Lead exposure of workers in the ceramics industry and relevant factors

To clarify lead exposure and factors relevant to it, an occupational health survey and air lead-concentration survey were conducted among 425 workers in the ceramics industry in the Seto region in Aichi Prefecture. As for biological monitoring, blood lead level was measured according to sex, job, product, factory size and duration of lead exposure. The following major findings were obtained in the present analysis. Workers making dolomite novelties showed higher blood lead levels than those making porcelain novelties, semi-porcelain novelties and tableware. The difference in blood lead level by job was statistically significant, but not that by factory size. In males, the highest blood lead level was found for spray painting work (28.7 micrograms/dl), followed by glazing work (28.0 micrograms/dl), kiln work (23.3 micrograms/dl) and painting work (22.3 micrograms/dl). In females, the blood lead level for painting work (13.5 micrograms/dl) was lower than those for glazing work (26.1 micrograms/dl) and kiln work (31.4 micrograms/dl). The blood lead level was significantly increased with the number of years of lead exposure in females (painting work). It was coincidentally clarified that the environmental lead concentration varied according to the job in which workers were engaged. As protective measures against lead exposure for workers in the ceramics industry, the development of nonlead paint and glaze and the introduction of more effective dust collectors at the workplace should be established.     

铝电解干法净化系统噪音危害分析及预防

铝电解干法净化系统噪音是一种生产性噪声,是铝电解行业中涉及面最广泛、对工作人员影响最严重的噪声。特别是主风机室噪音可达到90dB以上,长时间职业性暴露会造成工人听力损失,还会对神经系统、心血管系统、消化系统、精神心理及其他系统有不良影响。     

Hearing and occupation

Not only does the environment play a role as a source of risk factors for a hearing impairment, but a hearing impairment itself can adversely affect interaction with family members, workmates and friends, thus reducing social well-being. The number of work-related hearing impairments has been decreasing for last five years, but noise-induced sensorineural hearing loss is still the second most common work-related disease in Finland. The financial burden related to occupational hearing impairments includes costs of compensation, salaries of screening personnel, equipment, maintenance costs, costs resulting from loss of work for the employer and referrals to specialist clinics etc, which until now have not been calculated in Finland. Numerous questions still remain to be answered regarding the association of age, socioacousis, occupation and leisure activities with the development of sensorineural hearing impairment. Can hearing impairment acquired in childhood or in early adolescence predict the development of occupational hearing loss? What is the interactive role of such factors as ageing, chemicals, diet, environmental noise, genetic susceptibility and the individual's other diseases in the development of noise-induced hearing impairment?     

Cigarette smoking and hearing loss: the epidemiology of hearing loss study

CONTEXT: Clinical studies have suggested that cigarette smoking may be associated with hearing loss, a common condition affecting older adults. OBJECTIVE: To evaluate the association between smoking and hearing loss. DESIGN: Population-based, cross-sectional study. SETTING: Community of Beaver Dam, Wis. PARTICIPANTS: Adults aged 48 to 92 years. Of 4541 eligible subjects, 3753 (83%) participated in the hearing study. MAIN OUTCOME MEASURES: The examination included otoscopy, screening tympanometry, and pure-tone air-conduction and bone-conduction audiometry. Smoking history was ascertained by self-report. Hearing loss was defined as a pure-tone average (0.5, 1, 2, and 4 kHz) greater than 25-dB hearing level in the worse ear. RESULTS: After adjusting for other factors, current smokers were 1.69 times as likely to have a hearing loss as nonsmokers (95% confidence interval, 1.31-2.17). This relationship remained for those without a history of occupational noise exposure and in analyses excluding those with non-age-related hearing loss. There was weak evidence of a dose-response effect. Nonsmoking participants who lived with a smoker were more likely to have a hearing loss than those who were not exposed to a household member who smoked (odds ratio, 1.94; 95% confidence interval, 1.01-3.74). CONCLUSIONS: These data suggest that environmental exposures may play a role in age-related hearing loss. If longitudinal studies confirm these findings, modification of smoking habits may prevent or delay age-related declines in hearing sensitivity.     

Human blood samples as indicators of occupational exposure to persistent chlorinated hydrocarbons

The value of using human blood as an indicator of occupational exposure to persistent organochlorine compounds is demonstrated. Blood samples from a total of 35 persons divided into three different groups, with and without exposure to chlorinated hydrocarbons in the work atmosphere, have been investigated by gas chromatography using electron capture detection. It is shown that the group of workers with an occupational exposure to pentachlorobenzene, hexachlorobenzene, heptachlorostyrene and octachlorostyrene had a higher level of these chlorinated hydrocarbons in their blood samples than did the other groups. On the average, the concentration of hexachlorobenzene is about 20 times higher in blood samples from the occupationally exposed workers than from the control group. The level of hexachlorobenzene in blood samples of the control groups is low compared to recent studies of blood samples from the general population in other industrialized countries. Furthermore, the average value obtained for the exposed workers is of the same magnitude as the general population in these industrialized countries.     

The 3'' untranslated region of the carcinoembryonic antigen gene plays a minimal role in the regulation of gene expression

Hospital workers are occupationally exposed to various agents known or suspected to induce chromosome damage, the most studied being ionizing radiation. To determine the extent of chromosome damage in peripheral blood lymphocytes in this population, taking into account temporal changes and job titles, a re-analysis of cytogenetic studies performed in four Italian laboratories in the period 1965-1993 was carried out. A total of 871 hospital workers and 617 controls, mainly coming from ad hoc studies or surveillance programs in occupational groups potentially exposed to ionizing radiation, were examined. The exposed to controls frequency ratio of chromosome aberrations was evaluated as the measure of effect within each dataset by job title, using multivariate Poisson regression analysis, which allowed an efficient control of confounding. Increased frequency of chromosome-type aberrations among exposed subjects was found in all datasets, especially in those dealing with older data. Significantly higher frequencies are reported for various job titles, particularly for orthopedists, radiologists, anesthesists, and nurses among paramedical occupations. Decrease in exposure to ionizing radiation in hospital workers was documented through a targeted study in the critical group of radiologists. A similar time-related reduction in the frequency of chromosome-type aberrations also has been reported by the surveillance studies carried out over the most recent decades. These data substantiate the use of chromosome-type aberrations as biomarkers of exposure in this occupational setting in the period evaluated. However, the increases observed also in workers with doubtful exposure to ionizing radiation indicate that other chromosome-damaging agents may be involved and, in turn, suggest the extension of surveillance to a larger number of occupations.     

Growth behavior of the 2 f1-f2 distortion product otoacoustic emission in tinnitus

High-resolution hearing threshold and 2 f1-f2 distortion product otoacoustic emission (DP) were measured with the same in-the-ear sound probe and same calibration at 51 frequencies between 500 and 8000 Hz in 39 sensorineural hearing loss ears associated with tinnitus. Using a primary tone setting L1 = 0.4L2 + 39 that accounts for the nonlinear interaction of the two primary tones at the DP generation site at f2, DPs were elicited in a wide range from L2 = 65 to 20 dB SPL. We failed to find a uniform DP behavior in the 39 tinnitus ears tested. Seventeen of them behaved like impaired ears without tinnitus. In these ears a linearized DP growth was observed where the DP level decreased and the slope of the DP I/O functions steepened with increasing hearing loss and as a result both the DP level and the DP slope strongly correlated with hearing threshold. The other population, 22 tinnitus ears, exhibited a poor or even inverse relationship between DP level and hearing threshold, i.e., displayed an increase of DP level with increasing hearing loss. Despite the severe hearing loss but due to the high level, DPs could be recorded well in the frequency range that corresponded to the appearance of the tinnitus. The DP slope, however, increased with increasing hearing loss and, therefore, did still correlate with hearing threshold revealing pathological alteration. The data suggest that the DP level alone is hardly capable of assessing hearing impairment in tinnitus ears and may even be misleading. Thus just the DP slope seems to be the only reliable indicator of cochlear malfunction around the tinnitus frequency. The observed nonuniform DP behavior suggests different cochlear impairments in tinnitus ears. In those ears where the DP level decreases and the slope of the I/O functions increases with hearing loss, cochlear sensitivity and tuning are supposed to be diminished. In those ears where the DP level increases with increasing hearing loss, a reinforced mechanical distortion is hypothetized to be generated by cochlear hyperactivity that can be the source of both the abnormally high DP level and the tinnitus.     

Paracrine stimulation of cell growth by cholecystokinin/gastrin through cholecystokinin-B receptor on GH3 cells in vitro

Self-reported reproductive histories of male employees of a lead-zinc smelter were related to pre-conception measures of lead exposure to examine associations between paternal occupational lead exposure and adverse pregnancy outcome. The participants reported 2,021 pregnancies which resulted in 1,684 normal live births, 12 stillbirths, 30 birth defects, 203 spontaneous abortions, and 92 "other" outcomes. Birth defects and stillbirths were combined for the analysis. The risk of a stillbirth or birth defect was elevated for pre-conception employment in a high-lead-exposure compared with a low-lead-exposure job (odds ratio = 2.7, 95% confidence interval = 0.7, 9.6). A similar risk was found for pre-conception blood lead levels of 25-39 μg/dL and >/= 40 μg/dL when compared with blood lead levels of < 25 μg/dL (OR = 2.9, 95% CI = 0.6, 13.3, and OR = 2.5, 95% CI = 0.5, 11.6, respectively). No association was found between pre-conception lead exposure and spontaneous abortion. A relatively low response rate to the questionnaire and potentially erroneous reporting of reproductive outcomes by male workers are limitations of the study.     

Diurnal rhythm of physiologic functions in workers exposed to noise

To reveal the mechanisms of adaptation to occupational factors, the authors screened the workers exposed to noise for changes of pulse rate, blood pressure, catecholamines content, auditory threshold within a day. The study showed that adaptation to unfavorable work conditions deteriorates within a day (from morning to night shifts). Reliability of catecholamines level was conditioned by the night fall of catecholamines level and its changes within a day. Compromised adaptation to chronic unfavorable occupational factors result in unstable catecholamines level. Functional state of hearing is mediated by vegetative state including catecholamines content.     

Nested case-control study of esophageal cancer in relation to occupational exposure to silica and other dusts

BACKGROUND: Standardized proportionate mortality ratio (SPMR) was found to be 2.2 (95% CI = 1.3-3.5) for esophageal cancer (EC) among workers exposed to refractory brick dust in a large iron-steel complex in China. METHODS: A nested case-control design within a cohort of industrial workers. One hundred and twenty-five EC cases and 250 controls were identified from the death registry file. Interviews were conducted of the next of kin for past exposure information on job, domestic, and lifestyle factors. History of occupational exposure to various dusts was reconstructed from personnel files and by interviewing colleagues utilizing a job-exposure matrix. RESULTS: After adjusting for confounders, occupational exposure to silica dust was the most important risk factor among all variables investigated, with a 2.8-fold risk and a clear dose-response by length of exposure. Alcohol drinking (OR = 1.8) and coal cooking (OR = 2.0) were risk factors and high consumption of fruit diet (OR = 0.5) and meat diet (OR = 0.6) were protective factors. CONCLUSIONS: The relationship between occupational exposure to silica dust and the risk of EC found in an earlier SPMR study was confirmed. Ingestion of silica particles after lung clearance may increase the risk of EC among workers exposed to silica.     

Frontal lobe hypometabolism and depression in Alzheimer''s disease

PURPOSE: It is speculated that the susceptibility to urothelial cancer in dye workers who are exposed to aromatic amines is affected not only by occupational environmental factors but by host specific factors. We evaluated the interaction between glutathione S-transferase M1 gene deficiency and the occupational environmental factors associated with urothelial cancer. MATERIALS AND METHODS: The study included 137 workers who had prior exposure to dyestuff intermediates, of whom 36 had urothelial cancer. The prevalence of a glutathione S-transferase M1 gene polymorphism was investigated using polymerase chain reaction. The relationship between the glutathione S-transferase M1 0/0 gene and occupational environmental factors in the onset of urothelial cancer was examined by multivariate analysis. RESULTS: The prevalence of glutathione S-transferase M1 gene deficiency did not differ significantly between the urothelial cancer (21 cases, 58.3%) group and the cancer-free (47, 46.3%) group. It was estimated that 29.6% of the urothelial cancers in these dye workers was attributable to the glutathione S-transferase M1 0/0 gene. Analysis using multiple logistic models showed low predictive ability for urothelial cancer due to glutathione S-transferase M1 gene deficiency (p = 0.084, odds ratio 2.260, 95% confidence interval [CI] 0.904 to 5.652). A history of working in small factories (p = 0.000, odds ratio 7.404, 95% CI 2.854 to 19.206) and a long period of exposure (p = 0.016, odds ratio 5.051, 95% CI 1.371 to 18.612) significantly predicted cancer. CONCLUSIONS: We demonstrated a strong trend using the multiple logistic analysis of the contribution of glutathione S-transferase M1 gene polymorphism and occupational environmental factors. Therefore, the glutathione S-transferase M1 enzyme might have an important role in the detoxification of aromatic amine derived carcinogens. Occupational environmental factors, however, might contribute more than a glutathione S-transferase M1 gene deficiency to the occurrence of urothelial cancer among individuals exposed to aromatic amines, because of the extremely potent carcinogenicity of some occupational environmental factors.     

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.     

Behavioral determinants of occupational exposure to chemical agents.

Used the passive-active dimension of the job demand–control model (T. Theorell and R. A. Karasek, see record 83:28881) to examine the impact of behavioral factors on the exposure to and actual uptake of airborne lead in 2 lead exposed populations of male workers (18 from an electric accumulator factors and 18 from a lead smeltery) and to ascertain work-related determinants of hygienic behavior. Environmental exposure was assessed by measurement of the concentration of lead dust in ambient air at the workplace, and the intake of lead was assessed by measurement of the lead in blood level. In the work environment of Ss in active jobs, lower concentrations of lead in air were measures, but higher levels of lead in blood were observed in these workers. The opposite was true of workers in passive jobs. Differences in hygienic behavior (e.g., use of protective equipment) at work may explain these results. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A case-control study of HIV seroconversion in health care workers after percutaneous exposure. Centers for Disease Control and Prevention Needlestick Surveillance Group

BACKGROUND: The average risk of human immunodeficiency virus (HIV) infection after percutaneous exposure to HIV-infected blood is 0.3 percent, but the factors that influence this risk are not well understood. METHODS: We conducted a case-control study of health care workers with occupational, percutaneous exposure to HIV-infected blood. The case patients were those who became seropositive after exposure to HIV, as reported by national surveillance systems in France, Italy, the United Kingdom, and the United States. The controls were health care workers in a prospective surveillance project who were exposed to HIV but did not seroconvert. RESULTS: Logistic-regression analysis based on 33 case patients and 665 controls showed that significant risk factors for seroconversion were deep injury (odds ratio= 15; 95 percent confidence interval, 6.0 to 41), injury with a device that was visibly contaminated with the source patient's blood (odds ratio= 6.2; 95 percent confidence interval, 2.2 to 21), a procedure involving a needle placed in the source patient's artery or vein (odds ratio=4.3; 95 percent confidence interval, 1.7 to 12), and exposure to a source patient who died of the acquired immunodeficiency syndrome within two months afterward (odds ratio=5.6; 95 percent confidence interval, 2.0 to 16). The case patients were significantly less likely than the controls to have taken zidovudine after the exposure (odds ratio=0.19; 95 percent confidence interval, 0.06 to 0.52). CONCLUSIONS: The risk of HIV infection after percutaneous exposure increases with a larger volume of blood and, probably, a higher titer of HIV in the source patient's blood. Postexposure prophylaxis with zidovudine appears to be protective.     

The relationship of lead in soil to lead in blood and implications for standard setting

As part of a soil lead regulation process, this review was conducted to determine the association between lead in soil and established human health effects of lead or validated biomarkers of lead exposure. We reviewed only studies where soil exposure could be distinguished from other sources of lead and whose design could reasonably be used to infer a causal relationship between soil lead and either biomarkers or health effects. No such studies of health effects were found. Studies describing a quantitative relationship between soil lead and blood lead did meet our criteria: 22 cross-sectional studies in areas with polluted soil; and three prospective studies of soil lead pollution abatement trials. The cross-sectional studies indicated that, compared to children exposed to soil lead levels of 100 ppm, those exposed to levels of 1000 ppm had mean blood lead concentrations 1.10-1.86 times higher and those exposed to soil lead levels of 2000 ppm had blood lead concentrations 1.13-2.25 times higher. The prospective studies showed effects within the ranges predicted by the cross-sectional studies. Differences in results between studies were surprisingly modest and likely explainable by random sampling error, different explanatory variables included in data analyses and differences in methods of measuring lead in environmental specimens.     

Efficacy of lodoxamide 0.1% versus N-acetyl aspartyl glutamic acid 6% ophthalmic solutions in patients with vernal keratoconjunctivitis

The purpose of this study was to investigate environmental lead exposure in the general Taiwanese population. A total of 8828 Taiwanese adults selected by a multistage sampling method were investigated. Characteristics of the participants were ascertained by questionnaire and 10 ml venous blood was drawn by public health nurses. The blood specimens were distributed to six laboratories for blood lead level (BLL) measurement. A quality control program was applied during the analysis of the BLLs in order to improve precision and accuracy. The arithmetic mean BLL of the 8828 Taiwanese adults was 7.70 +/- 5.23 micrograms/dl, with a maximal level of 69.1 micrograms/dl. The median was 6.5 micrograms/dl and the 90th percentile was 14.0 micrograms/dl. After logarithmic transformation, the geometric mean was 1.84 +/- 0.67 microgram/dl. This study also found that elevated BLLs were associated with certain personal characteristics, i.e., gender, ethnic group, and education level; life-style factors, such as smoking, alcohol consumption, Chinese herbal drug consumption, milk consumption, and sources of drinking water; residential location, i.e., level of urbanization; and occupational history of lead exposure. However, age, floor level of residence, distance from house to road, and betel nut consumption were not associated with elevated BLLs. These results showed that BLLs in the Taiwanese population were not higher than those in developed and developing countries. Most of the influencing factors were also found in other studies; however, local factors such as ethnic group, Chinese herbal drug consumption, and sources of drinking water are important considerations in Taiwan when examining ways to prevent overexposure to lead in the general population.     

Renal effects of environmental and occupational lead exposure

Environmental and industrial lead exposures continue to pose major public health problems in children and in adults. Acute exposure to high concentrations of lead can result in proximal tubular damage with characteristic histologic features and manifested by glycosuria and aminoaciduria. Chronic occupational exposure to lead, or consumption of illicit alcohol adulterated with lead, has also been linked to a high incidence of renal dysfunction, which is characterized by glomerular and tubulointerstitial changes resulting in chronic renal failure, hypertension, hyperuricemia, and gout. A high incidence of nephropathy was reported during the early part of this century from Queensland, Australia, in persons with a history of childhood lead poisoning. No such sequela has been found in studies of three cohorts of lead-poisoned children from the United States. Studies in individuals with low-level lead exposure have shown a correlation between blood lead levels and serum creatinine or creatinine clearance. Chronic low-level exposure to lead is also associated with increased urinary excretion of low molecular weight proteins and lysosomal enzymes. The relationship between renal dysfunction detected by these sensitive tests and the future development of chronic renal disease remains uncertain. Epidemiologic studies have shown an association between blood lead levels and blood pressure, and hypertension is a cardinal feature of lead nephropathy. Evidence for increased body lead burden is a prerequisite for the diagnosis of lead nephropathy. Blood lead levels are a poor indicator of body lead burden and reflect recent exposure. The EDTA lead mobilization test has been used extensively in the past to assess body lead burden. It is now replaced by the less invasive in vivo X-ray fluorescence for determination of bone lead content.     

Brain cancer and occupational exposure to lead

A recent report in the literature suggested a link between occupational exposure to lead and brain cancer. To explore the hypothesis, we applied a job-exposure matrix for lead to the occupation and industry codes given on the death certificate of 27,060 brain cancer cases and 108,240 controls who died of non-malignant diseases in 24 US states in 1984-1992. Brain cancer risk increased by probability of exposure to lead among Caucasian men and women with high-level exposure, with a significant twofold excess among Caucasian men with high probability and high level of exposure to lead (odds ratio = 2.1; 95% confidence interval, 1.1-4.0). Risks were also elevated in the low- and medium-probability cells for African-American men with high-level exposure to lead. Trend by intensity level was statistically significant among African-American men (all probabilities combined). Although exposure assessment was based solely on the occupation and industry reported on the death certificate, these results add to other epidemiologic and experimental findings in lending some support to the hypothesis of an association between occupational exposure to lead and brain cancer risk. Analytic studies are warranted to further test this hypothesis.     

Use of selenite enrichment broth for the detection of Salmonella from stool: a report of one year experience at a provincial public health laboratory

Umbilical blood lead level, as an indicator for intrauterine exposure to lead, and neurobehavioral score, as an effect indicator, were determined in 101 neonates in Beijing area to explore the relationship between intrauterine lead exposure and neonatal neurobehavioral development. Results revealed that there was a negative relationship between neonatal umbilical blood lead level and their neurobehavioral score and behavioral ability. With umbilical blood lead level of 0.48 mumol/L as a cutoff value, there was a significant difference in neonatal behavioral ability score between groups of high and low blood lead levels. There also were significant differences in nonbiologically auditory and biological visual and auditory orientation reaction. It suggests that intrauterine lead exposure can cause adverse effects on neonatal neurobehavioral development, especially on their visual and auditory function.     

Occupational disease profile in Taiwan, Republic of China

Lack of knowledge of the exact contents of the materials and improper handling of the toxic chemicals lead to the occurrence of occupational illnesses in the developing countries. However, the incidence of occupational diseases was usually underestimated. This article presents the profile of occupational diseases in Taiwan from two sources, i.e. occupational disease benefit payments of labor insurance and the review of relevant literature. The primarily documented occupational diseases in Taiwan were pneumoconioses. The second most common occupational disease was carbon monoxide intoxication, followed by lead poisoning and noise-induced hearing loss. Less than five percent of occupational diseases were due to the other causes, including decompression syndrome, heat stroke, toxic hepatitis, neurological disorders and hematologic disorders. The number of occupational diseases recognized in Taiwan was considered to be seriously underestimated due to the shortage of occupational medical specialists. Priority in the development of occupational medicine in Taiwan is to educate industrial hygienists and physicians to recognize health hazards in the work environment and to diagnose occupational diseases. Recognition of occupational diseases could subsequently highlight the health hazards in the workplace and prevent workers from overexposure.