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In this article, we document a strategy for addressing the difficulties of analyzing complex chemical mixtures of endocrine-disrupting substances (EDSs) in surface waters. The overall approach includes effect-based assessments to detect mixtures of EDSs exerting real-world effects, the use of passive samplers for in situ extraction and preconcentration of compounds, effect-directed analysis to isolate causative substances and finally, nontargeted analysis to facilitate their identification. This package of integrated approaches can be instrumental to address endocrine-disrupting mixtures in water bodies because it balances chemical- and effect-based methods that are inclusive of the broad diversity of chemicals functioning as EDSs. These methods are complementary to each other and, when used together, result in a synergistic and multidisciplinary approach to holistically detect and manage complex mixtures of EDSs exerting a myriad of effects in aquatic ecosystems.

The terms organic micropollutants or emerging contaminants are used to refer to unregulated organic trace pollutants that are frequently detected in environmental matrices, especially surface waters (Magi et al., 2018). These compounds include pharmaceuticals and personal care products (PPCPs), pesticides and surfactants. They are released to aquatic environments mainly through effluent from wastewater treatment plants (WWTPs) (Chen et al., 2016; Yang et al., 2017). Although the pollutant concentrations often occur at trace or ultra-trace levels (ng L−1 or pg L−1), their presence is considered a potential risk to the environment and human health. Thus, monitoring programs are essential to determine their concentrations and consequent ecotoxicological risk in the environment (Fedorova et al., 2014; Ibrahim et al., 2013; Magi et al., 2018).

A semi-automated and sensitive method was developed for simultaneous determination of the six most consumed artificial sweeteners (AS) in surface waters using thin-film solid-phase microextraction (TF-SPME) and high-performance liquid chromatography (HPLC). A triple quadrupole mass spectrometer and an electrospray ionization source (ESI-MS) run in negative ionization and multiple reaction monitoring modes were employed for instrumental analysis. The TF-SPME method was optimized for the extraction phase, sample pH, desorption solvent, extraction time, and desorption time. In-house-synthetized-hydrophilic-lipophilic balance weak anion exchange (HLB-WAX) particles imbedded within a polyacrylonitrile (PAN) binder were selected as the extraction phase for the thin-film coating due to their cost-effectiveness and enhanced sensitivity for artificial sweeteners. Suitable analytical parameters that include linearity (R2 > 0.9914), recovery > 80%, inter, and intra-reproducibility less than 18% were obtained for the AS compounds studied. The developed method estimated limits of detection (LODs) ranging from 0.004 to 0.038 ng mL−1 The SPME method was successfully applied for the determination of ultra-trace levels of AS in water samples collected from Grand River (Ontario, Canada), downstream of three municipal wastewater treatment plants (WWTPs). Concentrations ranging from 0.03 to 20.3 ng mL−1 were found for the AS compounds studied.

A novel strategy for the analysis of 20 organochlorine pesticides (OCPs) monitoring in marine surface waters through ethylenevinyl acetate (EVA) passive samplers was developed and validated. The approach is based on the coupled of ultrasound-assisted solvent extraction (UASE) and headspace solid-phase microextraction (HS-SPME) as extraction method for OCPs from EVA samplers. The UASE-HS-SPME method was optimized with a 27-4 Plackett-Burman design, while the significant factors (salting out, temperature and extraction time) were optimized using a central composite design (CCD) combined with desirability function (DF). The OCPs detection was performed using multiple reaction monitoring (MRM) by gas chromatography-tandem mass spectrometry (GC-MS/MS). The optimum experimental conditions comprised: salting out: 23% wv-1 NaCl, temperature: 75°C and extraction time: 55 min. The optimized method was validated in terms of linearity (R20.9946), recovery (61%) and inter-day and intra-day reproducibility (19%) for 20 OCPs studied. The limits of detection (LODs) were ranging from 0.01 ng for α-hexachlorocyclohexane and 0.27 ng for endrin aldehyde. Finally, the methodology was tested in marine surface seawater of Southern Chile using EVA samplers, where twelve OCPs were detected at ultra-trace levels (ngL