Investigation of Heavy Metals Absorption and Accumulation in Leaves of Basella Alba L. (Malabar Spinach)

This study investigated the absorption and accumulation of heavy metals and minerals in the leaves of Basella alba L. irrigated with Adada River water, sewage effluent, and tap water over six weeks. The aim was to determine the levels of selected heavy metals and compare them with WHO/FAO permissible limits for vegetables. Fresh samples of B. alba were cultivated and irrigated separately with the three water sources. The concentrations of lead (Pb), arsenic (As), cadmium (Cd), mercury (Hg), nickel (Ni), and zinc (Zn) were analyzed before treatment and after 2, 4, and 6 weeks using standard analytical methods. The initial concentrations before treatment were low, with zinc having the highest value (0.877 µg/g), while lead, arsenic, cadmium, mercury, and nickel were present in trace amounts. Across all treatments, heavy metal concentrations increased progressively with irrigation duration, indicating continuous uptake and accumulation in the leaves. Sewage effluent irrigation showed the highest accumulation of arsenic, cadmium, mercury, and nickel, while tap water recorded the highest zinc concentration at week 6 (0.95 µg/g). Lead, cadmium, nickel, and zinc remained below WHO/FAO permissible limits, but mercury exceeded the safe limit of 0.03 µg/g at week 6 in all treatments, with the highest value recorded in sewage effluent (0.053 µg/g). Statistical analysis showed significant differences (P ≤ 0.05) across treatments and weeks. The study concludes that prolonged irrigation, especially with sewage effluent, increases heavy metal accumulation in B. alba, and mercury poses the greatest health risk. Regular monitoring of irrigation water and vegetables is recommended to ensure food safety.