Abstract: The National Water-Quality Assessment Program(NAWQA) implemented by the U.S.Geological Survey(USGS) has been introduced.The program has a section dedicated to study of pesticide pollution in surface water of the country,which includes a nation-wide survey and study of pesticide pollution in surface water(rivers and lakes) of the country in 1992-2001.Based on the study of the data collected during the survey,the section summed up a list of pesticides detected in the surface waters,their concentrations and geographic distribution,and seasonal variation of the concentrations as well,which are believed to be closely related to the use of pesticides and also to a series of factors,such as climate,physico-chemical properties of the pesticides and local hydraulic systems.A screening-level perspective on potential significance of pesticides to aquatic life and fish-eating wildlife was obtained by comparing concentrations measured in streams with water-quality benchmarks in the guidelines established by USEPA.The levels of pesticides detected in surface waters and seasonal variation patterns of pesticide concentrations in European countries have also been briefed.Shortcomings in the formulation of the existent water quality standard system of China were analyzed as well.Based on the above-mentioned studies,it is recommended that China should perform selective monitoring of the pesticides commonly used in China and find out characteristics of the temporal-spatial distributions of these pesticides in surface waters,and based on the laws of seasonal variations of their concentrations,push forward the work of formulation of benchmark criteria for evaluation of surface water quality and define risk assessment methods for pesticide residues in the surface waters of the country,and hence exercise overall control and management of pesticide pollution of surface waters in the country.

Key words: USA, pesticide, surface water, residue, assessment, review