Search for over 2000 current and legacy micropollutants on a wastewater infiltration site with a UPLC-high resolution MS target screening method

Abstract

A target screening method using ultra high performance liquid chromatography-high resolution mass spectrometry (UPLC-HRMS) was developed. The method was applied to 14 groundwater and 11 surface water samples of a former wastewater infiltration site, where raw wastewater was applied until 1985 and treated wastewater is applied since 2005. The measured data are compared with mass spectrometric data of over 2000 organic micropollutants (OMPs), including pharmaceuticals, personal care products, pesticides, industrial chemicals and metabolites of these classes. A total number of 151 and 159 OMPs were detected in groundwater and surface water, respectively, of which 12 have not been reported before in these matrices. Among these 12 compounds were 11 pharmaceuticals and one personal care product. The identity of 55 of the detected OMPs (35%) was verified by analysis of standard compounds. Based on the distribution in the study area, two groups of OMPs were clearly distinguished: current OMPs introduced with treated municipal wastewater since 2005 and legacy OMPs originating from infiltration of untreated wastewater until 1985. A third group included OMPs contained in historic as well as in current wastewater. During infiltration, OMPs with molecular mass >500 g/mol and log DOW > 3.9 were preferentially removed. Speciation had a strong impact with cationic OMPs showing high, neutral OMPs medium and anionic OMPs lowest elimination during infiltration. This target screening method proved useful to study a wide range of compounds, even in retrospect and at sites with poorly documented history and with a complex and variable hydrological situation.