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排序方式: 共有191条查询结果,搜索用时 31 毫秒
101.
Exhaust emissions of seventeen 2,3,7,8-substituted polychlorinated dibenzo-p-dioxin/furan (PCDD/F) congeners, tetra-octa PCDD/F homologues, 12 WHO 2005 polychlorinated biphenyl (PCB) congeners, mono-nona chlorinated biphenyl homologues, and 19 polycyclic aromatic hydrocarbons (PAHs) from three legacy diesel engines were investigated. The three engines tested were a 1985 model year GM 6.2 J-series engine, a 1987 model year Detroit Diesel Corporation 6V92 engine, and a 1993 model year Cummins L10 engine. Results were compared to United States’ mobile source inventory for on-road diesel engines, as well as historic and modern diesel engine emission values. The test fuel contained chlorine at 9.8 ppm which is 1.5 orders of magnitude above what is found in current diesel fuel and 3900 ppm sulfur to simulate fuels that would have been available when these engines were produced. Results indicate PCDD/F emissions of 13.1, 7.1, and 13.6 pg International Toxic Equivalency (I-TEQ) L−1 fuel consumed for the three engines respectively, where non-detects are equal to zero. This compares with a United States’ mobile source on-road diesel engine inventory value of 946 pg I-TEQ L−1 fuel consumed and 1.28 pg I-TEQ L−1 fuel consumed for modern engines equipped with a catalyzed diesel particle filter and urea selective catalytic reduction. PCB emissions are 2 orders of magnitude greater than modern diesel engines. PAH results are representative of engines from this era based on historical values and are 3-4 orders of magnitude greater than modern diesel engines. 相似文献
102.
Huff J 《Chemosphere》2012,89(5):521-525
Carcinogenesis bioassays were conducted by giving 2,4,6-trichlorophenol [2,4,6-TCP] in feed to groups of 50 male and female Fischer rats and male B6C3F1 mice for two years. Dietary concentrations were 0 [20/group], 5000 [0.5%], or 10,000 [1%] ppm. Female mice began with 10,000 and 20,000 ppm but after 38 weeks were lowered due to reduced body weights to 2500 and 5000 ppm for 67 weeks; exposures averaged 5200 and 10,400 ppm. Adverse effects at two years were leukocytosis and monocytosis of peripheral blood and hyperplasia of bone marrow in both sexes of rats. In mice, liver toxicity, including individual liver cell abnormalities, focal areas of cellular alteration, and focal and nodular areas of hyperplasia were commonly present. Regarding carcinogenic activity, TCP caused leukemias/lymphomas in male rats, and possibly in female rats and female mice as well, and induced liver tumors in male and female mice. Using NTP categories of evidence indicates ‘clear evidence of carcinogenicity’ for male rats [hematopoietic system tumors]; ‘equivocal evidence of carcinogenicity’ for female rats [hematopoietic system tumors]; ‘clear evidence of carcinogenicity’ for male and female mice [liver tumors]. 相似文献
103.
With the continued growth in demand for mineral resources and China's efforts in increasing investment in geological prospecting, economic impact evaluation of geological exploration becomes a research hotspot. 相似文献
104.
105.
Mining investment in Indonesia has been at a standstill for a decade. Clearly. international mining companies regard the country as a high risk destination for capital. Yet Indonesia is one of the most highly mineralised countries in the world and has expressed a desire to increase investment in the sector in the coming years. As a first step in this direction the government has introduced a new mineral and coal mining law to replace the highly regarded Contract of Work system. The government argues that this new law will reinvigorate mining investment in the country. This paper suggests that the new mining law will do little to improve the situation. Indeed, it is unlikely that Indonesia will become a preferred destination for mining investment in the foreseeable future. Poor regulatory architecture, endemic corruption, and a lack of institutional capacity continue to be of concern to investors. 相似文献
106.
Countries that rely on private investors to find and exploit their mineral resources need reliable indicators of their investment attractiveness. This study explores the use of exploration expenditures for this purpose, focusing primarily on Chile. 相似文献
107.
飞灰中二英热脱附行为的研究 总被引:1,自引:1,他引:1
研究了垃圾焚烧产生的飞灰中二噁英在隔绝空气受热条件下的热脱附行为及规律.通过气相和固体残留中二噁英的含量分析,推测了二噁英在不同温度条件下可能发生的几种化学反应和物理变化,同时研究了17种有毒二噁英的热脱附效率和飞灰的最佳热脱附条件.PCDD/Fs在200℃和300℃下平均脱附率分别为96.2%和95.5%,而400℃下的平均脱附率高达99.7%.结果表明,在300℃加热条件下,飞灰中的PCDD/Fs主要发生脱氯降解反应.在400℃下,飞灰中发生大量的前体合成反应,使PCDD/Fs含量显著增加. 相似文献
108.
采用欧洲经济合作与发展组织(OECD)的生物降解测试标准方法——301F测压呼吸计量法,考察了2-羟基-4-甲氧基二苯甲酮(BP-3)和2-羟基-4-甲氧基二苯甲酮-5-磺酸(BP-4)的好氧生物降解性能,并研究了降解动力学及共代谢现象。实验结果表明:BP-3和BP-4的可生物降解率分别为68.36%和41.34%;根据OECD快速降解性判定标准,BP-3划归为易快速降解物质,而BP-4为不易快速降解物质;两种物质的生物降解可用一级动力学描述,半衰期分别为1.986 d和2.806 d;根据欧盟法规《化学品的注册、评估、授权和限制》(REACH法规),BP-3和BP-4均非持久性物质;与苯甲酸钠共存时,BP-3和BP-4的降解过程均表现出共代谢现象。 相似文献
109.
二恶英具有"三致"毒性,是一种迄今为止发现过的最具致癌潜力的物质,即使在浓度很低的环境中人体也会发生诸多病变,国际癌症研究中心早已将其列入人类一级致癌物。对于钢铁行业,其主要产生于烧结和电炉炼钢两大生产工序;结合二恶英的性质及产生机理,对烧结、电炉炼钢、高炉炼铁等生产工序二恶英的产生情况进行了简要介绍。 相似文献
110.
How effective was the Kyoto protocol? International Environmental Agreements (IEA) have been on the rise over the past four decades; however, thus far their effectiveness is controversial. In view of the conflicting results found in the related literature, this paper addresses its effectiveness by utilizing for the first time the generalized synthetic control method (GSCM) to compare the emissions of the industrialized countries with a “No- Kyoto” counterfactual scenario that represents the expected emissions in the absence of the protocol. This method facilitates a robust comparison between treated and control countries as done by Almer and Winkler (2017) and account for the multiple treated units as done by Grunewald and Martinez-Zarzoso (2016), so as to capture the collective nature of the protocol. Results show that the protocol was successful in reducing the emissions of the ratifying countries approximately by 7% below the emissions expected under a “No-Kyoto” scenario, confirming the importance of accounting for the collective nature of the agreement. 相似文献