Publication
Sampling for Pharmaceuticals and Personal Care Products (PPCPs) and Illicit Drugs in Wastewater Systems: Are Your Conclusions Valid? A Critical Review
Publisher:
American Chemical Society (ACS)
Date:
26-07-2010
DOI:
10.1021/ES100779N
Abstract: The analysis of 87 peer-reviewed journal articles reveals that s ling for pharmaceuticals and personal care products (PPCPs) and illicit drugs in sewers and sewage treatment plant influents is mostly carried out according to existing tradition or standard laboratory protocols. Less than 5% of all studies explicitly consider internationally acknowledged guidelines or methods for the experimental design of monitoring c aigns. In the absence of a proper analysis of the system under investigation, the importance of short-term pollutant variations was typically not addressed. Therefore, due to relatively long s ling intervals, potentially inadequate s ling modes, or insufficient documentation, it remains unclear for the majority of reviewed studies whether observed variations can be attributed to "real" variations or if they simply reflect s ling artifacts. Based on results from previous and current work, the present paper demonstrates that s ling errors can lead to overinterpretation of measured data and ultimately, wrong conclusions. Depending on catchment size, sewer type, s ling setup, substance of interest, and accuracy of analytical method, avoidable s ling artifacts can range from "not significant" to "100% or more" for different compounds even within the same study. However, in most situations s ling errors can be reduced greatly, and s ling biases can be eliminated completely, by choosing an appropriate s ling mode and frequency. This is crucial, because proper s ling will help to maximize the value of measured data for the experimental assessment of the fate of PPCPs as well as for the formulation and validation of mathematical models. The trend from reporting presence or absence of a compound in "clean" water s les toward the quantification of PPCPs in raw wastewater requires not only sophisticated analytical methods but also adapted s ling methods. With increasing accuracy of chemical analyses, inappropriate s ling increasingly represents the major source of inaccuracy. A condensed step-by-step S ling Guide is proposed as a starting point for future studies.