الفهرس 
Introduction
Quality parametersOnly 14 pages are availabe for public view
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Abstract
Nitrate accumulation in Egyptian vegetable showed considerable high values as compared to those found in vegetables grown in several foreign countries in spite of the high intensity and long duration of light in Egypt, which favour nitrate reduction in plants. This could be mainly due to intensive application of nitrogen fertilizers alone by Egyptian farmers which results in imbalanced nutritional status of the plants and consequent high nitrate accumulation. Nitrate may harm the health of the consumer as it can be converted into nitrite in the human body. Nitrite inhibits oxygen transport by the blood or react with amines and be converted to nitrose amines which cause cancer. The current acceptable daily intake for nitrate for man according to the Eropean scientific committee is set as 3.7 mg NO3-. kg-1 body weight day-1, while the same limit of NO2 was recommended as 0.06 mg NO2-. 1kg-1 body weight day-1.CONCLUSION Under the same conditions of this experiment it can be concluded that, applying N fertilization in doses higher than the recommended one (40 kg N/fed) for lettuce and garden rocket vegetable gave increases in the fresh yield and nutrients content but at the same time increased the nitrate and nitrite accumulation over the safe limit for human health. This means that, the soil supplying power for B and Mo is not enough to supply those elements to the studied vegetables under high doses of nitrogen. The foliar application of B, Mo, Sa and As to the studied vegetable crops decreased the nitrate accumulation under the high N fertilization rates, which may be attributed to the increase in the formation and/or the activity of nitrate reductase enzymes which reduced NO3-N to NH4-N leading to the formation of amino acids and protein.