Assessment of pollution of aquatic flora residues of pesticide in areas intensively used for agricultural purposes

The aim of this study was to pilot the determination of the contamination state with residues of plant protection products of freshwater ecosystems in the areas of Podlasie voivodship characterized by intensive agriculture. The analytical studies indicated residues of 431 active ingredients (a.i.) of pesticides. The qualitative and quantitative determination was performed using liquid chromatography technique coupled with tandem mass spectrometry. The presence of residues was found in 85% of the samples tested . Out of the 431 substances tested, only 23 active substances were detected, with herbicides as the most numerous group (11 (a.i.). The results show that there are significant concentrations of pesticides in the water lance (Lemna L.), which confirms that this plant is an excellent bioindicator of freshwater ecosystems contamination.