The sediment quality guideline, ERL, is not a chemical concentration at the threshold of sediment toxicity

While it is being used as such, the sediment quality guideline ERL (effects range low) is not a threshold of any chemical concentration in sediment at which the probability of toxicity shows an abrupt increase. Similarly, while it has been done, there is no basis for assuming that multiple concentrations above an ERL increase the probability of toxicity.     

Science, policy and the management of sewage materials. The New York City experience

Development of national policy on sewage sludge management is a classic example of incremental policy formulation [Fiorino, D.J. 1995. Making Environmental Policy. University of California Press. Berkeley, CA. p. 269]. Consequently, policy has developed piecemeal, and results are, in some ways, different than intended. Land application of sewage sludge has not been a panacea. Many of the same types of policy are now being raised about it. We demonstrate this by examining the management of sewage materials by New York City from near the turn of the 20th century, when ocean dumping was viewed as a means to alleviate some of the gross pollution in New York Harbor, to when ocean dumping was banned, and thence to the present when sludge is applied to land as "biosolids." Lessons learned during this long, sometimes contentious history can be applied to present situations--specifically not understanding the long-term consequences of land-based reuse and disposal technologies.     

Laboratory and numerical investigation of flow and transport near a seepage-face boundary

Laboratory and numerical modeling investigations were completed to study the unconfined ground water flow and transport processes near a seepage-face boundary. The laboratory observations were made in a radial sand tank and included measurements of the height of the seepage face, flow velocity near the seepage face, travel time distribution of multiple tracer slugs, and streamlines. All the observations were reliably reproduced with a three-dimensional, axi-symmetric, variably saturated ground water flow model. Physical data presented in this work demonstrate and quantify the importance of three-dimensional transport patterns within a seepage-face zone. The results imply that vertically averaged flow models that employ Dupuit approximations might introduce error in the analysis of localized solute transport near a seepage-face boundary. The experimental dataset reported in this work will also be of interest for those who are attempting to validate a numerical algorithm for solving ground water and contaminant discharge patterns near a surface-water boundary.     

大气折光对水准高差的影响

安格斯·李潘(Angus-Leppan)研究大气折光理论,探索它在测量上的应用多年,并于1979年及1980年分别发表了在稳定和不稳大气状态下水准尺读数的折光改正公式。本文将这些公式进一步展开,简化,导出实用的高差改正公式,并用算例说明了折光对精密水准高程的严重影响。     

Correlations between metal uptake in the soft tissue of Perna perna and gill filament pathology after exposure to mercury

The accumulation of metal in soft tissues, filtration rate and gill filament morphology are correlated in the southern African rock mussel, Perna perna, during exposure to mercury (24 days) and recovery (24 days). The amount of Hg in soft tissues increased from 0.13 to 87.5 μg/g dry weight after 24 days exposure, and declined to 13 μg/g during recovery. Mean filtration rate fell from 3979 to 1818 ml/h/g dry weight by day 2, but recovered slightly through days 4 and 8 (3037 ml/h/g), with a higher average rate (5030 ml/h/g) being maintained over the 24–48 days recovery period. The initial decline in filtration coincided with epithelial cell deterioration presented as interstitial oedema, neural and epithelial cell degeneration and reduced ciliation. Between days 8 and 24, cilia regenerated and there was a general improvement in cell morphology. Gill filament morphology returned to near normal during the metal-free recovery period. The usefulness of P. perna as an indicator of pollution is discussed.     

卫星多普勒全短弧法定位程序ORB DOP调试成功

卫星多普勒全短弧定位程序ORBDOP是由西德应用大地测量研究所工学硕士施吕特先生1981年11月来我院讲学时提供给我院的多普勒测量数据处理应用软件包的一部分。它由加拿大J.Kouba的半短弧法程序GEODOP和西德H.Hauck所写的主要子程序INTORB所组成。原设计程序用FORTRAN Ⅳ语言编写,运行于iBM-360系列计算机。1983年下半年起,由大地系研究室讲师陈春明同志负责在湖北省计算中心利用日本进口的FACOM M-150机上进行调试。经过一年多的努力,上学期期末已掌握了程序操作各项技术要求,并对它作了一些     

GPS“盲测”技术初探

讨论了ＧＳＰ“盲测”技术的概念和应用,指出了拥有盲测功能的设备与市场上所谓“傻瓜机”的本质区别,并且举例说明了ＧＰＳ３用房参与盲测技术开发,拓宽ＧＰＳ应用领域的可能性与可行性。