Biochar and exogenous calcium assisted alleviation of Pb phytotoxicity in water spinach ( Ipomoea aquatica Forsk ) cultivated in Pb-spiked soil

The consumption of vegetables grown in Pb-polluted soils causes serious threats to human health around the globe. In this study, we evaluated the Pb toxicity alleviation in water spinach grown of pot experiments in Pb-spiked soil treated with biochar and exogenous calcium. The results showed that both biochar and exogenous calcium alleviated Pb stress in water spinach, which was mainly manifested on its improved soil health and increased growth and decreased Pb uptake. Incorporation of 3% biochar significantly reduced CaCl 2 extracted Pb by 53.6% and decreased Pb accumulation in roots (67.1%) and shoots (80.8%). Our also findings indicated that Pb detoxification mechanism of biochar and exogenous calcium was totally different, while they can induce a synergistic impact on water spinach Pb stress alleviation. The combination of biochar and exogenous calcium in Pb-contaminated soil remediation may complement each other and reduce Pb entry into the human body through vegetables.