Physical Chemistry 2010 - Workshop: Specific Methods for Food Safety and Quality

B2-IL: PESTICIDE’S TRANSFORMATION PRODUCTS: STABILITY AND TOXICITY STUDIES

1Laboratory for Environmental Research, University of Nova Gorica,
Vipavska 13, P.O. Box 301, 5000 Nova Gorica, Slovenia

2Laboratorie de Photochimie Moléculaire et Macrololéculaire, Universite Blaise Pascal,
CNRS UMR 6505 (Clermont-Ferrand), 63177 Aubiére Cedex, France

Legislation for food safety is mostly limited to pesticides monitoring and no attention is paid to the presence and toxicity of transformation products formed after pesticides application. Stability studies of three selected transformation products IMP - 2-isopropyl-6-methyl-4-pyrimidinol (diazinon hydrolysis product), TCP - 3,5,6-trichloro-2-pyridinol (chlorpyrifos degradation product), and 6CNA - 6-chloronicotinic acid (imidacloprid and acetamiprid degradation product) were performed under sunlight at room temperature (22°C) and in the dark in refrigerator (4°C) within 90 days of exposure. The results showed no change in concentration with samples kept in refrigerator in the darkness. On the other hand, aqueous solution of TCP exposed to sunlight resulted in high decrease of initial concentration within time. The toxicity assessment was performed using luminescent bacteria Vibrio fischeri and the results showed low toxicity in case of IMP and 6CNA, however, for TCP the calculated EC50 value after 30 minutes of exposure was 15.1 mg/L. Stability of the selected transformation products under UVC germicidal lamp at 245 nm indicated almost no decrease in concentration for IMP and 6CNA aqueous solution, but there was detected relatively high decrease in concentration of TCP.

Prof. Polonca Trebše is a full professor at the University of Nova Gorica, Slovenia and the dean of research activities at this university. One of the main fields of her interest is the development of laser-based methods for identification and determination of toxic compounds in foodstuff, combined with bioanalytical techniques – acethylcholinesterase based biosensor, FIA methods and liquid chromatography. She is the leader of a great number of international and national projects.