Arsenic-related Bowen's disease, palmar keratosis, and skin cancer.
(9/710)
Chronic arsenical intoxication can still be found in environmental and industrial settings. Symptoms of chronic arsenic intoxication include general pigmentation or focal "raindrop" pigmentation of the skin and the appearance of hyperkeratosis of the palms of the hands and soles of the feet. In addition to arsenic-related skin diseases including keratosis, Bowen's disease, basal-cell-carcinoma, and squamous-cell carcinoma, there is also an increased risk of some internal malignancies. Arsenic-related diseases are common in areas of the world where the drinking water has a high arsenic content. In this paper, we describe a 35-year-old male patient who had arsenic-related keratosis, squamous-cell carcinoma in the palmar area of his left hand, and Bowen's disease on his left thigh. The patient worked in a borax mine for 15 years, so he was exposed to arsenic in drinking water, airborne arsenic in his workplace, and had direct contact. The patient was treated for 11 months for arsenic-related keratosis until an axillary lymph node metastasis occurred; the lesion was excised and diagnosed to be malignant. Bowen's disease was detected when the patient was being treated for cancer. No other malignancy was found. The patient is still receiving regular follow-up care. (+info)
Seasonal variations in microbial populations and environmental conditions in an extreme acid mine drainage environment.
(10/710)
Microbial populations, their distributions, and their aquatic environments were studied over a year (1997) at an acid mine drainage (AMD) site at Iron Mountain, Calif. Populations were quantified by fluorescence in situ hybridizations with group-specific probes. Probes were used for the domains Eucarya, Bacteria, and Archaea and the two species most widely studied and implicated for their role in AMD production, Thiobacillus ferrooxidans and Leptospirillum ferrooxidans. Results show that microbial populations, in relative proportions and absolute numbers, vary spatially and seasonally and correlate with geochemical and physical conditions (pH, temperature, conductivity, and rainfall). Bacterial populations were in the highest proportion (>95%) in January. Conversely, archaeal populations were in the highest proportion in July and September ( approximately 50%) and were virtually absent in the winter. Bacterial and archaeal populations correlated with conductivity and rainfall. High concentrations of dissolved solids, as reflected by high conductivity values (up to 125 mS/cm), occurred in the summer and correlated with high archaeal populations and proportionally lower bacterial populations. Eukaryotes were not detected in January, when total microbial cell numbers were lowest (<10(5) cells/ml), but eukaryotes increased at low-pH sites ( approximately 0.5) during the remainder of the year. This correlated with decreasing water temperatures (50 to 30 degrees C; January to November) and increasing numbers of prokaryotes (10(8) to 10(9) cells/ml). T. ferrooxidans was in highest abundance (>30%) at moderate pHs and temperatures ( approximately 2.5 and 20 degrees C) in sites that were peripheral to primary acid-generating sites and lowest (0 to 5%) at low-pH sites (pH approximately 0.5) that were in contact with the ore body. L. ferrooxidans was more widely distributed with respect to geochemical conditions (pH = 0 to 3; 20 to 50 degrees C) but was more abundant at higher temperatures and lower pHs ( approximately 40 degrees C; pH approximately 0.5) than T. ferrooxidans. (+info)
Improvements in workplace safety--United States, 1900-1999.
(11/710)
At the beginning of this century, workers in the United States faced remarkably high health and safety risks on the job. Through efforts by individual workers, unions, employers, government agencies, scientists such as Dr. Alice Hamilton, and others, considerable progress has been made in improving these conditions. Despite these successes, much work remains, with the goal for all workers being a productive and safe working life and a retirement free from long-term consequences of occupational disease and injury. Using the limited data available, this report documents large declines in fatal occupational injuries during the 1900s, highlights the mining industry as an example of improvements in worker safety, and discusses new challenges in occupational safety and health. (+info)
Systemic sclerosis (scleroderma) in two iron ore mines.
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Six males with systemic sclerosis were observed in the work forces of two iron ore mines. The usual spectrum of clinical features encountered in systemic sclerosis patients were present. Histologic examination of pulmonary tissue was performed on three of the cases and showed features of both silicosis and scleroderma but to different degrees and stages of development. Exposure to high levels of silica-containing dusts had occurred in all six cases. (+info)
Heat stress and flame protective clothing in mine rescue brigadesmen: inter- and intraindividual variation of strain.
(13/710)
A climatic exposure was conducted for the 52 rescue brigadesmen of a mine while they wore flame protective clothing. We looked for individual parameters allowing prediction of tolerated exposure times in the climate tested. Of all individual parameters, only body temperature at the end of the Stoklossa heat tolerance test and physical fitness showed significant influence on the tolerated exposure time, although not very strongly. Age, body mass, and Body Mass Index showed no significant influence on the tolerated exposure time. It was found during a longitudinal study that the tolerance time within the climate for four subjects showed considerable variations, and so it was decided neither to take the result of the heat tolerance test as admittance criterion for the mine rescue service nor to perform a ranking of brigadesmen with respect to heat tolerance by this test. (+info)
Lung function, blood gases, pH and serum electrolytes of small-scale miners exposed to chrome ore dust on the Great Dyke in Zimbabwe.
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We measured and compared lung function indices and some blood parameters (gases, electrolytes, glucose, pH, red cell indices) of 54 male small-scale miners (SSM) chronically exposed to chrome ore dust to those of 50 nonmining control subjects (NMC) and 46 large-scale chrome miners (LSM) who had taken internationally recommended precautionary measures (secondary control). The respirable dust level in the SSM environment (6.0 +/- 0.5 mg/m3) was significantly higher (P < 0.001) than in the NMC and LSM environments (0.3 +/- 0.1 mg/m3 and 0.5 +/- 0.3 mg/m3, respectively). There were no significant differences in neither dust levels nor lung function status between NMC and LSM environments. The values of FVC, FEV1, PEFR and FEV1% of the SSM were 3.5 +/- 0.09 l, 2.61 +/- 0. 09 l, 6.07 +/- 0.36 l/second and 76.19 +/- 2.36%, respectively. These values were significantly lower than those of NMC (P < 0.01, respectively). However, the blood parameters of the SSM and NMC were not significantly different. The results are indicative of both restrictive and obstructive ventilatory defects in the SSM which may be attributed exposure to chrome ore dust in the environment. Associated risk factors appear to be advancing age, prolonged exposure to chrome ore dust and acid base disturbance. (+info)
Chrysotile, tremolite and fibrogenicity.
(15/710)
Recently published analyses have shown that the risks of mesothelioma and lung cancer in Quebec chrysotile miners and millers were related to estimated level of fibrous tremolite in the mines where they had worked. An analysis has therefore been made of radiographic changes in men who in 1965 were employed by companies in Thetford Mines where the same question could be examined for fibrogenicity. Of 294 men who met the necessary requirements, 129 had worked in six centrally located mines, where the tremolite content was thought to be high, 81 in 10 peripheral mines where it was thought to be low and 84 in both. The median prevalence of small parenchymal opacities (> or = 1/0) in chest radiographs read by six readers was higher among men ever than never employed in the central mines (13.6% against 7.4%), despite the fact that the mean cumulative exposure was lower in the former (430 mpcf.y vs 520 mpcf.y). After accounting by logistic regression for cigarette smoking, age, smoking-age interaction and cumulative exposure, the adjusted odds ratio for central mine employment was 2.44 (95% lower bound: 1.06). Together with other surveys of asbestos miners and millers, this study suggests that amphibole fibres, including tremolite, are more fibrogenic than chrysotile, perhaps to the same extent that they are carcinogenic, though the data available were not sufficient to address the latter question. (+info)
Chronic pulmonary function impairment caused by initial and recurrent pulmonary tuberculosis following treatment.
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BACKGROUND: A study was undertaken to establish the chronic effect of initial and recurrent treated pulmonary tuberculosis on impairment of lung function. METHODS: A total of 27 660 black South African gold miners who had reliable pulmonary function tests from January 1995 to August 1996 were retrospectively followed for the incidence of pulmonary tuberculosis to 1970. The lung function measurements in 1995-6 were related to the number of previous episodes of tuberculosis and to the time that had lapsed from the diagnosis of the last episode of tuberculosis to the lung function test. Miners without tuberculosis or pneumoconiosis served as a comparison group. RESULTS: There were 2137 miners who had one episode of tuberculosis, 366 who had two, and 96 who had three or more episodes. The average time between the diagnosis of the last episode of tuberculosis and the lung function test was 4.6 years (range one month to 31 years). The loss of lung function was highest within six months of the diagnosis of tuberculosis and stabilised after 12 months when the loss was considered to be chronic. The estimated average chronic deficit in forced expiratory volume in one second (FEV(1)) after one, two, and three or more episodes of tuberculosis was 153 ml, 326 ml, and 410 ml, respectively. The corresponding deficits for forced vital capacity (FVC) were 96 ml, 286 ml, and 345 ml. The loss of function due to tuberculosis was not biased by the presence of HIV as HIV positive and HIV negative subjects had similar losses. The percentage of subjects with chronic airflow impairment (FEV(1) <80% predicted) was 18.4% in those with one episode, 27.1% in those with two, and 35.2% in those with three or more episodes of tuberculosis. CONCLUSIONS: Tuberculosis can cause chronic impairment of lung function which increases incrementally with the number of episodes of tuberculosis. Clearly, prevention of tuberculosis and its effect on lung function is important and can be achieved by early detection and by reduction of the risk of tuberculosis through intervention on risk factors such as HIV, silica dust exposure, silicosis, and socioeconomic factors. (+info)