Priority organic compounds in wastewater effluents from the Mediterranean and Atlantic basins of Andalusia (Spain)

A comprehensive survey of the occurrence of organic compounds in 30 wastewater (WW) effluent samples from 21 urban wastewater treatment plants (WWTPs) from both secondary and tertiary treatments was carried out in the Mediterranean and Atlantic basins of the Andalusia region (south of Spain). For each sample, a total of 226 compounds including pesticides and some transformation products, polycyclic aromatic hydrocarbons (PAHs), phenolic compounds and volatile organic compounds (VOCs) were monitored with the aim of evaluating their occurrence in urban WW effluents. Compounds belonging to each class were detected. Among pesticides, insecticides such as clorfenvinphos and diazinon as well as herbicides such as diuron, sebuthylazine, terbuthylazine and terbuthylazine desethyl were the most frequently detected. The ubiquity of some compounds such as fluorene, phenanthrene and pyrene was also demonstrated. The compounds evaluated were detected at low concentrations (in general below 1 mu g L-1), except 4-tert-octylphenol, which was detected at extremely high concentrations (up to 443 mu g L-1). PAHs and VOCs were the compounds most frequently detected in the assayed samples, and they are the main sources of contamination in WWTPs, as well as some herbicides and transformation products.