Organophosphate Pesticide Residue Monitoring And Risk Assessment In The Pearl River Estuary

The present paper investigated the distribution of organophosphate pesticide residues (OPPs) in the waters of the Pearl River estuary. We sampling the water in July, August, October, November, December in 2010. We chose river Jiaomen, Shawan, Wanqingsha and Zhangsong as our study areas. We determinate the concentration of OPPs. The result showed that the levels of all OPPs ranged from 18.76～344.94ng/L, four main OPPs(Diehlorvos, Phorate, Dimethoate, Disulfoton) were predominant of the total OPPs, and they dominate 50% of the nine OPPs which we monitored. The seasonal distribution characteristics of OPPs indicated that OPPs contents was not changed with the temperature, it mainly affected by the atmospheric bulk deposition, surface runoff and the nearly usage. The correlation between the concentration of OPPs and the sampling station is low, that mainly because the complex sources of OPPs and the residue of OPPs is shorter.When compared with other areas, the OPPs concentration level in Pearl River estuary was some moderate. The quality and risk assessment results indicated the overall status of pesticide pollution was acceptable, but Phorate is on the critical point, it has potential risks on the ecological environment and human health. The other kind of OPPs can not be ignored either. The government should improve the environmental management of organic pesticides in the agricultural application.