Calibration of tracer concentration measurement and results

A reliable assessment of relevant substance flows is very important for environmental risk assessments and efficiency analysis of measures to reduce or avoid emissions of micropollutants like drugs to water systems. Accordingly, a detailed preparation of monitoring campaigns should include an accuracy check for the sampling configuration to prove the reliability of the monitoring results and the subsequent data processing. The accuracy of substance flow analyses is expected to be particularly weak for substances having high short-term variations of concentrations in sewage. This is especially the case linked to the observation of substance flows close to source in waste water systems.
The verification of a monitoring configuration in a hospital sewer in Luxembourg is in the centre of interest of the case study presented here. A tracer test in the sewer system under observation is an essential element of the suggested accuracy check and provides valuable information for an uncertainty analysis. The results illustrate the importance of accuracy checks as an essential element of the preparation of monitoring campaigns. Moreover the study shows that continuous flow proportional sampling enables a representative observation of short-term peak loads of the iodinated x-ray contrast media iobitridol close to source.

对相关物质流开展可靠评估，对于水环境系统的环境风险评价，以及针对药物等微污染物（micropollutants）减排、规避排放措施的效能分析均具有重要意义。据此，监测项目的详细筹备工作应包含对采样配置（sampling configuration）的准确性校验，以验证监测结果及后续数据处理流程的可靠性。对于污水中浓度存在显著短期波动的物质，其物质流分析的准确性往往相对薄弱；而在废水系统中针对源头附近的物质流开展监测时，这一问题尤为突出。
本案例研究的核心关注内容，即为卢森堡某医院污水管网中的监测配置验证工作。在所监测的污水管网系统中开展示踪试验（tracer test），是所提议的准确性校验的核心环节，同时可为不确定性分析（uncertainty analysis）提供极具价值的参考信息。研究结果证实了准确性校验作为监测项目筹备核心环节的重要性；此外，本研究表明，采用流量比例连续采样法（continuous flow proportional sampling）可对源头附近的碘代X射线造影剂碘比醇（iobitridol）的短期峰值负荷开展具有代表性的监测。