Spatial and temporal trend of sewage pollution indicated by coprostanol in Macao Estuary,southern China   总被引：1，自引：0，他引：1  

Peng X  Zhang G  Mai B  Min Y  Wang Z 《Marine pollution bulletin》2002,45(1-12):295-299

Bottom sediments and a ²¹⁰Pb dated sedimentary core in Macao Estuary were quantitatively analyzed with GC-MS for coprostanol and other sterols. Higher coprostanol concentrations were detected at Port Interior and Lower Qianshan River, indicative of serious sewage pollution from densely populated Macao Island and Zhuhai City. However, very low concentrations of coprostanol were detected around Coloane Island as well as Port Exterior and Maliuzhou River except sites adjacent sewage outlets. Coprostanol pollution in Macao Estuary originates mainly from locally direct discharge of untreated wastewater. The concentrations of coprostanol in ZJ-9 were mainly in range of 150–280 ng/g with an average of 210 ng/g for more than 20 years from early 1970s to early 1990s. However, it increased obviously since 1993, and reached the highest in 1995–1996. However, a sharp decrease of coprostanol concentration from 470 to 31 ng/g after 1996 was observed corresponding to the first wastewater treatment plant in Taipa Island going into action.  相似文献   

Stream-aquifer interactions: evaluation of depletion volume and residual effects from ground water pumping   总被引：8，自引：0，他引：8  

Chen X  Shu L 《Ground water》2002,40(3):284-290

Numerical modeling techniques were used to simulate stream-aquifer interactions from seasonal ground water pumping. We used stream-aquifer models in which a shallow stream penetrates the top of an aquifer that discharges ground water to the stream as base flow. Because of the pumping, the volume of base flow discharged to the stream was reduced, and as the pumping continued, infiltration from the stream to the aquifer was induced. Both base-flow reduction and stream infiltration contributed to total stream depletion. We analyzed the depletion rates and volumes of the reduced base flow and induced stream infiltration during pumping and postpumping periods. Our results suggested that for a shallow penetrating stream with a low streambed conductance, base-flow reduction accounts for a significant percentage of the total stream depletion. Its residual effects in postpumping can last very long and may continue into the next pumping season for areas where recharge is nominal. In contrast, the contribution of the induced stream infiltration to the total stream depletion is much smaller, and its effects often become negligible shortly after pumping was stopped. For areas where surface recharge replenishes the aquifer, the residual effects of base-flow reduction and thus its depletion volume will be significantly reduced. A stream of large conductance has a high hydraulic connection to the aquifer, but the relationship between stream conductance and stream depletion is not linear.  相似文献   

Mercury concentrations in the fur of steller sea lions and northern fur seals from Alaska     

Beckmen KB  Duffy LK  Zhang X  Pitcher KW 《Marine pollution bulletin》2002,44(10):1130-1135

We compared total mercury (THg) concentrations in the fur of northern fur seals (Callorhinus ursinus) from the depleted Pribilof Islands population with those of both declining and thriving populations of Steller sea lions (Eumetopias jubatus) from Prince William Sound (PWS) and Southeast Alaska (SEA), respectively. Relatively low wet weight concentrations (ranges) of THg were detected in the fur of Steller sea lion (SSL) pups (0.90-3.14 microg/g) and juveniles (0.56-6.75 microg/g) from both areas in 1998 and 2000 compared to northern fur seal (NFS) pups (3.15-8.14 microg/g) in 2000. The mean concentration +/- SD for SSLs sampled were 1.46 +/- 0.64 microg/g for pups (n = 22) and 2.74 +/- 2.89 microg/g for juveniles (n = 6). Analyses indicated higher THg concentrations from SSL pups from PWS compared to the SEA. Mean +/- SD. THg in the NFS pups was 4.90 +/- 1.42 microg/g (n = 34) and for post-partum dams was 7.84 +/- 1.78 microg/g (n = 12).  相似文献   

Evolution of Ore-Forming Fluids and Ag-Cu Polymetal Mineralization in the Lanping Basin, Yunnan   总被引：1，自引：0，他引：1  

Wang C. S.  Tang J. X.  Gu X. X.WT  ”BX 《地学前缘》2000,(Z1)

EVOLUTION OF ORE-FORMING FLUIDS AND Ag-Cu POLYMETAL MINERALIZATION IN THE LANPING BASIN, YUNNAN“KeyProjectforResourcesandEconomics” (95 0 2 0 0 1 0 1)oftheMinistryofLandResources  相似文献   

伊犁盆地侏罗系水西沟群层序地层学研究   总被引：2，自引：0，他引：2  

李盛富  王果  魏安心  齐军让  张中旺 《铀矿地质》2006,22(1):23-28

伊犁盆地侏罗系水西沟群是一套在基本一致的构造应力和沉积环境下形成的含煤碎屑岩建造,但在这套地层的中部(三工河组)出现了岩性、颜色的突变,并且对应的测井曲线也出现明显的突坎现象。笔者运用层序地层学的观点,从年代地层、岩性、体系域、沉积韵律以及测井曲线解释等5方面对这一现象进行了分析,认为该群中部存在一不整合面(或层序界面),并尝试对水西沟群层序地层进行重新划分。  相似文献   

GPS制导技术浅析及对抗策略     

丁志国  魏本杰  杨志强 《全球定位系统》2006,31(3):46-48

GPS导航技术应用于武器精确制导，大大提高了武器的制导能力和打击精度。卫星制导武器已逐渐成为战争的主要打击兵器，推动着作战样式的新发展。通过对GPS／INS（惯性导航）组合制导技术进行分析，针对弱点提出了干扰对策。  相似文献   

浅议电法找水中的一个误区   总被引：1，自引：0，他引：1  

魏荣科 《中国煤田地质》2006,18(5):56-57

在河北GY北部山前地带及河北TX西北部山区等环境条件下,采用电法找水,不应过分依赖于低阻岩带或灰岩溶隙选定井位,特别是电测深H型曲线,如低阻出现深度较浅,且未出现低阻平直段,曲线尾部又近于45°渐近线,则可能是浅层的亚粘土、砂质粘土形成的,不具备成井条件;而A型曲线如在深部(200～350m)出现高阻平直段,则可推测为基岩深部的脉状裂隙水反映。实践证明采用这种方法确定钻井点位是可行的,对于在我国北方寒武、奥陶系地层中寻找地下水资源,具有一定的参考价值。  相似文献   

攀枝花宝鼎矿区地温研究     

何广明  魏克敏 《中国煤田地质》2007,19(5):51-53,81

根据攀枝花宝鼎矿区＋900、＋700、＋500水平的地温分布特征,结合矿区地貌、水系、构造发育程度、地层岩性组合、覆盖层厚度、矿井采空区范围等条件,对该区深部地温的分布规律进行探讨研究,认为其热源可能来自岩浆余热,但地温异常与矿区各地质特征有关,为老矿区深部煤炭资源的开发,防治地热灾害提供了地温依据。  相似文献   

董申保教授在北京大学     

于洸  张立飞  魏春景 《高校地质学报》2007,13(3):613-616

70多年来,董申保老师一直从事地质学研究与教育工作,为我国地质行业发展与教育事业做出了巨大贡献,其中在北京大学学习、工作将近40年。2007年9月17日恭逢董先生九十华诞,我们将他在北大学  相似文献   

地震记录相似性的小波属性度量方法研究     

符志国  刘洋  魏修成  黄捍东 《物探化探计算技术》2007,29(1):7-11

为了提高三维低频资料(主频15Hz~30Hz)断层检测精度,探讨了小波地震属性与相干结合的检测方法。当断层的水平断距小,断层二侧地震记录的波形特征相似时,单靠相干方法已不能明显地反映断层。针对此问题,分析了多种相似性度量方法,最后从地震属性方法出发,提出基于小波属性体的相干方法改善检测效果。实际资料处理表明了该方法的合理性和实用性,不仅更细致地度量了相似性,还为地震勘探量化参数的精细分析提供了一条思路。  相似文献