health risk assessment and evaluation of nitrate and nitrite in salad vegetables of mashhad city

Introduction: nitrate and nitrite are parts of the nitrogen cycle and can enter human body through eating and drinking. in spite of the fact that nitrate is characterized as a safe compound,  it may turn into nitrite form in the body and react with amines to form dangerous compounds like nitrosamines, preventive cautions; therefore, the intake of nitrate should be controlled. the aim of this research was to analyze data and risk assessment of nitrate/nitrite content in four commonly used salad vegetables (onion, cucumber, lettuce, and, tomato) that were sold in the mashhad central vegetable market. methods: in this study, data from 1008 samples between 21st march 2019 to 20th march 2022 that were tested based on spectrophotometric method were analyzed by spss version 22 and compared with the iranian national standard and who limits. results: nitrate and nitrite mean values of four analyzed vegetables were: onion = 76±6 mg/ kg; 1.45±0.99 mg/kg, tomato = 95±15 mg/kg; 2.35±1.28 mg/kg cucumber 216±30 mg/kg, 2.50 ±1.30 mg/kg, lettuce 1050±234 mg/kg;2.89±1.54 respectively.  there was an increasing trend in nitrate levels over the 3 surveyed years.  the mean increase was significantly different between vegetables in 3 years (p<0.01). mean daily intake of nitrates from vegetables was within acceptable daily intake (adi) limit and the noncarcinogenic index was less than epa limits for children and adults. target hazard quotient (thq) and estimated daily intake (edi) of nitrite and nitrate were less than the edi value (1 mg/kg bw/day) and 3.70 mg/kg bw/day, respectively. but lettuce consumption should be controlled among children (thq=0.95). conclusion: nitric compounds intake from salad vegetables is considered safe for iranian consumers. however, the edi of nitrate from other sources, including processed meat products and drinking water, should be regarded.