An-Najah Staff

A study of the content of nitrate and nitrite in few different vegetables in Tulkarm district was conducted. This district is part of the West Bank land (Palestine). A total of 75 samples of five different types of vegetables (tomato, cucumber, onion, potato, and cabbage) were collected from randomly selected farms in three different areas in Tulkarm district (Thenabe, Al-Sha'raweya, and Al-Kafriyat). The nitrate content in the samples was analyzed using HANNA spectrophotometer (HI93728-0), while the nitrite content was analyzed using the AOAC Official Method 973.31. The results showed that the type of the vegetable has a great effect on the nitrate content, the highest nitrate content was found in potato with an average of 253.13mg/Kg, while the lowest nitrate content was found in tomato with an average of 16.95mg/Kg. The nitrate content was affected by fruit size; the small cucumber size shows a higher nitrate content than the large size fruits; It was found that the peels of the cucumber fruits contain higher nitrate content than the essence. Cabbage as a leafy vegetable shows a high nitrate content. The nitrite concentrations were low (less than 1mg/Kg) in all test crops. These levels of nitrite are considered acceptable. The different locations show no significant effect on the nitrate and nitrite contents in vegetables tested in this study. This study high lights an important issue which was not investigated before. Under the conditions of the study, the results indicated acceptable levels of both nitrate and nitrite content. However more work is needed to elaborate these results with more samples and different crops.