Ecological assessment of vegetable products grown in the city of Zhytomyr and its residential suburb

Abstract

The purpose of the given research was to carry out complex ecological assessment of vegetables grown in the city of Zhytomyr and in its residential suburb as to the content of nitrates and heavy metals in them. The results of the research showed that on the average from the whole amount of samples selected on the territory of the city the excess nitrate content was found in potatoes, bulb onion, green onion, garden radish and red beet. In the rest of vegetable and fruit samples the excess of the nitrate level was not found. In vegetables grown under the conditions of agroecosystems of suburban settlements the excess nitrate content was fixed in 44.6 % of the samples selected. Most often the excess of the norm was observed in potatoes (75 % of the samples). The comparative analysis of vegetable products grown under different conditions showed that vegetables grown in settlements of the residential suburb were more polluted with nitrates than those grown in urban ecosystems.It has been established that in the selected samples of vegetables grown under the conditions of the city higher content of heavy metals, especially lead and cadmium, is observed. From the total amount of the samples the most dangerous for human consumption proved to be leaf parsley in which the excess of lead, cadmium and zinc level was on the average 5.1, 7.3 and 3.2 times respectively, and the safest vegetable was garden carrot. As a result of the investigations into the content of heavy metals in vegetables grown in the residential suburb, it has been established that absolutely safe for man are garden carrot, red beet, cucumbers, tomatoes and onion in which the level of heavy metals is substantially lower than the maximum permissible one. Lead content in white head cabbage and parsley was fixed at the level of 1.25 and 3.45 mg/kg. Slight increase in cuprum content was found in white head cabbage, and in potatoes the content of zinc exceeding the norm was fixed. It has been proved that crop products grown under the conditions of urban ecosystems contain higher amount of heavy metals as compared with the same crops grown in the residential suburb.When conducting the investigations into the content of nitrates and heavy metals in different vegetable parts we found that distribution of pollutants among organs of plants was first of all determined by their species and biological characteristics of organs themselves.