Environmental surveys approach

The purpose of this paper is to describe MEPAS, a computer-based methodology for health impact estimation developed to support DOE site prioritization. MEPAS takes a physics-based approach based on characterization of exposures resulting from source-to-receptor transport at DOE sites. It is currently being used in DOE s Environmental Survey effort aimed at identification and prioritization of DOE sites. A Preliminary Summary Report has been issued for major DOE production sites (3), and a Final Summary Report for all DOE sites will be avail-able in 1990. 0097-6156/90/0431-0193 06.00/0... 

One difficulty in conducting a large number of applications is organizing the applications and their data. A standardized approach is needed to allow a consistent definition of environmental problems. For example, a formal classification of environmental problems can provide a framework for data organization. Although the approach was largely dictated by the Environmental Survey s classification, the MEPAS structure should be applicable to environmental problems in general. 

Methods. As discussed in the previous chapter, a number of approaches have been used to assess the presence of potentially toxic trace elements in water. The approaches used in this assessment include comparative media evaluation, a human health and aquatic life guidelines assessment, a mass balance evaluation, probability plots, and toxicity bioassays. Concentrations of trace elements were determined by atomic absorption spectrometry according to standard methods (21,22) by the Oregon State Department of Environmental Quality and the U.S. Geological Survey. 

Besides the LCA approach, also risk assessment can be performed analysing the chemical compounds or modelling via predictive exposure models. Both types of approaches have their justification to measure environmental concentrations of chemicals in the environment with laboratory measurement is still the most reliable way for determination. But it goes along with the disadvantage of high investments concerning time and money. Besides that laboratory approaches are limited in terms of space and time, and in consequence, the survey of many micro-pollutants and their... 

In view of these complexities, environmental studies that seek to verify proposed cause-effect relationships between contamination and response need to be carefully designed to avoid bias and misunderstanding. Most environmental assessments adopt a multi-tiered approach to testing, in which combinations of biological responses (biomarkers) are measured in tissue samples, body fluids or at the whole organism level to indicate exposure to or adverse effects of contamination.8. Auffret and colleagues60 surveyed Pacific oysters from the Atlantic coast of Brittany after the Erika oil spill between... 

The Patai Series publishes comprehensive reviews on all aspects of specific functional groups. Each volume contains outstanding surveys on theoretical and computational aspects, NMR, MS, other spectroscopical methods and analytical chemistry, structural aspects, thermochemistry, photochemistry, synthetic approaches and strategies, synthetic uses and applications in chemical and pharmaceutical industries, biological, biochemical and environmental aspects. 

In this chapter, the current and future capabilities of HPLC for the determination of trace organic compounds in aqueous environmental samples will be assessed. This assessment will include approaches to sample cleanup or analyte isolation for those species likely to be candidates for analysis by HPLC. Column technology, as it contributes to the use of HPLC for trace organic analyses, will be surveyed. Finally, detection of the compounds eluting from the system will be examined. The ultimate detector will always adequately identify and measure the compounds of interest. 

In the most straightforward risk-based approach, epidemiologic studies have developed exposure-response relationships based on biomarker measurements in hair, blood, urine, or other matrices (e.g., mercury, lead) (see Figure 5-2a). The relationships can be applied directly to new biomonitoring data to determine where on the exposure-response curve any person is. That may facilitate an understanding of risk, but it does not analyze sources of exposure, so other techniques (such as environmental sampling and behavioral surveys) may be needed to assess where the exposure came from. 

We have addressed the topic of metal bioavailability and metal toxicity in environmental samples. Traditionally, metal availability is investigated using a chemical approach. Afterwards, the concept of Water Effect Ratio (WER) was proposed by the U.S. EPA and employed bioassays (e.g., fish and invertebrate tests) to assess metal bioavailability and toxicity. In the HMBC approach discussed in this review, we have made use of a bacterial assay that is specific for metal toxicity to achieve this goal. This is only a preliminary survey of the potential applications of the HMBC concept. Some preliminary results on the use of MetPLATE for the fractionation of HMBC to obtain information on the factor(s) that control metal bioavailability in environmental samples were also presented. Using MetPLATE eliminates or diminishes the confounding factor represented by the presence of organic toxicants in a given sample. Further work is needed to refine the fractionation scheme. 

Various review articles [1-14] and textbook chapters [15,16] have dealt with the description and assessment of both direct and indirect phototransformations in the aquatic environment in the last 25 years. A major aspect of these studies was identification of the various reactive transients that are formed in sunlit natural waters, and to estimate or calculate their concentrations and their second-order reaction rate constants with contaminants in order to assess indirect phototransformation rates under environmental conditions. In this study, we maintain this reactive transient approach, outlining the main pathways of formation after absorption of light by natural organic matter. We also present a survey of studies addressing organic-matter-induced phototransformations of organic contaminants conducted during the last decade. This survey shows the importance of indirect phototransformations in the aquatic environment and illustrates how the transients responsible for such reactions may be identified. 

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