Anthropogenic pressure in a Portuguese river: endocrine-disrupting compounds, trace elements and nutrients

Natural organic compounds such as phytoestrogens and phytosterols found in various plants, as well as mycotoxins produced by fungi, can be found in aquatic environments. The aim of this study was to investigate the occurrence of three different classes of natural estrogenic compounds, i.e., phytoestrogens, phytosterols and mycotoxins, in estuarine water samples from the Ave River estuary. For that, water samples were collected at five sampling points distributed along the estuary at low tide, during 1 year, processed by solid-phase extraction (SPE) and analyzed by gas chromatography coupled to mass spectrometry (GC–MS). To correlate the presence of phytoestrogens and phytosterols in the estuarine water, local flora was collected on riverside. Trace elements content and physicochemical parameters such as nutrients and dissolved oxygen were also determined seasonally at each sampling point, to give insights for the evaluation of water quality and anthropogenic pressure. Both phytoestrogens and phytosterols showed a seasonal variation, with the highest values observed in spring and summer and the lowest in winter. Daidzein (DAID) was found up to 404.0 ng L−1 in spring and coumestrol (COUM) was found up to 165.0 ng L−1 in summer. The mycotoxin deoxynivalenol (DON) was ubiquitously determined with values ranging from 59.5 to 642.4 ng L−1. Nutrients and metals distribution and concentration varied among sampling stations and seasons. This study revealed for the first time the presence of mycotoxins, various classes of phytoestrogens and stigmasterol (STG) in estuarine water from the Ave River (Portugal), and the evaluation of the water quality confirmed that this estuary is still highly impacted by anthropogenic activities.