HPLC screening and GC-MS confirmation of triazine herbicides residues in drinking water from sugar cane area in Brazil

The extensive use of chlorotriazines as selective herbicides in agriculture and their relatively high persistence imply that these compounds are now p resent in the environment, contaminating surface and ground water. In Europ ean countries, United States and Canada, the drinking water ordinance deman ds a limited concentration of 0.5 mu g L-1 for the sum of all pesticides an d 0.1 mu g L-1 with respect to each compound, implying on the necessity of sensitive and selective analytical methods. In the present study we describ e two methods for the analysis of atrazine, simazine and ametryn residues i n surface and ground water collected from the Espraiado Stream watershed, R ibeirao Preto region, SP, Brazil. The HPLC method used for sample screening was based on herbicide extraction with dichloromethane:isopropanol (9:1, v /v) followed by reversed-phase chromatography (RP-8) with detection at 220 nm. The presence of herbicides was confirmed by GC-MS after ethyl acetate e xtraction. A total of 250 samples collected at different sites from October 1995 to July 1996 were analyzed. Ametryn residues were detected in 17 samp les but almost always at concentrations below those maximum levels recommen ded by international agencies of environmental control.