Evaluation of variation in essential nutrients and hazardous materials in spinach (Spinacia oleracea L.) genotypes grown on contaminated soil for human consumption

Abstract

Spinach (Spinacia oleracea L.) is an important leafy vegetable, rich in various essential nutrients required for human health. However, it may also accumulate hazardous materials in edible parts, and subsequently poses human health risk. Evaluation of variation in essential nutrients and hazardous materials in spinach genotypes is important for breeding desired genotypes for human consumption. In this study, we investigated 68 spinach genotypes for screening desired genotypes. Seven spinach genotypes, i. e. KBXX, XIBW, KBWZ, DBSC, LLCJ, QUAN and JXQD were identified as safe genotypes that contained contaminants in edible parts below permissible limit (Cd < 0.05 mg kg−1 FW, Pb < 0.1 mg kg−1 FW, nitrate < 3100 mg kg−1 FW) and are suitable for growing on Cd, Pb and nitrate co-contaminated soil without posing risk to human health. LLCJ and DBSC were found to be two excellent spinach genotypes for human consumption, due to their containing abundant beneficial nutrients and minimum hazardous materials. Spinach biomass was positively correlated with plant concentration of N, P, S and Ca (r = 0.244, 0.322, 0.414 and 0.301, respectively), P was positively correlated with concentrations of S, Fe, chlorophyll, cellulose, and protein (r = 0.348, 0.256, 0.255, 0.272 and 0.248, respectively) but negatively proportional to oxalic acid concentration (r = -0.274). These results indicate that adequate application of N, P, S and Ca fertilizers can improve the quality of spinach grown on co-contaminated soils.