Measurement of heavy metals in soil, plants and water samples based on multi-walled carbon nanotube modified with Bis(triethoxysilylpropyl)tetrasulfideby flame atomic absorption spectrophotometry

Heavy metals (HMs) are considered as the major environmental pollutants that accumulated in soil and plant. Consumption of such contaminated plants by humans and animals would ultimately harm the health of communities. This study aims to evaluate the amount of copper(Co), cadmium(Cd), and lead(Pb) in soil and cultivated plants that are irrigated by the city of Zabol’s wastewater. Also, the heavy metals determined in 20 mL of Zabol’s water based on Bis(triethoxysilylpropyl)tetrasulfide (S4[C3H6Si(OEt)3]2, TEOSiP-TS) modified on MWCNTs as an adsorbent by the uniform dispersive -micro-solid phase extraction (UD-μ-SPE) at optimized pH. In this study, 52 samples including wheat, corn grain, and wild spinach, as well as agricultural soil were selected randomly from three village stations. The concentrations of heavy metals in plants, soils, and water samples were measured using a flame atomic absorption spectrometer (F-AAS). The one-way ANOVA test was applied to compare the mean value of heavy metals at the three mentioned stations. The results indicate that the amount of lead at all three stations and in all types of plants exceeds the permissible range. The amount of copper in plant species and water is lower than the permitted range, while it is higher in agricultural soil. By optimizing parameters, the linear range (LR) and the detection limit (LOD) of Cu, Cd, and Pb were obtained 1.5-1000 μg L-1, 1-200 μg L-1, 5-1500 μg L-1 and 0.5 μg L-1, 0.25 μg L-1, 1.5 μg L-1, respectively in water samples (RSD%<2). This study indicates that irrigation of agricultural fields using wastewater causes the accumulation of heavy metals in soil and plants.