Abstract
Trace and potentially toxic elements represent one class of food contaminants that has stimulated research. In markets, two main methods of growing vegetables are generally available: conventional and organic. Conventional farming has been the target of some concerns about the use of agrochemicals, especially the excessive use of pesticides, whereas organic agriculture minimizes the use of agrochemicals. As the main route for potentially toxic elements’ absorption by humans is by food intake, it is important to evaluate if the method of cultivation influences their concentrations. This study evaluated the levels of potentially toxic elements and nutrients on four leafy vegetables: curly lettuce, collard greens, escarole, and rocket, cultivated by conventional and organic farming. We found that Al, Ba, Fe, and Sr levels were higher in conventional samples, whereas K, Pb, and Zn were higher in organic. Amongst the elements analysed, values of Fe, Al, and K were around 0.2, 0.3, and 70 g kg−1, respectively, except in collard greens, in which the values were lower. On the other hand, Ba, Sr, and Mn presented higher concentration in collard greens compared to the other vegetables in conventional cultivation (~ 35, 80, and 120 mg kg−1, respectively). The principal component analysis result shows that the samples were grouped according to the type of vegetable, regardless of the type of cultivation. Despite this, the evaluation of the cultivation by different types of farming is important in order to choose the healthiest option.
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Funding
This study was financed in part by the Coordenação de Aperfeiçoamento de Pessoal de Nível Superior—Brasil (CAPES) pro-equipment project (proposal no. 189683) CAPES no. 11/2014, and was supported by grant #2016/10796–5, São Paulo Research Foundation (FAPESP). da Silva V.D. is a student and a scholarship holder of Scientific and Technological Initiation Without Remuneration (ICT-SR) from UFSCar and is thankful to the Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq). Gabriel, G.V.M. is thankful to the Coordenação de Aperfeiçoamento de Pessoal de Nível Superior—Brasil (CAPES)—Finance Code 001 (process no. 88882.306808/2018–01).
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VDS performed the experiments and wrote the manuscript. GVMG contributed in the performance of the experiments, participated on the discussion, and reviewed and edited the manuscript. WGB and APF performed the multivariate analysis and reviewed and edited the manuscript. JBC reviewed and edited the manuscript. LCO reviewed and edited the manuscript, participated on the discussion, and contributed with the resources. All authors approved the final version of the manuscript for publication.
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da Silva, V.D., de Mello Gabriel, G.V., Botero, W.G. et al. Leafy vegetables marketed as organic and conventional: assessment of essential and non-essential elements’ content. Environ Monit Assess 194, 758 (2022). https://doi.org/10.1007/s10661-022-10439-4
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DOI: https://doi.org/10.1007/s10661-022-10439-4