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PubMed2001

Phytochelatin production in freshwater algae Stigeoclonium in response to heavy metals contained in mining water; effects of some environmental factors.

Production of phytochelatins (PC) in two freshwater, filamentous green algae of the genus Stigeoclonium, in response to heavy metals contained in mining water was studied. Stigeoclonium sp. grown abundantly in ditches with the mining water (southern Poland) accumulated high amounts of heavy metals. The other studied alga Stigeoclonium tenue Kütz. was isolated from unpolluted lake water in the Netherlands. Both algae exposed to the heavy metal mixture (17 microM; mainly zinc) contained in the hard, alkaline (pH 8.2) mining water produced similar amounts of phytochelatins (PC2 and PC3): 500-600 nmol SH g(-1) dry weight. After water acidification to pH 6.8, a > 2-fold increase of the total phytochelatin level as well as the appearance of longer chain peptide PC4 in the cells of both algae was observed. The concentration of labile forms of zinc in the acidified mining water was four times as high as that in the alkaline water. The heavy metal mixture (17 microM) in non-complexing solution of pH 6.8 caused a comparable phytochelatin production in both Stigeoclonium strains as the same mixture present in the acidified mining water. However, in the non-complexing solution of pH 8.2, the metal mixture induced in algae more PCs than at pH 6.8. A positive effect of bicarbonate enrichment in the solution on the PC production in S. tenue was also observed. Stigeoclonium sp. exposed to high concentrations (10 microM) of individual metals (Zn, Pb and Cd available as free cations) synthesised much higher amounts of phytochelatins (PC2-PC4) than in response to the metal mixture contained in the mining water. The order of PC induction by the studied metals in the Stigeoclonium sp. was Cd > Pb > Zn. Addition of suspended solid matter to the heavy metal solution resulted in essential quantitative changes in phytochelatins in algal cells; a considerable decrease of PC2, PC3 and PC4 levels was observed. The PC production in algae of the genus Stigeoclonium exposed to the heavy metal mixture is discussed in the context of various metal bioavailability and the algal adaptation to complex aquatic environment.

Bicarbonates↗
PubMed2001

Estimation of radon concentrations in coal mines using a hybrid technique calibration curve.

The results of epidemiological studies in various countries show that radon and its progeny cause carcinogenic effects on mine workers. Therefore, it becomes of paramount importance to monitor radon concentrations and consequently determine the radon dose rates in coal mines for the protection of coal miners. A new calibration curve was obtained for radon concentration estimation using hybrid techniques. A calibration curve was generated using 226Ra activity concentration measured by a HPGe detector-based gamma-ray spectrometer versus alpha-track-density rate due to radon and its progeny on CR-39 track detector. Using the slope of the experimentally determined curve in the units of Becqueral per kilogram (Bq kg-1) per unit alpha-track-density per hour (cm-2 h-1), radon concentrations (Bq m-3) were estimated using coal samples from various coal mines in two provinces of Pakistan, Punjab and Balochistan. Consequently, radon dose rates were computed in the simulated environment of the coal mines. Results of these computations may be considered with a caveat that the method developed in this paper provides only a screening method to indicate the radon dose in coal mines. It has been shown that the actual measurements of radon concentrations in the coal mines are in agreement with the estimated radon concentrations using the hybrid-technique calibration curve.

Calibration↗
PubMed2001

Influence of illegal gold mining on mercury levels in fish of north Sulawesi's Minahasa Peninsula, (Indonesia).

North Sulawesi's Minahasa Peninsula currently is experiencing intense illegal gold mining activity. It has been estimated that 200 t of mercury are used annually in Indonesia in the recovery of gold from the illegal mines. To date no study has assessed the environmental impact of this illegal activity on the nearby aquatic biota. To address this concern, we compared tissue mercury levels from several sites, including a reference site and a site near an illegal mine. Fish from the region of the illegal mine contained 30 times the mercury content of fish at the reference site. Moreover, whole fish tissue levels were four times those recommended by the World Health Organization for consumption restrictions and often two-fold higher than recommended for total restriction on fish consumption. The environmental and human health implications of these levels are of grave concern; citizen education programmes are required to alert indigenous peoples of the risks associated with mercury exposure and fish consumption guidelines put into place. A more comprehensive effort to identify major sources and effects are required. Such information can be used to determine the correct course of action that needs to be taken to close existing illegal mines and prevent future illegal mining activities.

Animals↗
PubMed2004

Macroscopic and microscopic observations of particle-facilitated mercury transport from New Idria and Sulphur Bank mercury mine tailings.

Mercury (Hg) release from inoperative Hg mines in the California Coast Range has been documented, but little is known about the release and transport mechanisms. In this study, tailings from Hg mines located in different geologic settings--New Idria (NI), a Si-carbonate Hg deposit, and Sulphur Bank (SB), a hot-spring Hg deposit--were characterized, and particle release from these wastes was studied in column experiments to (1) investigate the mechanisms of Hg release from NI and SB mine wastes, (2) determine the speciation of particle-bound Hg released from the mine wastes, and (3) determine the effect of calcinations on Hg release processes. The physical and chemical properties of tailings and the colloids released from them were determined using chemical analyses, selective chemical extractions, XRD, SEM, TEM, and X-ray absorption spectroscopy techniques. The total Hg concentration in tailings increased with decreasing particle size in NI and SB calcines (roasted ore), but reached a maximum at an intermediate particle size in the SB waste rock (unroasted ore). Hg in the tailings exists predominantly as low-solubility HgS (cinnabar and metacinnabar), with NI calcines having >50% HgS, SB calcines having >89% HgS, and SB waste rock having approximately 100% HgS. Leaching experiments with a high-ionic-strength solution (0.1 M NaCl) resulted in a rapid but brief release of soluble and particulate Hg. Lowering the ionic strength of the leach solution (0.005 M NaCI) resulted in the release of colloidal Hg from two of the three mine wastes studied (NI calcines and SB waste rock). Colloid-associated Hg accounts for as much as 95% of the Hg released during episodic particle release. Colloids generated from the NI calcines are produced by a breakup and release mechanism and consist of hematite, jarosite/alunite, and Al-Si gel with particle sizes of 10-200 nm. ATEM and XAFS analyses indicate that the majority (approximately 78%) of the mercury is present in the form of HgS. SB calcines also produced HgS colloids. The colloids generated from the SB waste rockwere heterogeneous and varied in composition according to the column influent composition. ATEM and XAFS results indicate that Hg is entirely in the HgS form. Data from this study identify colloidal HgS as the dominant transported form of Hg from these mine waste materials.

California↗
PubMed2004

Site-specific characterization of Castromil Brownfield area related to gold mining activities.

Castromil is one of the gold mining areas in Portugal that has been abandoned since 1940. This area, which was first mined in Roman times, is located within a Hercynian granite body near the contact with Silurian metasediments. Gold is essentially disseminated along veins in the silicified granite, running NW-SE, related with a shear zone and frequently associated with sulphides (arsenopyrite and basically pyrite). In paragenetic terms, three stages of mineralization are considered: ferro-arseniferous (quartz + arsenopyrite I + pyrite I + pyrrhotite + bismuth), zinciferous (sphalerite + chalcopyrite), and remobilization (arsenopyrite II + galena + gold). Due to the lack of laws and environmental education, Castromil is today a gold mining heritage site where we can detect the consequences of an incautious exploration (tailings, wells and adits located in the old explored zone) and where a residential area is located. In order to characterize the actual state of the old mining area the trace metal contamination of soils and waters by mining activities was investigated. In the studied area 106 soil samples, 15 waters and 20 plants were sampled and analysed. The soil samples were analysed for 32 elements by ICP-AES. Waters were analysed by ionic chromatography and ICP-MS for major and trace elements. Plants were analysed for As, Fe and Pb by AAS. The results are discussed taking into account the risk-based standards for soils and groundwater's (target and intervention values) proposed by Swartjes (1999). The results show elevated concentration of As and Pb which were found in soils collected from agricultural areas. Foodstuff plants species collected in the Castromil agricultural area show high concentrations of As in the leaves (cabbage and lettuce) and in the tubers (potatoes). Groundwaters in the mining area contain high concentrations of As that exceeds the intervention values. The area must to be subject to a remediation process, considering the actual risks to humans and ecosystems and the risks due to contaminant migration.

Environmental Monitoring↗
PubMed2004

Submicrometer elemental carbon as a selective measure of diesel particulate matter in coal mines.

A monitoring method for diesel particulate matter was published as Method 5040 by the National Institute for Occupational Safety and Health (NIOSH). Organic and elemental carbon are determined by the method, but elemental carbon (EC) is a better exposure measure. The US Mine Safety and Health Administration (MSHA) proposed use of NIOSH 5040 for compliance determinations in metal and nonmetal mines. MSHA also published a rulemaking for coal mines, but no exposure standard was provided. A standard based on particulate carbon is not considered practical because of coal dust interference. Interference may not be a problem if an appropriate size-selective sampler and EC exposure standard are employed. Submicrometer dust concentrations found in previous surveys of nondieselized, underground coal mines were relatively low. If a large fraction of the submicrometer dust is organic and mineral matter, submicrometer EC concentrations would be much lower than submicrometer mass concentrations. Laboratory and field results reported herein indicate the amount of EC contributed by submicrometer coal dust is minor. In a laboratory test, a submicrometer EC concentration of 31 microg m(-3) was found when sampling a respirable coal dust concentration over three times the US compliance limit (2 mg m(-3)). Laboratory results are consistent with surveys of nondieselized coal mines, where EC results ranged from below the method limit of detection to 18 microg m(-3) when size-selective samplers were used to collect dust fractions having particle diameters below 1.5 microm-submicrometer EC concentrations were approximate 7 microg m(-3). In dieselized mines, submicrometer EC concentrations are much higher.

Carbon↗
PubMed2005

Radioactivities related to coal mining.

Natural radioactivity concentrations due to the coal mining in Gabal El-Maghara, North Sinai, Egypt, were determined using gamma-ray spectroscopy. Coal, water and soil samples were investigated in this study. The (226)Ra, (232)Th and (40)K activity concentrations in coal before extraction were 18.5 +/- 0.5, 29.5 +/- 1.2 and 149.0 +/- 8.4 Bq kg(-1), respectively. These concentrations were reduced to 18-22% after extraction due to the clay removal of the coal ore. The activity contents of the water and soil samples collected from the surrounding area did not show any evidence of enhancement due to the mining activities. Absorbed dose rate and effective dose equivalent in the mine environment were 29.4 nGy h(-1) and 128.0 microSv a(-1), respectively. The measured activity concentrations in the mine environment and the surrounding areas (5 km away from the mine) are similar to that found in other regions in North and South Sinai. Based on the measurements of gamma-ray emitting radionuclides, the mine activity does not lead to any enhancement in the local area nor represents any human risk.

Coal↗
PubMedDate not supplied

Respirable dust exposures in U.S. surface coal mines (1982-1986).

Exposure of miners to respirable coal mine dust and to respirable quartz silica at surface coal mines in the United States during 1982-1986 were evaluated by job category using data collected by coal mine operators and Mine Safety and Health Administration (MSHA) inspectors. Average coal mine dust concentrations were usually well below the MSHA Permissible Exposure Limit (PEL) for all job categories, but at least 10% of the samples obtained from some coal preparation plant job areas and most drilling job areas had concentrations that exceeded the 2.0 mg/m3 limit. In contrast, a very high proportion of samples from surface mine driller areas exceeded the quartz PEL. Of all samples collected for highwall drill operators and helpers, 78% and 77%, respectively, were greater than the 0.1 mg/m3 quartz exposure limit (average concentrations were .32 and .36 mg/m3, respectively). Although MSHA compliance data may not be entirely adequate for assessing chronic exposure to quartz, these data and the results of other NIOSH studies nonetheless indicate excessive exposure to silica in a group of surface coal miners.

Air Pollutants, Occupational↗
PubMed1995

Estimating possible fraud in coal mine operators' samples of respirable dust.

Coal mine operators are required to sample miners' exposure to respirable dust on a regular basis. A method has been developed for screening all operator samples for detecting possible instances of fraud. This method relies on the occurrence of very low concentration (VLC = 0.1 mg/m3) samples more frequently than expected. The number of underground mine sections from which 50% or more of all samples for FY 1990 were VLC (VLC-50 sections) was compared to the expected number, which was estimated by assuming that the occurrence of VLC samples could be described with a binomial probability distribution. Out of 1983 continuous mining sections, there were 147 VLC-50 sections vs. 7.3 expected (O/E = 20.1). Moreover, these 147 sections occurred more frequently than expected among small as opposed to large mines. For sections using conventional mining methods, 19 of 175 were VLC-50 vs. 0.9 expected (O/E = 20.8). There was one VLC-50 longwall section vs. 0.003 expected. For 99 bituminous and anthracite hand-loading sections the observed number of VLC-50 sections was 65 vs. 78 expected (O/E = 0.8). It is suggested that, except for hand-loading and longwall sections, sampling programs should be investigated at mines with VLC-50 sections.

Coal↗
PubMed2001

Airborne radon and its progeny levels in the coal mines of Godavarikhani, Andhra Pradesh, India.

In India, out of about 0.7 million miners, nearly 0.5 million persons are directly engaged in coal operations. Radon and its progeny levels have been quantified in the coal-mining environment of Godavarikhani, Andhra Pradesh, India using solid-state nuclear track detectors. Seasonal and mine depth variations in radon levels have been recorded resulting in the identification of locations with a high radon level as areas with no mining activity, active mining operational zones and return air ventilation paths. All these radon levels were below the permissible levels. The average concentrations of radon and its progeny levels were found to be 144 +/- 61 Bq m(-3) and 20 +/- 11 mWL (working level) respectively in the two-incline mine, and these values for the five-incline mine are recorded as 315 +/- 71 Bq m(-3) and 30 +/- 9 mWL respectively.

Air Pollutants, Occupational↗
PubMed2002

Exposure to 222Rn in ten underground mines in Iran.

Concentrations of 222Rn were measured in ten non-uranium underground mines in Iran, including three metal mines and seven coal mines. Two active techniques were applied for these measurements (1) activated charcoal and (2) scintillation cell. A maximum mean concentration of 1.33 kBq.m(-3) was found in the Robat-Karim manganese mine with a hot spot of 12 kBq.M(-3), while the concentration in the Venarge-Qom manganese mine was less than 10 Bq.m(-3), leading to annual effective dose equivalents of 8.3 mSv and (0.06 mSv respectively. The mean concentration levels of 222Rn in coal mines were found to be almost 500 Bq.m(-3), leading to annual effective dose equivalent of 3 mSv.

Adsorption↗
PubMed1985

The radiological impact of mining in a Th-rich Norwegian area.

The radiological impact of former mining activities in the Fen area in southern Norway has been assessed. The area is known to have enhanced concentrations of Th. A recent epidemiological study suggested a significant increment of lung cancer among the former miners, and the doses to the miners have been assessed. The main contributor to the effective dose equivalent in one of the mines was inhaled 220Rn progeny. Water in drilled wells and in nearby lakes has been analysed for 220Rn and Ra. Uranium and Th analyses were performed on mine and lake water. The mining activity does not seem to have contaminated drinking water significantly. The tailings from Nb production has enriched Ra and Th concentrations. The tailings and the possible use of waste rock from the mining are probably the most important environmental results of the mining activities.

Air Pollutants, Radioactive↗
PubMed1998

Intercomparison of radon and decay product measurements in an underground mine and EPA Radon Laboratory: a study organized by the IAEA International Radon Metrology Programme. International Atomic Energy Agency.

The International Atomic Energy Agency (IAEA) in Vienna and the European Union (EU) in Bruxelles formed the "International Radon Metrology Programme" (IRMP, scientific secretary: F. Steinhäusler, University of Salzburg, Austria). The IRMP is designed to assess and foster the improvement of radon and decay product measurements that are made around the world. Within the framework of the IRMP, the U.S. Environmental Protection Agency Radiation and Indoor Environments National Laboratory (EPA) in Las Vegas, Nevada, organized jointly with the U.S. Bureau of Mines an international intercomparison exercise at a former uranium mine (Twilight Mine, Colorado) and the EPA Radon Laboratory. The main objective of this exercise was to compare radon and radon decay product instruments under both well-controlled as well as widely fluctuating exposure conditions. The laboratory exposures occurred under relatively steady radon and decay product conditions, with a moderate equilibrium ratio, while the conditions in the mine fluctuated greatly and the equilibrium ratio was low. An additional purpose of the exercise was to provide a forum for manufacturers and measurement organizations worldwide to exchange information and plan improvements in their operations and calibration programs. Altogether 19 organizations from seven countries intercomparing 32 different radon and radon decay product instruments participated in this exercise. This paper summarizes the results from the analysis of the experimental data obtained in the Bureau of Mines Twilight Mine in July of 1994, as well as the results from the EPA Radon laboratory in August of 1994.

Calibration↗
PubMed2000

Uranium mining and lung cancer among Navajo men in New Mexico and Arizona, 1969 to 1993.

Navajo men who were underground miners have excess risk of lung cancer. To further characterize the long-term consequences of uranium mining in this high-risk population, we examined lung cancer incidence among Navajo men residing in New Mexico and Arizona from 1969 to 1993 and conducted a population-based case-control study to estimate the risk of lung cancer for Navajo uranium miners. Uranium mining contributed substantially to lung cancer among Navajo men over the 25-year period following the end of mining for the Navajo Nation. Sixty-three (67%) of the 94-incident lung cancers among Navajo men occurred in former uranium miners. The relative risk for a history of mining was 28.6 (95% confidence interval, 13.2-61.7). Smoking did not account for the strong relationship between lung cancer and uranium mining. The Navajo experience with uranium mining is a unique example of exposure in a single occupation accounting for the majority of lung cancers in an entire population.

Adult↗
PubMed1996

Surveillance of the mosquito Aedes aegypti and its biocontrol with the copepod Mesocyclops aspericornis in Australian wells and gold mines.

A survey of the dengue vector mosquito Aedes aegypti was undertaken using funnel traps to detect immature stages (larvae and pupae) in flooded disused mine shafts and wells in Charters Towers, Queensland, Northern Australia. The town has a history of dengue fever since 1885 when goldminers were the first recorded victims. During the latest dengue epidemic in 1993, 2% of the population had laboratory-confirmed dengue virus Type 2, despite source reduction of Ae.aegypti breeding-sites at ground level or above. This led to suspicions that dengue vector Ae.aegypti breeding-sites might be below ground level. When surveyed in March 1994, Ae.aegypti immatures were found in 9/10 wells and 1/6 mine shafts. The water in wells and mines had similar characteristics-except that turbidity was higher in the mines, which more often contained predators of mosquito immatures. The copepod Mesocyclops aspericornis was collected from water in 1/10 wells and 2/6 mine shafts. Laboratory predation trials resulted in 95.5-100% predation by 25 copepods/l on Ae.aegypti first-instar larvae up to 200 larvae/l. Five wells containing Ae.aegypti in the survey were inoculated with fifty indigenous M.aspericornis, and five wells (one positive and four negative in the survey) were left untreated as controls. Nine months later, in December 1994, Ae.aegypti had been eliminated from all five treated wells but all untreated control wells contained Ae.aegypti, except for one well that contained a natural population of M.aspericornis. The role of wells and mines as winter/ dry season refuges of Ae.aegypti in northern Australia is reviewed, and we recommend the use of M.aspericornis as a cost-effective, environmentally acceptable and persistent agent for the sustainable control of Ae.aegypti, especially in inaccessible breeding sites.

Aedes↗
PubMed2002

Nested case-control study of lung cancer in four Chinese tin mines.

OBJECTIVES: To evaluate the relation between occupational dust exposure and lung cancer in tin mines. This is an update of a previous study of miners with high exposure to dust at four tin mines in southern China. METHODS: A nested case-control study of 130 male lung cancer cases and 627 controls was initiated from a cohort study of 7855 subjects employed at least 1 year between 1972 and 1974 in four tin mines in China. Three of the tin mines were in Dachang and one was in Limu. Cumulative total exposure to dust and cumulative exposure to arsenic were calculated for each person based on industrial hygiene records. Measurements of arsenic, polycyclic aromatic hydrocarbons (PAHs), and radon in the work sites were also evaluated. Odds ratios (ORs), standard statistic analysis and logistic regression were used for analyses. RESULTS: Increased risk of lung cancer was related to cumulative exposure to dust, duration of exposure, cumulative exposure to arsenic, and tobacco smoking. The risk ratios for low, medium, and high cumulative exposure to dust were 2.1 (95% confidence interval (95% CI) 1.1 to 3.8), 1.7 (95% CI 0.9 to 3.1), and 2.8 (95% CI 1.6 to 5.0) respectively after adjustment for smoking. The risk for lung cancer among workers with short, medium, and long exposure to dust were 1.9 (95% CI 1.0 to 3.5), 2.3 (95% CI 1.3 to 4.1), and 2.3 (95% CI 1.2 to 4.2) respectively after adjusting for smoking. Several sets of risk factors for lung cancer were compared, and the best predictive model included tobacco smoking (OR=1.6, 95% CI 1.1 to 2.4) and cumulative exposure to arsenic (ORs for different groups from low to high exposure were 2.1 (95% CI 1.1 to 3.9); 2.1 (95% CI 1.1 to 3.9); 1.8 (95% CI 1.0 to 3.6); and 3.6 (95% CI 1.8 5 to 7.3)). No excess of lung cancer was found among silicotic subjects in the Limu tin mine although there was a high prevalence of silicosis. Exposures to radon were low in the four tin mines and no carcinogenic PAHs were detected. CONCLUSIONS: These findings provide little support for the hypothesis that respirable crystalline silica induces lung cancer. Ore dust in work sites acts as a carrier, the exposure to arsenic and tobacco smoking play a more important part in carcinogenesis of lung cancer in tin miners. Silicosis seems not to be related to the increased risk of lung cancer.

Adult↗
PubMed1991

Occupational health and safety regulation in the coal mining industry: public health at the workplace.

The strategy for preventing occupational disease and injury in the coal mining industry employs several elements. Standards are set and enforced; technical assistance, research, and development are provided; and surveillance is conducted. Compensation for black lung is a vivid reminder of the consequences of failure to prevent disease. And, workers are represented by a union that encourages active participation in all aspects of this strategy. There are significant problems in each of these elements. Regulatory reform threatens to weaken many standards, there is a decline in government research budgets, surveillance is not well monitored, and compensation for black lung is significantly more difficult to obtain now than in the past. Moreover, the conservative governments of the past decade are not friendly towards unions. Nevertheless, the fundamental structure of disease and injury prevention remains intact and, more importantly, it has a historical record of success. The Mine Safety and Health Act provided for a wide array of basic public health measures to prevent occupational disease and injury in the mining industry. These measures have been effective in reducing both risk of fatal injury and exposure to respirable coal mine dust. They are also associated with temporary declines in productivity. In recent years, however, productivity has increased, while risk of fatal injury and exposure to respirable dust have declined. At individual mines, productivity with longwall mining methods appear to be associated with increases in exposure to respirable dust. These trends are not inconsistent with similar trends following implementation of regulations by OSHA. When OSHA promulgated regulations to control exposure to vinyl chloride monomer, enforcement of the standard promoted significant efficiencies in vinyl chloride production (5). Similarly, when OSHA promulgated its standard regulating exposure to cotton dust, this effort provoked modernization in the cotton textile industry (14). It is not inevitable that occupational health and safety regulations are associated with negative economic performance. On the contrary, in some instances, public health on the job and productivity are complementary.

Accidents, Occupational↗
PubMed1986

Lung asbestos content in long-term residents of a chrysotile mining town.

The effects of long-term exposure to very small amounts of chrysotile asbestos are controversial. To examine this problem, the lung asbestos content from 7 long-term (25 yr and greater) residents of Thetford Mines, Quebec, who were never employed in the chrysotile mining and milling industry, was analyzed. Thetford Mines is a chrysotile mining town with a demonstrated ambient atmospheric concentration of chrysotile asbestos approximately 200 to 500 times that in urban areas of North America. Data on the residents' lungs were compared with those obtained from 20 long-term (25 yr and greater) chrysotile industry workers from Thetford Mines and 20 members of the general population of Vancouver. The median concentrations of chrysotile and tremolite in the Thetford residents were only about one fiftieth of those of the chrysotile workers, but about 10 times that of the population of Vancouver. Because long fibers of asbestos are generally thought to be more dangerous than short ones are, the sizes of fibers from these 3 groups were also examined. The fiber size distribution of the asbestos from the Thetford residents was significantly longer than that of the Vancouver population, and resembled that of the chrysotile workers. Because epidemiologic studies have consistently failed to find an increased respiratory disease incidence in lifelong residents of Quebec chrysotile mining towns who were never employed in the chrysotile industry, these findings imply that even asbestos burdens much higher, and fiber size distributions much longer, than those of the general population of most North American cities, are not associated with demonstrable pathologic effects.

Aged↗