The effect of home processing methods on the levels of pesticides and heavy metal contaminants in cassava, cocoyam and yam grown at two mining towns in Ghana, Akwatia and Obuasi

Abstract

Urbanization, industrialization, agriculture and mining processes have greatly accelerated toxins in foods rendering food safety to be a global concern. Pesticides and heavy metals are some contaminants that accumulate in foods to cause health hazards. The study evaluates the effect of processing on levels of pesticide (OC, OP and Synthetic pyrethroids) and heavy metal (Pb, Mn, Cd and As) contaminants in cassava, cocoyam and yam in two mining towns (Obuasi and Akwatia) in Ghana. Samples were collected, prepared and processed as fried, boiled and roasted products. Already processed commodities were also bought from the markets. Pesticide residues screened using GC showed no residues in all categories of samples. The heavy metals were analyzed using AAS. Fifty percent of commodities from the markets exceeded the WHO permissible limits compared to the proportion of processed samples from the farms which was 41.67%. With similar trends, unprocessed samples from Akwatia had higher heavy metal contaminant than those from Obuasi. The contamination levels showed a decreasing trend in the processed samples. The results showed that higher levels of Mn and As were recorded in the market and processed farm commodities compared to the WHO permissible limits for food. The levels in the unprocessed samples, reduced to acceptable limits after frying and drying. The levels of Cd in both processed and unprocessed samples were found to be within safe limits of the WHO standard. The hazard indices of the metals in the commodities except Pb in the unprocessed cassava (HI = 5) were of no risk (<1). It is pertinent to assume that consumption of the market and processed commodities will be of no risk of As, Cd and Mn toxicity to the populace within the area