Toxic and Essential Metals in Staple Foods Commonly Consumed by Students in Ekiti State, South West, Nigeria

Abstract

Humans are exposed to Toxic Metals(TMs) and Essential Metals (EMs) through different sources but the most important are staple foods. Exposure to TMs and EMs may bring about harmful and beneficial effects respectively. Previous studies on the assessment of TMs and EMs levels in staple foods commonly consumed in Nigeria were focused on general populace while less attention had been paid to staple foods consumed by students within University campuses. Hence, this study was designed to determine the concentrations of selected TMs and EMs in staple foods commonly consumed by University students given the peculiar nature of their feeding habit. A structured questionnaire to obtain information on the kinds of staple foods consumed was administered to 200 consenting students of Ekiti State University, Ado Ekiti. Some samples of staple foods were identified. The identified staple foods were purchased from food vendors and local market in the research location and sorted into categories. Staple foods were oven dried at 105° C for 24 hrs and pulverized. One gramme each of staple food was digested using dry ashing. The digests were analysed for Zinc, Copper, Lead and Cadmium using atomic absorption spectrophotornetes, Data were subjected to descriptive statistics and compared with permissible limits as set by FAOIWHO guidelines for food standard Questionnaire indicated the followings: Spaghetti, jollof rice, rice with stew, wheat with soup, white and red beans, akara (beans cake), moin-moin, melon, groundnut, yam, amala,( cassava and yam flour), garri (fried cassava), eba, potato as staple foods usually consumed by the University students. The staple foods were categorized into cereals, legumes and tubers respectively. In the staple foods, the mean (mg/kg) of zinc, copper, Cadmium and Lead ranged respectively as follows: 11.1±5.34-16.6±11.9, 3.70±3.30-5.60±5.10, 0.02±0.02-0.28±0.23 and 0.10±0.10-0.22±0.17.respectively.Hightest concentrations (mg/kg) of zinc (16.6±11-9) and cadmium (0.28±0.23) were found in cereals while the highest concentration of copper (5.60±5.10) and lead (0.22±0.17) were found in legumes and tubers respectively. The concentrations of zinc, copper, and lead were within the permissible limits set by FAO/WHO guildelines for food standard while cadmium concentration in cereals such as rice and wheat were above the permissible limits Staple Foods consumed by the University students were relatively safe in terms of toxic and essential metals contamination except cereals whose cadmium level exceeded the permissible limit.