Reducing cadmium bioaccumulation in Theobroma cacao using biochar: basis for scaling-up to field. Issue 6 (June 2022)

• Record Type: Journal Article
• Authors: López, Julián E.; Arroyave, Catalina; Aristizábal, Adriana; Almeida, Byrone; Builes, Santiago; Chavez, Eduardo
• Is Part Of: Heliyon. Volume 8:Issue 6(2022)
• Publication Date: 2022-06
• Subjects: Soil pH -- Cocoa beans -- Potentially toxic element -- Soil remediation -- Bioavailable Cd; Research -- Periodicals; Medical sciences -- Periodicals; Natural history -- Periodicals; Social sciences -- Periodicals; Earth sciences -- Periodicals; Physical sciences -- Periodicals; 507.2
• DOI: 10.1016/j.heliyon.2022.e09790
• Languages: English
• ISSNs: 2405-8440

Abstract

Abstract: The intake of Cd-enriched food is the main Cd pathway for the nonsmoking population. In some cases, Cd bioaccumulates in edible plant parts which comprise risk to consumers, because of Cd is a harmful heavy metal that can cause potent environmental and health hazards. For instance, Cd enrichment of cacao seeds have led to Cd enrichment of cacao-based products. In Latin America and the Caribbean, Cd bioaccumulation in cacao seeds occurs in different regions with diverse edaphoclimatic conditions, which makes it difficult to select soil remediation alternatives. Limited resources require that potential amendments must be carefully investigated through laboratory and/or greenhouse conditions before scaling up to field experiments. In this study, we evaluated the effectiveness of four biochars: coffee-, quinoa-, and inoculated- and palm-biochar, derived from three feedstocks: coffee husk, quinoa straw, and oil palm residues, respectively. Biochars were applied in two rates (1 and 2% w/w) in two soils, one moderately acidic and one slightly alkaline (Cd-spiked and non-spiked). CCN-51 cacao plants were used for the greenhouse experiment. After 130 days, biometric parameters, the bioavailability of Cd in the soil, and the concentration of Cd and mineral nutrients in the plants were measured. Quinoa biochar at the 2% significantly decreased ( P < 0.01), by ∼71%, bioavailable Cd in moderately acidic and slightly alkaline soils, and leaf-Cd by ∼48%. Soil pH, electrical conductivity, and effective cation exchange capacity were significantly ( P < 0.01) correlated with bioavailable soil and leaf-Cd. Biochar characteristics, such as ash contents, basic cations content, and surface functional groups could be used as indicators for the selection of biochars to reduce Cd uptake by cacao. Additionally, application of quinoa derived biochar provided P and K, which could increase productivity to offset mitigation costs. Overall, incorporation of quinoa biochar at 2% rate is effective for lowering bioavailable Cd in different soil types which reduces leaf-Cd in cacao plants. Highlights: Biochar ash content helps to increase soil pH and reduce Cd bioavailability. Quinoa biochar at 2% reduced up to 80% bioavailable Cd in moderately acidic and slightly alkaline soils. Quinoa biochar at 2% lowered, up to 48%, Cd concentration in cacao plants. Soil pH, CECe, and EC were significant and negative related to bioavailable and plant-Cd. Ash content could be used as a guide for selecting biochars for Cd remediation. Abstract : Soil pH, Cocoa beans, Potentially toxic element, Soil remediation, Bioavailable Cd.