Bioaccumulation of heavy metals in hot pepper grown in biochar and animal manure-amended soil

Heavy metals are non-biodegradable and persist in the environment longer, contaminating the food chain. Phytoremediation has emerged as a reliable, eco-friendly, cost-effective and sustainable approach that utilizes plants to remediate soil contaminants. The study assesses the ability of hot pepper (Capsicum annuum cv. Georgia Flame) grown under seven soil amendments- vermicompost, inorganic fertilizer, sewage sludge, organic fertilizer, chicken manure, horse manure, and biochar on heavy metals remediation. The research was conducted in an RCBD split-plot design, and heavy metal concentrations were analyzed using an inductively coupled plasma-optical emission spectrometer (ICP-OES). The results revealed that the average concentration of K (105.69 mgKg -1 ) and Mg (12.8 mgKg -1 ) were the highest in hot pepper fruits. However, Zn (0.16 mgKg -1 ) was found in the maximum amount among all heavy metals, whereas Cr (0.002 mgKg -1 ) was found in the minimum amount. Biochar with amendments enhanced the bioaccumulation of heavy metals, suggesting it as an essential amendment for heavy metal remediation. The average bioaccumulation factor (BAF) of Pb (0.72), Mn (0.07), and Cr (0.16) was less than 1, indicating no effect on soil metal remediation. Conversely, Cd (5.69), Mg (22.76), Zn (10.07), Ni (117.2) and Cu (46.37) exhibited a BAF value exceeding 1, suggesting that the peppers have the potential to remediate these particular soil metals. Though Cd, Ni, Mg, Cu and Zn showed a BAF value greater than 1, their accumulation in the fruits remained within the permissible limit. Hence, hot pepper is considered a potential crop for remediating heavy metals. • Hot pepper ( Capsicum annuum cv. Georgia Flame ) can be a potential crop in remediating heavy metals such as Cd, Ni, Cu and Zn contaminated sites. • Biochar, when combined with other amendments, enhanced metal uptake. • All the heavy metals in hot pepper fruits were below the safety limit, confirming their suitability for consumption. • Phytoremediation using hot pepper can be a cost-effective, sustainable and eco-friendly approach in heavy metal remediation from agricultural land.