Analytical methods relevant to the European Commission's 2012 proposal on Priority Substances under the Water Framework Directive

Abstract

This report collects information on chemical analytical methods for the analysis of the new proposed priority substances (PS) of the European Water Framework Directive (WFD) and some existing PS for which the Environmental Quality Standards (EQS) have been changed under the first review of the PS list. First, analytical “standard” methods (ISO, CEN, US EPA) were searched. Then, the EU Member States (MS) were asked via the Chemical Monitoring and Emerging Pollutants (CMEP) expert group to provide validated “in-house methods” used as a national reference and to report their limits of detection (LODs) or quantification (LOQs). Finally, published literature articles were searched to get an overview of today’s analytical performance. The achieved method limits of quantification (LOQs) are compared with one third (1/3) of the EQS, mandatory for WFD compliance monitoring. Very low annual average AA-EQS values in the picogram-per-liter (pg/l) concentration range have been set for several of the new proposed PS: For Cypermethrin 80 pg/l (8 pg/l for coastal salt waters), for Dichlorvos 60 pg/l in coastal waters, for Dicofol 32 pg/l in coastal waters, for 17-alpha-ethinylestradiol 35 pg/l (7 pg/l in coastal waters), for 17-beta-estradiol 80 pg/l in coastal waters, and for Heptachlor/Heptachlorepoxide 0.2 pg/l (10 fg/l in coastal waters). Dicofol and Heptachlor/Heptachlorepoxide, for which biota EQS have been set (biota EQS: 33 μg/kg, and 6.7 ng/kg, respectively), however, are intended to be analysed in biota. Moreover, a very challenging water EQS has been set for the already existing PS Brominated Diphenylethers (BDEs) (49 femtogram-per-liter (fg/l), and 2.4 fg/l in coastal waters). However, it is intended that BDEs be analysed in biota (EQS: 8.5 ng/kg). In addition, the water EQS for Polyaromatic Hydrocarbons (PAHs) has been lowered to 0.17 ng/l, and a biota EQS of 2-10 μg/kg added, which is more easy to reach. In general, it is very difficult to reach with currently available analytical instruments LOQs in the low pg/l concentration range. A possibility could be the use of gas chromatography (GC) with high resolution mass spectrometry (HRMS). This technique, however, is not generally available in normal water monitoring laboratories. Also in the field of liquid chromatography mass spectrometry (LC-MS), instruments with improved sensitivity have become available in the last years. Moreover, lower LOQs can be achieved by extracting higher volumes of water (10-1000 liters). These large-volume techniques, however, are very work and time intensive, and very costly, and are therefore not useful for routine WFD compliance monitoring (analysis of one sample per month). The most challenging substances proposed as new PS are: Cypermethrin (EQS: 80 pg/l, and 8 pg/l for coastal salt waters), Dichlorvos (EQS: 60 pg/l in coastal waters), 17-alpha-ethinylestradiol (EQS: 35 pg/l, and 7 pg/l in coastal waters), and 17-beta-estradiol (EQS: 0.4 ng/l, and 80 pg/l in coastal waters). Dicofol, Dioxins and dioxin-like compounds, Heptachlor/Heptachlorepoxide, Hexabromocyclododecane (HBCDD), Perfluorooctane sulfonic acid (PFOS), and the BDEs are intended to be analysed in biota. Minor analytical problems could be encountered for the following substances: Aclonifen (EQS: 0.12 μg/l, and 12 ng/l for coastal salt waters), Bifenox (EQS: 12 ng/l, and 1.2 ng/l for coastal waters), Cybutryne (=Irgarol) (EQS: 2.5 ng/l), Diclofenac (EQS: 0.10 μg/l, and 10 ng/l for coastal waters), Quinoxyfen (EQS: 0.15 μg/l, and 15 ng/l for coastal waters), and Terbutryn (EQS: 65 ng/l, and 6.5 ng/l for coastal waters).