Inorganic Dust Research Articles

Respiratory effects of coal dust exposure: clinical effects and diagnosis.

During the past two decades, growing evidence has been reported on the role of respirable inorganic dust in the development of airflow obstruction, impaired diffusion capacity, chronic bronchitis, and emphysema, irrespective of the extent of possible pneumoconiotic abnormalities. These nonpneumoconiotic effects associated with dust exposure in miners and the relationship between dust exposure and mortality are reviewed. When pneumoconiotic changes can be visualized by different radiologic techniques, including computed tomography (CT) and high-resolution CT, assessment of the respiratory impairment in coal workers at present requires evaluation of the ventilatory and gas exchange capacity.

Appraisal of work hazards and safety in the industrial estate of Jeddah

An environmental study for the appraisal of work hazards and safety in Jeddah Industrial Estate (JIE), Saudi Arabia has been conducted. The study is based upon a representative (stratified random) sample of 44 enterprises, including 52 plants and employing 5830 workers.Nearly 2/3 of the workers have heat exposure, orginating from climatic heat and heat dissipated from industrial operations, while exposure to noise is slightly less, and is attributed to noisy operations and machinery and to lack of meticulous maintenance; both exposures are mild in most of the plants and moderate in some. Mild exposures to nonionizing radiations (UV and IR) and to deficient illumination occur in 25% and 19.2% of the plants studied. Respiratory exposure to chemical agents (organic and inorganic dusts, metal fumes, gases and vapours - including asphyxiants, irritants, liver and nervous system offenders and acid and alkali mists) occurs in 75% of the plants, particularly in the medium-size enterprises plants; however, is mainly mild with a few moderate and severe exposures. Skin absorption contributes to absorption of chemical agents in 29% of the plants, and direct skin contact to chemicals (particularly to lubricating oils) occurs in 81% of the plants.Meanwhile, only eight plants, out of the 32 plants where controls for physical hazards are required (51.2%), apply engineering controls, and even in a few of these plants the efficiency of the control measures has been rated 'bad'. A few of them provide personal protective equipment, and even no maintenance to this equipment is provided.The level of safety is better in the large plants than in the small and medium-size plants; the safety score is the best in the recently established plants, while is the worst in the plastic industry, which is relatively old. The appraisal of fire protection is better than that of the safety, due to efficient supervision of the General Directorate of Civil Defense (GDCD). However, most of the safety problems are managerial and are preventable.First aid is present in all enterprises, as required by the Saudi Labor Laws; however, an in-plant medical service is present in 75% of the large enterprises, in 31.6% of the medium-size and in only 17.6% of the small enterprises. Also, satisfactory medical, accidents and absenteeism records exist in only 15.9% of the enterprises; safety supervision exists in 27.3, and safety education exists in 91% of them, while no environmental monitoring is carried out in any enterprise. Sanitation facilities exist in satisfactory numbers in most of the enterprises; however, their maintenance is poor in most of them, due to lack of hygienic supervision. All enterprises dispose of their liquid wastes into the JIE sewerage system without any treatment, while the solid wastes are collected by the city authorities in 56.8% of them; both wastes are anticipated to cause environmental pollution problems.

Detection of irradiated mushrooms and kiwi fruits by thermoluminescence measurement

Control methods for the detection of irradiated food are needed since exposure to ionizing radiation is a new technique of commercial food processing applied in many countries. A simple and rapid method for the identification of irradiated fresh kiwi fruits and mushrooms is presented. Thermoluminescence (TL) signals of irradiated dried herbs and spices are known to be due to inorganic dust particles adherent to the surface and may be used for the detection of radiation exposure. In the technique described here the discrimination between radiation exposed food samples and unirradiated samples was improved by the preparation of TL samples enriched in extraneous inorganic material and further by the determination of the optimal integration interval giving the highest signal to background ratios. This method yields a more reliable discrimination than whole sample TL techniques.

Primary liver cancer and occupational exposure.

In a dynamic population-based case-referent study on primary liver cancer and occupational exposure, the work histories of 344 cases and 861 referents, derived from the follow-up of the whole Finnish population in 1976-1978 and 1981, were analyzed by industry, occupation, and agent. After adjustment for alcohol consumption, elevated odds ratios were found for the categories other agricultural workers (mainly milkmaids), clerical workers, persons exposed to welding fumes and those exposed to other inorganic dusts (mainly silica). One possible explanation for the excess among milkmaids was exposure to dust from cattle feed contaminated with aflatoxins. The excess among clerical workers was probably due to nonoccupational factors or chance because occupational exposure was generally rare. The excesses for welding fumes and inorganic dusts, although compatible with occupational etiology, contradict the results of many previous studies carried out among workers exposed to silica dust and welders.

Reduced FVC among California Grape Workers

Pulmonary disease due to organic and inorganic dust inhalation represents a significant health problem in the agricultural community. In response to concern over the potential adverse health effects of agricultural exposures, and to address the question of whether the specific crop worked was associated with decreased lung function, we conducted a cross-sectional survey of pulmonary function in a population of 238 grape workers, 355 tomato workers, and 166 citrus workers in California's Central Valley. In addition, 92 workers (66 males and 26 females) performed spirometry before and after an 8-h work shift. Multiple regression analysis of pulmonary function in all 759 workers revealed that age, height, and smoking-adjusted mean preshift FVC was lower in grape workers than in citrus workers in each of three sex and age groups studied: decreased 314 ml for males greater than or equal to 25 yr of age p less than 0.05, 82 ml for males less than 25 yr, and 83 ml for females greater than or equal to 20 yr. Mean adjusted preshift FVC was also lower in grape workers than tomato workers (decreased 249 ml in males greater than or equal to 25 yr [p less than 0.05], 51 ml for males less than 25 yr, and 46 ml for females greater than or equal to 20 yr). Adjusted mean FEV1 was not different by crop, but FEV1/FVC and forced-expiratory flow from 25 to 75% of the FVC (FEF25-75) were significantly elevated in grape workers of the three age and sex groups compared with citrus or tomato workers.(ABSTRACT TRUNCATED AT 250 WORDS)

Zymosan-induced chemiluminescence of alveolar macrophages: Depression by inorganic dust constituents

A method has been developed which allows the incubation of alveolar macrophages as weakly affixed monolayers in siliconized glass dishes. Without vigorous mechanical agitation and without using proteolytic enzymes, these cells were subsequently transferred to cuvettes where the zymosan-stimulated chemiluminescence of the suspended cells was measured. In vitro incubations of activated rabbit alveolar macrophage monolayers with airborne dusts from four West German sites (1 to 200 micrograms/10(6) cells), fly ash fractions of a special waste incinerator at Hamburg (50 to 1,000 micrograms/10(6) cells), and quartz dust DQ 12 (5 to 200 micrograms/10(6) cells) resulted in a dose- dependent depression of the zymosan-stimulated chemiluminescence. The depression of chemiluminescence was correlated with particle numbers, estimated dust surface, and antimony and lead masses of the dusts to which the cells were exposed. Cytotoxicity was better correlated with these parameters than with dust mass.

Silicosis in a Himalayan village population: role of environmental dust.

The Himalayan villages of Chuchot Shamma and Stok were surveyed because silicosis had been suspected from the radiographs of some of the inhabitants. The villages are agricultural, and Chuchot is exposed to frequent dust storms. Chest radiographs of villagers aged 50-62 were assessed blind by two independent observers using ILO criteria. In Chuchot five of seven men and all of the nine women examined showed varying grades of silicosis, compared with three of 13 men and seven of 11 women in Stok, which lies 300 metres higher and is exposed to fewer dust storms. The difference in prevalence of silicosis between the two villages was significant, as was the differences between men and women. Three patients from the village adjoining Chuchot were later found to have radiological evidence of progressive massive fibrosis. A necropsy on a man in a neighbouring village in the Indus valley showed classical silicosis in a hilar lymph node. Chemical analysis of the inorganic dust in the lung showed that 54.4% was elemental silicon [corrected]. This was similar to the silicon [corrected] content of dust samples collected from houses in Chuchot, which included particles of respirable size. X-ray microanalysis showed that quartz formed 16-21% of the inorganic lung dust. This study suggests that silicosis is common among the older inhabitants of these Himalayan villages. The dust exposure is clearly environmental and not industrial. Further studies are needed to define the extent and severity of silicosis in this community and to examine possible preventive measures.

Relationship of inflammatory cell cytokines to disease severity in individuals with occupational inorganic dust exposure

The pneumoconioses due to chronic occupational exposure to asbestos, coal, or silica are characterized by an alveolar macrophage-dominated alveolitis with exaggerated spontaneous release of mediators: oxidants, chemotaxins for neutrophils, and fibroblast growth factors. Bronchoalveolar lavage was performed on 66 non-smoking inorganic dust-exposed individuals with a chest x-ray greater than or equal to 1/0 stratified by presence or absence of restrictive respiratory impairment, and 28 unexposed non-smoking controls. Both dust-exposed groups stratified by presence or not of impairment had increased numbers of total cells recovered by lavage compared to normals, and those with respiratory impairment (n = 40) had a significant increase in percent and number of neutrophils recovered. Similarly, only those with respiratory impairment had macrophages that spontaneously released significant amounts of the oxidants superoxide anion and hydrogen peroxide. There was a significant trend for the release of fibronectin by macrophages from controls to dust-exposed without impairment to those with impairment. Both dust-exposed groups also had increased release of alveolar macrophage-derived progression growth factor, but this was significantly less than macrophages from patients with idiopathic pulmonary fibrosis. Since occupational exposure was virtually identical in inorganic dust-exposed individuals with versus without respiratory impairment, the quantitative differences in the release of macrophage mediators may be due to factors in host susceptibility.

Inorganic particles induce secretion of a macrophage homologue of platelet-derived growth factor in a density-and time-dependent manner in vitro.

The inhalation of inorganic dust can lead to the development of interstitial pulmonary fibrosis, characterized by the accumulation of fibroblasts and connective tissue matrix in the lung interstitium. The fibrosis causes alterations in the architecture of the lung parenchyma, resulting in abnormal gas exchange and hypoxemia. In a rat model of asbestos exposure, inhaled fibers are deposited on alveolar duct bifurcations, followed by an accumulation of alveolar macrophages at the sites of dust deposition. The alveolar macrophage is thought to be a major mediator of the pulmonary inflammatory response to inhaled dust. Platelet-derived growth factor (PDGF) is a cytokine that has potent chemotactic and mitogenic effects on mesenchymal cells, such as fibroblasts and smooth muscle cells. We studied the secretion of an alveolar macrophage-derived homologue of PDGF in response to carbonyl iron spheres or chrysotile asbestos fibers in vitro. We demonstrate here that rat alveolar macrophages attached to a plastic substrate produce 69 +/- 79 picograms (pg) of PDGF per 10 million macrophages. This is similar to amounts recovered from human platelets. In contrast, macrophages exposed to iron spheres secrete 429 +/- 177 pg of PDGF/10(6) macrophages after 24 h in culture. Exposure to asbestos fibers increased the PDGF production to 628 +/- 213 pg/10(6) cells. PDGF secretion was influenced by the particles in a density- and time-dependent manner. We hypothesize that PDGF and other cytokines secreted by macrophages mediate the development of dust-induced lung disease.

Clinical guidelines and indications for bronchoalveolar lavage (BAL): occupational lung diseases due to inhalation of inorganic dust

Clinical guidelines and indications for bronchoalveolar lavage (BAL): occupational lung diseases due to inhalation of inorganic dust

Inflammation and immune reactions in interstitial lung disease (ILD) associated with inorganic dust exposure

Inflammation and immune reactions in interstitial lung disease (ILD) associated with inorganic dust exposure

Inflammatory and immune reactions associated with inorganic dust exposure: comparison between patients with and without clinical lung involvement

Inflammatory and immune reactions associated with inorganic dust exposure: comparison between patients with and without clinical lung involvement

CHARACTERIZATION OF AIRBORNE DUST IN A SOFT PAPER MILL

The characteristics of airborne dust in a soft paper production plant have been characterized by scanning and transmission electron microscopy. A combination of X-ray diffraction, electron diffraction and energy-dispersive X-ray flouresence spectroscopy (EDX) was used to determine the structure and composition of the different components. Size distribution determination and phase identification were carried out. Besides the cellulose fibres, fibres of kaolinite, wollastonite, talc and other silicates were also identified. Gravimetric analysis and fibre counting by optical phase contrast microscopy were used to determine total dust and fibre concentrations. Total dust exposure at the plant was generally below 3 mg m-3. The respirable fraction of the total dust concentrations varied from 15 to 70%. The inorganic dust was 36 +/- 15% of the total dust. The ratio of inorganic fibres to total fibre concentration at the plant varied between 10 and 15%.

Evaluation of Alveolar Macrophage Particle Burden in Individuals Occupationally Exposed to Inorganic Dusts

Alveolar macrophages recovered by bronchoalveolar lavage from individuals with occupational inorganic dust exposure are laden with particles. We evaluated 42 non-smoking males with long-term exposu...

Symposium on Health Effects of Occupational Exposure to Inorganic Dusts

Ce symposium a pour but de discuter des differents aspects des maladies pulmonaires provoquees par les particules minerales. Comme la pneumoconiose, ces maladies nouvelles issues des industries petrochimiques ou de fibres minerales, sont caracterisees par une tres grande fibrogenese au niveau pulmonaire

Special neutrophil elastase inhibitory activity in BAL fluid from patients with silicosis and asbestosis

Pneumoconiosis is defined as the disease resulting from a chronic exposure to different inorganic dusts. In order to assess the lung defence against the effects of dust exposure, we studied the bronchoalveolar lavage (BAL) fluids from 30 silicotic patients (9 of them having a diagnosis of progressive massive fibrosis (PMF)) and 8 subjects with a diagnosis of asbestosis. Total protein content, N-acetyl-beta-D-glucosaminidase activity, free elastase-like activity, immunoreactive alpha 1-proteinase inhibitor (alpha 1PI) and neutrophil elastase inhibitory capacity (NEIC) were determined, and the values obtained were compared to those of 14 control BAL fluids. In all of the patients, our data showed a significant increase of total protein content and free elastase-like activity. In contrast, N-acetyl-beta-D-glucosaminidase activities did not reach statistical significance. Values concerning immunoreactive alpha 1PI and NEIC were significantly raised only in patients with PMF and with asbestosis. When the ratio NEIC/immunoreactive alpha 1PI was calculated, a significant difference was noticed in the asbestosis group; on the other hand, this ratio was significantly reduced in the group of PMF patients. After neutrophil elastase addition, an electrophoretic study by SDS-PAGE and immunoblotting was carried out; it showed more proteolysed alpha 1PI in the BAL fluids having a lowered NEIC/alpha 1PI ratio. These facts could be explained by the presence of inhibitors of neutrophil elastase different from alpha 1PI.

Cancer risks associated with 10 inorganic dusts: Results from a case‐control study in Montreal

A multicancer site, multifactor case-control study was undertaken to generate hypotheses about possible occupational carcinogens. Probing interviews were carried out with eligible cases, comprising all incident cases of 20 types of cancer who were male, aged 35-70 years, and a resident in Montreal. The interview was designed to obtain detailed lifetime job histories and information on potential confounders. Each job history was reviewed by a team of chemists and industrial hygienists who translated it into a history of occupational exposures. These occupational exposures were then analyzed as potential risk factors in relation to the sites of cancer included; 3,726 cases were interviewed. For each site of cancer analyzed, controls were selected from among the other sites in the study. This report concerns the associations between the 12 main types of cancer in our series and 10 inorganic dusts that are found mainly in construction and metal industries. All site-exposure combinations were investigated. After intensive control for confounding, nonadenocarcinoma (NAC) of the lung was associated with long duration-high level exposure to silica (odds ratio [OR] = 1.4), excavation dust (OR = 1.9), concrete dust (OR = 2.5), abrasives dust (OR = 1.4), and alumina (OR = 1.5). It was difficult to disentangle the relative effects of those substances, and confounding among them was a distinct possibility. Although residual confounding by some uncontrolled factors may explain the elevated ORs, the results were compatible with the hypothesis of a nonspecific relation between NAC of the lung and respirable inorganic dusts as a class. Other associations that remained suggestive after in-depth analysis were silica and stomach cancer (OR = 1.2) and concrete dust and lymphoma (OR = 2.9).

Occupational health in the Negev: a model for regional planning.

In the Negev region of Israel, I tested a model approach to occupational health planning. This model included components assessing exposures, measuring adverse health outcomes, and evaluating health services. I analyzed employment survey data, compiled an exposure data base, and carried out site visits covering 10,707 employees (over 50% of the regional industrial work force). Site visits identified exposure hazards of inorganic and organic dusts, heavy metals, chemicals, pesticides, and noise. I identified elevated relative regional injury rates by Standard Morbidity Ratios (SMRs) in a variety of industries, including sixfold increases for mining and non-metallic minerals manufacture (SMR 6.8, 99% CI 6.1-7.7). Review of biological monitoring data suggested deficiencies in pesticide and heavy metals surveillance. A survey of primary care clinics estimated 13,707 cases of occupational injury and illness untreated by existing occupational medical services. Based on these findings, I formulated regional occupational health planning goals, including targeting high-risk industries for increased preventive activities. This regional approach, combining multiple measures of occupational health status, can serve as a model for assessing local public health planning needs.

Induction of thoracic malignancy in inorganic dust pneumoconiosis.

Pulmonary carcinoma is now the leading cause of death due to cancer in men and women. Aside from cigarette smoking, occupational exposure to carcinogens is the most important cause of lung cancer, accounting for up to one third of all cases. The following article is a review of occupationally induced thoracic neoplasms with an emphasis on those related to the inhalation of inorganic dust. After introducing some basic terms, describing the research methods, and reviewing the process of carcinogenesis, current information on the relationship between exposure to asbestos, synthetic mineral fibers, silica, and other nonfibrous mineral dusts and the development of lung cancer and malignant mesothelioma of the pleura will be presented. The goal of this article is to provide the practicing radiologist with knowledge and insight into this difficult area.

The effect of cigarette smoking on the detection of small radiographic opacities in inorganic dust diseases.

Whether cigarette smoking can cause radiographic opacities indistinguishable from those due to pneumoconiosis remains controversial. The situation becomes clearer when one limits the abnormalities to those that can be standardized under the International Labour Office (ILO) classification system. The bulk of the evidence indicates that, using the ILO system, cigarette smoking alone is not associated with radiographic opacities that would be mistaken for pneumoconiosis with sufficient frequency to be of any practical importance. The effects of cigarette smoking, as a cofactor, in conjunction with occupational dust exposure depend on the type of dust. No relationship has been convincingly demonstrated for coal dust or silica. Only with asbestos exposure does there appear to be a significant cigarette smoking-associated increase in the frequency of irregular radiographic opacities. This increase does not appear to translate into a restrictive impairment in pulmonary function. The limited information available indicates that the features of asbestosis on high-resolution computed tomography are not similarly related to cigarette smoking. Additional research is needed to substantiate the relationship between smoking and occupational exposure to dust of many types, and also the possible imaging and pathophysiologic significance of their interactions.