Overview
Yimer and colleagues measured cadmium, chromium, and lead in drinking water, animal feed, and fresh whole milk from dairy cows at five sites in Kombolcha metropolitan town, Ethiopia, using flame AAS. Chromium was below the method detection limit in all milk samples. Cadmium and lead were detected in milk at all sites. Lead exceeded FAO/WHO reference values at some sites. The Borkena reservoir site had higher cadmium linked to industrial wastewater discharge; Ras Anges had higher lead. The study documents a water-to-feed-to-milk contamination pathway associated with nearby brewery and industrial operations.
Key numbers
Overall milk mean (mg/L):
- Cadmium: 0.0112 +/- 0.0029 mg/L
- Lead: 0.0205 +/- 0.0004 mg/L
- Chromium: below detection limit (MDL 0.005 mg/L)
Selected site-specific cadmium (mg/L): Abisha Ager 0.0360 +/- 0.0157 (highest); Borkena 0.0145 +/- 0.0024. Selected site-specific lead (mg/L): Ras Anges site higher than the others; Legehida lower.
FAO/WHO reference values used by authors: cadmium 0.02 mg/kg, lead 0.02 mg/kg for milk. Lead at Ras Anges and other sites exceeded 0.02 mg/L.
Methods (brief)
Flame AAS (NovAA 350, Analytik Jena). Method detection limits: cadmium 0.0017 mg/L, chromium 0.005 mg/L, lead 0.001 mg/L.
Evidence fitness
Small convenience sample from a single metropolitan town in Ethiopia with documented industrial wastewater contamination. The chromium non-detection is consistent with the method detection limit and the matrix. These values reflect a specific contaminated periurban setting and should not be used as regional or global baseline estimates. The water-feed-milk pathway data are useful for understanding contamination mechanisms in settings near industrial sources.
Related evidence
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