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Historical exposure to inorganic mercury at the smelter works of Abbadia San Salvatore, Italy.

Metallic mercury production from cinnabar ore may result in high exposures to inorganic mercury, that are difficult to assess separately from the exposures originating from underground extraction, and previously have only been scantily described. We retrieved and analysed the air and biological mercury determinations on workers involved in the smelting process of the Abbadia San Salvatore mine (Monte Amiata, Italy). Native mercury was not present in the ore, and the exposure in the underground extraction was low. The smelter operated from 1897 to 1983. Blood and urine (24/h urine collections and concentration samples) had been sampled in 1968 to 1982, and analysed for mercury by atomic absorption spectrophotometry, and relate to all subjects. Exposure to mercury in air had been determined in a small set of personal samples in 1982. The data relate to all jobs in the smelter process, and all jobs entailed substantial exposure to mercury. The overall distribution of breathing zone air, blood and urinary levels is right-skewed and similar to the log-normal distribution (air, median 48 micrograms/m3, n = 49; blood, arithmetic mean AM 49 micrograms/L; geometric mean GM 26 micrograms/L, n = 192; urinary excretion, AM 140 micrograms/24 h, GM 78 micrograms/24 h, n = 839; and urinary concentration, AM 160 micrograms/L, GM 83 micrograms/L, n = 632). Air, blood and urinary values show a high ratio of the between- and within-job variance, indicating differences in exposure by job. Cinnabar pigment production, of which the exposure has not been characterised previously, was the job with the highest air (AM 160 micrograms/m3) and urinary levels (excretion AM 690 micrograms/24 h; concentration AM 1100 micrograms/L). Other jobs with high urinary levels were soot purification, laboratory work, and bottling. Cleaning of condensers showed the highest blood level (AM 280 micrograms/L). There is a downwards time trend in mercury concentration in blood and in urine. The corresponding trend is not seen for urinary excretion levels, the reason for this being unclear. Roasters, which is the most frequently monitored group, show however a decreasing trend in all sets of data (e.g. the mean of urinary excretion decreased from 300 micrograms/24 h in 1968/69 to 50 micrograms/24 h in 1980/81). The mercury exposure experienced by the smelters of Abbadia San Salvatore is in line with the few available data on workers from other mercury mines and smelters, and our data confirm the high exposure levels in this occupational group, in particular at cinnabar pigment production, soot purification, and condenser cleaning.

Aerosols↗

Ethnic differences in the prevalence of nonmalignant respiratory disease among uranium miners.

OBJECTIVES: This study (1) investigates the relationship of nonmalignant respiratory disease to underground uranium mining and to cigarette smoking in Native American, Hispanic, and non-Hispanic White miners in the Southwest and (2) evaluates the criteria for compensation of ethnic minorities. METHODS: Risk for mining-related lung disease was analyzed by stratified analysis, multiple linear regression, and logistic regression with data on 1359 miners. RESULTS: Uranium mining is more strongly associated with obstructive lung disease and radiographic pnuemoconiosis in Native Americans than in Hispanics and non-Hispanic Whites. Obstructive lung disease in Hispanic and non-Hispanic White miners is mostly related to cigarette smoking. Current compensation criteria excluded 24% of Native Americans who, by ethnic-specific standards, had restrictive lung disease and 4.8% who had obstructive lung disease. Native Americans have the highest prevalence of radiographic pneumoconiosis, but are less likely to meet spirometry criteria for compensation. CONCLUSIONS: Native American miners have more nonmalignant respiratory disease from underground uranium mining, and less disease from smoking, than the other groups, but are less likely to receive compensation for mining-related disease.

Colorado↗

Nonoccupational exposure to chrysotile asbestos and the risk of lung cancer.

BACKGROUND: Heavy industrial exposure to asbestos causes lung cancer and mesothelioma, but it remains unknown whether much lower environmental exposure to asbestos also causes these cancers. Nevertheless, regulatory agencies, including the Environmental Protection Agency (EPA), have assessed the risk of lung cancer by extrapolating known risks from past industrial exposure to asbestos to today's much lower environmental asbestos levels (roughly 100,000 times lower). We also tested the EPA's model for predicting the risk of asbestos-induced lung cancer in a population of women with relatively high levels of nonoccupational exposure to asbestos. METHODS: Mortality among women in 2 chrysotile-asbestos-mining areas of the province of Quebec was compared with mortality among women in 60 control areas, and age-standardized mortality ratios were derived. With the help of an expert panel, we estimated past exposure to asbestos among women in the mining areas and used these data with the EPA's model to predict the relative risk of lung cancer. We then compared this prediction with the observed mortality ratios. RESULTS: On the basis of the estimated exposure in the asbestos-mining areas, a relative risk of death due to lung cancer of 2.1 was predicted by the EPA's model, amounting to about 75 excess deaths from lung cancer in this population. By contrast, we calculated a standardized mortality ratio of 1.0 and a standardized proportionate mortality ratio of 1.1 (P> 0.05), suggesting that there were between 0 and 6.5 excess deaths from lung cancer among the women with nonoccupational exposure to asbestos. Seven deaths from pleural cancer were observed (relative risk=7.63; P<0.05). CONCLUSIONS: We found no measurable excess risk of death due to lung cancer among women in two chrysotile-asbestos-mining regions. The EPA's model overestimated the risk of asbestos-induced lung cancer by at least a factor of 10.

Adult↗

Cancer in asbestos-mining and other areas of Quebec.

Employing incidence data from the Quebec Tumor Registry, we examined the relative risks of cancer of all sites for the years 1969-73 in the asbestos-mining, rural, and metropolitan counties of Quebec Province, Canada. Generally, rates for males exceeded those for females, and the relative risks in the asbestos-mining counties for 7-10 different sites of cancer, all of low incidence, were from 1.50 to 8.08 times those of other rural counties of the Province for both sexes. Metropolitan counties exhibited equally high risk for many of these sites. We discovered higher risks among males in asbestos-mining counties for cancer of the pleura, peritoneum, lip, tongue, salivary gland, mouth, and small intestine and higher risks among females for cancer of the pleura, lip, kidney, salivary gland, and for melanoma. Because of the likelihood of a long latent period for asbestos-related cancers, the risks we observed were possibly the product of since-altered occupational and environmental conditions existing 20-30 years ago in the asbestos-mining areas. The similarities in risks for most cancers in asbestos-mining and urban areas were noteworthy.

Asbestos↗

Occupational diseases in South African mines--a neglected epidemic?

A major difficulty in assessing incidence and prevalence of occupational diseases among the workforce employed on South African mines is the lack of epidemiological data. Published and unpublished data were collated and analysed for the period 1915-1988 in order to provide insights into occupational disease trends. Using proxies for incidence rates, it was demonstrated that the rates of silicosis and tuberculosis were likely to be high. In the case of silicosis among black miners, disease was contracted in a relatively short period on average. The stabilisation of the black workforce on the mines, which started in 1975 and continues, is an important factor likely to lead to an increase in occupational disease rates. Recommendations for improved data reporting and research are made, in particular the need to identify occupational groups at high risk and the calculation of prevalences.

Adult↗

Seq2Saccharide: Discovering Oligosaccharides and Aminoglycosides Natural Products by Integrating Computational Mass Spectrometry and Genome Mining.

Natural oligosaccharides and aminoglycosides are important sources of new drug candidates, especially in the development of antibiotics. In the past, discovering novel saccharides has been time-consuming and costly. However, the rapid expansion of high-throughput data, including genomic and mass spectrometry data sets, has greatly increased opportunities for natural saccharide discovery. Yet, due to the complex biosynthesis pathways of saccharides, no existing method can predict their structures with high precision. To address this, we introduce Seq2Saccharide, a tool designed to automate saccharide natural product discovery by integrating both genomic and mass spectrometry data. To enhance accuracy, Seq2Saccharide predicts hundreds or thousands of putative structures for each gene cluster. The correct structure is then identified from these predictions using a mass spectral search. Benchmarks against saccharides in the MiBIG database show that Seq2Saccharide outperforms existing methods in predicting the structure of saccharides. Furthermore, mass spectrometry analysis indicates that the variable search module can correct mispredictions from genome mining. By searching genomic and mass spectrometry data of microbial strains, Seq2Saccharide correctly identified the biosynthetic gene cluster for the polysaccharide oligosaccharide trestatin B.

Aminoglycosides↗

Respiratory abnormalities in employees of the hard rock mining industry.

Respiratory symptoms, forced vital capacity, and the single breath N2 test were assessed in male employees (25 to 54 yr of age) who had been employed for more than 5 yr in the mining industry in Manitoba. The results were compared with those in a similar group of men selected from the general population. The prevalence of cough and/or phlegm in both nonsmoking and smoking mining employees was significantly greater than that in the sample of the general population (p less than 0.05). In both nonsmokers and ex-smokers amongst the mining employees, the parameters derived from the single breath N2 test tended to be lower and maximal expiratory flow rates tended to be higher than in comparable groups in the general population sample. In smokers, FVC, FEV1, FEV1/FVC, maximal expiratory flow rates, RV/TLC, and the slope of phase III were significantly worse in smelter workers than in underground workers. Alterations in lung function in those who worked underground, but not in those who worked in the smelter, was related to the duration of employment in the industry. The data suggest that exposure to mining irritants may result in disorders of lung function, and that this effect is greater in cigarette smokers.

Adult↗

Mining for putative regulatory elements in the yeast genome using gene expression data.

We have developed a set of methods and tools for automatic discovery of putative regulatory signals in genome sequences. The analysis pipeline consists of gene expression data clustering, sequence pattern discovery from upstream sequences of genes, a control experiment for pattern significance threshold limit detection, selection of interesting patterns, grouping of these patterns, representing the pattern groups in a concise form and evaluating the discovered putative signals against existing databases of regulatory signals. The pattern discovery is computationally the most expensive and crucial step. Our tool performs a rapid exhaustive search for a priori unknown statistically significant sequence patterns of unrestricted length. The statistical significance is determined for a set of sequences in each cluster with respect to a set of background sequences allowing the detection of subtle regulatory signals specific for each cluster. The potentially large number of significant patterns is reduced to a small number of groups by clustering them by mutual similarity. Automatically derived consensus patterns of these groups represent the results in a comprehensive way for a human investigator. We have performed a systematic analysis for the yeast Saccharomyces cerevisiae. We created a large number of independent clusterings of expression data simultaneously assessing the "goodness" of each cluster. For each of the over 52,000 clusters acquired in this way we discovered significant patterns in the upstream sequences of respective genes. We selected nearly 1,500 significant patterns by formal criteria and matched them against the experimentally mapped transcription factor binding sites in the SCPD database. We clustered the 1,500 patterns to 62 groups for which we derived automatically alignments and consensus patterns. Of these 62 groups 48 had patterns that have matching sites in SCPD database.

Gene Expression Profiling↗

Epidemiology of occupational noise-induced hearing loss in Poland throughout 1971--1979.

In Poland a uniform system for registering occupational diseases is mandatory. Special individual statistical cards of diagnosed cases are delivered from all over the country to the Institute of Occupational Medicine in Lodź, where the incidence of diseases is analysed using electronic data processing system; such procedure is aimed, among others, at specification of prophylactic needs. Due to this, epidemiological studies could be carried out of the prevalence of occupational noise -- induced hearing loss in the total national economy throughout 1971--1979. Of the 35 mln Polish population, approx. 5 mln. 240 thous. persons are employed in industry, in this about 600 000 workers exposed to noise levels posing a risk of the hearing impairment of (Leq greater than or equal to 90 dB-A). It was found that occupational noise -- induced hearing loss was most frequent among all occupational diseases and its incidence rate exceeded 16 new cases annually per 100 000 employees. The highest incidence rate concerned transport means industry, coal mining and textile industry. The data analysis, by age and exposure duration, showed that the disease mostly affects those aged 40 -- 49 and 50 -- 59, as well as those exposed to excessive noise levels for over 20 years. In addition, the distribution of occupational noise -- induced hearing loss in specific areas throughout the country, considering the degree of industrialization, was analysed. The highest incidence rate was found in the Southern and Western areas of Poland. The above information seems to be essential for setting up more efficient hearing conservation program in industry.

Adult↗

Absolute bioavailability of lead acetate and mining waste lead in rats.

The primary purpose of this study was to generate data that could be used to determine the absolute bioavailability of lead using data from a previous study in which soil containing lead from mining waste was mixed with feed. Young male and female Sprague-Dawley rats (7-8 weeks of age, five/sex/group) were given either soluble lead acetate mixed in a purified diet (AIN-76) at three different dose levels (1, 25, and 250 ppm Pb for 30 consecutive days) or intravenously at doses of 0.02, 0.20, and 2.0 mg Pb/kg BW for 29 days. A control group (purified diet only) was also included. The intravenous groups were used to provide maximal absorption (lead presumed to be 100% bioavailable) and accumulation data for lead in blood, bone, and liver. The lead acetate groups were used to evaluate the comparability of the present study with a previous study that compared bioavailable lead from ingested soil and lead acetate. Group mean whole blood, bone and liver lead concentration values increased with increasing dose levels for all treatment groups. A linear relationship was observed between blood lead concentration and dose following intravenous administration of lead and this provided empirical support for using blood lead concentrations at supposed steady state (approximately 30 days) to compute the bioavailability of lead administered by different routes and from different sources. The absolute bioavailability values of mining waste lead in soil were low based on the results for all tissue types. Absolute bioavailability values for lead acetate in dosed feed for blood, bone, and liver were approximately 6-, 19-, and 20-fold greater, respectively, than mining waste lead. Based on the current design and test system used, the absolute bioavailability of mining waste lead in soil administered in feed was approximately 3% based on blood data and less than 1% based on bone and liver data. These data are consistent with the low solubility of the constituent lead mineral phases in Butte soils.

Administration, Oral↗

Contamination of houses by workers occupationally exposed in a lead-zinc-copper mine and impact on blood lead concentrations in the families.

OBJECTIVE: To evaluate the pathway of leaded dust from a lead-zinc-copper mine to houses of employees, and the impact on blood lead concentrations (PbB) of children. METHODS: High precision lead isotope and lead concentration data were obtained on venous blood and environmental samples (vacuum cleaner dust, interior dustfall accumulation, water, paint) for eight children of six employees (and the employees) from a lead-zinc-copper mine. These data were compared with results for 11 children from occupationally unexposed control families living in the same city. RESULTS: The median (range) concentrations of lead in vacuum cleaner dust was 470 (21-1300) ppm. In the houses of the mine employees, vacuum cleaner dust contained varying higher proportions of mine lead than did airborne particulate matter measured as dustfall accumulated over a three month period. The median (range) concentrations of lead in soil were 30 (5-407) ppm and these showed no evidence of any mine lead. Lead in blood of the mine employees varied from 7 to 25 micrograms/dl and was generally dominated by mine lead (> 60%). The mean (SD) PbB in the children of the mine employees was 5.7 (1.7) micrograms/dl compared with 4.1 (1.4) micrograms/dl for the control children (P = 0.02). The PbB of all children was always < 10 micrograms/dl, the Australian National Health and Medical Research Council goal for all Australians. Some of the control children had higher PbB than the children of mine employees, probably from exposure to leaded paint as six of the eight houses of the control children were > 50 years old. In five of the eight children of mine employees > 20% of PbB was from the lead mine. However, in the other three cases of children of mine employees, their PbB was from sources other than mine lead (paint, petrol, background sources). CONCLUSIONS: Houses of employees from a lead mine can be contaminated by mine lead even if they are not situated in the same place as the mine. Delineation of the mine to house pathway indicates that lead is probably transported into the houses on the clothes, shoes, hair, skin, and in some cases, motor vehicles of the workers. In one case, dust shaken from clothes of a mine employee contained 3000 ppm lead which was 100% mine lead. The variable contamination of the houses was not expected given the precautions taken by mine employees to minimise transportation of lead into their houses. Although five out of the eight children of mine employees had > 20% mine lead in their blood, in no case did the PbB of a child exceed the Australian National Health and Medical Research Council goal of 10 micrograms/dl. In fact, some children in the control families had higher PbB than children of mine employees. In two cases, this was attributed to a pica habit for paint. The PbB in the children of mine employees and controls was independent of the source of lead. The low PbB in the children of mine employees may reflect the relatively low solubility (bioavailability) of the mine dust in 0.1 M hydrochloric acid (< 40 %), behaviour--for example, limited mouthing activity--or diet.

Adult↗

UTAB: a computer database on residues of xenobiotic organic chemicals and heavy metals in plants.

The UTAB Database contains information concerned with the uptake/accumulation, translocation, adhesion, and biotransformation of both xenobiotic organic chemicals and heavy metals by vascular plants. UTAB can be used to estimate the accumulation of chemicals in vegetation and their subsequent movement through the food chain. The database contains actual data from papers in the published literature dating from 1926 for organic chemicals and from 1976 for heavy metals. At present the database is comprised of more than 37,000 records pertaining to 900 different organic chemicals, 21 heavy metals, and over 350 plant species. Each record contains information on a single combination of species, chemical, and dose. Other information includes the application and destination sites, amount accumulated, rates of uptake or translocation, products and sites of biotransformation, experimental condition parameters, and the source paper. Thus, the database can be used to quickly obtain specific data pertaining to a chemical, plant species, mine spoil, etc. or it can be used for the comparative analysis of a set of data pertaining to groups of chemicals and plants.

Databases, Bibliographic↗

[Evaluation of the effectiveness of medical prevention of pneumoconiosis based on studies of its incidence in selected coal mines].

In a group of 3,938 persons--pit miners of 3 coal mines--employed over 8 years, full-size X-ray pictures of the chest have been taken and through a special questionnaire information has been collected on the length of employment, workstation, risk of dustiness, exposure to fibrogenic dusts outside the mine. Basing on the studies, the mean annual incidence of pneumoconiosis in particular mines has been calculated. The data has been compared with the mean annual incidence rate of pneumoconiosis calculated for 10 years prior to epidemiological studies and based on the primary selection by means of small-size pictures. This comparison indicated that the full-size pictures revealed 3-7 times more pneumoconioses as compared to the hitherto applied system. The comparison of full-size and small-size X-ray pictures demonstrated that the lesions visible in full-size pictures have not been registered in small-size pictures in as many as half of the cases. The obtained results indicate that the effectiveness of the hitherto applied system of medical prevention of pneumoconiosis is insufficient. A change in this system is indispensable; miniature roentgenography should be replaced by full-size X-ray pictures.

Adult↗

Effect of different grouping strategies in developing estimates of personal exposures: specificity versus precision.

There has been increasing interest in recent years in developing strategies in epidemiology for the summarization of occupational exposures, strategies that serve to clarify observed relationships between occupational exposure and health outcomes. Where source occupational exposure data are scarce, it is common to assemble exposure groups with the goal of increasing the extent to which data-based exposure estimates are available for an entire cohort. There has been little guidance, however, on the effect of different grouping strategies on the observed fit between exposure and health outcome. This investigation examined the effect of the use of different exposure summarization strategies on observed relationships between dust exposure and lung function decline among coal mine workers. The dust exposure and spirometry data employed were gathered in the National Study of Coalworkers' Pneumoconiosis. An analysis of variance procedure was carried out to characterize the variability of the dust exposure data, employing single variables relating to mine identity, occupation, and year, as well as two- and three-way multivariate combinations of these variables. The resulting combinations were ranked according to the standard deviation of the observed exposure range to reflect the relative specificity of the various approaches. Sequential arrangements of single- and multiple-variable combinations were constructed, alternately employing highly specific codes or broad categories for mine, occupation, and year. Annual exposure estimates were constructed on the basis of these sequences and used in tandem with longitudinal change in forced expiratory volume (FEV1) in linear multiple regression procedures. Height, age, smoking status, and dust exposure were employed as predictor variables. The results show that the use of broad categorization approaches had a substantial impact on observed regression coefficients. The largest change was observed for categorization according to occupation, which resulted in two- to three-fold increases in the magnitude of observed regression coefficients. These results suggest that the use of highly specific exposure summarization approaches may result in regression outcomes which are marked by a high degree of attenuation, and that consideration of the precision of summarized exposure estimates is an important component of an effective exposure assessment strategy.

Adult↗

Effects of oral exposure to mining waste on in vivo dopamine release from rat striatum.

Several single components of mining waste (arsenic, manganese, lead, cadmium) to which humans are exposed at the mining area of Villa de la Paz, Mexico, are known to provoke alterations of striatal dopaminergic parameters. In this study we used an animal model to examine neurochemical changes resulting from exposure to a metal mixture. We used microdialysis to compare in vivo dopamine release from adult rats subchronically exposed to a mining waste by oral route with those from a control group and from a sodium arsenite group (25 mg/kg/day). We found that arsenic and manganese do accumulate in rat brain after 2 weeks of oral exposure. The mining waste group showed significantly decreased basal levels of dihydroxyphenylacetic acid (DOPAC; 66.7 +/- 7.53 pg/ microl) when compared to a control group (113.7 +/- 14.3 pg/ microl). Although basal dopamine release rates were comparable among groups, when the system was challenged with a long-standing depolarization through high-potassium perfusion, animals exposed to mining waste were not able to sustain an increased dopamine release in response to depolarization (mining waste group 5.5 +/- 0.5 pg/ microl versus control group 21.7 +/- 5.8 pg/ microl). Also, DOPAC and homovanillic acid levels were significantly lower in exposed animals than in controls during stimulation with high potassium. The arsenite group showed a similar tendency to that from the mining waste group. In vivo microdialysis provides relevant data about the effects of a chemical mixture. Our results indicate that this mining waste may represent a health risk for the exposed population.

Administration, Oral↗

Exposures to Legionella pneumophila and Chlamydia pneumoniae in South African Mine Workers.

Exposures of South African mine workers to Legionella pneumophila and Chlamydia pneumoniae were studied over a period of six months. Seroprevalence data were compared with data from a group of factory workers. Antibodies to L. pneumophila serogroups 1-4 were demonstrated in 36% of the mine workers and 10% of the factory workers (p < 0.0001). Seroconversion occurred in 18% of the mine workers during the study period. Antibodies to C. pneumoniae were present in 66% of the mine workers and 22% of the factory workers (p < 0.0001). Seroconversion was demonstrated in 17% of the mine workers during the six months of follow-up. A significant association between the presence of respiratory symptoms and seroconversion was demonstrated (p < 0.025). The data suggest that mine workers are at increased risk for infections with L. pneumophila and C. pneumoniae. Legionella pneumophila; Chlamydia pneumoniae; mine workers; factory workers; risk factors; seroprevalence; seroconversion

Journal Article↗

Pre-operational survey of a U mine near Val Vedello, Italy.

Results obtained from radiometric research carried out from 1980-81 in the region of U mines in the Val Vedello are provided. Data are presented on 222Rn, 226Ra and natural U concentrations in spring and surface waters. Concentrations were found to be relatively low. There is some increase in the vicinity of the exploratory U mine but this is, at least up to the present, only of a local character. Data are presented on external gamma exposure, 210Pb and 210Po in foodstuffs and in the urine of normal and exposed population as well as 226Ra in milk and vegetable samples. The aim of this study is to outline a preliminary map of natural radioactivity on the site before starting the mining activity. This will enable us later to detect changes caused by the U mining, milling and mill-tailing disposal operations.

Air Pollutants, Radioactive↗