Heavy metals accumulation in wheat (Triticum aestivum L.) roots and shoots grown in calcareous soils treated with non-spiked and spiked sewage sludge

With growing urbanization and agriculture, the quantity of sewage sludge production increases every year. For the purpose of risk management, it is crucial to figure out how much heavy metals are transported to different parts of plants when sewage sludge is used. A greenhouse experiment was carried out to investigate the accumulation of heavy metals in wheat (Triticum aestivum L.) grown in 30 calcareous soils. The soils in this study were subjected to three different treatments: soils treated with sewage sludge at a rate of 2.5%, soils treated with sewage sludge at a rate of 2.5% and enriched with heavy metals, and control soils that received neither sewage sludge nor heavy metals. Wheat grown in sewage sludge-treated soils had the highest mean dry matter, and was 2.11 and 1.25 times greater than wheat grown in control and spiked-sewage sludge-treated soils, respectively. In all treatments, wheat roots had greater heavy metal levels than wheat shoots. Among all the heavy metals examined, Pb and Cu had the highest bioconcentration factors for roots and shoots (BCFRoots and BCFShoots) in control and sewage sludge-treated soils, followed by Cd in spiked-sewage sludge-treated soils, and Co and Ni had the lowest BCFRoots and BCFShoots across all treatments. In spiked-sewage sludge-treated soils, the root restriction for heavy metals translocation was more important for Co, Cu, and Ni than for Pb and Zn, indicating that wheat can be grown safely in a variety of calcareous soils amended with sewage sludge with high content of Cd, Co, Cu, and Ni. Reducing the transfer of Pb and Zn from soils to wheat in soils treated with sewage sludge yet having high concentrations of these heavy metals should be considered as a top priority strategy for preserving wheat products. Since a wide range of calcareous soils was used in this study and because calcareous soils make up the majority of soils in the Middle East, the findings are relevant for all of the countries in this region.