Investigation of the Amount of Phosphate and Nitrate Accumulation in Consumable Onion in Hamedan City

Consumption more of level nitrate and phosphates threatens human health. Vegetable and fruits are the great sources of nitrate and phosphate in human diet. The purpose of study is to determine the amount of nitrate and phosphate in consuming onions of Hamedan.
Sampling performed randomly to number of 10 onion samples in 3 repetition in April and February 2015 & 2016. Concentration of nitrate and phosphates analyzed by spectrophotometer after extracting by method acid digestion and dry ash. For statistical processing of results used from software SPSS v.20 and T-independent and one sample T-test.
Results showed that nitrate average in white and red onions in April was 60.65mg/kg and 275.97mg/kg respectively and in February was 194.85mg/kg and 244.67mg/kg respectively. Also phosphate average in white and red onions in April is 6205.11mg/kg and 13526.87 mg/kg respectively and in February is 6124.12 mg/kg and 7512.11 mg/kg respectively.
Findings showed that the concentration of nitrate and phosphate in red onions of collected in April and white onions collected in February are more than WHO standard. In this study the reason of high nitrate and phosphate in the consumed onions in Hamedan is probably use of unsuitable, unbalanced and high amount of nitrate and phosphate manures. Therefore regular monitor of products by “Deputy of Food and Drug” of Medical Science University is seems to be necessary.