Iesce Maria Rosaria, della Greca Marina, Cermolal Flavio, Rubino Maria, Isidori Marina, Pascarella Luigia
Dipartimento Chimica Organica e Biochimica, Università Federico II di Napoli, Via Cinthia 4, 80126 Napoli, Italy.
Environ Sci Pollut Res Int. 2006 Mar;13(2):105-9. doi: 10.1065/espr2005.10.285.
N-methylcarbamate insecticides are widely used chemicals for crop protection. This study examines the hydrolytic and photolytic cleavage of benfuracarb, carbosulfan and carbofuran under natural conditions. Their toxicity and that of the corresponding main degradation products toward aquatic organisms were evaluated.
Suspensions of benfuracarb, carbosulfan and carbofuran in water were exposed to sunlight, with one set of dark controls, for 6 days, and analyzed by 1H-NMR and HPLC. Acute toxicity tests were performed on Brachionus calyciflorus, Daphnia magna, and Thamnocefalus platyurus. Chronic tests were performed on Pseudokirchneriella subcapitata, and Ceriodaphnia dubia.
Under sunlight irradiation, benfuracarb and carbosulfan gave off carbofuran and carbofuran-phenol, while only carbofuran was detected in the dark experiments. The latter was degraded to phenol by exposure to sunlight. Effects of pH, humic acid and KNO3 were evaluated by kinetics on dilute solutions in the dark and by UV irradiation, which evidenced the lability of the pesticide at pH 9. All three pesticides and phenol exhibited acute and higher chronic toxicity towards the aquatic organisms tested.
Investigation on the hydrolysis and photolysis of benfuracarb and carbosulfan under natural conditions provides evidence concerning the selective decay to carbofuran and/or phenol. Carbofuran is found to be more persistent and toxic.
The decay of benfuracarb and carbosulfan to carbofuran and the relative stability of this latter pesticide account for many papers that report the detection of carbofuran in water, fruits and vegetables.
N-甲基氨基甲酸酯类杀虫剂是广泛用于作物保护的化学品。本研究考察了在自然条件下丙硫克百威、丁硫克百威和克百威的水解和光解裂解情况。评估了它们及其相应主要降解产物对水生生物的毒性。
将丙硫克百威、丁硫克百威和克百威在水中的悬浮液置于阳光下照射，设置一组黑暗对照，照射6天，然后通过1H-NMR和HPLC进行分析。对萼花臂尾轮虫、大型溞和宽角弯额溞进行急性毒性试验。对斜生栅藻和 dubia 角突网纹溞进行慢性试验。
在阳光照射下，丙硫克百威和丁硫克百威释放出克百威和克百威酚，而在黑暗试验中仅检测到克百威。后者经阳光照射降解为苯酚。通过在黑暗中对稀溶液进行动力学研究以及紫外线照射评估了pH值、腐殖酸和硝酸钾的影响，这证明了该农药在pH 9时不稳定。所有三种农药和苯酚对所测试的水生生物均表现出急性和较高的慢性毒性。
在自然条件下对丙硫克百威和丁硫克百威水解和光解的研究提供了有关其选择性降解为克百威和/或苯酚的证据。发现克百威更持久且毒性更大。
丙硫克百威和丁硫克百威降解为克百威以及后一种农药的相对稳定性解释了许多报道在水、水果和蔬菜中检测到克百威的论文。
