Phytotoxicity of Chlorpyrifos to White Mustard (Sinapis alba L.) and Maize (Zea mays L.): Potential Indicators of Insecticide Presence in Water

Abstract

Chlorpyrifos is a hazardous insecticide and important pollutant of the environment. The EU Directive 2008/105/EC lists it as one of the priority water pollutants. Its presence is mainly detected by chemical methods but, since biological tests have gained in importance in the last few years, this study aimed to assess the potentials of white mustard (Sinapis alba L.) and maize (Zea mays L.) as indicators of water pollution. The phytotoxic effects of chlorpyrifos (rates 0.05-10μg a.i./l) were assessed based on physiological (germination energy and germination) and morphological traits (root and shoot length, fresh and dry weights) of the tested species. A slightly modified filter paper method was used and the results were processed by Duncan`s multiple range test and Probit analysis (EC50). According to the Directive, the maximal allowable concentration (MAC) of chlorpyrifos in water is 0.1μg a.i./l. When applied at the MAC value, chlorpyrifos inhibited germination energy and germination (11.25%) of white mustard, as compared to the control (91.5; 93.5%), and its hypocotyls and epicotyls failed to form. At the rates 50% below the MAC, germination energy and germination (87.75; 88.25%) were significanty inhibited, as well as root and shoot growth of seedlings. Chlorpyrofos did not affect the germination energy and germination of maize, while all morphological traits were significantly reduced by chlorpyrifos at the MAC rate. The EC50 of chlorpyrifos was 0.09μg a.i./l for germination of white mustard and 3.21μg a.i./l for maize.

Insekticid hlopririfos prema Direktivi 2008/105/EC svrstan je među prioritetne polutante vode i takođe značajan polutant životne sredine. Njegovo prisustvo se detektuje uglavnom hemijskim metodama, međutim biološki testovi sve više dobijaju na značaju u poslednjih nekoliko godina te je cilj ovog rada bila procena potencijala bele slačice (Sinapis alba L.) i kukuruza (Zea mays L.) kao bioindikatora kontaminacije vode. Fitotoksični efekti hlopririfosa (količine 0,05- 10μg a.m./l vode) su procenjeni preko fizioloških (energija klijanja i klijavost) i morfoloških parametara (dužina korena i izdanka, sveža i suva masa korena i izdanka) ispitivanih vrsta. Korišćena je modifikovana metoda na filtar hartiji. Podaci su obrađeni Dankanovim testom višestrukih poređenja i Probit analiza pri određivanju toksičnosti (EC50). Prema pomenutoj Direktivi, maksimalno dozvoljena količina (MAC) hlorpirofosa u vodi je 0,1 μg a.m./l vode. Pri primeni hlorpirifosa u MAC količini, energija klijanja i klijavost semena bele slačice (11,25%) su bile značajno inhibirane u poređenju sa kontrolom (91,5; 93,5%) dok je formiranje hipokotila i epikotila izostalo. U količini 50% nižoj do MAC (0,05 μg a.m. /l), energija klijanja i klijavost (87,75; 88,25%) su u poređenju sa kontrolom bile značajno smanjene, kao i dužina korena i izdanka ponika. Hlorpirifos nije uticao na energiju klijanja i klijavost semena kukuruza, dok su morfološki parametri bili značajno smanjeni već pri primeni inskticida u količini od 0,1 μg a.m./l. Toksičnost hlorpirifosa, to jest EC50 za klijavost semena bele slačice je iznosila 0,09 μg a.m./l, a za kukuruz 3,21 μg a.m./l vode.