Tracing Urban Wastewater Contaminants into the Atlantic Ocean by Nontarget Screening.

Oceans are the ultimate sink for many of the over 100 million man-made substances. Until now, monitoring was limited to a reduced number of targeted persistent organic pollutants, reaching open waters mainly via atmospheric deposition. However, the composition and fate of the thousands of pollutants reaching the marine environment though wastewater discharges from coastal sources remain largely unexplored. By combining a newly developed nontarget screening (NTS) workflow and high-resolution mass spectrometry (HRMS), we have identified over 500 sewage-derived contaminants occurring in the ocean. Samples from the NE Atlantic contained this anthropogenic imprint at distances over 50 km from the coastline and >500 m depth, beyond the continental margin. The range of identified compounds spans from pharmaceuticals and personal care products to food additives and industrial chemicals, including several that have never been reported in the environment, as they escaped conventional targeted analytical methods. Predicting the effects of the continuous input of this chemical "cocktail" on marine ecosystems is a formidable challenge, since 40% of the detected compounds lack information regarding their use and ecotoxicity.

Removal of pharmaceuticals in urban wastewater: High rate algae pond (HRAP) based technologies as an alternative to activated sludge based processes.

Microalgae biotechnology is a promising tool for many applications, including the elimination of nutrients and other contaminants from wastewater. In this work, we measured the removal efficiency of two wastewater treatment processes: an activated-sludge based conventional process and another based on microalgae biotechnology using high-rate algae ponds (HRAPs). The latter was tested using two different configurations. In the first one, HRAPs were placed after an UASB reactor and used as a tertiary treatment to remove nutrients. In the second, the UASB reactor was disconnected so the HRAPs were directly fed with pretreated wastewater. Additional treatment was performed using dissolved air flotation (DAF). The performances of both configurations (UASB-HRAP and HRAP-DAF) were compared to that of the conventional line including primary and secondary biological treatments and operating in parallel within the same wastewater treatment plant (WWTP). Sixty-four out of 81 target PhACs were detected in the influent of the WWTP, at an average concentration of 223 µg L-1, whereas 55 and 54 were measured in the conventional (14 µg L-1) and non-conventional (17 µg L-1) effluents. Average removal efficiencies were similar (94 vs. 92%) for both treatment lines when comparing total PhACs concentrations. The compositional patterns of the resulting effluents, however, were not, suggesting the occurrence of differential removal mechanisms depending on the chemicals and wastewater treatments considered. Highly consumed compounds such as ibuprofen and acetaminophen were predominant in the non-conventional effluent (>1 µg L-1), denoting lower removal than in the conventional line. On the other hand, elimination of diclofenac and some specific antibiotics and diuretics (e.g., hydrochlorothiazide) was between 15 and 50% higher using HRAPs. Overall, the efficiency of the microalgae technology removing PhACs was found to be comparable to that used in conventional WWTPs. This, combined with a higher efficiency removing nutrients, shows the potential of HRAP technology for wastewater treatment as an alternative (or addition as tertiary treatment) to more conventional approaches based on activated sludge.