Cadmium Prevalence in Cacao (Theobroma cacao L.) and Potential Remediation Strategies

Cadmium (Cd) is a carcinogenic element that has no significant role in plant growth and development. Cadmium accumulated in plants enters the food chain and can cause human health risk problems. Recently, Cd accumulation in cacao beans has developed an interest in researchers and scientists to work on how to alleviate its toxicity and uptake in cacao. This review discusses the current research on Cd agglomeration in cacao plant and highlights insight processes that help to decrease Cd uptake in cacao and also propose potential strategies to restrict Cd uptake and accumulation in cacao. This is very important to use the remediation approaches to reduce Cd concentration in cacao beans, the raw material of chocolate. In this regard, biochar and organic amendments may be used to remediate Cd from soil, because these materials can immobilize Cd in soil via precipitation, surface complexation, and adsorption mechanisms. Inorganic amendments such as liming and micronutrient application may increase soil pH, be adsorbed by negative charges, and thus help to alleviate Cd toxicities. Roots can also fix a great amount of Cd in their cells because the absorbed Cd content might not be transferred to the aboveground plant parts. Thus, careful attention is needed to the alarming situation of Cd agglomeration in the cacao agroecosystems. The selection of low Cd-accumulating genotypes may be used for developing future breeding programs and plantation of low Cd-accumulating varieties to decrease Cd contents in cacao beans.