Document Type : Original Article
Authors
1 PhD Student of Soil Chemistry and Fertility
2 Emeritus professor of Tarbiat Modares University
3 Professor of Isfahan University of Technology
Abstract
Nitrate (NO3) is an essential nutrient for growth of plants, but high concentration of nitrate in human diet increases risk of serious illnesses such as gastric cancer and infantile methemoglobinemia. Vegetables constitute the major source of nitrate, providing 80% of the average daily human dietary intake. Unbalanced fertilization and overuse of nitrogen-based fertilizers are the main reasons for excess accumulation of nitrate in vegetables.In regard with the recent concerns about contamination of vegetables to nitrate, the present study was conducted to compare nitrate accumulation in edible parts of some predominant crops in Isfahan province in comparision with critical level of nitrate in vegetables.Predominant crops grown in Isfahan including potato (Solanumtuberosum) which is basic vegetable in human diet and cucumber (Cucumissativus) which is basic raw-used vegetable were sampled in cold season (mid-October until end-November), with high probability of nitrate accumulation, from pioneer greenhouses and farms. Nitrate concentration in edible parts of compound sampled plants were measured by diazo method. Interpolation maps of nitrate hazard quotient for children and adults based on per capita consumption of these crops were drawn. Results showed that mean nitrate concentrations in cucumber and potato samples collected from all cities were below permisible level. According to the results obtained from interpolation maps of nitrate and the fact that in all cities THQ for nitrate was below 1 (Maximum 0.051 and O.2 for potato and cucumber, respectively). Therefore, the health quality of the studied crops in terms of nitrate concentrations was acceptable. Although continuous monitoring of crops is essential.
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