Some active ingredient of herbicides, after application, can create a risk for ground and surface water. The aim of investigations was monitoring of herbicidal pollution in ground and surface water on arable areas. The investigations were conducted in the years 2000-2002. The samples were collected (from stationary points located in the south-west Poland) twice a year (in spring and autumn about 3-6 weeks after nominal term of herbicide application). Surface water was sampled in 27 points and ground water in 18 wells. The residues of herbicide active ingredients (triazine and phenoxy acids) were determined using HPLC methods with UV detection and GLC method with ECD detection. The residues of active compounds in surface water (in spring and autumn) were detected. Residues at concentrations exceeding the EU safety standards were detected most frequently in springtime. The contamination levels in excess admissible limits were found in ca. 15% of surface water samples. In ground water (from wells) residues were detected sporadically and its level was very low (ca. 0.01- 0.1 mg=dm").

One of the negative aspects of the intensive use of herbicides is related to the selection of resistant biotypes (Gasquez 2001). Of all biotypes resistant to herbicides, 93 species do not respond to sulfonylurea herbicides (ALS-inhibiting herbicides). The acetolactate synthase (ALS) enzyme is the first step in biosynthesis of a branched chain amino acids (valine, leucine, isoleucine). In Poland the problem of resistance to sulfonylurea herbicides has been discussed since 2001 (Rola and Marczewska 2002). Resistance tests of Apera spica-venti biotypes were conducted in the greenhouse conditions. Chlorsulfuron was applied at the four-leaf stage of development at rates ranging from 11.25 to 360 g/ha. In confirmation of resistance to chlorsulfuron as identified in biological tests, the chemical analyses were performed. The analyses investigated the influence of different doses of chlorsulfuron on free amino acids content in the aboveground part of resistant and susceptible Apera spica-venti. The analyses were carried out applying high performance liquid chromatography method (HPLC). The resistance of the biotype was confirmed in amino acids analysis. In the resistant biotype followed the increase of valine, leucine and isoleucine concentration in comparison with untreated plants and those susceptible to chlorsulfuron biotype.