This study characterized Cd, Pb, Cr, Cu, Fe, Mn, Se, Zn, Co, Ni, and Mo in milk and cheese from the Kvemo Kartli region of Georgia, an area with documented heavy metal contamination from the Madneuli copper/gold mine and RMG mining operations near the Mashavera River. Of 195 milk samples from 9 villages, 7 showed Pb above permissible limits (ranging 0.027 to 1003 mg/L — note the 1003 mg/L value appears typographically anomalous; the likely intended range is 0.027 to 1.003 mg/L); Cd was below detection (<0.001 mg/L) in all milk samples. For Sulguni and Imeruli cheese, Pb exceeded EU/Codex limits (Sulguni: mean 0.25 mg/kg; Imeruli: mean 0.12 mg/kg vs. EU limit 0.020 mg/kg), while Cd in both cheeses remained below the permissible limit. The study provides the first comprehensive ICP-MS characterization of these traditional Georgian cheeses in the context of mining-area contamination.
Key numbers
All values for milk in mg/L; cheese in mg/kg wet weight. Method: ICP-MS (Agilent 7800). n=195 milk samples; n=25 cheese samples.
Raw milk (9 villages):
- Pb: 0.004–0.048 mg/L (most samples below EU limit of 0.020 mg/L, but 7 samples exceeded; highest from Kvemo Bolnisi, Bolnisi, Mitskineti, Ratewani villages)
- Cd: <0.001 mg/L (below LOD 0.00001 mg/L across all villages)
- Cu: 0.42–1.28 mg/L in Sabereti and Vanati villages (above EU limit of ~0.05 mg/L)
- Cr, Ni, Mn, Se, Mo, Zn, Fe, Co: generally below permissible limits
Imeruli cheese (n=16):
- Pb: mean 0.12 mg/kg ww (exceeds EU 0.020 mg/kg)
- Cd: 0.002 mg/kg ww (below Georgian MPC)
Sulguni cheese (n=9):
- Pb: mean 0.25 mg/kg ww (exceeds EU 0.020 mg/kg)
- Cd: 0.007 mg/kg ww (below Georgian MPC)
- Mn, Cr, Se, Mo, Zn, Fe above Georgian/EU limits in both cheese types
The authors note that Pb concentration is typically higher in cheese than raw milk because most Pb is bound to casein; fermentation/curd formation concentrates casein and thus Pb.
Methods (brief)
ICP-MS (Agilent 7800). Sample prep: dry ashing in open porcelain crucibles with nitric acid (65%), muffle furnace 450°C, dissolution in concentrated HNO3, dilution. LOD for milk: Pb = 0.00006 mg/L; Cd = 0.00001 mg/L. LOD for cheese: Pb = 0.00018 mg/kg; Cd = 0.00024 mg/kg. Calibration: 10-point curves (R ≥ 0.9999). Quality: ISO 17034 traceable CRMs; GOST 26929-94 national standard method. Lab participates in annual inter-laboratory proficiency testing; not independently accredited but state research institute.
Implications
Certification: Kvemo Kartli is a documented mining-contaminated zone where Pb in both milk and cheese exceeds EU regulatory limits. Sourcing dairy from mining-adjacent regions in the Caucasus requires heightened testing. The casein-binding mechanism means that cheese concentrates Pb from milk, so cheese Pb will typically exceed milk Pb even when milk itself meets limits.
Courses: Demonstrates how mining industry proximity drives milk and cheese contamination through soil → pasture → animal → milk → cheese pathways. The Madneuli and RMG mines provide a well-documented point source.
App: Contributes geographic breakdown data for milk and cheese under a high-contamination mining-region scenario.