Analysis on the Present Nitrate and Nitrite Pollution of Vegetable in Pudong of Shanghai City

Both nitrate and nitrite contents of vegetable samples from the agricultural area in Pudong,Shanghai,were measured.The results showed that the nitrate content in the vegetable samples decreased orderly as leaf vegetables,melons,beans and eggplants,and the nitrate content of vegetables cultivated in the greenhouse was much higher than that of vegetables of open field.Some leaf vegetables of greenhouse were seriously polluted by the nitrate,the nitrate-induced pollution in Chinese cabbage,swamp morningglory,chicken's feather veggie,amaranth,and greengrocery reached the third grade level,and specially the nitrate-induced pollution index of chicken's feather veggie was 1.28.The nitrite content in vegetable samples was in order of leaf vegetables>legumes>eggplants>melons,and the nitrite content of lettuce,chicken's feather veggie,haricot bean,swamp morningglory and amaranth,which accounted for 13.9% of the total vegetables,exceeded the pollution standard.