Detalle de: Main findings and conclusions of the implementation of Directive 76/464/CEE concerning the monitoring of organic pollutants in surface waters (Portugal, April 1999–May 2000)

The purpose of this paper is to relate the implementation of Directive 76/464/CEE concerning the survey of priority dangerous substances and indicate the main priority pollutants encountered throughout a systematic monitoring program carried out in Portugal during a period of 14 months (April 1999-May 2000). Contrary to what it seems, the implementation of such a Directive is not straightforward owing to the large number of compounds and samples to be analyzed at trace levels. During this period of time, 115 priority semivolatile organic compounds (SVOCs), 41 volatile organic compounds (VOCs), six organotin compounds, 14 heavy metals, phosphate, nitrates, nitrites and ammonia were determined in 644 surface water samples (corresponding to 14 months and 46 sites). In addition, priority SVOCs were also determined in sediment, mussels and fish (muscle and liver). This paper reports the procedure and analytical tools used and necessary to determine the levels of 115 priority toxic and persistent semivolatile organic compounds selected from the EC Council Directive list (76/464/EEC). An advanced analytical protocol was developed involving enrichment of water samples in Oasis solid-phase extraction cartridges (SPE) in the Lisbon laboratory with a Gilson ASPEC XL automated extraction system and by sending the enriched cartridges to Barcelona by aeroplane at 4 degrees C, where elution and analysis were performed. Final determination was performed with gas chromatography-electron ionization mass spectrometry (GC-EI-MS). Acidic herbicides were determined by liquid chromatography with diode array detection. Owing to the great amount of data generated throughout the monitoring study, statistical analysis of the more representative contaminants was performed, allowing the identification of the more relevant contamination sources, percentages of findings and the description of their temporal and spatial (geographical) distributions. Recommendations and compounds that should be included in future monitoring programs are given.