排序方式: 共有16条查询结果,搜索用时 15 毫秒
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疾病预防控制机构废水具有重金属种类繁多、含病原体数量大、间断性排放等特点,通过运用混凝沉淀+曝气生物滤池(BIOFOR)+ClO2消毒工艺对其废水进行处理,处理后废水达到《医疗机构水污染物排放标准(》GB18466-2005)排放标准。 相似文献
2.
Damodar S. Airan 《Journal of the American Water Resources Association》1973,9(5):1035-1040
ABSTRACT: Piped water supply and sewerage have been taken almost for granted in the developed countries. However, most people in the United States have little knowledge of the condition of public health amenities in the developing countries. The paper reviews the importance, background and current status of water and wastewater facilities in India. The relative situation in urban and rural areas, conventional practices in environmental hygiene, the programs for improvement and the problems involved with possible solutions are given. The case history of a town is also included for illustrative purposes. 相似文献
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Chao Lu Kanglan Deng Chun Hu Lai Lyu 《Frontiers of Environmental Science & Engineering》2020,14(5):82
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Mathias B. Forrester 《毒物与环境化学》2013,95(4):739-743
Many lupine species (Genus Lupinus) contain toxic compounds, although the amount of these substances varies by the plant part and species. This investigation described the epidemiology of 138 lupine exposures reported to Texas poison centers during 1998–2005. Almost 88% of the lupine exposure calls occurred in March and April, and 90% of the calls came from the central portions of the state. Sixty-one percent of the calls involved female patients, and 91% of the patients were age <6 years. The lupine exposure occurred at the patient's own residence in 79% of the cases. Of the reported lupine exposures, 93% were handled outside of health care facilities, and, of those cases with a known medical outcome, few moderate or major effects, and no deaths, were reported. The most frequently noted clinical effect among cases during 2000–2005 was vomiting, affecting 8% of the cases. In conclusion, most reported lupine exposures in Texas came from the central parts of the state, occurred in spring, and involved young children. Typical reported lupine exposures in Texas were not likely to have adverse outcomes. 相似文献
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中国耕地变化的空间格局与重心曲线动态分析 总被引:10,自引:0,他引:10
采用罗伦兹曲线、重心模型等G IS技术,利用1980 s和2000年两期覆盖全国跨度10多年的土地利用数据,构造耕地指数、耕地变化指数对中国耕地空间分布及其空间变化格局进行分析。主要结论:①中国耕地主要分布在黑、川、蒙、豫、鲁等北部和中部省份,其中苏、粤、冀、鲁、浙等19个省份的耕地有所减少,黑、蒙、吉、新等13个省份的耕地有所增加;②胡焕庸线之东南40%的国土面积分布着全国88%的耕地;西北60%的国土面积分布着全国12%的耕地,中国耕地空间分布可划分为高度稀疏区、低度稀疏区、一般过渡区、低度集聚、高度集聚区等5种类型;③中国耕地变化区域类型可适度划分为高度增长区、中度增长区、低度增长区、基本不变区、低度减少区、中度减少区、高度减少区等7大类型。顾及耕地质量背景下的中国耕地空间分布格局及变化特征等应进一步研究。 相似文献
6.
为研究青藏高压系统对川渝地区春夏季臭氧(O3)污染的影响机制,对2015~2018年每年4~9月的中国气象局高空全要素填图数据(Micaps PLOT High)、川渝14个城市的国控环境监测站点O3监测数据及气象台站数据进行了研究分析.结果表明:O3浓度的高低与青藏高压中心位置分布的状况和数量密切相关,中心分布越密集、出现的极值区域越多和中心个数越多时,同期地表温度越高,O3浓度越高(尤其是中心位置出现在100°E和28°N的频数越多,地表温度越高,导致较多O3极值的出现).对比分析同年逐月与逐年同月高压脊线南北偏移情况对O3浓度的影响,发现高压脊线越往北跳,对应日照时数越长,O3浓度越高.综合分析高压中心和高压脊线对川渝地区O3影响的共同作用,发现高压中心和高压脊线分别主要通过控制地表温度和日照时数来影响O3浓度,且同一时段,二者对O3浓度影响的效果和程度也存在差异,有时对O3浓度的增加表现为协同作用,有时为拮抗作用. 相似文献
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为探讨石英不同Ti-Li心电子自旋共振(ESR)信号的光晒退特征及其测年意义,对典型花岗岩类基岩样品、河流现代表层沉积物样品及地质历史时期沉积物样品的石英Ti-Li心option A、Ti-Li心option B、Ti-Li心option C、Ti-Li心option D和Ti-Li心option E的ESR信号光晒退特征进行了系统研究。结果显示:(1)不同Ti-Li心ESR信号可在较短时间内(260 h)完全晒退,表明Ti-Li心是优良的石英ESR测年信号心;(2)石英的赋存环境对同一Ti-Li心ESR信号晒退“归零”所需的时间具有明显的影响作用。相比于基岩石英和地质历史时期沉积物石英,现代河流沉积物石英因其已经接受了一定时间的光晒退作用而具有更快的光晒退“归零”速率;(3)石英同一Ti-Li心的光敏感特性会因石英经历的地质循环过程的不同而改变,相比于基岩,沉积物因经历了更复杂的地质过程而具有了深陷阱电子,所以需要更长的光晒退归零时间;(4)同一样品的不同Ti-Li心表现出了相同的光晒退特征,说明不同类型的Ti-Li心具有相同的光敏特性;(5)Ti-Li心option B在某些自然样品中不易观察,Ti-Li心option D和Ti-Li心option E信号较为微弱,因此,Ti-Li心option A是进行沉积物石英ESR测年的最佳信号心。 相似文献
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Mathias B. Forrester 《毒物与环境化学》2013,95(2):285-292
The cyclooxygenase-2 (COX-2) inhibitor rofecoxib was withdrawn from the US market on September 30, 2004, and valdecoxib was withdrawn on April 7, 2005. The impact of these actions on COX-2 inhibitor exposures reported to poison control centers was unknown. The objective of this study was to describe the pattern of COX-2 inhibitor exposures reported to Texas poison control centers before and after rofecoxib and valdecoxib were withdrawn. The number of celecoxib, rofecoxib, and valdecoxib exposures reported to Texas poison control centers each month during 1999–2006 was identified and examined for changes over time. Comparisons were made with respect to those exposures reported immediately prior to withdrawal (October 2003–September 2004) and to exposures after withdrawal (April 2005–December 2006). The mean monthly number of reported exposures prior to withdrawal was 18.8 for celecoxib, 20.3 for rofecoxib, 13.3 for valdecoxib, and 51.5 for total COX-2 inhibitors. The mean monthly number of reported exposures after withdrawal was 9.3 for celecoxib, 1.8 for rofecoxib, 1.3 for valdecoxib, and 12.3 for total COX-2 inhibitors, representing declines of 51, 91, 90, and 76%, respectively. The withdrawal of rofecoxib and valdecoxib from the market resulted in a decrease in the number of COX-2 inhibitor exposures reported to Texas poison control centers. However, rofecoxib and valdecoxib exposures continued to be reported for a long time after withdrawal. Reported celecoxib exposures declined even though it was not withdrawn from the market. 相似文献
10.
In this study, the effects of environmental hypercapnia on hemato-immunological parameters and the activities of respiratory enzymes such as carbonic anhydrase (CA) and Na+, K+-ATPase were investigated in rainbow trout (Oncorhynchus mykiss) tissues (gill, liver and kidney). Batches of 12 fish were exposed to 4.5 mg L?1 (control) and 14 mg L?1 CO2. No mortalities occurred during the 14 days of the experimental period. Red blood cell (RBC), hemoglobin (Hb), and hematocrit (Ht) levels, and innate immune parameters such as nitro blue tetrazolium (NBT), lysozyme, and myeloperoxidase activities, and the melano-macrophage frequency were negatively affected by elevated CO2 levels. Patterns of change in CA activity differed among the gill, liver, and kidney. Compared with the activities of CA in the control group, the CA enzyme was significantly stimulated at day 7 in the gill tissue, whereas it was stimulated at day 14 of the experiment in the liver tissue of fish exposed to 14 mg L?1 CO2 (P < 0.05). In contrast to the pattern of CA enzyme activities, the Na+, K+-ATPase enzymes were stimulated significantly in the liver after day 7 but inhibited in the kidney and gill (P < 0.05). These results suggest that a subchronic exposure to hypercapnia of rainbow trout tissues may lead to adaptive changes in the respiratory enzymes and negatively affects hemato-immunological parameters. 相似文献