Contents and evaluation of vegetables nitrate in Nanning city

On the basis of investigation and analysis of vegetable samples in Nanning, the results showed that the average contents of nitrate in various vegetables were leaf vegetables (1932.1mg.kg~(-1)) root vegetables (944.1mg.kg~(-1)) onion-garlic vegetables (488.6mg.kg-1) gourd vegetables (183.6mg.kg~(-1)) eggplant and tomato(157.6mg.kg~(-1)) bean vegetables (147.0mg.kg~(-1)) water vegetable(62.0mg.kg~(-1)). The results indicated that vegetables were contaminated to different degree: serious pollution in leaf vegetable, then in root vegetables and onion-garlic vegetables, with index of pollution were from 1.04～6.60, of which most were higher than 2.0 and index of pollution in the other vegetables were less than 1, showing no contamination.