Monitoring and Assessing Health Risk of Exposure to Nitrate Residues in Agricultural Products; Case Study in Qom Province, Iran

This study was designed to investigate the rate of nitrate residual of major vegetables marketed in the region of Qom province and to estimate the human health risk assessment. In the first stage of this work, four groups of vegetables (lettuce, tomatoes, onion and potatoes) were selected. In two seasons, summer, and autumn, for 4 months165 vegetable samples (lettuce 35, tomatoes 45, onion 35, and potatoes 40) were analyzed to assess the levels of nitrates in vegetables. In the second stage of the study, health risk assessment from intake of vegetables was investigated. Concentration of nitrate in vegetables samples including lettuce (200 ± 65 mg kg−1), onion (187 ± 43 mg kg−1), potato (87 ± 33 mg kg−1) and tomato (294 ± 67 mg kg−1) were determined. Results showed that the average daily dose of nitrate (mg/kg/day) for age groups from vegetables distributed in Qom province is less than the ADI value (3.70 mg/kg BW/day) and the hazard quotient (HQ) of nitrate was less than 1, respectively, so that consumption of such vegetables is not dangerous to consumers' health. Hazard index (HI) for all age groups was less than one were calculated, however, the hazard index is higher for the age group of 5-18 years compared to other age groups. According the results of the cancer risk assessment, the mean cancer risk calculated for all groups by consumption of onion, tomato, and potato products is higher than the acceptable limits (the acceptable level of 1 case per 10000) estimated. Although the results obtained from the health risk assessment of nitrate residual amount in vegetable samples showed no significant hazard for consumers, due to the large share of vegetables in the daily food basket, it is inevitable to continuously monitor nitrate during cultivation and storing the product at the distribution levels.