A specific study was designed and carried out at the Loire River Basin in France, in order to estimate the measurement uncertainty, including the contribution of sampling. Following recommendations from the Eurachem Guide on Uncertainty arising from sampling, the duplicate method was selected. The study was conducted in 2017 under routine and operational conditions with the accredited laboratories selected by the Loire-Bretagne Water Agency. In overall, 35 monitoring stations were chosen for estimating the spatial variability, and among them 11 monitoring stations were singled out for estimating the temporal variability from April to December. To reduce both the number of analysis and the costs of this study, an unbalanced design was used. Finally, a robust analysis of variance was used to evaluate the measurement uncertainty by means of RANOVA2 software. For some parameters (e.g., calcium, dissolved organic carbon, nitrates, phosphates, suspended matter, metals), the expanded measurement uncertainty estimated using robust ANOVA was found to be lower than 20 % and was thus used to calculate the lower and upper confidence interval limits at 95 %. For parameters having an expanded measurement uncertainty greater than 20 % (e.g., most pesticides, chlorophyll a, biochemical oxygen demand, ammonium, nitrites, Kjeldahl nitrogen), the lower and upper confidence interval limits at 95 % were established using an alternative approach: the expanded uncertainty factor (FU) derived from log-transformed data.

中文翻译：

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法国卢瓦尔-布列塔尼河流域地表水中水质参数的测量不确定性估计，包括采样产生的贡献

在法国卢瓦尔河流域设计并开展了一项具体研究，以估计测量不确定度，包括采样的贡献。根据 Eurachem 取样不确定性指南的建议，选择了重复方法。该研究于 2017 年在常规和操作条件下与卢瓦尔-布列塔尼水务局选定的认可实验室进行。总体上选择了35个监测站进行空间变异性估计，其中挑选出11个监测站进行4-12月的时间变异性估计。为了减少本研究的分析次数和成本，使用了不平衡设计。最后，通过 RANOVA2 软件，使用稳健的方差分析来评估测量不确定性。对于某些参数（例如，钙、溶解有机碳、硝酸盐、磷酸盐、悬浮物、金属），发现使用稳健方差分析估计的扩展测量不确定度低于 20%，因此用于计算置信区间的下限和上限限制在 95%。对于扩展测量不确定度大于 20% 的参数（例如，大多数农药、叶绿素 a、生化需氧量、铵、亚硝酸盐、凯氏氮），95% 的置信区间下限和上限使用替代方法确定：来自对数转换数据的扩展不确定性因子 (FU)。悬浮物、金属），发现使用稳健方差分析估计的扩展测量不确定度低于 20%，因此用于计算 95% 的置信区间下限和上限。对于扩展测量不确定度大于 20% 的参数（例如，大多数农药、叶绿素 a、生化需氧量、铵、亚硝酸盐、凯氏氮），95% 的置信区间下限和上限使用替代方法确定：来自对数转换数据的扩展不确定性因子 (FU)。悬浮物、金属），发现使用稳健方差分析估计的扩展测量不确定度低于 20%，因此用于计算 95% 的置信区间下限和上限。对于扩展测量不确定度大于 20% 的参数（例如，大多数农药、叶绿素 a、生化需氧量、铵、亚硝酸盐、凯氏氮），95% 的置信区间下限和上限使用替代方法确定：来自对数转换数据的扩展不确定性因子 (FU)。