Measurement of Nitrate concentration and health risk assessment in Spinach and Imperial irrigated with municipal wastewater

Authors
nayereh sadat hosseini 1
merdad Cheraghi 1
hajar Merrikhpour 2
bahare Lorestani 1
1 Islamic Azad University Hamedan
2 Sayyed Jamaleddin Asadabadi University
Abstract
Introduction and Aims: Absorption and distribution of nitrate in agriculture products have significantly important because high concentrations of nitrate in foodstuffs, especially in leaf vegetables, leads to increased risk of stomach and intestinal cancers in adults and methemoglobinemia in infants. This study is done for the first time in a laboratory environment to study the effect of various concentrations of municipal wastewater on nitrate accumulation in leaf vegetables.

Materials and Methods: This experiment is accomplished as in greenhouse environment. For this purpose, seeds of leaf vegetables including garden cress (Lepidium satrivum) belongs to Brassicaceae and spinach (Spinacia oleracea) belongs to Chenopodiaceae were purchased and sown in greenhouse and were irrigated as 4 treatments: T1 (irrigation only by means of well, “control treatment”), T2 (irrigation with raw wastewater once a week), T3 (irrigation with raw wastewater twice a week) and T4 (irrigation only with raw wastewater). The experiment performed in three replications in order to gain a proper statistical condition. After growth and preparation of samples, the amount of nitrate was measured in edible parts of each of samples by means of JENWAY model of spectrophotometer device at 400 nm wavelength. To compare the average of nitrate concentration in samples, ANOVA test at a level of 5 percent and SPSS software were used.

Results: According to the results, the effect of various wastewater treatments on the amount of accumulated nitrate in leaf vegetables was meaningful. In a comparison of treatments with the control treatment, the most nitrate accumulation was observed in T4 (irrigation only with raw wastewater). The amount of accumulated nitrate in different treatments of vegetables was in the allowable range of world health organization report and lower than the range of toxicity threshold (p < 0/05). The nitrate concentration in different spinach treatments was also further than similar treatment of garden cress (p < 0/05).

Conclusion: In the present study, the amount of nitrate concentration differed in various families of leaf vegetables. Irrigation with municipal raw wastewater increased the nitrate concentration of atmospheric organs of studied leaf vegetables in terms of quality. Due to their harmful effects on human societies and endangering food safety, more precautions are required to reduce such effects.
Keywords
wastewater
Nitrate
Lepidium satrivum
Spinacia oleracea
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