ملخص: To elucidate the photochemical behaviour of carbendazim (or MBC) in super.cial waters, photolysis studies have been carried out in aqueous solutions at several pH using a UV light source (high pressure mercury arc lamp) or a solar light simulator (xenon arc lamp). The kinetics of photodecomposition of carbendazim was determined using HPLC– DAD and the identi.cation of photoproducts was carried out with HPLC–MS (ESI negative and positive mode). According to the experimental results carbendazim is a rather stable molecule in the dark or in environmental conditions. The pH in.uence of the environmental medium on the photodegradation rate has been con.rmed. The photochemical process can be considerably accelerated in alkaline solutions using HPK-quartz irradiation (quantum e.ciency at pH 9 U ¼ 3:1  103 degraded molecule per absorbed photon) while the photodegradation is not as e.- cient under a simulated sun irradiation (quantum e.ciency in the suntest U ¼ 104 at pH 7). Three photoproducts have been tentatively identi.ed in pure water: 2-aminobenzimidazole, benzimidazole isocyanate and monocarbomethoxy-guanidine (issued from the cleavage of the benzimidazole ring). The last one seems very stable and could be accumulated in the environment.

لغة: إنجليزية