Geochemical analysis of cadmium (Cd) concentrations in cacao crops and associated surface samples in the region of Guaviare

Cadmium (Cd) is a naturally occurring heavy metal that poses significant environmental and health risks due to its mobility and toxicity. This study focuses on assessing Cd concentrations in soils and cacao seeds from three different cacao farms located in Calamar, Retorno, and San José in the department of Guaviare, Colombia, an area lacking prior extensive research. The primary objective of this study is to determine both total and bioavailable Cd levels to understand the potential environmental and health risks associated with cacao cultivation in this region. The findings indicate that the organic matter content in the soils of San José and Calamar exceeds the recommended lower limit, contributing to improved soil quality. However, excessive organic matter could lead to soil acidification and increased metal mobility. The pH analysis revealed acidic conditions in the Retorno sample, suggesting a potential for future heavy metal leaching. Cd concentrations in the soil samples from Guaviare were found to be below the detection limit of 30 ppb, significantly lower than those reported in other Colombian regions. The bioavailability of Cd, measured using the Tessier extraction method, showed low levels in Calamar (1.09 ppb), Retorno (2.58 ppb), and San José (1.22 ppb), correlating with the low total Cd concentrations. This study also identified factors such as soil pH and organic matter content as critical determinants of Cd bioavailability. ICP-MS analysis of cacao seeds revealed very low Cd concentrations: Calamar (49.29 ppb), Retorno (95.43 ppb), and San José (51.23 ppb), well below international safety standards set by EFSA, WHO, and the EU. This alleviates concerns regarding the commercial viability of cacao products from Guaviare, as the Cd levels do not pose a significant health risk. The present thesis shows the complexity of Cd distribution and recommends that future research should focus on long-term monitoring of Cd bioavailability and soil-plant interactions to inform sustainable agricultural practices and mitigate potential health risks.

• Autores: Giraldo Stapper, David Roberto
• Tipo de recurso: Trabajo de grado de pregrado
• Fecha de publicación: 2024
• Institución: Universidad de los Andes
• Repositorio: Séneca: repositorio Uniandes
• Idioma: eng
• OAI Identifier: oai:repositorio.uniandes.edu.co:1992/74446
• Acceso en línea: https://hdl.handle.net/1992/74446
• Palabra clave: Guaviare; Cacao; Cadmium; ICP-MS; Atomic absorption; XRF; Geochemistry; Geociencias
• Rights: openAccess
• License: Attribution-NonCommercial-NoDerivatives 4.0 International