RESUMO
In the frame of the international SOILSAMP project, funded and coordinated by the National Environmental Protection Agency of Italy (APAT), uncertainties due to field soil sampling were assessed. Three different sampling devices were applied in an agricultural area using the same sampling protocol. Cr, Sc and Zn mass fractions in the collected soil samples were measured by k(0)-instrumental neutron activation analysis (k(0)-INAA). For each element-device combination the experimental variograms were calculated using geostatistical tools. The variogram parameters were used to estimate the standard uncertainty arising from sampling. The sampling component represents the dominant contribution of the measurement uncertainty with a sampling uncertainty to measurement uncertainty ratio ranging between 0.6 and 0.9. The approach based on the use of variogram parameters leads to uncertainty values of the sampling component in agreement with those estimated by replicate sampling approach.
Assuntos
Monitoramento Ambiental/métodos , Poluentes do Solo/análise , Agricultura , Calibragem , Cromo/análise , Monitoramento Ambiental/estatística & dados numéricos , Itália , Controle de Qualidade , Reprodutibilidade dos Testes , Escândio/análise , Sensibilidade e Especificidade , Manejo de Espécimes/métodos , Incerteza , Zinco/análiseRESUMO
This paper reports one practical method to estimate the measurement uncertainty including sampling, derived by the approach implemented by Ramsey for soil investigations. The methodology has been applied to estimate the measurements uncertainty (sampling and analyses) of (137)Cs activity concentration (Bq kg(-1)) and total carbon content (%) in suspended particle sampling in a freshwater ecosystem. Uncertainty estimates for between locations, sampling and analysis components have been evaluated. For the considered measurands, the relative expanded measurement uncertainties are 12.3% for (137)Cs and 4.5% for total carbon. For (137)Cs, the measurement (sampling+analysis) variance gives the major contribution to the total variance, while for total carbon the spatial variance is the dominant contributor to the total variance. The limitations and advantages of this basic method are discussed.
Assuntos
Interpretação Estatística de Dados , Água Doce/análise , Regulamentação Governamental , Monitoramento de Radiação/instrumentação , Radioisótopos/análise , Manejo de Espécimes/instrumentação , Poluentes Radioativos da Água/análise , Algoritmos , Exposição Ambiental/análise , Água Doce/química , Itália , Monitoramento de Radiação/métodos , Proteção Radiológica/métodos , Reprodutibilidade dos Testes , Sensibilidade e Especificidade , Manejo de Espécimes/métodos , Ultrafiltração/instrumentação , Ultrafiltração/métodosRESUMO
The National Environmental Protection Agency of Italy (APAT) performed a soil sampling intercomparison, inviting 14 regional agencies to test their own soil sampling strategies. The intercomparison was carried out at a reference site, previously characterised for metal mass fraction distribution. A wide range of sampling strategies, in terms of sampling patterns, type and number of samples collected, were used to assess the mean mass fraction values of some selected elements. The different strategies led in general to acceptable bias values (D) less than 2sigma, calculated according to ISO 13258. Sampling on arable land was relatively easy, with comparable results between different sampling strategies.
Assuntos
Interpretação Estatística de Dados , Monitoramento de Radiação/métodos , Poluentes Radioativos do Solo/análise , Itália , Doses de Radiação , Monitoramento de Radiação/normas , Reprodutibilidade dos Testes , Tamanho da Amostra , Sensibilidade e EspecificidadeRESUMO
In the frame of the international SOILSAMP project, funded and coordinated by the Italian Environmental Protection Agency, an agricultural area was established as a reference site suitable for performing soil sampling inter-comparison exercises. The reference site was characterized for trace element content in soil, in terms of the spatial and temporal variability of their mass fraction. Considering that the behaviour of long-lived radionuclides in soil can be expected to be similar to that of some stable trace elements and that the distribution of these trace elements in soil can simulate the distribution of radionuclides, the reference site characterised in term of trace elements, can be also used to compare the soil sampling strategies developed for radionuclide investigations.
Assuntos
Interpretação Estatística de Dados , Monitoramento de Radiação/métodos , Monitoramento de Radiação/normas , Poluentes Radioativos do Solo/análise , Poluentes Radioativos do Solo/normas , Solo/normas , Itália , Doses de Radiação , Valores de Referência , Reprodutibilidade dos Testes , Tamanho da Amostra , Sensibilidade e Especificidade , Manejo de Espécimes/métodosRESUMO
This paper aims to quantify the soil sampling uncertainty arising from the short-range spatial variability of elemental concentrations in the topsoils of agricultural, semi-natural, and contaminated environments. For the agricultural site, the relative standard sampling uncertainty ranges between 1% and 5.5%. For the semi-natural area, the sampling uncertainties are 2-4 times larger than in the agricultural area. The contaminated site exhibited significant short-range spatial variability in elemental composition, which resulted in sampling uncertainties of 20-30%.
Assuntos
Algoritmos , Interpretação Estatística de Dados , Modelos Estatísticos , Monitoramento de Radiação/métodos , Poluentes Radioativos do Solo/análise , Simulação por Computador , Itália , Doses de Radiação , Reprodutibilidade dos Testes , Tamanho da Amostra , Sensibilidade e Especificidade , Manejo de Espécimes/métodosRESUMO
Metals and radionuclides in water systems can be easily adsorbed on suspended matter and, finally, they could eventually accumulate in the aquatic environment. The assessment of the health of a water body needs also sampling of the suspended matter fraction. In this paper sampling systems to characterise contaminants associated with the suspended matter fraction are described, with a particular attention to the collection and preservation of samples. Sampling must be representative, to obtain reliable conclusions. In this context it is stressed the importance of the evaluation of the sampling uncertainty, which contributes to a large extent to the total uncertainty.
Assuntos
Monitoramento Ambiental/métodos , Água Doce/análise , Sedimentos Geológicos , Manejo de Espécimes/métodos , Poluição da Água/análise , Adsorção , Automação , Monitoramento Ambiental/instrumentação , Filtração , Sedimentos Geológicos/química , Compostos Inorgânicos/análise , Itália , Compostos Orgânicos/análise , Tamanho da Partícula , Manejo de Espécimes/instrumentação , Suspensões , Água/análise , Água/normas , Poluição da Água/prevenção & controleRESUMO
The paper reports a methodology adopted to face problems related to quality assurance in soil sampling. The SOILSAMP project, funded by the Environmental Protection Agency of Italy (APAT), is aimed at (i) establishing protocols for soil sampling in different environments; (ii) assessing uncertainties associated with different soil sampling methods in order to select the "fit-for-purpose" method; (iii) qualifying, in term of trace elements spatial variability, a reference site for national and international inter-comparison exercises. Preliminary results and considerations are illustrated.