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The contamination of freshwater with microplastics (MPs) has been established globally. While the analysis of MPs has predominantly involved spectroscopic methods for revealing particle numbers, the potential of employing spectroscopy for mass estimation has been underutilized. Consequently, there is a need to enhance our understanding of the mass loads of MPs and ensure the complementarity and comparability of various techniques for accurate quantification. This study presents the first comparative results on urban water samples using micro Fourier-transform infrared (μ-FTIR) imaging and pyrolysis-gas chromatography-mass spectrometry (Py-GC-MS) to identify and quantify MPs in both particle numbers and mass concentration. Two sampling campaigns in summer and winter were conducted at 11 locations within the Amsterdam canal network. An advanced in-situ volume-reducing sampling pump was employed to collect MPs from the surface water within the size fraction of 10-300 μm. The analysis revealed MP concentrations within the range of 16-107 MP/m 3 , estimated to be 2.0-789 μg/m 3 by μ-FTIR imaging and 8.5-754 μg/m 3 by Py-GC-MS. The results of the two analysis techniques showed good comparability in terms of the general trends of MP abundances, with variations in polymer compositions due to the inherent inter-methodological differences. Elevated MP concentrations were observed in the city center compared to the suburban areas. In addition, seasonal differences in MP abundances were noted at the locations with high human activity., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier Ltd.. All rights reserved.)

The quality of surface waters is threatened by pollution with low concentrations of bioactive chemicals, among which those interfering with steroid hormone systems. Induced by reports of anti-progestogenic activity in surface waters, a two-year four-weekly survey of (anti-)progestogenic activity was performed at three surface water locations in the Netherlands that serve as abstraction points for the production of drinking water. As certain endogenous and synthetic progestogenic compounds are also potent (anti-)androgens, these activities were also investigated. Anti-progestogenic and anti-androgenic activities were detected in the majority of the monitoring samples, sometimes in concentrations exceeding effect-based trigger values, indicating the need for further research. To characterize the compounds responsible for the activities, a high resolution Effect-Directed Analysis (hr-EDA) panel was combined with PR and AR CALUX bioassays, performed in agonistic and antagonistic modes. The influent and effluent of a domestic wastewater treatment plant (WWTP) were included as effluent is a possible emission source of active compounds. As drivers for androgenic and progestogenic activities several native and synthetic steroid hormones were identified in the WWTP samples, namely androstenedione, testosterone, DHT, levonorgestrel and cyproterone acetate. The pesticides metolachlor and cyazofamid were identified as contributors to both the anti-progestogenic and anti-androgenic activities in surface water. In addition, epiconazole contributed to the anti-progestogenic activities in the rivers Rhine and Enclosed Meuse. This study showed the strength of hr-EDA for the identification of bioactive compounds in environmental samples and shed light on the drivers of (anti-)progestogenic and (anti-)androgenic activities in the aquatic environment., (Copyright © 2021 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Conjugates of estrogenic chemicals, endogenous as well as xenobiotic, are mainly excreted via bile into the intestine. Therefore, measurement of estrogenic activity in bile yields useful information about an organism's internal exposure to (xeno-)estrogens. Although previous studies in The Netherlands have reported estrogenic activity in male fish bile, the contribution of natural hormones and xenobiotic substances to this activity is unknown. To identify compounds responsible for estrogenic activity in fish bile, we developed a bioassay-directed fractionation method for estrogenic chemicals. In this approach, the in vitro reporter gene assay ER-CALUX (Estrogen Responsive Chemical Activated Luciferase Gene Expression) was used to assess estrogenic activity in deconjugated bile samples and to direct RP-HPLC fractionation and chemical analysis (by GC-MS) of estrogenic compounds. The method was applied to bile from male breams (Abramis brama) collected at three locations in The Netherlands. At one of these locations, the River Dommel, extremely high levels of plasma vitellogenin and a high incidence of intersex gonads in these male breams have previously been observed, indicating the exposure to estrogens. In this study, the natural hormones 17beta-estradiol, estrone, and estriol accounted for the majority of estrogenic activity in male bream bile. At the River Dommel, the synthetic contraceptive pill component ethynylestradiol was found in effective concentrations as well. The detected natural and synthetic hormones may be responsible forthe estrogenic effects observed in wild bream from this location. Furthermore, a large number of xenobiotic chemicals was detected at relatively high levels in bile, including triclosan, chloroxylenol, and clorophene. Although chloroxylenol was shown for the first time to be weakly estrogenic, these compounds did not contribute significantly to the estrogenic activity observed.