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

• Published in: Environmental monitoring and assessment Vol. 189; no. 10; p. 499
• Main Authors: Akele, M. L., Abebe, D. Z., Alemu, A. K., Assefa, A. G., Madhusudhan, A., de Oliveira, R. R.
• Format: Journal Article
• Language: English
• Published: Cham Springer International Publishing 01.10.2017; Springer Nature B.V
• Subjects: Absorption spectroscopy; Analysis; Animals; Atmospheric Protection/Air Quality Control/Air Pollution; Atomic absorption analysis; atomic absorption spectrometry; Atomic absorption spectroscopy; Cadmium; Carcinogens; Cattle; chemometrics; Chromium; Classification; Clustering; coal; Copper; Cow's milk; dairy farming; Dairy farms; diet; Discriminant analysis; Earth and Environmental Science; Ecology; Ecotoxicology; Environment; Environmental Management; Environmental monitoring; Environmental Pollutants - analysis; Environmental science; Ethiopia; Farms; Female; Food; Food Contamination - analysis; foods; freezers; Health risks; Heavy metals; Hydrogen peroxide; Leaching; Lead; Manganese; Metal concentrations; Metals; Metals, Heavy - analysis; Milk; Milk - chemistry; Milk - standards; Monitoring/Environmental Analysis; principal component analysis; Principal components analysis; provenance; risk; Risk Assessment; Spectral analysis; Spectrometry; Spectrophotometry, Atomic; toxicity; Trace Elements - analysis; Trace metals; Zinc; Gondar Ethiopia; Ethiopia; Kjeldahl digestion; Risk assessment; Chemometrics; Raw cow’s milk; Trace metals; Atomic absorption spectrometry
• ISSN: 0167-6369; 1573-2959; 1573-2959
• DOI: 10.1007/s10661-017-6203-0

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 3 /H 2 O 2 (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.