Occurrence and sources of selected phenolic endocrine disruptors in Ria de Aveiro, Portugal

Ria de Aveiro (Portugal) is a shallow coastal lagoon of high economic and ecological importance. Hardly any data on its chemical pollution by polar organic pollutants are available in literature. This study focused on the presence and sources of a series of phenolic endocrine-disrupting compounds (EDCs) in this area, including parabens, alkylphenolic compounds and bisphenol-A (BPA). A number of possible sources of pollution are present in the area, including the large harbours present in the lagoon, the city of Aveiro and the rivers discharging into the area. A recently constructed submarine wastewater outfall, located a few kilometres from the lagoon inlet has also been suggested as a possible source of pollution to Ria de Aveiro in several publications. The aim of the current field study was to investigate the occurrence and main sources of phenolic endocrine disruptors in Ria de Aveiro.

An extensive sampling campaign was performed, with surface water and wastewater grab samples taken at over 50 locations, in duplicate on different days. Samples were treated using solid phase extraction and analysed by liquid chromatography tandem mass spectrometry.

Concentrations in lagoon water were generally low: not exceeding 20 ng/L for most analytes. Levels in river water exceeded those in the lagoon by a factor 3 to 500 (o-phenylphenol (PhP) and nonylphenoxy ethoxy acetic acids (A9PEC), respectively), with concentrations up to 700 ng/L for BPA and 7,300 ng/L for A9PEC. Samples from the harbours showed EDC levels similar to those in the rest of the lagoon, but in the city of Aveiro, elevated concentrations were observed for alkylphenol ethoxylates (A9PEO), A9PEC, PhP and BPA. Wastewater effluents showed low levels for parabens, whilst alkylphenolic compounds reached several micrograms per litre. The effluents are discharged into the ocean via a submarine outfall, but as marine water near the outfall showed slightly elevated concentrations only for A9PEO, it does not seem to be a significant source of these EDCs for the area.

All the studied phenolic EDCs were detected in the study area, with high levels found in some of the rivers discharging into the lagoon, and generally low concentrations in the lagoon itself. The main sources for all investigated EDCs were the rivers Caster and Antuã which discharge into the lagoon. The city of Aveiro was identified as a secondary source. As the tidal water exchange volume is much larger than the freshwater input from the rivers, concentrations of phenolic EDCs remained low in the lagoon.