Assessment of Nitrate Exposure in Beijing Residents via Consumption of Vegetables

To know the nitrate contents in vegetables and nitrate exposure in Beijing residents,341 samples of various vegetables in season were collected and analyzed during Mar.-May,2006.Nitrate contents were analyzed according to GB/T 5009.33—2003.Daily consumption of vegetables was calculated by the method of food accountant and then daily intake of nitrate was calculated.The content of nitrate in vegetables was arranged in the following descendent order:leafy vegetables root and stem vegetables onions and garlic melonslegumes flower vegetables egg plants.The contents of nitrate in different species differed greatly,which implied that they were cultivated in different places under different conditions.According to the results of the assessment,the median daily intake of nitrate via vegetables was 328.21 mg(median)among Beijing residents.The results indicate that the exposure of nitrate,only via vegetables,exceeds the ADI established by JECFA,and development of measures to monitor and control it is urgently needed.