| Improved reliability in the interpretation of geochemical measurements by the quantification of uncertainty from sampling |
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| 作者姓名： | Michael H. Ramsey Paul D. Taylor Katy A. Boon |
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| 作者单位： | Centre for Environmental Research, Department of Biology and Environmental Science, School of Life Sciences, University of Sussex, Brighton, UK |
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| 摘 要： | All geochemical measurements require the taking of field samples, but the uncertainty that this process causes is often ignored when assessing the reliability of the interpretation, of the geochemistry or the health implications. Recently devised methods for the estimation, optimisation and reduction of this uncertainty have been evaluated by their application to the investigation of contaminated land. Uncertainty of measurement caused by primary sampling has been estimated for a range of six different contaminated land site investigations, using an increasingly recognized procedure. These site investigations were selected to reflect a wide range of different sizes, contaminants （organic and metals）, previous land uses （e.g. tin mining, railway sidings and gas works）, intended future use （housing to nature reserves） and routinely applied sampling methods. The results showed that the uncertainty on measurements was substantial, ranging from 25% to 186% of the concentration values at the different sites. Sampling was identified as the dominant source of the uncertainty （〉70% of measurement uncertainty） in most cases. The fitness-for-purpose of the measurements was judged using the optimized contaminated land investigation （OCLI） method. This identifies the optimal level of uncertainty that reduces to overall financial loss caused by the measurement procedures and the misclassification of the contamination, caused by the uncertainty. Generally the uncertainty of the actual measurements made in these different site investigations was found to be sub-optimal, and too large by a factor of approximately two. The uncertainty is usually limited by the sampling, but this can be reduced by increasing the sample mass by a factor of 4 （predicted by sampling theory）. It is concluded that knowing the value of the uncertainty enables the interpretation to be made more reliable, and that sampling is the main factor limiting most investigations. This new approach quantifies this problem for the first time, and allows sampling procedures to be critically evaluated, and modified, to improve the reliability of the geochemical assessment.
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| 关 键 词： | 地球化学 可靠性 土壤 水 抽样法 |
Improved reliability in the interpretation of geochemical measurements by the quantification of uncertainty from sampling |
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| Michael H. Ramsey Paul D. Taylor Katy A. Boon.Improved reliability in the interpretation of geochemical measurements by the quantification of uncertainty from sampling[J].Chinese Journal of Geochemistry,2006,25(B08):209-210. |
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| Abstract: | |
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| Keywords: | uncertainty sampling fitness-for-purpose measurement |
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