Analysis of Watermelon from Some Selected Farms In Greater Accra Region for Nutritional and Toxicological Elements

Abstract

Watermelon is largely made of water and sugar with some antioxidants such as lycopene, lutein, and cryptoxanthin. It also contains elements such as potassium, calcium, sodium, etc. for the well-being of the body. However contamination of watermelon can occur along the production line. Contaminants include pesticide residues and heavy metals such as Zinc, Manganese, and Nickel from the soil. This study investigated the levels of essential elements (e.g., Ca, Mg, Fe, Mn, Zn, Cu, Cr, Co, Ni) and toxic elements (Cd, Pb, As) from selected farms and compared levels of elements in watermelon and soil. Watermelon samples were taken from selected farms in the Ada East District in the Greater Accra Region. Each fruit together with its seeds were homogenised, frozen, freeze dried, digested and analysed using the AAS for the determination of toxic and essential elements (Fe, Mn, Cu, Mg, Ca, Co, Cr, Ni, Zn, Pb, As and Cd). Soil was sampled from the selected farms and analysed as well. It was observed that watermelon samples analysed contained the selected essential elements with the exception of chromium and cobalt, which were below their detection limits. Nickel was detected in watermelon from all farms with the exception of farm C. The levels of nutritional elements found in watermelon samples were within WHO acceptable limits for food. Watermelon samples from farm C recorded levels of Pb and As above FAO/ WHO acceptable limits in food. All elements (toxic and essential) that were found in the watermelon samples also were present in the soil with the exception of As which was found in the soil but not the fruit. A positive correlation was observed between the concentration of elements (toxic and essential) in the soil and the watermelon samples.