Occurrence and Fate of Organic and Organometallic Pollutants in Municipal Wastewater Treatment Plants and Their Impact on Receiving Waters (Adour Estuary, France)
Résumé
To achieve a “Good Environmental Status by 2015,” as demanded by the water framework directive, monitoring programs are needed to furnish data on target compounds. In this study, a first evaluation of influents and main emissions of 3 local wastewater treatment plants (WWTP) in the Adour estuary (southwest of France) was performed for 23 pollutants (10 musk fragrances, 5 alkylphenols, and 8 organometallics), as well as receiving estuarine water from the same area. High frequency of occurrence of these compounds was found in influents samples (musks: 22–100%; alkylphenols 11–100%; organometallics 0–100%) and effluents (musks: 0–100%; alkylphenols 0–100%; organometallics 0–100%). The removal efficiencies were calculated and varied from negative values up to 98% with the lowest values for synthetic musk compounds. Temporal variability of the target compounds also was studied, and a few tendencies were observed. Estimation of the daily output of each WWTP into the estuary also showed that galaxolide, nonylphenol, monobuthyltin, and inorganic mercury were the compounds discharged into the environment at the highest concentrations. Finally, the occurrence of these compounds in estuarine waters was evaluated; most of them were present at concentrations below the limits of quantification (musks: 0.53–41.5 ng/L; alkylphenols 3.4–410 ng/L; organometallics 0.02–0.70 ng/L) suggesting a low impact in the resulting receiving waters.