Levels of Aflatoxin M1 and selected heavy metals (Pb, Cd, Cr, Cu, Zn, Fe, As, and Hg) in the breast milk of lactating mothers in South Eastern, Nigeria

Abstract

In this study, the level and frequency of breast milk AfM1 and selected heavy metals as biomarkers of maternal exposure was assessed. Selected heavy metals (Pb, Cd, Cr, Cu, Zn, Fe, As, and Hg) were analyzed using Atomic Absorption Spectrophotometry while AfM1 levels were assessed by HPLC with fluorescence detection after aflatoxin extraction. The mean (±standard deviation) concentration of AfM1 in the breast milk samples was 4.02 ± 1.12 ng/L and 100% of all the samples contained AfM1 at 2.33–7.08 ng/L. AfM1 concentration was positively and significantly (p < 0.01) associated with the daily consumption of cassava-based foods, groundnut oil, maize, tomatoes and dry fruit (p < 0.05). The mean (±standard deviation) values of these heavy metals were Cd: 0.029 ± 0.013 mg/L, Cr: 0.019 ± 0.011 mg/L, Cu: 0.035 ± 0.013 mg/L, Fe: 0.049 ± 0.039 mg/L, Pb: 0.038 ± 0.013 mg/L and Zn: 0.009 ± 0.008 mg/L. The result of the estimated daily intake of breast milk by the breastfed infant show that heavy metals such as Pb, Fe, and Cd are ingested more daily than other metals analyzed. There was a weak positive but non-significant correlation between heavy metal content and daily intake of maternal diet except for beans where a significant correlation (p < 0.01) was found with Cr, Cu, and Zn exposure. A weak positive but non-significant correlation was also observed between exposure to heavy metals such as Cu, Fe and Pb and maternal diets. None of the samples exceeded the national and international legal regulatory limits for AfM1 and the selected heavy metals in breast milk except chromium. Nevertheless, the presence of these contaminants still presents a health risk.