Istituto di Chimica Agraria ed Ambientale, Università Cattolica del Sacro Cuore, Piacenza, Italy.
Pest Manag Sci. 2011 Jun;67(6):656-64. doi: 10.1002/ps.2105. Epub 2011 Feb 18.
Quinoxyfen is a fungicide of the phenoxyquinoline class used to control powdery mildew, Uncinula necator (Schw.) Burr. Owing to its high persistence and strong sorption in soil, it could represent a risk for soil organisms if they are exposed at ecologically relevant concentrations. The objective of this paper is to predict the bioconcentration factors (BCFs) of quinoxyfen in earthworms, selected as a representative soil organism, and to assess the uncertainty in the estimation of this parameter. Three fields in each of four vineyards in southern and northern Italy were sampled over two successive years.
The measured BCFs varied over time, possibly owing to seasonal changes and the consequent changes in behaviour and ecology of earthworms. Quinoxyfen did not accumulate in soil, as the mean soil concentrations at the end of the 2 year monitoring period ranged from 9.16 to 16.0 µg kg⁻¹ dw for the Verona province and from 23.9 to 37.5 µg kg⁻¹ dw for the Taranto province, with up to eight applications per season. To assess the uncertainty of the BCF in earthworms, a probabilistic approach was used, firstly by building with weighted bootstrapping techniques a generic probabilistic density function (PDF) accounting for variability and incompleteness of knowledge. The generic PDF was then used to derive prior distribution functions, which, by application of Bayes' theorem, were updated with the new measurements and a posterior distribution was finally created.
The study is a good example of probabilistic risk assessment. The means of mean and SD posterior estimates of log BCFworm (2.06, 0.91) are the 'best estimate values'. Further risk assessment of quinoxyfen and other phenoxyquinoline fungicides and realistic representative scenarios for modelling exercises required for future authorization and post-authorization requirements can now use this value as input.
苯氧喹啉类杀菌剂喹氧灵用于防治白粉病，Uncinula necator（Schw.）Burr。由于其在土壤中具有高持久性和强吸附性，如果以生态相关浓度暴露，它可能对土壤生物构成风险。本文的目的是预测喹氧灵在蚯蚓中的生物浓缩因子（BCF），蚯蚓被选为代表性土壤生物，并评估该参数估计的不确定性。在意大利南部和北部的四个葡萄园的每个葡萄园的三个地块，在连续两年内进行了采样。
测量的 BCF 随时间变化，可能是由于季节性变化以及蚯蚓行为和生态学的相应变化。喹氧灵没有在土壤中积累，因为在 2 年监测期结束时，Verona 省的土壤浓度均值范围为 9.16 至 16.0 µg kg⁻¹ dw，而 Taranto 省的浓度范围为 23.9 至 37.5 µg kg⁻¹ dw，每季最多使用八次。为了评估蚯蚓中 BCF 的不确定性，首先使用加权自举技术构建了一个通用概率密度函数（PDF），该函数考虑了知识的变异性和不完整性。然后使用通用 PDF 来导出先验分布函数，通过贝叶斯定理应用，将新的测量值与先验分布函数进行更新，并最终创建后验分布。
该研究是概率风险评估的一个很好的例子。对数 BCFworm（2.06，0.91）的平均值和标准差后验估计的平均值是“最佳估计值”。现在，未来授权和授权后要求的建模练习的现实代表性情景需要对喹氧灵和其他苯氧喹啉类杀菌剂进行进一步风险评估，并可以将此值用作输入。
