空间数据基础设施（SDI）中涉及到的一些概念

近期以来，就信息管理，特别是空间数据的处理问题展开了讨论，诸如数据库、数据市场、数据交换站、数据处理、互操作性及空间数据基础设施等新概念都成为未来处理空间数据的得力工具，上述概念有的非常相近以至于很难对它们乃至它们的应用进行区分。本文论述了数据库、数据市场、数据处理、互操作性SDI的概念，指出了这些概念之间的相似点及其内在联系。     

有关边界测量测量标准的几点设想

去年，作者曾在宾西法尼亚州参与了重编边界测量测量标准工作。在编写过程中，对通用提出的几个州及国家标准进行了复。本文指出了通用标准中存在的诸多问题，并指出了要新的边界测量测量标准的构想。     

利用土壤信息检验地质雷达的应用

在美国，自１９７８年以来，地质雷达已经作为一种土壤学工具在使用，国家合作土壤测量大纲曾经使用地质雷在突测土壤的性质，这些性质影响到土壤的利用，管理和分类，地质雷达主要用于估测土壤的变化性和分类的成分组成，图示横向范围，估测土壤层位和地质层的深度与厚度，以及对土壤进行测绘和解释，并非所有土壤同样适合地质雷达技术，土壤测量报告中发表的土壤绘图和分类被用来评价土壤和场对地于地质雷达的适用性，此外，用于定     

A description of how metal pollution occurs in the Tinto-Odiel rias (Huelva-Spain) through the application of cluster analysis

In the last few decades, the study of space-time distribution and variations of heavy metals in estuaries has been extensively studied as an environmental indicator. In the case described here, the combination of acid water from mines, industrial effluents and sea water plays a determining role in the evolutionary process of the chemical makeup of the water in the estuary of the Tinto and Odiel Rivers, located in the southwest of the Iberian Peninsula.Based on the statistical treatment of the data from the analysis of the water samples from this system, which has been affected by processes of industrial and mining pollution, the 16 variables analyzed can be grouped into two large families. Each family presents high, positive Pearson r values that suggest common origins (fluvial or sea) for the pollutants present in the water analyzed and allow their subsequent contrast through cluster analysis.     

Surveillance for previously unmonitored organic contaminants in the San Francisco Estuary

The San Francisco Estuary Regional Monitoring Program initiated surveillance monitoring to identify previously unmonitored synthetic organic contaminants in the San Francisco Estuary. Organic extracts of water samples were analyzed using gas chromatography-mass spectrometry in full scan mode. The major contaminant classes identified in the samples were fire retardants, pesticides, personal care product ingredients, and plasticizers. Evidence from the literature suggests that some of these contaminants can persist in the environment, induce toxicity, and accumulate in marine biota and in higher food chain consumers. The major sources of these contaminants into the marine environment are the discharge of municipal and industrial wastewater effluents, urban stormwater, and agricultural runoff. As a proactive effort, it is suggested that surveillance studies be used routinely in monitoring programs to identify and prevent potential problem contaminants from harming the marine environment.     

Polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans in sediments from Hong Kong

Concentrations of 2,3,7,8-substituted polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs) were determined in 14 sediment samples collected from four sites in the Mai Po Marshes Nature Reserve (within a RAMSAR Site) and from another six sites in Victoria Harbour and along the Hong Kong coastline. Elevated levels of PCDDs, and particularly OCDD, were detectable in all samples collected from the Mai Po Marshes and five of the six sites. In contrast to PCDDs, PCDFs were mainly found in sediment samples collected from industrial areas (Kwun Tong and To Kwa Wan) in Victoria Harbour. PCDD/F levels and congener profiles in the samples from the Mai Po Marshes Nature Reserve in particular show strong similarities to those reported in studies which have attributed similar elevated PCDD concentrations to nonanthropogenic PCDD sources.