Analysis of trace metal concentrations in raw cow’s milk from three dairy farms in North Gondar, Ethiopia: chemometric approach

Abstract

Concentrations of essential (Cu, Mn, and Zn) and toxic (Cr, Cd, and Pb) trace metals in 30 raw cow's milk samples were quantified using flame atomic absorption spectrometry. The samples were collected from the Nara-Awudarda, Tana-Abo, and Kosoye Amba-Rass sites in North Gondar, Ethiopia, preserved in a deep freezer (-20 °C), and then digested by Kjeldahl apparatus with HNO/HO (5:2; v/v) at 300 °C for 2.5 h. The data were subject to principal component analysis (PCA) and partial least square-discriminant analysis (PLS-DA). Overall hazard quotient (HQ) and carcinogenic risk (CR) values were also estimated to assess metal-related health risks. The mean concentrations of Cr, Mn, Cu, Zn, Cd, and Pb in the milk samples ranged 0.468-0.828, 1.614-2.806, 0.840-1.532, 1.208-5.267, ND-0.330, and ND-0.186 mg/kg, respectively. The lowest values were obtained for Kosoye Amba-Rass milk samples, while the highest were found for those collected from Nara-Awudarda milk samples, probably due to high mineral enrichment and metal leaching (especially Cd and Pb) from coal deposits. PCA revealed clustering of samples with respect to their geographic origin. Validation of PLS-DA model showed 100% classification efficiency using external validation samples and detected Cd and Cu as trace metal markers. The HQ and CR values were within the safe level; however, the former is close to the alert threshold level for Nara-Awudarda milk samples. Thus, further studies on common foodstuffs, constituting a higher proportion in the local diet, are required in this area to provide a complete risk assessment.

Determination of the Level of Heavy Metals in Cow’s Milk Collected from Butajirra and Meskan Districts, South Central Ethiopia.

“…Results presented in Table 4 and 5 show that, the average Cr concentration, in cow's milk analyzed ranged from 0.00 -0.4 ppm which is lower than 0.845 -0.895 and 0.468-0.828 ppm reported by Belete et al (2014) and Akele et al (2017) in Ethiopia respectively and higher than 0.055 -0.075 and 0.0 -0.11 ppm reported by Alem et al (2015) in Ethiopia and Ahmad et al (2016) in Bangladesh respectively. Only sample CM13 one exceeded the permissible limit.…”

Determination of some Heavy Metals Concentration in some Dairy Products from Three Different Regions of Basrah, Iraq

“…1-3). Another study of trace metal concentrations in Ethiopia by Akele et al (2017) reported that the range of Cu (0.8-1.532 µg .g -1 ), Pb (0.120-0.186 µg .g -1 )and Cd (0.244-0.330). In the present study, the range of Fe levels in buffalo's milk was found to be less than cow's milk (see fig.…”

“…Indeed, some studies are in agreement with those reported in the literature from other countries. In their papers that the levels of Fe, Cu, Pb, Cd and Ni in cow and buffalo's milk and their products were unsafe for consumers (Licata et al, 2012;Malhat et al, 2012;Temiz & Soylu, 2012;Tona et al, 2013;El-Ansary & El-Leboudy, 2015;Ojezele et al, 2017), while others have reported no significant effect cause any adverse health concerns to consumers (Najarnezhad & Akbarabadi, 2013;Belete et al, 2014;Cadar et al, 2015;Najarnezhad et al, 2015;Perez-Carrera et al, 2016;Ahmad et al, 2017;Akele et al, 2017). More reviews providing in-depth discussions can be found in recent papers (Noori et al, 2016;Ziarati et al, 2018).…”

“…The cost of each case of foodborne illness ranged from $ 1,626 to $ 1,766 (Scharff, 2012;2015;Minor et al, 2015). There are several studies from different areas, were concerning the Fe, Cu and Pb contaminations in milk and milk products (Enb et al, 2009;Abdulkhaliq et al, 2012;Belete et al, 2014;Meshref et al, 2014;Cadar et al, 2015;Perez-Carrera et al, 2016;Akele et al, 2017;Paz et al, 2018;Iqbal et al, 2019).…”

Nutritional Quality, Level of Chemical Contaminants and Adulterants in Milk and Dairy Products in Ethiopia: A Review

“…The research done by Akele et al [59] reported heavy metal concentrations in milk samples in the following decreasing order: Zn > Mn> Cu > Cr > Cd > Pb in Chilga and Dembia and Mn> Zn > Cu > Cr in Wogera milk samples. The highest concentration in milk samples is probably due to high mineral enrichment and metal leaching (especially Cd and Pb) from coal deposits cross contamination in the chain.…”