Under Directive 2008/105 / EC, chlorpyrifos is one of the priority water pollutants. Its presence is mainly detected by chemical methods, although bioindicators are gaining in importance. The effect of chlorpyrifos (0.05-10 µg L-1) was evaluated on germination energy -GE and germination -G, length, fresh and dry weight of roots and shoots of barley and cucumber seedlings. In the bioassay, chlorpyrifos applied at MAC rate (0.1 µg L-1) caused a significant inhibition of GE and G of barley and at 0.5 µg L-1 of cucumber seeds, compared to control. At 50 % MAC (0.05 1 µg L-1), length, fresh and dry weight of roots and shoots of both tested plants were significantly inhibited, while in treatments with 0.5 µg L-1 and higher rates, there was no formation of hypocotyl and epicotyl of barley, i.e. hypocotyl of cucumber seedlings.Prema Direktivi 2008/105/EC, hlorpirifos je jedan od prioritetnih polutanata voda. Njegovo prisustvo se uglavnom detektuje hemijskim analizama, iako su sve značajnije i metode koje uključuju bioindikatore. U radu je procenjen uticaj hlorpirifosa (0,05-10 µg L-1) na energiju klijanja -EK, klijavost -K, dužinu, svežu i suvu masu korena i izdanka ječma i krastavca, kao potencijalnih indikatora. Hlorpirifos je izazvao značajnu inhibiciju EK i K semena ječma u MDK količini (0,1 µg L-1), a kod semena krastavca u količini 0,5 µg L-1, u odnosu na kontrolu. U količni 50% manje od MDK (0,05 µg L-1), dužina, sveža i suva masa i korena i nadzemnog dela obe test biljke su bili značajno smanjeni, dok u tretmanima sa preko 0,5 µg L-1 hlopririfosa, formiranje hipokotila i epikotila kod ječma, odnosno hipokotila kod krastavca, je izostalo
