratio (OR) = 3.0, 95% confidence interval (95% CI) 0.35-25.6). No differences in corneal thickness were found in currently or previously exposed workers and those never exposed. No increase in corneal thickness was found after v before the shift. CONCLUSION: Despite low concentrations of triethylamine and no corneal oedema, workers exposed to triethylamine reported vision symptoms. Possible explanations for these symptoms without corneal oedema are that triethylamine affects ciliary muscle function or that the corneal oedema was transient and not present when corneal thickness measurements were taken. No chronic effects were found in previously exposed workers. Further research is needed to elucidate the mechanism for the reported vision symptoms, which occurred below the current United States eight hour time weighted standard of 100 mg/m3 and the American Conference of Governmental Industrial Hygienists (ACGIH) recommended value at the time of our study of 40 mg/m3. We recommend that air concentrations be maintained to meet the current recommended ACGIH threshold of 4.1 mg/m3.     

Chemical mixtures in the workplace. Research and practice

1. Exposures to mixtures of chemicals in occupational settings and in the environment are of increasing concern. No single approach is appropriate for determining the risk associated with exposure to chemical mixtures. 2. The effects of coexposure of chemicals can occur in different stages of metabolism, including uptake, elimination, biotransformation, and binding. 3. Solvents represent the most widespread use of multicomponent mixtures in industry today. Solvents have the ability to inhibit the metabolism of other chemicals. 4. Lifestyle factors such as exercise, alcohol use, smoking, and the use of medications can affect the uptake and metabolism of chemicals. The effects of these factors are of particular significance in interpreting the results of biological monitoring of exposed workers.     

Monitoring liver disorders in vinyl chloride monomer workers using greyscale ultrasonography

Recognition that vinyl chloride could be hepatotoxic led to a survey of workers to determine whether changes had been induced by past exposure, and to evaluate standard liver function tests as monitors of early liver abnormalities. Standard liver function tests were found to be unsuitable for the detection of such abnormalities in the population at risk. Of 487 workers examined, 102 (20-9%) had abnormalities on initial testing but only two were finally shown to have portal hypertension; in both cases, thrombocytopaenia provided the first diagnostic evidence since liver function tests were normal. Furthermore, 40 (35-7%) of 112 control subjects had initial test abnormalities. A sample of 19 workers with various exposures to vinyl chloride monomer were examined blind by greyscale ultrasonography. Five with minimal or no exposure were confirmed as normal but 12 of the remainder had abnormalities. These consisted of an enlarged portal vein (seven instances), splenomegaly (eight), and changes in hepatic texture (seven). Five of these 12 cases had previously been considered normal. It was concluded that greyscale ultrasonography had many advantages over standard methods for screening workers exposed to hepatotoxic chemicals, and should be the subject of a large scale evaluation.     

Clinical overview of occupational lung disease

The workplace has been a source of lung injury for centuries, yet awareness of the types of injuries has varied over time. Because of distinctive differences among the occupational lung disorders, a continual update of the clinical findings, dose response data, physiologic characteristics, and radiographic findings is needed. The radiologist plays a key role for the evaluation of miners, foundry or factory workers exposed to mineral dusts, and of workers exposed to the "biologic" dusts, infectious agents, cancer causing agents, and chemicals causing interstitial lung diseases. This overview includes a discussion of classification systems, criteria for diagnosis of occupational lung diseases, the pulmonary clinician's evaluation, and important aspects of specific disorders and concludes with a discussion of pulmonary disability determination.     

Occupational skin diseases in Washington State, 1989 through 1993: using workers' compensation data to identify cutaneous hazards

OBJECTIVES: This study sought to characterize occupational dermatoses and cutaneous hazards. METHODS: Workers' compensation claims filed for skin disease in the Washington State Fund were analyzed for 1989 through 1993; incidence rates for industries and employers were calculated, and cutaneous hazards associated with the highest rates were identified. RESULTS: A total of 7445 claims were filed for skin disorders, principally contact dermatitis; 675 (9.1%) involved more than 3 missed work-days. The rate of accepted skin disorder claims was 1.0 per 1000 full-time employee-years. The highest incidence rates (4.6 to 30.7 accepted claims per 1000 full-time employee-years) were in certain manufacturing industries (plastics related, concrete products, aircraft parts, sporting goods, and boat building), wholesale farm product raw materials, automotive glass replacement, and beauty shops. Seven of the 10 employers with the highest incidence rates (19.6 to 85.5 accepted claims per 1000 full-time employee-years) used fiber-reinforced plastics (composites) and exposed workers to epoxy and other resin systems associated with contact dermatitis. CONCLUSIONS: Workers' compensation data identify known and emerging workplace cutaneous hazards and show promise for targeting prevention efforts.     

Sister-chromatid exchanges and cell-cycle kinetics in the lymphocytes of workers occupationally exposed to a chemical mixture in the tyre industry

Cytogenetic studies of clinically healthy workers employed in the rubber industry showed an increase in chromosome aberrations (CAs), sister-chromatid exchanges (SCEs) and a decrease in proliferation indices (PIs). The aim of the present study was to establish, using the SCE and PI tests, genotoxic effects of hazardous chemicals in the rubber industry. An increase in mean SCEs in the lymphocytes of vulcanizers as compared to controls was observed. Since the PI in the exposed group was insignificantly decreased as compared to the controls, it could be concluded that the SCE test is the most sensitive cytogenetic test for the detection of a genotoxic effect of chemicals in the rubber industry. There was no evidence in the present study that the genotoxic effect of chemicals in the rubber industry was enhanced by cigarette smoking.     

Contrast nephrotoxicity: predictive value of urinary enzyme markers in a rat model

Asbestos, proven to be carcinogenic in humans and animals, is reported to have no genotoxic effect. Asbestos workers have an increased risk of lung cancer, mesothelioma, and other tumours. Earlier findings showed that crocidolite can induce DNA strand breaks in cultured rat embryo cells as assessed by nick translation. We investigated DNA double-strand breaks in white blood cells (WBC) of ten workers occupationally exposed to asbestos. According to our results, obtained with neutral filter elution, individuals who had been exposed to asbestos fibres showed two to four times more DNA double-strand breaks (dsb) in white blood cells than ten non-exposed persons. The induced DNA fragments are of about 250 kb (compared to chromosomal DNA of Saccharomyces cerevisiae standard marker). Using additionally the chromosomal DNA protective method of agarose-plugs, DNA fragments in the range of 200 to 1000 kb have been found in the white blood cells of the same ten workers occupationally exposed to asbestos. In the white blood cells of non-exposed subjects no DNA fragments could be detected with this method. Compared to 51 non-exposed persons, elevated anti-ds DNA antibody concentrations were found in ten workers occupationally exposed to asbestos. The fact that workers occupationally exposed to asbestos have distinctly more double-strand breaks and anti-ds DNA antibodies could mean that an increased incidence of DNA-fragments may be an important indicator in the chronic effect of asbestos-associated carcinogenesis. Apparently, the chronic effects of asbestos observed here do not seem to be identical with that of previously reported acute in vitro effects.     

Lung function in workers in a chicken slaughterhouse in the city of Maracaibo, Venezuela

In order to evaluate the respiratory health status in workers exposed to antigenic substances (chicken feathers, serum and dropping), typical of usual practice in the avian slaughter-house, pulmonary function was studied on 49 exposed workers, and in a sample of 49 people with similar anthropometric characteristics, non exposed to these substances, by means of occupational-medical history, spirometric tests, hematologic and biochemical tests, and postero-anterior chest x-rays. The values for the spirometric parameters varied with sex, age, weight, size, smoking habits, length of employment and exposure time, and there were no significant differences between exposed and control groups as a whole; showing significant differences with decreasing values for CVF, VEF1, PFE, FEF-25% and FEF-50% in the intermediate zone workers, and in subjects with short exposure time (< 1 year). Prevalence of clinical findings in the exposed population was significantly higher than the non exposed group (p < 0.001). Laboratory tests showed reduction of monocytes cells in the exposed group (p < 0.05) in addition, in the exposed women there was an increase of the eosinophiles, total proteins and globulines (p < 0.05). The frequency of radiographic findings was significantly higher in the exposed group (p < 0.006), and they were no specific. The lack of association between clinical findings, laboratory and radiographic findings, with the spirometric results, could be explained by the short period of exposure, individual and collectives hygienic conditions and size of the sample.     

Medical surveillance of the lead exposed worker. Current guidelines

1. The "lead standards" established by OSHA for general industry in 1978 and the construction industry in 1993 require employers and clinicians to follow very specific guidelines for protecting lead exposed workers. Depending on the level of exposure, medical surveillance may be legally required. 2. Lead affects multiple body systems and can cause permanent damage. Low level exposures that in the past were thought safe are now considered hazardous as new information emerges about the toxicity of lead. 3. Lead poisoning, if undetected, often results in misdiagnosis and costly care. Adults are exposed to lead in many different workplace settings. All clinicians caring for lead exposed workers need to be informed about the health effects of lead, employer and physician responsibilities, and worker rights. 4. Occupational and environmental health nurses can help identify workers at risk and prevent lead poisoning by education and early intervention through collaboration with the workers, the employer, the company physician, and other health and safety professionals.     

Sleepiness as measured by modified multiple sleep latency testing varies as a function of preceding activity

Although female breast cancer rates are lower in China than in Western countries, rates have been rising rapidly in China. This increase may be due to changes in established breast cancer risk factors, but it is possible that exposure to occupational and environmental carcinogens in Shanghai also have contributed to the rise in incidence. We used data collected by the Shanghai Cancer Registry and the Chinese Third National Census to study the risk of breast cancer by occupation and by occupational exposures. Standardized incidence ratios (SIRs) were used to compare observed cases to expected numbers of cases, based on the incidence rates for Shanghai and the number of women in each occupation according to the 1982 census. Statistically elevated SIRs for breast cancer were seen for a number of professional occupational categories, with the greatest risk seen among scientific research workers (SIR = 3.3). Administrative clerks, political and security personnel, and makers of rubber and plastics products also had significant excesses. Significant deficits of risk were seen for the categories of production and related workers, construction workers, and transportation equipment operators. For specific occupations, the highest SIRs were observed among doctors of Chinese-Western medicine (SIR = 14.7, 95% CI = 5.9-30.3) and doctors of Chinese medicine (SIR = 7.2, 95% CI = 4.4-11.4). We also found excesses among teachers at each level of education, librarians, clerical workers, electrical and electronic engineers, nurses, lab technicians, accountants and bookkeepers, rubber manufacturing products makers, weavers, and knitters. SIRs were significantly elevated for high probability of exposure to organic solvents (SIR = 1.4). For benzene exposure, we found significant excesses for overall exposure (SIR = 1.1) and for medium level of exposure (SIR = 1.3). There was no evidence of an association between risk and electromagnetic fields (EMF) exposure. Based on a small number of exposed, SIRs were elevated for both medium probability and high level of exposure to pesticides. The elevations in occupations reported here support some previous reports. Our finding of an increased risk associated with benzene also has been reported previously; the finding for organic solvents is new. However, the literature on the risk of breast cancer related to occupational exposures is limited and there is no consistent body of literature for any of the exposures studied here. Further, many comparisons were made and the problem of multiple hypothesis testing cannot be ignored in a survey such as ours.     

Epidural injection of ketamine for perineal analgesia in the horse

Work-related respiratory symptoms, acute lung function changes and personal endotoxin exposure were studied in 61 workers from a potato processing plant. According to their job title mean endotoxin exposure level, workers were divided into low (AM = 21 EU/m3) and high (AM = 56 EU/m3) exposure categories. Shortness of breath and chest tightness during work were reported by 18% and 16% of the workers, respectively, mainly in the low endotoxin exposure category. A total of 148 across-shift lung function changes were measured during three consecutive afternoon shifts. The mean FEV1 and MMEF showed a decrease over the work shift, being largest on the first working day after a 3-day absence from work. Workers exposed to high endotoxin levels showed a larger across-shift decrease in lung function than workers exposed to low endotoxin exposures, the effect being most pronounced on the first day after a 3-day absence from work. At the start of the second work shift, FVC, FEV1 and MMEF were lower than at the start of the first work shift. This difference was larger for high exposed workers. High exposed workers with work-related respiratory symptoms showed an 8-10% across-shift change in FVC, FEV1 and MMEF We conclude that significant across-shift decreases in lung function of potato processing workers is related to endotoxin exposure levels above 53 EU/m3 over 8 hr.     

The characteristics of formulating a diagnosis in diseases of the temporomandibular joint

Pulmonary diseases caused by dust occupy a leading place in occupational morbidity structure. Those diseases inspire much attention due to their high prevalence, especially in ecologically hazardous regions where the workers are under "double exposure". Upper respiratory tract diseases serve as a trigger for all respiratory disorders in workers exposed to dust. Early diagnosis of respiratory disorders includes history, clinical data, X-ray examination and assessment of pulmonary ventilation and together with concurrent cardiovascular diagnosis is necessary for well-justified prophylaxis.     

Biomonitoring of workers exposed to lead. Genotoxic effects, its modulation by polyvitamin treatment and evaluation of the induced radioresistance

A population monitoring study was performed, by using the micronucleus (MN) assay in human peripheral lymphocytes, to investigate whether occupational exposure to lead is genotoxic to workers. In addition to the exposed workers group, two more groups were studied, an external group from a factory without exposure to lead and an internal control group, from the same factory as the exposed workers, but that were not directly exposed to lead. Measures of lead levels at working place and in blood were calculated, and blood samples were collected to carry out a MN study. The results from these studies indicate that the blood from workers directly exposed contained high levels of lead, compared with the other groups, and a significant increase in the frequency of both the total number of MN and the number of binucleated cells carrying MN appeared. In addition, a study on the antimutagenic effects of a polyvitamin rich diet was conducted by measuring the frequency of MN after the workers had a four month daily intake of a polyvitamin-polymineral complex. These results clearly show a significant reduction of the MN frequency evaluated after this treatment, obtaining values that were even lower than those obtained in the internal control group. Finally, a challenge assay was carried out to determine response to gamma-radiation as indication of any kind of radiosensitivity or radioresistance. The results of this experiment did not show any significant variation in the increase of the frequency of MN after challenge irradiation in the lead exposed workers; nevertheless this increase was significantly reduced in the sample obtained after the polyvitamin treatment indicating a radioresistance response.     

Long-term exposure to jet fuel: an investigation on occupationally exposed workers with special reference to the nervous system

In the present study the results of a neurological and neurophysiological health examination of 29 aircraft factory workers chronically exposed to jet fuel vapors are presented. The exposed subjects were classified into a heavily exposed and a less heavily exposed group. The examination included a standardized clinical neurological examination, measurements of the conduction velocities in the peripheral nerves, and threshold determinations of vibratory sensations in the extremities. All 13 persons examined in the heavily exposed group and 7 of the 16 in the less heavily exposed group stated that they had repeatedly experienced acute effects (dizziness, respiratory tract symptoms, heart palpitations, a feeling of pressure on the chest, nausea, headache) of the jet fuel vapors in the inhaled air. A high rate of symptoms indicative of neurasthenia and psychasthenia and symptoms and signs indicative of polyneuropathy was observed both in the heavily exposed group and in the two groups combined in comparison with reference groups. Considering the presented facts concerning (a) the acute effects on repeated occasions, (b) the high rates of symptoms indicative of neurasthenia and psychasthenia and symptoms and signs indicative of polyneuropathy, and (c) the differences in the observations made between the two groups with varying degrees of exposure to jet fuel, the authors interpreted the results as indicative of a possible effect of long-term exposure to jet fuel on the nervous system.     

Chronic and acute respiratory effects among grain mill workers

Exposure to flour dust may induce chronic respiratory manifestations as well as acute ventilatory effects. We compared the prevalence of respiratory symptoms, ventilatory impairment, and variations in pulmonary function over the workshift in a group of mill workers exposed to wheat flour and in referent workers. One hundred and forty-two men exposed to flour in a mill and 37 referent workers were included in this study. Each subject completed a standardized questionnaire. Pulmonary function tests were performed before and after the workshift. The assessment of environmental exposure to flour showed high concentrations during some jobs with a high percentage of inhalable particles and a low concentration of respirable particles. The exposed workers had a significantly higher prevalence of usual cough and usual phlegm than the referents. The prevalence of asthma, based on the questionnaire, was similar. Before the workshift, the exposed workers had significantly lower mean lung function values for peak flow rate and forced expiratory flow rate at 75% of the vital capacity than the referents. After the workshift, all the lung function values showed a slight decrease, significant for forced vital capacity and forced expiratory volume during 1 s in both groups. Among the exposed workers, the asthmatic subjects had a significantly higher decrease across the shift than the nonasthmatic workers. This result is probably linked to bronchial hyperreactivity. Among nonasthmatic subjects, the decrease was larger in nonexposed workers than in exposed workers. A higher prevalence of respiratory symptoms and lower pulmonary function values were observed among mill workers by comparison with referents. Moreover, the data suggest that asthmatic status and the time of spirometric measurements need to be taken into account in epidemiological studies on exposure to airborne allergens. In addition, the study does not exclude a healthy worker effect with selection of dust-resistant subjects or better identification of asthmatic subjects among the workers exposed to an allergenic substance than among the nonexposed workers.