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991.
992.
本文报道了成都磷肥及其原料矿石中外照射剂量水平;用国家标准规定的方法测定了磷肥及其矿石中^226Ra含量;调查了同一生产厂家不同批号磷肥中^226Ra含量变化情况;估算出施用磷肥后可能带来的放射性环境污染,并对磷肥中^226Ra可能导致的农田环境影响作了简要评价? ? 相似文献
993.
Wei Wang Jianguo Jiang Xuelong Wu Shunwen Liang 《Journal of Material Cycles and Waste Management》2000,2(2):65-69
In China, controlling environmental pollution resulting from solid waste (SW) and hazardous waste (HW) has become one of the
most pressing tasks in the field of environmental engineering. It is reported that the annual generation of industrial solid
waste (ISW) in China exceeded 0.6 billion tons in the 1990s, and is increasing every year. Although ISW management has been
strengthened in recent years, about 40% of SW is put in uncontrolled landfill without appropriate treatment. According to
statistics from the national Environmental Protection Agency, the cumulative ISW uncontrolled landfill in China had reached
6.6 billion tons by the end of 1995, occupying around 55 000 hectares of land. Although some major uncontrolled landfills
were constructed, nonetheless groundwater contamination resulted from the use of low-standard liners and poor management.
Furthermore, about 20 million tons of ISW was discharged into the environment illegally, and a third of this waste was discharged
directly into water bodies, making ISW one of the greatest pollution sources for surface water and ground water. Environmental
pollution accidents resulting from SW occur about 100 times a year in China, and environmental issues frequently arise because
of ISW pollution. The practices of SW management, treatment, and disposal started relatively late in China, and for a long
time the management of SW pollution has received little attention compared with water and air pollution management. China
faces problems such as the insufficiency of management laws and regulations, insufficient investment, inadequate treatment
and disposal technology, and a lack of qualified technicians. At present, most treatment and disposal technology cannot meet
the requests for solid waste pollution control. In order to protect, restore, and improve environmental quality in China and
to realize sustainable development, the safe management and disposal of solid and hazardous wastes is a pressing challenge.
In recent years, much attention has been paid to SW management in China, and investment to develop management and treatment
technologies has increased. In 1995, the Law for Solid Waste Pollution Protection was issued, and work on solid waste treatment
and disposal began to be legally managed. SW treatment and disposal facilities have been constructed, and now operate in some
large and medium-sized cities. In particular, rapid improvements have been seen in ISW recycling, collection, and disposal
of municipal solid waste and regional HW management. All the figures in this paper are from 1995, and represent the situation
in China in that year.
Received: April 18, 2000 / Accepted: May 15, 2000 相似文献
994.
Metal contamination in sediments of the western Bohai Bay and adjacent estuaries, China 总被引:5,自引:0,他引:5
Feng H Jiang H Gao W Weinstein MP Zhang Q Zhang W Yu L Yuan D Tao J 《Journal of environmental management》2011,92(4):1185-1197
Twelve sediment cores were collected in July 2007 in open waters of western Bohai Bay, the Port of Tianjin, and the adjacent estuaries of the Haihe and Yongding Rivers. While overall concentrations of trace metals at incremental depths in these cores met the Marine Sediment Quality (GB18668-2002) criteria of China, the magnitude of both metal enrichment factors (EF) and geoaccumulation indices (I(geo)) suggested that pollution with Ag, Cd, Cr, Cu and Zn was occurring in the estuaries and Port. Risk analysis also suggested that Ag and Ni concentrations were sufficiently elevated as to cause adverse biological effects in the study area. Although metal concentrations in western Bohai Bay were of less concern, a positive relationship between EF values and excess (210)Pb activity for several metals suggested that their concentrations were increasing over time. 相似文献
995.
996.
Zhenghong Tang Ruopu Li Xu Li Weiguo Jiang Aaron Hirsh 《Journal of the American Water Resources Association》2014,50(1):234-245
The digital elevation model data from traditional stereo photogrammetric methods are inadequate in providing accurate vertical parameters to feed hydrologic models for low‐lying, extremely flat areas. High‐resolution light detection and ranging (LiDAR) data provide the robust capability of capturing small variations in low‐relief playa wetlands. The Rainwater Basin in south‐central Nebraska includes a complex of seasonally shallow playa wetlands that attract millions of migratory waterfowl every spring and fall. This research focuses on the development of a procedure with applicable protocols to produce LiDAR‐derived three‐dimensional wetland maps and to extract the critical surface parameters (i.e., watershed boundaries, flow direction, flow accumulation, and drainage lines) for playa wetlands. The topo‐hydrologic conditions of playa wetlands were evaluated at the watershed level. The results show that in the Rainwater Basin, 70.7% of the historic hydric soil footprints identified in the Soil Survey Geographic (SSURGO) database were not functioning as topographically depressional wetlands. This finding was confirmed by a recent five‐year Annual Habit Survey showing that 69.8% of the historic hydric soil footprints did not function during the spring migratory bird seasons between 2004 and 2009. The majority of playa wetlands' topographic conditions have been substantially changed and the SSURGO data cannot fully reflect current topographic reality in the Rainwater Basin. 相似文献
997.
998.
999.
Crowding during the morning peak hours at a platform staircase in a subway station in China was studied in this paper. Passenger flow was surveyed with normal evacuation time recorded. The evacuation process was simulated with the software buildingEXODUS. Predicted results on the total evacuation time and maximum flow capacity of the selected staircase were compared with the field observations. Two parameters, the width of staircase utilized per person and the maximum upstairs walking speed used in the software were identified to be noticeably different from the field studies. Predictions agreed better with the observations after tuning these two parameters. It is concluded that the evacuation simulation software can be applied for safety design with appropriate tuning on the key parameters through field tests. 相似文献
1000.
石油野外作业工人体力劳动强度分级调查 总被引:1,自引:0,他引:1
据GB3869—83标准对江汉油田测量、地震、钻井、井下四类野外作业34名工人、24个工种进行了体力劳动强度分级调查,其结果:测量作业为Ⅰ~Ⅱ级;钻井作业Ⅱ级占5/8,Ⅲ级占1/4;井下作业Ⅲ级占2/3;地震作业Ⅲ、Ⅳ级各占4/9、2/9。说明前两类基本属中等强度劳动,后两类大部分属重强度劳动。 相似文献