Effect of Boiling on Heavy Metal and Cyanide Concentrations and Associated Health Risks in Cassava and Cocoyam From a Gold Mining Area in Kade, Ghana.

Abstract

This study investigated heavy metal and cyanide contamination in cassava (Manihot esculenta) and cocoyam (Colocasia esculenta) cultivated near gold mining operations in Kade, Ghana. It evaluated the efficacy of traditional cooking methods in reducing contaminant levels. Samples were collected systematically from six locations situated within 2 km of an active mining site and were analyzed quantitatively for cadmium (Cd), mercury (Hg), arsenic (As), and cyanide concentrations. Analysis revealed that unprocessed cassava contained Hg (0.301-0.426 mg/kg), As (0.010-0.020 mg/kg), Cd (0.024-0.030 mg/kg), and cyanide (0.301-0.620 mg/kg), with unprocessed cocoyam exhibiting comparable concentration ranges. Although these concentrations remained generally below WHO standards, thermal processing substantially reduced contaminant levels, decreasing Hg by 65%-80%, As by 85%-95%, and Cd by 60%-75% in both crops. Health risk assessment calculations demonstrated that unprocessed samples presented potential risks, particularly for children, with hazard index values for As (23.36-25.10) and Hg (2.53-2.39). However, thermal processing effectively reduced these values below the threshold of concern. The findings demonstrate that while heavy metal and cyanide contamination persists in root crops near mining sites, traditional cooking methods reduce exposure risks. These findings have important ramifications for public health regulations in mining communities since they show that proper food preparation techniques can significantly reduce the health risks related to exposure to cyanide and heavy metals in the diet.