The Huanghebei Coalfield, one of the coal production bases in North China, was considered as a coalfield without coal‐bed methane (CBM) during past decades. In recent years, however, CBM has been discovered in coal‐bearing successions. In order to understand the CBM geological characteristics and accumulation process in this area, fifteen coal samples were collected and analyzed with respect to coal maceral and reflectance. The result shows that the gas distribution is uneven and the content varies in different areas even for the same coal bed. The storage of CBM is affected by geological factors such as burial depth, geological structures, and magmatic intrusion, among which the former two are more important in the formation of CBM. Deep burial of coal beds with the presence of cap‐rock mudstone can seal CBM. The CBM is also accumulated and preserved at the place where normal faults are distributed. Magmatic intrusion causes contact metamorphism and controls the CBM formation by heating the coal‐bearing successions. The obtained data indicate the geological conditions in northeastern Zhaoguan Mine are preferable for CBM formation and conservation; recent exploration estimates the CBM geological reserves up to 282.16 Mm3 and average of reserve abundance at 0.1662 × 108 m3 km?2. The Changqing Mine is a potential prospect in terms of CBM exploration since its geological conditions (structures and burial depth) are similar to the Zhaoguan Mine and its cap rock is even better. 相似文献
Xuanwei and Fuyuan, two counties located in southwest China, are areas with exceptionally high lung cancer incidence since the 1970s. In this study, questionnaires from a total of 18 communes, and 28 administrative villages (consisting of 280 small villages) in the two counties were fulfilled and collected. The sampling sites were randomly chosen in consideration of the incidence rate of lung cancer and the types of coal used. The sampling sites were divided into high lung cancer occurrence areas and low lung cancer occurrence areas. Industrial and environmental information was investigated and finally analyzed for the possible relationship to the lung cancer. It indicated that 78.1 % of the villages in high lung cancer incidence areas had been found using smoky coal or coking coals in people’s everyday lives; 43.4 % of these villages located near the coking factories, 31.1 % near the iron-zinc smelters and 11.8 % near the chemical industries. In the low lung cancer incidence areas, 78.8 % of the villages had been found using non-smoky coals (anthracite) in people’s everyday lives; 26.9 % of these villages are near the coking factories, 23.1 % near the iron-zinc smelters and 5.8 % near the chemical industries. Logistic regression analysis indicated that the coal type used was a foremost risk factor related to incidence of lung cancer [β > 0, Exp (β) >1, P < 0.05]. The use of smoky coals and coking coals seemed to be a hazardous factor for lung cancer generation, while non-smoky coals seemed to have no significant relationship to the lung cancer incidence. The results in this study added basic and important data and should be helpful for the future study on the etiology of lung cancer. 相似文献
The completion and operation of the Three Gorges Reservoir in China have increased the frequency of geo-hazards and dangers in the area. To monitor and to warn of geo-hazards effectively, the Chinese government has invested billions of funds for constructing a monitoring and warning engineering system. Similar to other social infrastructure investments, a reasonable assessment of investment returns is necessary. Therefore, this study proposes an economic benefit assessment model, which considers both the expected and the actual values. The economic benefit of the geo-hazard monitoring and warning engineering in the Three Gorges Reservoir areas is evaluated. Based on the engineering characteristics, the model reasonably defines the frontier of the input and output and adds the casualties and the losses of ecological environment into the economic benefit evaluation index system. A case study on the Zhangjiawan landslide in Guojiaba Town, Zigui County, was conducted. The evaluation results show that (1) land has the largest benefit in direct reductional loss (total of 56.7 %), while the largest indirect reductional losses of the hazard-bearing bodies are in agricultural production and ecological environment (total of 97.6 %); (2) the costs-to-expected return ratio of landslide monitoring and warning engineering is 1:280, whereas the cost-to-actual benefit ratio is 1:30; (3) the accumulation of relevant information and the public knowledge of geological disasters should be strengthened.
Chemical oxygen demand(COD)is widely used as an organic pollution indicator in wastewater treatment plants.Large amounts of organic matter are removed during treatment processes to meet environmental standards,and consequently,substantial greenhouse gases(GHGs)such as methane(CH4)are released.However,the COD indicator covers a great amount of refractory organic matter that is not a pollutant and could be a potential carbon sink.Here,we collected and analysed COD data from 86 worldwide municipal wastewater treatment plants(WWTPs)and applied a model published by the Intergovernmental Panel on Climate Change to estimate the emission of CH4 due to recalcitrant organic compound processing in China’s municipal wastewater treatment systems.Our results showed that the average contribution of refractory COD to total COD removal was55%in 86 WWTPs.The amount of CH4 released from the treatment of recalcitrant organic matter in 2018 could have been as high as 38.22 million tons of carbon dioxide equivalent,which amounts to the annual carbon sequestered by China’s wetlands.This suggests that the use of COD as an indicator for organic pollution is undue and needs to be revised to reduce the emission of GHG.In fact,leaving nontoxic recalcitrant organic matter in the wastewater may create a significant carbon sink and will save energy during the treatment process,aiming at carbon neutrality in the wastewater treatment industry. 相似文献
Science China Earth Sciences - Global warming has altered the thermodynamic and dynamic environments of the climate system, thus affecting the energy budget and water cycle process of the... 相似文献
Natural Hazards - The U.S. 2020 hurricane season was extraordinary because of a record number of named storms coinciding with the COVID-19 pandemic. This study draws lessons on how individual... 相似文献