Insecticides used in pest control to obtain higher and more stable yields are one of the sources of chemical pollution of the environment with bad impact on all biological systems. In this context, in this paper we show the remanent character of the insecticides imidacloprid and dimethoate in the roots of the tested plant – lettuce (Lactuca sativa) – cultivated in protected areas. The experimental field was set according to the randomised block method with three replications both in the solarium and in the glasshouse, between 2009 and 2010. Sampling was done 24 hours and 7 days, respectively, after using the insecticides. We suggested and applied the high-performance liquid chromatography method to detect insecticides UV-VIS. As a result of processing chromatographic information, we could draw the conclusion that the remanence of imidacloprid 24 hours after application in the lettuce roots cultivated in the solarium and in the glasshouse was 3.40411 ppm (parts per million or mg/kg) and 9.02731 ppm, respectively. The remanence of the imidacloprid 7 days after application in the tested lettuce roots, according to the chromatogrammes was 1.23337 ppm in the lettuce roots cultivated in the solarium and 6.30109 ppm in the lettuce roots cultivated in the glasshouse. Twenty-four hours after application, dimetoat was identified in the lettuce roots cultivated in the glasshouse in concentration of 3.32746 ppm, while it could not be detected in the lettuce roots cultivated in the solarium. The absence of the dimethoate in the lettuce roots was also identified 7 days after application in the roots of the lettuce cultivated in both the glasshouse and the solarium.

remanence; imidacloprid; dimetoat; roots; lettuce

Presentation: oral