The nitrate contents in commercial vegetables and assessment of nitrate exposure in Nanjing residents

OBJECTIVE To know the nitrate contents in vegetables and nitrate exposure in Nanjing residents. METHODS The vegetable samples were collected in 11 markets, and 980 samples in 44 groups of vegetables were analyzed according to GB / T5009.33. Daily consumption of vegetables was calculated by the method of food accountant and semi-quantitative food frequency questionnaire, and then daily intake of nitrate was calculated. RESULTS The nitrate content of special vegetables (Lu hao) was highest (2.64×103mg / kg, median), and the second was leafy vegetables (1.60×103mg / kg, median). The nitrate contents arranged in the following descendent order: special vegetables﹥leafy vegetables﹥stem vegetables﹥root vegetables﹥melons vegetables﹥cabbage vegetables﹥fruit vegetable﹥beans﹥bulb vegetables﹥fungi vegetables. The contents of nitrate differed greatly in the same category, and also in different varieties. The median daily intake of nitrate via vegetables was 463 mg (median) among Nanjing residents, which exceeded the ADI (300 mg / d) established by WHO / FAO by 1.5 times. The results indicated that the first three exposure were leafy vegetables, stem vegetables and root vegetables. CONCLUSION Nitrate pollution of commercial vegetables in Nanjing is serious. The exposure of nitrate, only via vegetables, greatly exceeds the ADI.