Study confirms low risk of dietary exposure to potential toxic elements from Ghana grown rice
Although an important staple for more than half of the world’s population, rice cultivation on contaminated soils and/or irrigation with contaminated water can undermine the nutritional quality of the grains produced. Efforts aimed at increasing rice production for food security must, therefore, include regular monitoring of soil and water quality in the production ecosystems. Against the backdrop of a Government of Ghana initiative to expand local rice production to meet consumer demand, a study of the potential toxic element (PTE) status of rice fields in northern Ghana was conducted to build on and further validate findings of an earlier assessment of rice fields in southern Ghana.
Read this open access paper on the FACETS website.
For the current study, soil, water, and grain samples were collected from rice fields in the Upper East and Northern regions of the country. In each region, three study sites were selected in each of the three existing rice production ecosystems, i.e., rainfed upland, rainfed lowland and irrigated lowland. Only fields cultivated with the same rice variety were included in the study to eliminate error due to varietal differences in metal(loid) uptake. In addition to determining soil pH, electrical conductivity, and texture, all the soil, water and grain samples were analysed for their total arsenic, cadmium and lead concentrations. One-way analysis of variance (ANOVA) was used to compare data for the three production ecosystems in each region while the student’s t-test was used to compare means between the two regions.
The study findings revealed significant differences in soil texture as well as soil and water PTE concentrations which, in turn, influenced rice grain PTE concentrations. Arsenic, cadmium and lead concentrations found in all the soil samples were, however, within permissible limits reported in the literature for uncontaminated soils. The provisional guideline concentrations given by the World Health Organization (WHO) for arsenic, cadmium and lead in drinking water were also not exceeded by values recorded in the irrigation water samples. Furthermore, all rice grain arsenic, cadmium and lead concentrations recorded were below current maximum permissible limits. While these findings indicate a low risk of dietary exposure to PTEs from the grains sampled for this study, the influence of geogenic factors on soil, water and grain PTE concentrations highlights the need for continued monitoring of the country’s rice production ecosystems to safeguard the health of consumers.
Read the paper — Survey of rice (Oryza sativa L.) production ecosystems in northern Ghana confirms low risk of exposure to potential toxic elements from local grain consumption by Eureka E.A. Adomako, Kow Aboagye-Ghunney, and Prince Owusu.
