Periodic study with selected mineral elements levels of cow and goat milk samples obtained from two animal markets in Benin City and estimated daily intake of studied heavy metals

Abstract

This work entailed periodic investigations of raw goat and cow milk samples collected from Eyan and Technical College Road Animal Markets in Benin City, Nigeria; for levels of Ca, Fe, Zn, Cu, Co, Cr, Cd and Pb. The collection of samples was carried out on a weekly basis for a period of four weeks. Another portion of the work was concerned with the estimation of daily intake (EDI) of the examined heavy metals through milk consumption. Determinations of the examined mineral elements were carried out in accordance with standard methods. Significantly, atomic absorption spectrophotometry using buck scientific model 210VGP atomic absorption spectrophotometer was used for Ca, Fe, Zn, Cu, Co, Cr, Cd, and Pb Levels determinations. Estimation of daily intake (EDI) of the examined heavy metals through milk consumption was by calculation. Data generated were statistically evaluated using International Business Machine (IBM) Statistical Package for Social Sciences (SPSS). Results indicate variations in the levels of the examined mineral elements with respect to both sampling period and location. The observed variations were statistically significant (P˂0.05). Also discernable from results, was that in the studied goat milk samples, Ca with a mean total value of 127.802mg/kg occurred highest, while Pb with a mean total value of 0.005mg/kg was the lowest occurring of the examined mineral elements. Similar trend of result was obtained for the studied cow milk samples. Results from the portion of work on the estimation of daily intake of the examined heavy metals through milk consumption, indicate that with respect to goat milk, EDI Value of 17.694μg/kg/daily consumption, obtained for Zn in males within the studied age bracket (1-5years) was the highest; while the EDI of 0.009μg/kg/daily consumption, recorded for Pb in both male and female within the studied age group bracket (17 years and above) was the lowest. Similar pattern of EDI results was obtained for the EDI values of the examined heavy metals through cow milk consumption. The occurrence of toxicologically relevant lead and cadmium in all the studied milk samples, is an indication of the need for measure that would minimize the exposure of the animals to contaminated foliage and water, to be put in place.