Contents of Nitrate,Nitrite and Vitamin C of Vegetables in Heshan City

The contents of nitrate,nitrite and vitamin C in different edible parts of 15 vegetables purchased from Heshan were determined.According to the limit standards for nitrate and nitrite pollution at home and aboard,the safety of 15 vegetables were evaluated.The fruits of Cucumber,towel gourd,Aubergine,Legume and Dasheen and the caudexes of Lotus root belong to the first class vegetables can be eaten in fresh,after salted or cooked.The leaves of Lettuce and the fruits of Radish belong to the second class vegetables,which can be eaten after salted or cooked.The leaves of Flowering Cabbage,Little Cabbage,Water Convolvulus,Chinese Kale and Sweet potato belong to the third class vegetables,which can only be eaten after cooked.The petiole and the root of Little Cabbage,the leaves of Chinese Mustard and Lettuce belong to the fourth class vegetables.The petiole and the root of Flowering Cabbage and Caudexes and the root of Water Convolvulus belong to the fifth class vegetables.The last two class vegetables were inedible or can be eaten in limited quantities.