Lung cancer risk by geologic coal deposits: A case-control study of female never-smokers from Xuanwei and Fuyuan, China.

Coal types vary around the world because of geochemical differences in their source deposits; however, the influence of coal emissions from different deposits on human health remains unexplored. To address this issue, we conducted the first study of the relationship between coal use from various deposits and lung cancer risk in Xuanwei and Fuyuan, counties in China where lung cancer rates are among the highest in the world among female never-smokers due to use of bituminous ("smoky") coal for heating and cooking. We conducted a population-based case-control study of 1031 lung cancer cases and 493 controls among never-smoking women in Xuanwei and Fuyuan. Logistic regression models were used to estimate associations between coal use from various deposits across the lifecourse and lung cancer risk. There was substantial heterogeneity in risks by coal deposit (p = 7.8E-05). Compared to non-smoky coal users, risks by smoky coal deposit ranged from OR = 7.49 (95% CI: 3.43-16.38) to OR = 33.40 (95% CI: 13.07-85.34). Further, women born into homes that used smoky coal and subsequently changed to non-smoky coal had a higher risk (OR = 10.83 (95% CI: 4.61-25.46)) than women born into homes that used non-smoky coal and changed to smoky coal (OR = 4.74 (95% CI: 2.03-11.04, pdifference = 0.04)). Our study demonstrates that various sources of coal have considerably different impact on lung cancer in this population and suggests that early-life exposure to carcinogenic emissions may exert substantial influence on health risks later in life. These factors should be considered when evaluating the health risks posed by exposure to coal combustion emissions.

Household air pollution and lung cancer in China: a review of studies in Xuanwei.

Over half of the world's population is exposed to household air pollution from the burning of solid fuels at home. Household air pollution from solid fuel use is a leading risk factor for global disease and remains a major public health problem, especially in low- and mid-income countries. This is a particularly serious problem in China, where many people in rural areas still use coal for household heating and cooking. This review focuses on several decades of research carried out in Xuanwei County, Yunnan Province, where household coal use is a major source of household air pollution and where studies have linked household air pollution exposure to high rates of lung cancer. We conducted a series of case-control and cohort studies in Xuanwei to characterize the lung cancer risk in this population and the factors associated with it. We found lung cancer risk to vary substantially between different coal types, with a higher risk associated with smoky (i.e., bituminous) coal use compared to smokeless (i.e., anthracite) coal use. The installation of a chimney in homes resulted in a substantial reduction in lung cancer incidence and mortality. Overall, our research underscores the need among existing coal users to improve ventilation, use the least toxic fuel, and eventually move toward the use of cleaner fuels, such as gas and electricity.

Coal dust exposure and mortality from ischemic heart disease among a cohort of U.S. coal miners.

BACKGROUND: Particulate exposure from air pollution increases the risk of ischemic heart disease (IHD) mortality. Although coal miners are highly exposed to coal dust particulate, studies of IHD mortality risk among coal miners have had inconsistent results. Previous studies may have been biased by the healthy worker effect. METHODS: We examined the dose-response relationship between cumulative coal dust exposure, coal rank, and IHD mortality among a cohort of underground coal miners who participated in the National Study of Coal Workers' Pneumoconiosis. RESULTS: After adjusting for age, smoking, and body mass index, risk of IHD mortality increased at higher levels of coal dust exposure. Mortality risk was also associated with coal rank region. CONCLUSION: There was an increased risk of mortality from IHD associated with cumulative exposure to coal dust, and with coal rank. The effect of coal rank may be due differences in the composition of coal mine dust particulate. The association of risk of IHD mortality with cumulative particulate exposure is consistent with air pollution studies.

Variations in concentrations and compositions of polycyclic aromatic hydrocarbons (PAHs) in coals related to the coal rank and origin.

The release of unburnt coal particles and associated polycyclic aromatic hydrocarbons (PAHs) may cause adverse impacts on the environment. This study assessed variations in the concentration and composition of PAHs in a set of fifty coal samples from eleven coal basins worldwide. The maximum PAH concentrations at high volatile bituminous rank were recorded in samples from a single basin. Considering the entire sample set, the highest PAH concentrations were in fact found outside of this rank range, suggesting that the maceral composition and thus the coal's origin also influenced PAH concentrations. The examination of the PAH compositions revealed that alkylated 2-3 ring PAHs remain dominant compounds irrespective of coal rank or origin. Multivariate analysis based on PAH and maceral content, bulk and maturity parameters allowed the recognition of seven groups with different rank and origin within the coal sample set.

Carbon dioxide sorption capacities of coal gasification residues.

Underground coal gasification is currently being considered as an economically and environmentally sustainable option for development and utilization of coal deposits not mineable by conventional methods. This emerging technology in combination with carbon capture and sorptive CO2 storage on the residual coke as well as free-gas CO2 storage in the cavities generated in the coal seams after gasification could provide a relevant contribution to the development of Clean Coal Technologies. Three hard coals of different rank from German mining districts were gasified in a laboratory-scale reactor (200 g of coal at 800 °C subjected to 10 L/min air for 200 min). High-pressure CO2 excess sorption isotherms determined before and after gasification revealed an increase of sorption capacity by up to 42%. Thus, physical sorption represents a feasible option for CO2 storage in underground gasification cavities.

Characterization of Santa Catarina (Brazil) coal with respect to human health and environmental concerns.

The current paper presents the concentration, distribution, and modes of occurrence of trace elements of 13 coals from south Brazil. The samples were collected in the state of Santa Catarina. Chemical analyses and the high ash yields indicate that all studied coals are rich in mineral matter, with SiO(2) and Al(2)O(3) dominating as determined by inductively coupled plasma-atomic emission spectrometry (ICP-AES). Quartz is the main mineral species and is associated with minor levels of feldspars, kaolinite, hematite, and iron-rich carbonates. The contents of trace elements, including As, Pb, Cd, Ni, Cr, Mn, Be, V, U, Zn, Li, Cu, Tl, and Ni, in coals were determined. A comparison of ranges and means of elemental concentrations in Santa Catarina, Brazil, and world coals shows that the ranges of most elements in Santa Catarina coal are very close to the usual worldwide concentration ranges in coal.

Variation in lung cancer risk by smoky coal subtype in Xuanwei, China.

Lung cancer rates in Xuanwei County have been among the highest in China for both males and females and have been causally associated with exposure to indoor smoky (bituminous) coal emissions that contain very high levels of polycyclic aromatic hydrocarbons. There are numerous coal mines across the County. Although lung cancer risk is strongly associated with the use of smoky coal as a whole, variation in risk by smoky coal subtype has not been characterized as yet. We conducted a population-based case-control study of 498 lung cancer cases and 498 controls, individually matched to case subjects on age (+/-2 years) and sex to examine risk by coal subtype. Odds ratios (ORs) and 95% confidence intervals (CIs) for coal subtype were calculated by conditional logistic regression, adjusting for potential confounders. Overall, smoky coal use was positively and statistically significantly associated with lung cancer risk, when compared with the use of smokeless coal or wood (OR = 7.7, 95% CI = 4.5-13.3). Furthermore, there was a marked heterogeneity in risk estimates for specific subtypes of smoky coal (test for heterogeneity: p = 5.17 x 10(-10)). Estimates were highest for coal of the Laibin (OR = 24.8, 95% CI = 12.4-49.6) and Longtan (OR = 11.6, 95% CI = 5.0-27.2) coal types and lower for coal from other subtypes. These findings strongly suggest that in Xuanwei and elsewhere, the carcinogenic potential of coal combustion products can exhibit substantial local variation by specific coal source.

[FTIR spectroscopic study on the stress effect of compositions of macromolecular structure in tectonically deformed coals].

Fourier transform infrared spectroscopy (FTIR) was applied to the study of the stress effect of compositions of macromolecular structure in tectonically deformed coals. The results showed that in different kinds of tectonically deformed coals, the absorption band of aromatic structure, aliphatic structure and oxygen functional groups nearly consistent in the peak wave number, but the intensity of the peak is different which is justly influenced by different deformation degree and deformation mechanism of tectonically deformed coals under tectonic stress. In the metamorphic and deformed environments of the low, middle and high coal rank, for tectonically deformed coals, with the increasing stress, hydrogen-enriched degree and oxygen-enriched degree decrease, while the degree of ring condensation increases. But there are differences in the change of compositions contents of macromolecular structure. This might indicate that the FTIR could be used in the stress effect of compositions of macromolecular structure in tectonically deformed coals.

[Investigation on the nitrogen functionality of volatile through FTIR spectroscopy equipped with a long path distance gas cell].

Nitrogen functionalities of volatile of three different rank coals, namely TONGCHUAN lean coal, SHENMO bituminite and YIBIN anthracite, were studied by using Fourier transform infrared spectroscopy (FTIR) equipped with 16 m long path distance gas cell. The detection problem of low content of nitrogen in volatile was successfully solved because of the application of the long path distance gas cell. In the long path distance gas cell, the infrared penetrates the sample more times than in a normal gas cell. Results from the analysis of spectra obtained by FTIR show that there are four functionalities of nitrogen in volatile, including pyrrole-type nitrogen, pyrindine-type nitrogen, pyridine-N-oxide nitrogen, and nitrile nitrogen. Comparison of research results of nitrogen group between coal and volatile suggests that the difference in fate of nitrogen between volatile and coal results from the macromolecular nitrogen group of coal decomposition under the effect of temperature.

Liners for waste containment constructed with class F and C fly ashes.

Hydraulic conductivity of a Class F fly ash containing residual organic carbon was evaluated in this study using laboratory and field tests. Compacted specimens of the Class F fly ash mixed with various materials (sand, Class C fly ash, and bottom ash) were prepared in the laboratory at various water contents and different compactive efforts. Hydraulic conductivity of the compacted specimens was measured using flexible-wall permeameters. A test pad was constructed to determine whether a low hydraulic conductivity liner could be constructed with Class F fly ash mixtures. Sealed double-ring infiltrometers and two-stage borehole permeameters were used to measure the field hydraulic conductivity of the test pad. Specimens were also removed from the test pad for hydraulic conductivity testing in the laboratory. Results of the study showed that mixtures of Class F and Class C fly ashes along with coarse aggregate can be compacted to hydraulic conductivities needed for landfill liners provided compaction is wet of optimum water content. The field tests showed that constructing a fly ash liner with hydraulic conductivities similar to those found in the laboratory is challenging, and requires careful attention to factors that result in cracks and permeable interlift regions that result in high field hydraulic conductivity. Leachate collected from the base of the test pad also showed that metal leaching must be considered when designing a liner with fly ash.

Prevalence of pneumoconiosis and its relationship to dust exposure in a cohort of U.S. bituminous coal miners and ex-miners.

Information on radiographic evidence of coal workers' pneumoconiosis (CWP) is presented for a group of 3,194 underground bituminous coal miners and ex-miners examined between 1985 and 1988. Prevalence of CWP was related to estimated cumulative dust exposure, age, and rank of coal. On the basis of these data, miners of medium to low rank coal, who work for 40 years at the current federal dust limit of 2 mg/m3, are predicted to have a 1.4% risk of having progressive massive fibrosis on retirement. Higher prevalences are predicted for less severe categories of CWP. Miners in high rank coal areas appear to be at greater risk than those mining medium and low rank coals. Ex-miners who said that they left mining for health-related reasons had higher levels of abnormality compared to current miners.