Comparative Assessment of Nitrate Concentrations in Vegetables Grown on Commercial and Subsistence Farms in the Saratov Region

Abstract

Background: Food safety is one of the prerequisites for a healthy diet of the population of the Russian Federation. At the same time, successful functioning of modern agricultural complexes is almost impossible without a widespread use of various agrochemicals, including nitrogen-containing fertilizers. The objective of our study was to conduct a comparative assessment of the nitrate content of vegetables grown on commercial and subsistence farms located in industrially contaminated areas of the region and used as local food. Materials and methods: The research was carried out in the summer and autumn periods of 2017–2019 in a number of polluted areas of the Saratov Region. Nitrate concentrations in local vegetables were measured by a potentiometric method. Results: We established that the nitrate content of vegetables grown in most environmentally disadvantaged areas varied greatly. Concentrations of this contaminant depended on the type of vegetables, growing conditions and region; yet, they did not exceed the maximum permissible level in any vegetable sample tested. At the same time, the level of nitrates in crops grown on commercial farms was significantly higher than that in vegetables grown in private gardens (p < 0.05) due to a more extensive application of nitrate fertilizers in the form of commercially produced ammonium nitrate. Private gardeners, on the opposite, use biomass species, usually legumes, contributing to a better conversion of nitrates into proteins and preventing their excessive accumulation in the produce.