Forgot your password?
New user?
New Window Opens on the Secret Life of Microbes: Scientists Develop First Microbial Profiles of Ecosystems
CAS announces the release of SciFinder Scholar for Mac OS X
Press Releases
Press Releases
| Check out our New Publishers' Select for Free Articles |
Accreditation and Quality Assurance: Journal for Quality, Comparability and Reliability in Chemical Measurement (v.7, #5)
A practical approach to assessment of sampling uncertainty by Paolo de Zorzi; Maria Belli; Sabrina Barbizzi; Sandro Menegon; Andrea Deluisa (pp. 182-188).
The paper reports the approach followed in the SOILSAMP project, funded by the National Environmental Protection Agency (ANPA)of Italy. SOILSAMP is aimed at assessing uncertainties associated with soil sampling in agricultural, semi-natural, urban, and industrial environments. The uncertainty assessment is based on a bottom-up approach, according to the Guide to the Expression of Uncertainty in Measurement published by the International Organization for Standardization (ISO). A designated agricultural area, which has been characterized in terms of elemental spatial distribution, will be used in future as a reference site for soil sampling intercomparison exercises.
Keywords: Keywords Soil sampling; Uncertainty; Reference sampling; Intercomparison; Sampling device
Designing a contaminated soil sampling strategy for human health risk assessment by L. Malherbe (pp. 189-194).
Human health risk assessment is a site-based approach used to identify the potential health hazards which are induced by an old site contamination. For a proper evaluation of the daily doses of contaminants to which people will be exposed given the future occupation of the site, both a characterization and a quantification of soil pollution are needed. Such information can be provided by soil sampling. Thus the choice of the location, the number, depth and type of soil samples is very important and ought to follow a well-defined strategy. A review of contaminated site sampling practices in Europe and North America could not identify any completely formalized sampling strategy for human health risk assessment. On the contrary there are several approaches which can be roughly classified into two categories: a systematic sampling scheme over the whole site, on the one hand, and a sampling design driven by an initial knowledge of the contamination sources and fitted to the suspected pollution pattern, on the other. The first approach provides a complete coverage of the site but it may be rather expensive and entail useless sampling. The performance of the second depends on the quality of prior information. Actually both methods can be combined as explained hereafter. In view of the specificity of each site, the requirements of health risk assessment and the time and cost constraints, it seems difficult to work out a typical soil sampling strategy suitable for all sites. However, some recommendations can be made according to the site dimensions, the nature, degree and heterogeneity of contamination, and the (future) use of the site. The scientist should thus rely on a thorough examination of all available information (site history, geology and hydrogeology, soil properties, contaminants behaviour , etc.) to delimit contaminated areas as homogeneous as possible and then distribute the sampling points (e.g.using a sampling grid). They should also take the potential exposure paths into account in order to define the areas and soil strata to be sampled as a priority. Statistical and geostatistical tools can be helpful for formulating a sampling strategy as well as for interpreting the collected data.
Keywords: Keywords Sampling strategy; Soil sampling; Contaminated sites; Risk assessment
Evaluation of the sampling procedure adopted by the EU pesticide residue control programme to assess consumer exposure to high acute toxicity pesticides – methamidophos in sweet peppers by Ricardo J. N. Bettencourt da Silva; Maria João Lino; Júlia Ribeiro Santos; M. Filomena G. F. C. Camões (pp. 195-201).
Food chemical control, particularly control involving the analysis of pesticide residues in fruits and vegetables, is routinely performed on composite samples. This sample design is adequate for the control of the majority of pesticides which have only long-term effects. However, from the viewpoint of consumer risk assessment, this sample design is inadequate for pesticides with relevant acute toxicity, when their residues occur in large food items the consumption of which may represent an important fraction of a single meal or an important fraction of the consumption in 24 h. This work presents the results of the Portuguese official pesticide residue control authority concerning the variability of methamidophos concentration in sweet pepper units, collected from the market, in the framework of the EU 1999 co-ordinated programme for the official control of pesticides in products of vegetable origin. The results were expressed with uncertainty and the conclusion was that the observed dispersion cannot be allocated to the method precision. The studied samples presented a variability factor (ratio between the maximum and the mean concentration of the units) ranging from 1.8 to 3.5 supporting the need to consider a variability factor representing the potential unit-to-unit variation in residues concentration for the purpose of consumer risk assessment.
Keywords: Keywords Sampling; Sample heterogeneity; Uncertainty; Pesticides; Residues; Vegetables
Intercomparison of suspended particles sampling methodologies by C. Galas; Umberto Sansone; Maria Belli; Sabrina Barbizzi; Philippe Cyffroy; Giovanni Paolo Fanzutti; Volodya Kanivets; Rita Ocone; Raffaella Piani; Milena Repetti; Michele Riccardi; Cinzia Terzoni; Oleg V. Voitsekhovitch (pp. 202-208).
Sampling and sample preparation/processing are known to carry large, but typically unknown uncertainty contribution to the final analytical data and there is a lack of qualitative and quantitative data on the comparability of results achieved by the different sampling methods.To this end, an intercomparison programme was founded by the European Commission, in which different institutions participated using their own ”in-situ” methods (”ANPA”, ”EDF” and ”MIDIYA”) for collection of water and suspended material in freshwater bodies. The main criterion for this intercomparison was the agreement among the 137Cs activity concentrations in the dissolved phase (Bq l–1), those associated with the suspended particles (Bq g–1) and the concentrations of total suspended material (TSM) in the water body (mg l–1). The results show that the sampling systems provide TSM concentration results with low accuracy; on the contrary, they are recommended for the determination of 137Cs activity concentration in the dissolved phase. Concerning the determination of radiocaesium activity concentration in the suspended particles, the ”EDF” system provides the more reliable results.
Keywords: Keywords Intercomparison; Uncertainty; Sampling device; Suspended particles; Radiocaesium
Proficiency test on the determination of mineral oil from polluted soils by I. Mäkinen; Anna-Mari Suortti; Seppo Pönni; Sami Huhtala (pp. 209-213).
Mineral oil products are abundant sources of environmental contamination. A Finnishproficiency test was carried out to investigate the quality of data provided in an analysis of mineral oil in polluted soils. The homogeneity and stability of the samples were tested. The calculated concentration or the median value of the results was used as the assigned value because of the unavailability of certified reference materials (CRMs). The samples were analysed using an infrared spectroscopy (IR) or gas chromatography (GC) procedure. Even if the participating laboratories had little experience with GC, the results were promising. Hence, the GC procedure will replace IR as the new ISO standard (ISO/DIS 16703) in the near future in many Finnish environmental laboratories. There is a need for CRMs for the determination of mineral oil using the GC method due to common contamination problems caused by mineral oil.
Keywords: Keywords Mineral oil; Petroleum hydrocarbon; Polluted soil; Proficiency test
”Demonstration” vs. ”designation” of measurement competence; the need to link accreditation to metrology
by Paul De Bièvre; Philip D. P. Taylor; K. Brinkmann (pp. 215-216).
Primary reference materials and traceability chain for gas composition by Linzhen Wang; Qiao Han (pp. 217-219).
This article briefly describes research on the development of primary reference gases and the traceability system of gas measurement at the National Research Center for Certified Reference Materials, China.
Keywords: Keywords Primary reference materials; Traceability system; Intercomparison