Nitrate Content in Potato (Solanum tuberosum L.) and Onion (Allium cepa L.) and Its Human Health Risk Assessment in the Fields with the Highest Cultivated Area in Kermanshah Province, Iran

The major portion of daily dietary nitrate that enters the human body is derived from vegetable consumption. High concentration of nitrate in edible parts of vegetables causes a variety of poisonings, anemia in children and production of carcinogen nitrosamine in adults. To investigate the concentration of nitrate in potatoes and onions grown in Kermanshah province, sampling was carried out from the fields located in different counties at the time of harvest in the summer and autumn of 2019. After washing, drying, grinding, and extracting the samples, the nitrate concentrations were determined with a spectrophotometry method. The results showed that the mean nitrate concentration in potato and onion samples (94.56 and 74.62 mg kg-1 FW, respectively) of all regions was significantly lower than the World Health Organization standard limit (250 and 1000 mg kg-1 FW, respectively). The highest concentration of nitrate in potato (153.70 mg kg-1 FW) and onion (98.02 mg kg-1 FW) was observed in samples from the Qasr-e-Shirin and Kermanshah, respectively. The non-cancer hazard quotient (HQ) of nitrate via potato and onion consumption was below 1 for all age receptor groups. Although, it does not seem to be a particular problem with consuming these vegetables; however, the evaluation of nitrate concentration in potato and onion samples is recommended at regular time intervals.