Phytotoxicity of chlorpyrifos to white mustard (Sinapis alba L.) and maize (Zea mays L.): Potential indicators of insecticide presence in water

Chlorpyrifos is a hazardous insecticide and important pollutant of the environment.\udThe EU Directive 2008/105/EC lists it as one of the priority water pollutants. Its presence\udis mainly detected by chemical methods but, since biological tests have gained in importance\udin the last few years, this study aimed to assess the potentials of white mustard\ud(Sinapis alba L.) and maize (Zea mays L.) as indicators of water pollution. The phytotoxic\udeffects of chlorpyrifos (rates 0.05-10μg a.i./l) were assessed based on physiological (germination\udenergy and germination) and morphological traits (root and shoot length, fresh\udand dry weights) of the tested species. A slightly modified filter paper method was used\udand the results were processed by Duncan`s multiple range test and Probit analysis (EC50).\udAccording to the Directive, the maximal allowable concentration (MAC) of chlorpyrifos\udin water is 0.1μg a.i./l. When applied at the MAC value, chlorpyrifos inhibited germination\udenergy and germination (11.25%) of white mustard, as compared to the control (91.5;\ud93.5%), and its hypocotyls and epicotyls failed to form. At the rates 50% below the MAC,\udgermination energy and germination (87.75; 88.25%) were significanty inhibited, as well\udas root and shoot growth of seedlings. Chlorpyrofos did not affect the germination energy\udand germination of maize, while all morphological traits were significantly reduced by\udchlorpyrifos at the MAC rate. The EC50 of chlorpyrifos was 0.09μg a.i./l for germination of\udwhite mustard and 3.21μg a.i./l for maize