Chronic oil pollution harms Magellanic penguins in the Southwest Atlantic     

García-Borboroglu P  Boersma PD  Ruoppolo V  Reyes L  Rebstock GA  Griot K  Rodrigues Heredia S  Adornes AC  da Silva RP 《Marine pollution bulletin》2006,52(2):193-198

Petroleum pollution is a problem for seabirds along the Southwest Atlantic coast. Twenty-five groups from Salvador, Brazil (12 degrees 58'S) to San Antonio Oeste, Argentina (40 degrees 43'S) survey or rehabilitate sick or oiled seabirds. Four groups, one each in Brazil and Uruguay, and two in Argentina, kept counts of birds found alive and in need of rehabilitation. An average of 63.7% of the seabirds found were Magellanic penguins (Spheniscus magellanicus), with 3869 reported since 1987. Mainly adult penguins were found in Argentina (1605 of 2102 penguins of known age class) and Uruguay (158 of 197). Juveniles were most common in Brazil (234 of 325). Oil fouling was the most frequent cause of injury or sickness. The number of oiled penguins reported in their wintering range has greatly increased since the early 1990s and is strongly correlated with petroleum exports from Argentina. Our results show that chronic petroleum pollution is a problem for wildlife from Southern Brazil through Northern Argentina, and regulations and enforcement are failing to protect living resources.  相似文献   

A tracer dilution method for fracture characterization in bedrock wells     

Brainerd RJ  Robbins GA 《Ground water》2004,42(5):774-780

This investigation was undertaken to develop an integrated method of downhole fracture characterization using a tracer. The method presented can be used to locate water-bearing fractures that intersect the well, to determine the ambient fracture flow rate and hydraulic head, and to calculate fracture transmissivity. The method was tested in two fractured crystalline bedrock wells located at the University of Connecticut in Storrs. The method entails injecting a tracer (uranine dye) into the well, while at the same time water is pumped out of the well. After steady-state conditions are reached, a borehole tracer concentration profile is developed. The dilution of the tracer is used to locate the inflowing fractures and to determine their flow rate. The fracture flow rate, plus the drawdown in the well, is then used to determine the fracture hydraulic head, transmissivity, and ambient flow rate.  相似文献   

The development of the SCAT process for the assessment of oiled shorelines     

Owens EH  Sergy GA 《Marine pollution bulletin》2003,47(9-12):415-422

The Shoreline Cleanup Assessment Team (SCAT) process is a tool to assess oiled shorelines and is now an integral component of spill response operations. The key element of a SCAT survey is a systematic documentation using standard terms and definitions of the shoreline in the areas affected by an oil spill. SCAT programs were initially established to provide objective and accurate shoreline oiling information directly to cleanup operations. The role of the SCAT program has since expanded and the information generated by the field teams is used now by planners and decision-makers and to develop shoreline treatment recommendations, to select appropriate treatment techniques, and to establish the level or degree of treatment that is appropriate. This latter point is an integral part of establishing shoreline treatment criteria or standards and treatment end points.  相似文献   

北京某住宅楼复合地基处理实践     

赵杰伟  王志智  尚润祥 《岩土工程技术》2006,20(1):29-32

通过夯扩挤密桩对新近回填的杂填土和素填土进行加固处理,消除了地层的湿陷性和其下的液化层;并利用夯扩桩与CFG桩共同作用形成复合地基提高了地基承载力,达到了设计目的。  相似文献   

Baseline study of submerged marine debris at beaches in Curaçao, West Indies   总被引：1，自引：0，他引：1  

Nagelkerken I  Wiltjer GA  Debrot AO  Pors LP 《Marine pollution bulletin》2001,42(9):786-789

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Temporal changes in the vertical distribution of flow and chloride in deep wells   总被引：2，自引：0，他引：2  

Izbicki JA  Christensen AH  Newhouse MW  Smith GA  Hanson RT 《Ground water》2005,43(4):531-544

The combination of flowmeter and depth-dependent water-quality data was used to evaluate the quantity and source of high-chloride water yielded from different depths to eight production wells in the Pleasant Valley area of southern California. The wells were screened from 117 to 437 m below land surface, and in most cases, flow from the aquifer into the wells was not uniformly distributed throughout the well screen. Wells having as little as 6 m of screen in the overlying upper aquifer system yielded as much as 50% of their water from the upper system during drought periods, while the deeper parts of the well screens yielded 15% or less of the total yield of the wells. Mixing of water within wells during pumping degraded higher-quality water with poorer-quality water from deeper depths, and in some cases with poorer-quality water from the overlying upper aquifer system. Changes in the mixture of water within a well, resulting from changes in the distribution of flow into the well, changed the quality of water from the surface discharge of wells over time. The combination of flowmeter and depth-dependent water quality data yielded information about sources of high-chloride water to wells that was not available on the basis of samples collected from nearby observation wells. Changing well design to eliminate small quantities of poor-quality water from deeper parts of the well may improve the quality of water from some wells without greatly reducing well yield.  相似文献   

Impact of offsite sediment transport and toxicity on remediation of a contaminated estuarine bay     

Pascoe GA  McLaren P  Soldate M 《Marine pollution bulletin》2002,44(11):1184-1193

Sediment of Ostrich Bay, an arm of Dyes Inlet on Puget Sound, was historically contaminated with ordnance compounds from an onshore US Navy facility. An initial recommendation for a sediment cover to mitigate benthic risks was followed by studies of sediment transport and deposition to determine whether contaminated sediment from Dyes Inlet or other offsite sources in Puget Sound may contribute to Ostrich Bay impacts. A Sediment Trend Analysis (STA) identified net sediment transport pathways throughout the bay and inlet by examining changes in grain size distributions in multiple adjacent samples. Results indicated that fine-grained sedimentary material transports into and deposits throughout the Dyes Inlet system, with no erosion or transport out of Ostrich Bay. Echinoderm larvae mortality bioassay results were elevated in fine-grained sediments of both Ostrich Bay and Dyes Inlet. Ordnance compounds were undetected, and although sediment mercury concentrations were elevated at 0.48-1.4 mg/kg in both waterbodies, the relationship with toxicity was weak. Results of the studies and sedimentation modeling indicate that impacted sedimentary material deposits throughout the Dyes Inlet/Ostrich Bay system from unknown sources and will prevent natural recovery of Ostrich Bay as well as negate long-term effectiveness of active remedial measures. Stakeholders have recognized that remediation of the bay can be achieved only after the toxicity of depositing sediment decreases.  相似文献   

荒漠动植物群落类型与演化过程概览     

波利.  GA 李胜功 《世界沙漠研究》1994,(2):19-23

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巴哈马的阿巴科岛外声学传播时间和动态高度偏差现象间的关系     

Maul  GA 张淑芝 《海洋技术学报》1994,13(2):12-17

倒置回声测深仪（ＩＥＳ＇Ｓ）是用来测量ＩＥＳ到海表面环行声学传播时间。推荐这些相当谦价的海底安装的仪器是为了以下几个目的：ａ．长期监测特殊站点的动力变化（如热容量、温跃层、动力高度偏差等）；ｂ．卫星高度计的公海标准，ｃ．研究近岸验潮仪和近海验潮仪之间不同的海平面信号。为测量海平面的变化，特别是厘米级精确度的变化，必须获得传输时间和动态高度偏差之间的精确关系。假设在动态高度偏差和传播时间之间有不变的  相似文献   

桩锚支护中锚杆自由段对锚杆预应力影响分析     

陈全飞  赵杰伟  刚玉印 《岩土工程技术》2018,(1)

以北京某医院深基坑支护工程为背景,结合现场桩锚支护体系预应力锚杆的实测数据,综合分析不同自由段下锚杆预应力值随时间变化规律。认为相同条件下自由段越长,锚杆预应力值损失率越小。  相似文献