Magdas et al. 2012 — Isotopic and elemental profile of Romanian organic apple juices
This study characterized H, C, O stable isotope ratios and nine trace element concentrations (Cu, Cr, Ni, Zn, Pb, Co, As, Cd, U) in 31 organic single-strength apple juices from four Transylvanian regions of Romania (2010 harvest). The primary purpose was authenticity and adulteration testing; the elemental data are incidentally the key contamination finding. All reported concentrations of Pb, Cd, As, and U were below US-EPA drinking water limits. Nickel exceeded the drinking-water upper limit (40 µg/L) in samples from Maramures, Alba, and Cluj regions, and the regional mean exceeded the limit only for Maramures. Copper exceeded the limit (1000 µg/L) for one juice from Alba.
Key numbers
Concentrations in µg/L (ICP-MS, Perkin Elmer ELAN DRC-e):
| Element | Alba mean | Maramures mean | Cluj mean | Salaj mean |
|---|---|---|---|---|
| As | 0.63 | 0.45 | 0.27 | 0.39 |
| Cd | 0.43 | 0.40 | 0.31 | 0.28 |
| Pb | 3.42 | 3.10 | 1.56 | 2.73 |
| Ni | 22.30 | 45.74 | 34.74 | 17.64 |
| Cr | 39.05 | 54.96 | 94.30 | 35.86 |
| U | 0.14 | 0.04 | 0.02 | 0.04 |
| Cu | 509.45 | 301.80 | 269.10 | 180.86 |
| Zn | 281.00 | 178.72 | 65.65 | 99.46 |
| Co | 1.22 | 0.66 | 0.64 | 0.49 |
Range across all samples: Pb 0.02–11.02 µg/L; Cd 0.14–1.06 µg/L; As 0.18–1.14 µg/L; U 0.02–0.52 µg/L; Ni 10–103 µg/L; Cr 10.6–252 µg/L; Cu 35.6–1224 µg/L.
Unit note: all values are µg/L (in juice as-consumed). To convert to ppb (µg/kg), multiply by ~1.04 (juice density ≈ 1.04 kg/L) — negligible correction for comparison purposes.
US-EPA drinking water limits for comparison: Pb 15 µg/L, Cd 5 µg/L, U 30 µg/L, As 10 µg/L, Ni 40 µg/L, Cr 100 µg/L, Cu 1000 µg/L. Pb, Cd, As, and U all below limits in all samples. Ni exceeded in some Alba, Maramures, and Cluj samples. Cu exceeded for one Alba sample.
Methods (brief)
ICP-MS (Perkin Elmer ELAN DRC-e) with Meinhard nebulizer; samples diluted 1:20 v/v with ultrapure HNO3 digestion. Isotope ratios by IRMS (Delta V Advantage, Thermo Scientific) for 18O, 2H, and 13C. No arsenic speciation (total As only). No Hg reported. No Sn, Al reported. Method was designed for authenticity fingerprinting; contamination data are secondary findings. Calibration R > 0.998 for all elements.
Implications
Certification: Romanian organic apple juice shows Pb well below action levels in all 31 samples (max 11 µg/L vs FDA action level of 10 ppb = 10 µg/kg). Nickel is the only element of potential concern, with some samples exceeding drinking-water reference values in Maramures and other regions.
Courses: Useful case study on isotopic fingerprinting for geographic origin of fruit juices; elemental profiles complement isotope data for fraud detection.
App: Apple juice from European organic sources shows Pb and Cd at low concentrations. Ni shows regional variability and may be relevant for sensitive populations.