Ecological safety of sunflower seeds in the conditions of agricultural intensification

Abstract

Sunflower cultivation using intensive technologies, which manifests itself in the disruption of crop rotation, high rates of mineral fertilisers and pesticides, leads to an increased risk of products contaminated with heavy metals, nitrates, and pesticide residues. The purpose of this study was to identify the risks of toxic substances accumulation in the soil and sunflower seeds. In this study, the atomic absorption spectrophotometric method was used to determine the content of toxic substances in soil and sunflower seeds. The content of alkaline-hydrolysed nitrogen, mobile phosphorus, exchangeable potassium, the reaction of the soil solution pH, as well as the content of mobile forms of heavy metals: lead, cadmium, copper, zinc, mercury, cobalt, and molybdenum; boron, and radioactive caesium were determined in the soil after sunflower cultivation. The factual content of soil contaminants was compared with their maximum permissible concentrations. The study investigated the content of heavy metals, namely, lead, cadmium, copper, and zinc, as well as nitrates in sunflower seeds. Their content was compared with the values of maximum permissible concentrations. The coefficients of accumulation of the heavy metals under study by sunflower seeds were calculated. Thus, copper and zinc are most intensively absorbed from the soil and accumulate in sunflower seeds, while lead is the least absorbed. The findings suggest that since no excess of the permissible levels of heavy metals and nitrates in sunflower seeds was found, there is a higher probability of their increased accumulation in sunflower by-products: seed husks, stems, leaves, petioles, and roots. The study results can be used in organic sunflower cultivation