Abstract：
Aquatic organisms are exposed to ever-changing complex mixtures of chemicals throughout their lifetime. Component-Based Mixture Risk Assessment (CBMRA) is a well-established methodology for water contaminant-mixture management, the use of which is growing due to improved access to reference ecotoxicity data and extensive monitoring datasets. It enables the translation of measured exposure concentrations of chemicals into biological effect values, and thus to quantitatively estimate the risk of the whole water sample (i.e., as a mixture). However, many factors can bias the final risk decision by impacting the risk metric components; thus, a careful design of the CBMRA is needed, taking into primary consideration the specific features of the dataset and mixture risk assessment assignments. This study systematically addressed the effects of the most common approaches used for handling the concentrations of chemicals below the limit of detection/quantification (LOD/LOQ) in CBMRA. The main results included: i) an informed CBMRA procedure that enables the tracking of the risk decisions triggered by substances below LOD/LOQ, ii) a conceptual map and guidance criteria to support the selection of the most suitable approach for specific scenarios and related interpretation; iii) a guided implementation of the informed CBMRA on dataset of pesticide concentrations in Italian rivers in 2020 (702,097 records).
摘要：
水生生物在其整个生命周期中暴露于不断变化的复杂化学物质混合物。基于成分的混合物风险评估（CBMRA）是一种完善的水污染物混合物管理方法，由于更好地获取参考生态毒性数据和广泛的监测数据集，其使用正在增加。它可以将测得的化学物质暴露浓度转化为生物效应值，从而定量估计整个水样的风险(即，作为混合物)。然而,许多因素会影响风险度量成分，从而使最终的风险决策产生偏差；因此，需要对CBMRA进行仔细的设计，主要考虑数据集和混合物风险评估分配的具体特征。这项研究系统地解决了用于处理CBMRA中低于检测/定量极限（LOD/LOQ）的化学品浓度的最常用方法的影响。主要结果包括：i）知情的CBMRA程序，能够跟踪由低于LOD/LOQ的物质触发的风险决策，ii）概念图和指导标准，以支持为特定情景和相关解释选择最合适的方法；iii）在2020年意大利河流农药浓度数据集（702,097条记录）上指导实施知情的CBMRA。
