Average content of nitrate in 16 kinds of examed vegetables was 2 76 timcs as much as that of the world health standard,but that of nitrite was normal.The average content of 4 types of heavy mental in 4 kinds of examed vegetables:copper was normal,lead was beyond the standard,cadmium and chrmiurn in one kind of them were normal,Pesticide residues in 11 kinds of examed vegetables:8 kinds were normal,3 kinds were beyond the standard Applying high dose of chemical N fertilizer and applying fertilizer unprope...