Paudel et al. 2024 — Heavy metals in packaged fruit juices, Kathmandu
This study measured Fe, Cu, Zn, and Pb in 16 packaged fruit juice samples (orange, apple, mango, and lychee from 4 brands) purchased from Kathmandu retail markets. Lead was below the detection limit in all 16 samples, while Fe, Cu, and Zn were detected and generally within WHO/FAO reference levels for drinking water. One apple juice sample (Brand C) had Fe at 3.649 mg/L, exceeding the WHO provisional reference of 2 mg/L but within estimated daily iron intake ranges for adults. The results are relevant to confirming low Pb contamination in commercially packaged fruit juices from Nepal.
Key numbers
| Metal | Matrix | Range (mg/L) | WHO/FAO reference (mg/L) | Notes |
|---|---|---|---|---|
| Fe | Orange juice | 0.572–0.762 | 2.0 (JECFA PMTDI) | All within reference |
| Fe | Mango juice | 0.362–0.624 | 2.0 | All within reference |
| Fe | Apple juice | 0.277–3.649 | 2.0 | Brand C exceeds at 3.649 |
| Fe | Lychee juice | 0.279–1.770 | 2.0 | All within reference |
| Cu | Orange juice | ND–0.574 | 2.0 | Max in Brand C |
| Cu | Mango juice | ND | 2.0 | Not detected in any brand |
| Cu | Apple juice | ND–0.023 | 2.0 | Trace only |
| Cu | Lychee juice | ND–0.041 | 2.0 | Trace only |
| Zn | Orange juice | 0.0511–0.2026 | 3.0 | All within reference |
| Zn | Mango juice | ND–0.0700 | 3.0 | Within reference |
| Zn | Apple/Lychee | ND–0.0287 | 3.0 | Trace or ND |
| Pb | All 4 juices | ND (all 16 samples) | 0.01 | Below detection limit |
Note: units are mg/L (liquid juice as measured). WHO reference for Pb in drinking water = 0.01 mg/L. Codex ML for Pb in fruit juice = 0.03 mg/kg (general), 0.04 mg/kg (grape), 0.05 mg/kg (berry/small fruit). Comparisons here use drinking water standards per the authors’ stated rationale.
n=16 samples (4 brands × 4 juice types), each prepared in triplicate. FAAS (Model AA240FS, air-acetylene flame). Wet acid digestion with aqua regia + HNO3. Whatman No. 42 filter paper. R² values for calibration: Fe 0.995, Cu 0.999, Zn 0.999, Pb 0.978. Limitation: small sample (n=16), only 4 metals measured; no speciation for As.
Methods (brief)
FAAS (Varian AA240FS) with air-acetylene flame. Wet acid digestion: 50 mL juice + aqua regia (5 mL) + concentrated HNO3 (5 mL), heated to boiling, cooled, filtered through Whatman No. 42, diluted to 100 mL. Calibration curves from stock standards. Samples run in triplicate. No certified reference materials mentioned.
Implications
Certification: Pb not detected in any of 16 packaged juices from Nepal; reassuring data for packaged product claims. Fe in one apple juice sample exceeded 2 mg/L but this is not a priority toxic metal.
Courses: Illustrates that packaged juice Pb is often ND or well below action levels in well-regulated commercial production; useful contrast with unprocessed/artisanal sources.
App: Supports low-to-negligible Pb risk flag for commercially packaged fruit juices (apple, mango, orange, lychee) from mainstream brands.