Title : Reduction of lead and cadmium accumulation in coriander grown in contaminated soil using peanut shell waste
Abstract:
Background: The contamination of agricultural soils with lead (Pb) and cadmium (Cd) represents a significant environmental and food safety concern. These toxic metals can be transferred from soil to edible plants, enter the food chain, and adversely affect human health. This study aimed to evaluate the effectiveness of peanut shell waste as an inexpensive, readily available, and environmentally friendly biosorbent for reducing Pb and Cd accumulation in coriander (Coriandrum sativum L.) grown in contaminated soil.
Methods: Peanut shells were repeatedly washed with deionized water, dried, ground into fine particles, and passed through a sieve. The prepared peanut shell powder was added to soil contaminated with Pb and Cd, while contaminated soil without peanut shell amendment served as the control. Coriander seeds were planted in the prepared soils, and the aerial parts of the plants were collected over three successive harvests. Following standard preparation and digestion procedures, Pb and Cd concentrations in the soil and coriander samples were determined using atomic absorption spectrometry. All experiments were conducted in triplicate. The data were analyzed using analysis of variance followed by Duncan’s multiple range test.
Results: The addition of peanut shell powder did not significantly reduce the total concentrations of Pb and Cd in the soil. However, the accumulation of both metals in the aerial parts of coriander was significantly lower than that observed in the control group (P ≤ 0.05). The reduction in Pb and Cd accumulation increased over time, with the greatest effect observed at the final harvest. At this stage, Pb and Cd concentrations in coriander grown in peanut-shell-amended soil were more than 70% lower than those measured in the control plants. These findings suggest that peanut shell waste limited the bioavailability and transfer of Pb and Cd from contaminated soil to coriander.
Conclusion: Peanut shell waste significantly reduced Pb and Cd accumulation in coriander without causing a significant reduction in the total concentrations of these metals in the soil. Therefore, this agricultural by-product could serve as a natural, economical, and environmentally friendly soil amendment for restricting heavy-metal transfer to edible crops and improving food safety.
Keywords: Peanut shell waste; Lead; Cadmium; Coriander; Contaminated soil; Biosorption; Food safety
