Organic pollutants in surface waters from Portugal using chemometric interpretation

Surface water samples from 45 sampling points across Portugal have been ana lyzed monthly by automated Solid Phase Extraction (SPE) and Gas Chromatogra phy-Mass Spectrometry (GC/MS) in SIM and SCAN modes. Sampling was carried o ut during a period of six months (April-September, 1999), in order to deter mine the levels of contamination of 72 organic compounds mainly selected fr om the EC Council Directive list (CEC 76/464/EEC). Atrazine, simazine, deet hylatrazine, alachlor, metolachlor, Irgarol, terbuthylazine, tributhylphosp hate, 2,4,6-trichlorophenol, 2-chlorophenol, 3-chlorophenol, pentachlorophe nol, dimethoate, lindane, linuron, propanil, o,p'-DDD, op'-DDT, op'-DDE and malathion were the main detected compounds. Although Irgarol, terbuthylazi ne, deethylatrazine and deisopropylatrazine are not listed in the EC Direct ive, these herbicides and transformation products are currently in use and they were also included in the monitoring program and detected at some site s. Fifty-nine percent of the samples were below 0.1 mug 1(-1), the detectio n limit required by the EEC Drinking Water Directive (DWD). Some compounds were detected at values higher than the DWD, e.g. atrazine (2.7 mug 1(-1))a nd alachlor (5.43 mug 1(-1)) in April. Simazine was also present with a hig h value (2.3 mug 1(-1)) in September. Tributhylphosphate (5.40 mug 1-1) and 2,4,6-trichlorophenol (2.31 mug 1(-1)) were also found at high concentrati ons near industrial sites. Chemometric interpretation of the more represent ative contaminants was performed by means of Principal Component Analysis, allowing the resolution of the more relevant contamination sources and the description of their temporal and spatial (geographical) distributions.