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PubMed1987

Pathological findings in mine workers: II. Quality of the PATHAUT data.

To assess the feasibility of using the pathology automation system (PATHAUT) for research, the quality of the data was explored by examining who comes to autopsy, the quality of the autopsy material, interobserver variability, and repeatability of diagnoses. The data indicated that autopsy rates in the gold mining industry, especially for whites, are high and that even among blacks, gold miners are represented in proportions exceeding the relative size of the working population. Because of the perception of the autopsy service as a means of obtaining compensation, miners with occupational diseases fully compensated in life are probably underrepresented. The autopsy material submitted for full autopsy is generally better preserved than cardiorespiratory organs that are sent for examination. The gold mining industry has a high proportion of full autopsies as does the Iron and Steel Corporation of South Africa. Full autopsies are more commonly performed on older deceased miners. This was true for both blacks and whites. The allocation of material to pathologists for full autopsies and examinations of the cardiorespiratory organs were clearly not random, and this may affect comparisons among pathologists. Active tuberculosis, silicosis, and emphysema prevalences appeared fairly comparable across pathologists; however, there was wide variability in the prevalence of bronchiolitis as determined by the pathologists. Agreement between the diagnoses on PATHAUT and reclassifications by single pathologists was very good for the severity of emphysema and the histological type of bronchogenic carcinoma.

Autopsy↗
PubMed1993

Estimating historical exposure to silica among mine and pottery workers in the People's Republic of China.

A quantitative retrospective exposure assessment method was developed for use in a nested case-control study of lung cancer among mine and pottery workers exposed to silica dust in the People's Republic of China. Exposure assessment was carried out in 20 mines (10 tungsten, 6 iron/copper, and 4 tin) and nine pottery factories. A job title dictionary was developed and used in both the collection of historical exposure information and work histories of 1,668 (316 cases and 1,352 controls) study subjects. Several data abstraction forms were developed to collect historical and current exposure information and employees' work histories, starting in 1950. A retrospective exposure matrix was developed on the basis of facility/job title/calendar year combinations using available historical exposure information and current exposure profiles. Information on the amount of respirable, thoracic, and free silica content in total dust was used in estimating exposure to silica. Starting in 1950, 6,805 historical estimates had been carried out for 14 calendar-year periods. We estimated the average total dust concentration to be 9 mg/M3, with a range from 28 mg/M3 in earlier years to 3 mg/M3 in recent years. Several exposure indices [such as cumulative dust, average dust, cumulative respirable (< 5 mu in particle size) and thoracic (< 10 mu in particle size) silica dust, average respirable and thoracic silica dust, exposure-weighted duration, and the highest/longest exposure] were calculated for individuals by merging work history and historical exposure matrix for each study subject. We developed these various measures of exposure to allow investigators to compare and contrast different indices of historical exposure to silica.

Case-Control Studies↗
PubMed1994

A retrospective mortality study of workers exposed to arsenic in a gold mine and refinery in France.

A historical mortality study of a cohort of employees of a gold mining and refining company was carried out in Salsigne, France. A major goal of the study was to investigate the relationship between lung cancer mortality and exposure to arsenic, radon, silica, and other contaminants of the working environment. A twofold excess of lung cancer was found both among miners and smelters, mainly concentrated among workers who had experienced exposure to past levels of arsenic, radon, and silica. The consistency of the results in the mine and the refinery are suggestive of a carcinogenic risk from both soluble and insoluble arsenic, although the potential role of other factors cannot be dismissed.

Arsenic Poisoning↗
PubMed1995

Occupational exposures to fibers and quartz at 19 crushed stone mining and milling operations.

From 1979 to 1982, the National Institute for Occupational Safety and Health (NIOSH) conducted a cross-sectional exposure assessment and mortality study of selected crushed stone facilities in the United States. This study was undertaken in part to address concerns that asbestos exposures could be occurring in some crushed stone operations due to the presence of amphibole and serpentine minerals. The investigation was also designed to characterize exposures to crystalline silica and other mineral compounds. Nineteen crushed stone operations, mining limestone, granite, or traprock were surveyed to assess exposures to respirable and total dusts, mineral compounds including crystalline silica, asbestos, and mineral fibers. At the initiation of the study, crushed stone operations were selected from a Mine Safety and Health Administration (MSHA) listing of the active industry in 1978. With the exception of requiring inclusion of the traprock operation in Maryland where asbestos fibers were initially discovered, a stratified sample of operations was randomly selected by rock type (granite, limestone, traprock, or sandstone). However, because of reluctance or refusal of some companies to participate and because of the closures of some of the selected operations, replacements were randomly selected. Some replacement selections were likewise replaced due to lack of cooperation from the companies. The studied sample included only 10 of the 27 randomly selected operations in the original sample. Asbestos fibers were detected at one traprock facility, the Maryland operation where asbestos was originally found. Measured personal exposures to fibers exceeded the NIOSH Recommended Exposure Limit (REL) for two out of 10 samples. All of the samples were below the MSHA Permissible Exposure Limit (PEL), which was in effect at the time of the survey. However, due to the presence of nonasbestos mineral fibers in the environment, it could not be stated with certainty that all of the fibers counted by phase contrast microscopy were asbestos. A variety of silicate mineral fibers (other than those classified by NIOSH as asbestos) were detected in the traprock operations and at one granite operation. Crystalline silica was detected at 17 of the 19 surveyed crushed stone operations. Overexposures to crystalline silica were measured at 16 of the crushed stone operations; approximately one in seven personal-respirable dust samples (14%) exceeded the MSHA PEL for crystalline silica. Approximately 25% of the respirable dust samples exceeded the NIOSH REL for crystalline silica. Mill operators and mill laborers consistently had the highest and most frequent overexposures to crystalline silica.

Asbestos↗
PubMed1998

Trace metal levels in chironomid larvae and sediments from a Bolivian river: impact of mining activities.

The effect of mining activity on metal accumulation in sediments and Chironomidae in a river in Bolivia was assessed. Surficial sediments and midge larvae (Chironomidae, Diptera) were collected at five sampling sites. Concentrations of the trace metals Cd, Cu, Cr, Ni, Pb, and Zn were measured in organisms and sediments by inductively coupled plasma atomic emission spectrometry. Sediments were subjected to two different extraction procedures to identify total trace metals and reducible trace metals. Geochemical characteristics of the sediment were analyzed: total organic carbon (TOC), Fe and Mn oxides, and particle size distribution. To determine the relative importance of the different sediment factors contributing to the variation in metal accumulation by the chironomid larvae, nonlinear regression models were constructed. No increase in metal concentration in sediment could be measured downstream of the mining activity. Larval concentrations, however, increased markedly. Only for zinc and chromium was a significant amount of variation (48 and 73%, respectively) found. The lack of relationship for the other metals probably was due to a unmeasured exposure route, the overlying water.

Animals↗
PubMed1998

Biomarker assessment of the effects of coal strip-mine contamination on channel catfish.

A suite of biomarkers was used to evaluate acute (1-day) to semichronic (3-month) heavy metal-induced toxicity in channel catfish, lctalurus punctatus, caged at an abandoned strip mine and a noncontaminated reference site. Assays performed include indicators of metabolic, hematological, osmoregulatory, and genotoxic stress. Two cage designs were used to evaluate the importance of exposure routes: one excluding contact with the sediments and the other allowing contact with water and sediments. Significant DNA strand breakage was observed in catfish exposed to both exposure regimens, but evidence of DNA repair was observed only in water-exposed catfish. Transient increases in hemoglobin, delta-aminolevulinic acid dehydratase, and hematocrit levels were observed at 1 month's exposure for both exposure regimens, followed by a return to control levels for the duration of the study. Environmental conditions (i.e., weather-related changes in water quality) may have contributed to the variable plasma chloride and glucose levels observed in all catfish exposed to strip-mine wastes. The transient changes in biomarkers followed by a return to reference values represent an initial stress and an acclimation to normal levels.

Animals↗
PubMed1999

Discriminating the ecotoxicity due to metals and to low pH in acid mine drainage.

Several techniques have been developed to assess the ecotoxicity of contaminated watercourses. Most of these techniques involve chemical alterations of water samples, by diluting it or by adding chelating agents. These changes become particularly severe when assessing the toxicity of samples with very low pH and with high quantities of contaminants. Trying to overcome this problem, a novel toxicity test, specific for acid waters, was previously developed and field validated. The toxicity of acid samples is assessed using the survival time of Ceriodaphnia dubia. During this study, the novel test was applied to a field situation, where an aquatic system is seriously impacted with acid mine drainage. Its efficiency was tested and compared with two classical toxicity tests: the Microtox and the median lethal dilution with C. dubia. The survival time test was performed without adjusting pH and after adjusting pH to a fixed value (pH 2, 3, and 4). At pH 2 and 4 no acceptable results were obtained; at pH 3 it was possible to distinguish the toxicity due to pH from the toxicity due to other toxicants. The test conducted at local pH was able to discriminate toxicity sources only for highly contaminated samples. The toxicity evaluation of acid mine drainage samples was possible neither with the median lethal dilution test nor with Microtox.

Animals↗
PubMed2000

Iron ore mines leachate potential for oxyradical production.

The ecotoxicological effects of mining effluents is coming under much greater scrutiny. It appears necessary to explore possible health effects in association with iron ore mining effluents. The present results clearly demonstrate that iron-ore leachate is not an inert media but has the potential to induce lipid peroxidation. Peroxidation was assessed by measuring oxygen consumption in the presence of a reducing agent such as ascorbate or NADPH and a chelator such as EDTA. Labrador iron ore is an insoluble complex crystalline material containing a mixture of metals (Fe, Al, Ti, Mn, Mg,ellipsis, ) in contrast to the iron sources used for normal lipid peroxidation studies. The metal of highest percentage is iron (59. 58%), a metal known to induce oxyradical production. Iron ore powder initiated ascorbic acid-dependent lipid peroxidation (nonenzymatic) in liposomes, lipids extracted from rat and salmon liver microsomes, and intact salmon liver microsomes. It also revealed an inhibitory effect of NADPH-dependent microsomes lipid peroxidation as well as on NADPH cytochrome c reductase activity. However, nonenzymatic peroxidation in rat liver microsomes was not significantly inhibited. Cytochrome P450 IA1- and IIB1-dependent enzymatic activities as well as P450 levels were not affected. The inhibition could be due to one of the other components of iron ore leachate (Mn, Al,ellipsis, ). These effects of iron-ore leachate indicate that a potential toxicity could be associated with its release into lakes. Further studies are necessary to explore in vivo effects on aquatic animals.

Animals↗
PubMed2001

Toxicity of uranium mine-receiving waters to caged fathead minnows, Pimephales promelas.

Larval fathead minnows (Pimephales promelas) were placed at four exposure sites for 7 days in each of five lakes surrounding the Key Lake uranium mine in northern Saskatchewan, Canada. Fish placed in lakes receiving Mo-contaminated mill effluent demonstrated higher mortalities than those placed in lakes receiving Ni-contaminated mine-dewatering effluent, which was not significantly different from reference sites. No significant differences were detected in fish growth among the study lakes because of the high (90%) mortality in Fox and Unknown lakes. Principal components analysis characterized exposure sites by total and dissolved metal concentration. Stepwise multiple regression of fish mortality on principal components generated from total metal data revealed that principal component 1 could account for 84% of the variance associated with fish mortality. Careful examination of the metals that correlated strongly with principal component 1 and with fish mortality suggested that dietary Se toxicity probably resulted in the differential fathead minnow mortality observed among study lakes.

Animals↗
PubMed2001

Air pollution caused by opencast mining and its abatement measures in India.

Opencast mining dominates coal production in India. A survey was conducted to evaluate its local atmospheric impact. Emissions data were utilised to compute dust generation due to different mining activities. Work zone air quality, ambient air quality and seasonal variations are described revealing high pollution potential due to suspended particulate matter (SPM) and consequent impact on human health. Air pollution control measures involve planning and implementing a series of preventive and suppressive measures in addition to dust extraction systems. Different abatement measures are enumerated. Pollution control by trees, the tolerance of trees to different air pollutants and plant species useful for controlling pollution are also discussed. There is a need for wider application of dust control chemicals on haul roads. Sustainable management of pollution can be achieved by the proper implementation of suggested abatement measures.

Air Pollution↗
PubMed2002

Characterisation of sequential leachate discharges of mining waste rock dumps in the Tinto and Odiel rivers.

Mining waste rock dumps (WRDs) are potential sources of pollution, which after rainfall produce leachate discharges, loaded with acid mining drainage (AMD). The discharges generally occur in two phases: initial rapid leaching over a period of 1-7 days, followed by a period of variable duration during which leaching decelerates. The relative preponderance of each phase depends on the characteristics of the WRD, including its antecedent hydrological condition, and the temporal pattern and amount of rainfall.

Environmental Monitoring↗
PubMed2002

Heavy equipment maintenance wastes and environmental management in the mining industry.

Maintenance wastes, if not managed properly, represent significant environmental issues for mining operations. Petroleum hydrocarbon liquid wastes were studied at an Australian site and a review of the literature and technology vendors was carried out to identify oil/water separation technologies. Treatment technologies and practices for managing oily wastewater, used across the broader mining industry in the Asia-Pacific region, were also identified. Key findings from the study were: (1) primary treatment is required to remove grease oil contamination and to protect secondary oily wastewater treatment systems from being overloaded; (2) selection of an effective secondary treatment system is dependent on influent oil droplet size and concentration, suspended solids concentration, flow rates (and their variability), environmental conditions, maintenance schedules and effectiveness, treatment targets and costs; and (3) oily wastewater treatment systems, based on mechanical separation, are favoured over those that are chemically based, as they simplify operational requirements. Source reduction, through housekeeping, equipment and reagent modifications, and segregation and/or consolidation of hydrocarbon waste streams, minimizes treatment costs, safety and environmental impact.

Costs and Cost Analysis↗
PubMed1994

Bioavailability of metals and arsenic to small mammals at a mining waste-contaminated wetland.

In support of a baseline ecological risk assessment evaluating the impacts of mining wastes at the Milltown Reservoir Sediments Superfund site in Montana, a food chain transfer analysis was performed for resident small mammals. Deer mice (Peromyscus maniculatus) and meadow voles (Microtus pennsylvanicus) were trapped from a 200 A portion of a mixed upland and palustrine wetland, and concentrations of As, Cd, Cu, Pb, and Zn in carcass, liver, kidney, and testes were quantified. Concurrent to small mammal trapping, samples of grasses, forbs, and soils were collected and analyzed for metal and As residues. Using a linear multimedia food-chain model, assuming a forage base of wetland vegetation from the site, ingestion of local surface water, and incidental ingestion of soils with vegetation, body burdens of the metals and As in the herbivores were estimated. As a means of estimating potential element bioavailability at the site, the modeled body burdens were compared with measured element concentrations in herbivore tissues. The analysis indicates that the bioavailabilities of As, Cd, Cu, Pb, and Zn were equal to or less than 0.2% for internal organs and 0.1% for carcasses, on a microgram/g tissue wet weight basis. Available site data on soil pH, cation exchange capacity, and extractable elements fraction supported the limited release of soil elements. These results suggest that the bioavailable fraction of mining waste metals in riparian wetland soils may be quite small, and, for the Milltown Reservoir site, lower than originally anticipated.

Animals↗
PubMed1986

Silicosis in the iron-ore mine in Kiruna, Sweden, and the future need for silicosis control.

From 1931 to 1977 a total of 144 cases of silicosis have been diagnosed in the iron-ore mine in Kiruna, Sweden. Drilling, loading and tapping caused all cases of silicosis. In 24% of the cases, the disease had progressed after the diagnosis. The progression of the disease after diagnosis showed no significant correlation to the length of the exposure but a dose-response relationship was present between the cumulative quartz exposure and the stage of silicosis 20 years after the diagnosis. Signs of tuberculous infection were found in 17%. There was a significant relationship between tuberculosis and progression of the silicosis. Mortality was increased in association with silicosis stage II-III and in stages with concomitant tuberculosis infection. Half of the cases of silicosis had been diagnosed before 1942, and after 1960 no more cases in stages II or III were diagnosed. The mean concentration of respiratory quartz was approximately 0.8 mg/m3 in the 1950s and early 1960s and decreased progressively to below 0.05 mg/m3 in the late 1970s. The cumulative incidence rate, with respect to the decade in which the exposure began, was 0.021% in 1951-1960. With an unaltered dose-response, less than one case of silicosis per 500 workers may be expected among those who start working underground in the 1980s. Evidently silicosis is no longer a major health risk among those who start working underground in this mine today, and it is recommended that the 40-year-old regulations for the medical prevention of silicosis be revised.

Adult↗
PubMed2001

Heavy metal localisation in mycorrhizas of Epipactis atrorubens (Hoffm.) Besser (Orchidaceae) from zinc mine tailings.

The metal distribution within mycorrhizal and nonmycorrhizal roots of Epipactis atrorubens collected from zinc mine tailings and an area rich in heavy metal ores (both located in southern Poland) was investigated. The tailings, consisting of post-flotation material, were characterised by high levels of toxic elements such as Zn, Pb, and Cd, while soil outside the tailings was also strongly enriched in heavy metals. Atomic absorption spectrometry and proton-induced X-ray emission analysis revealed that heavy metals were mostly accumulated within orchid roots. Elemental maps from proton-induced X-ray emission showed that plant root epidermis and fungal coils which had developed within cortical cells of roots collected from the zinc mine tailings were the main places of Zn and Pb accumulation, associated with increased concentrations of Fe, Cd, Ti, Mn, Si, Ca, and S. The mean content of Pb and Zn in the coils was 4 to 5 times higher than in the root epidermis. In mycorrhizal roots from the tailings a statistically significant decrease in Pb and Zn content towards the inside of the root was observed. The mean content of Pb in coils from roots of plants growing outside the tailings was about 1% of the concentration in root coils from the tailings. Coils selected from orchid roots originating from a site outside the tailings contained comparatively high concentrations of Zn, Cd, and Cu, which was probably due to the high content of these elements in the soil. The results presented suggest a biofiltering effect against heavy metals by orchid mycorrhizal fungi.

Industrial Waste↗
PubMed1994

A 10-year incidence survey of respiratory cancer and a case-control study within a cohort of nickel mining and refining workers in New Caledonia.

The incidence of lung, pleural, nasal, larynx, and pharynx cancer in relation to work in the nickel mining and refining industry was studied from 1978 to 1987 in the male population of the French territory of New Caledonia in the South Pacific. The results showed no greater risk in the population of nickel workers than in the general male population. The incidence of respiratory cancer in New Caledonia was found to be comparable to that of industrialized countries, except for pleural cancer for which there was an excess risk in New Caledonia. A case-control study within the cohort of nickel industry workers comprised 80 lung cancer, 12 larynx cancer, 20 pharynx cancer cases, and 298 controls, and took account of 18 substances to which workers were exposed, five of them nickel compounds. None of the substances, or any other occupational variable, was shown to increase the risk of respiratory cancer, except for cancer of the larynx in relation to level and duration of exposure to dust and engine exhaust fumes on mining sites (odds ratios ranged from five to 5.4 and were significant). These results provide no evidence that exposures specific to the nickel industry in New Caledonia increase the risk of respiratory cancer. This might be due to the involvement of less airborne nickel than the amount observed in positive studies elsewhere. The high incidence of respiratory cancer in New Caledonia, compared with other South Pacific islands, might be attributable to an environmental risk connected with the presence of mineral fibers in the geologic strata, as well as to tobacco and alcohol consumption levels similar to those prevailing in France.

Age Factors↗
PubMed2005

Metal concentrations and mycorrhizal status of plants colonizing copper mine tailings: potential for revegetation.

A field survey of metal concentrations and mycorrhizal status of plants growing on copper mine tailings was conducted in Anhui Province, China. Available phosphorus and organic matter in the tailings were very low. High concentrations of Pb, Zn, As and Cd as well as Cu were observed on some sites. The dominant plants growing on mine tailings belonged to the families Gramineae and Compositae, and the most widely distributed plant species were Imperata cylindrica, Cynodon dactylon and Paspalum distichum. Coreopsis drummondii also grew well on the arid sites but not on wet sites. Very low or zero arbuscular mycorrhizal (AM) fungal colonization was observed in most of the plants, but extensive mycorrhizal colonization was recorded in the roots of C. drummondii and C. dactylon. Metal concentrations in plant tissues indicated that I. cylindrica and P. distichum utilized avoidance mechanisms to survive at high metal concentrations. The investigation suggests that remediation and revegetation of heavy metal contaminated sites might be facilitated by selection of tolerant plant species. Isolation of tolerant AM fungi may also be warranted.

Arsenic↗
PubMed2005

Effects of acid mine drainage and acidity on the activity of Choroterpes picteti (Ephemeroptera: Leptophlebiidae).

Survival and behavior of the mayfly Choroterpes picteti (Leptophlebiidae) exposed to acid mine drainage (AMD: pH 3.3-6.4) and a reservoir polluted with arsenic (pH 6.8) from Sao Domingos mine (Portugal) were studied in laboratory and in situ bioassays (48 h) with the Multispecies Freshwater Biomonitor, and compared with water from a reference river and acidified reference water (acid only). Metal body-burdens showed a negative pH dependency for Mn and As, a positive one for Pb, and for Zn, Cu, Co, and Cd a decrease at pH < 4.4. Generally, survival decreased with decreasing pH. The 48-h LC(50) (pH) for AMD and for acid only were similar (pH 4.8-4.9); however, the LT(20) (h) at pH 3.3 revealed AMD to be less toxic than acid only. C. picteti show diurnal rhythm with increased locomotor activity in the night. The circadian rhythm was weakened by acid exposure, but less so by AMD exposure. Compared to reference river water, ventilation was stimulated at pH < 6.0 in acid only and in reservoir water. Locomotion was stimulated at pH 5 in acid only and reservoir; however, it was reduced in all other treatments, when compared to reference river water. Under acid-only exposure, both locomotion and ventilation were significantly higher compared to AMD exposure at the corresponding pH values. The laboratory results were field validated.

Acids↗