Elbagory et al. 2025 — Potentially toxic elements in melon fruits, Ganges-Yamuna River Basin
This study assessed eight potentially toxic elements (PTEs: Cd, Cr, Cu, Pb, As, Fe, Mn, Zn) in four melon varieties (watermelon: Arka Shyama and Crimson Sweet; muskmelon: Cantaloupe and Kajri) grown at 10 riverbank sites in the Ganga-Yamuna Basin of Northern India. Concentrations were measured in dry-weight edible pulp by ICP-OES. Cd, Pb, and As levels in some watermelon samples exceeded WHO/FAO permissible limits (Cd >0.05 mg/kg in certain samples; Pb approaching 0.11 mg/kg). Muskmelons showed slightly higher Cu and As concentrations. Health risk indices (HRI, DIM, THQ) all remained below 1, indicating no acute non-carcinogenic risk at current contamination levels and consumption rates, though Cd, Cr, Pb, and Fe HRI values approached 0.5 in watermelon varieties.
Key numbers
All concentrations in mg/kg dry weight (DW).
Watermelon (Arka Shyama):
| Metal | Range (mg/kg DW) | Mean ± SD |
|---|---|---|
| Cd | 0.05–0.20 | 0.13 ± 0.05 |
| Cr | 0.60–0.95 | 0.79 ± 0.14 |
| Cu | 1.50–4.90 | 3.40 ± 1.24 |
| Pb | 0.03–0.07 | 0.05 ± 0.02 |
| As | 0.01–0.03 | 0.02 ± 0.01 |
| Fe | 93.5–110.5 | 100.4 ± 5.25 |
| Mn | 11.5–15.4 | 13.6 ± 1.31 |
| Zn | 8.0–18.0 | 14.1 ± 3.70 |
Watermelon (Crimson Sweet):
| Metal | Range (mg/kg DW) | Mean ± SD |
|---|---|---|
| Cd | 0.05–0.25 | 0.13 ± 0.07 |
| Pb | 0.01–0.11 | 0.05 ± 0.04 |
| As | 0.01–0.08 | 0.04 ± 0.02 |
Muskmelon (Cantaloupe), selected metals:
| Metal | Range (mg/kg DW) | Mean ± SD |
|---|---|---|
| Cd | 0.05–0.20 | 0.13 ± 0.05 |
| As | 0.02–0.08 | 0.05 ± 0.02 |
| Cu | 2.40–4.80 | 3.62 ± 0.80 |
Muskmelon (Kajri), selected metals:
| Metal | Range (mg/kg DW) | Mean ± SD |
|---|---|---|
| Cd | 0.05–0.23 | 0.13 ± 0.05 |
| As | 0.02–0.07 | 0.05 ± 0.02 |
| Cu | 3.30–4.10 | 3.74 ± 0.26 |
WHO/FAO Cd MPL for fruit: 0.05 mg/kg. WHO Pb MPL: 0.1 mg/kg. As MPL: not established for fresh fruit in Codex (general vegetables: 0.1 mg/kg). Several Cd values in both watermelon and muskmelon exceed the 0.05 mg/kg WHO MPL.
Health risk indices (HRI) remained below 1 for all PTEs and varieties. THQ values were all < 0.0007. DIM was highest for Fe (0.40–0.44 mg/kg/day) followed by Zn (0.04–0.06 mg/kg/day). PCA and HCA analyses identified localized hotspot sites (particularly L3, L4, L6 in Saharanpur district).
Methods (brief)
ICP-OES (Perkin Elmer 7300 DV). Edible pulp separated, oven-dried at 60°C to constant weight, ground to powder. Digestion: 2 g dry powder + 20 mL HNO3/HClO4 (3:1), self-digested overnight (12 h), then hot plate at 150°C for 1 h, closed system. Diluted to 50 mL with 3% HNO3, filtered through Whatman No. 41. Certified reference materials (BCR679) and standard reference materials (1000 mg/L stock, Merck) used for validation. n=50 per variety (composite of 5 fruits × 10 sites), each sample analyzed 3 times. Reporting basis: dry weight (DW).
Note: As reported as total arsenic (tAs), not speciated. Speciation into iAs vs. organic As not performed.
Implications
Certification: Cd exceeds WHO/FAO MPL in multiple samples from both watermelon and muskmelon grown near Indian riverbanks; relevant for products containing melon from Ganga-Yamuna region. Cd mean of 0.13 mg/kg DW (wet weight equivalent ~0.013–0.02 mg/kg assuming ~85–90% moisture) is at or above the WHO threshold.
Courses: Strong case study for riverbank cultivation risk — sewage discharge, irrigation with contaminated water, and localized soil contamination drive PTE accumulation in summer fruits. PCA/HCA methodology well illustrated.
App: Supports elevated Cd and As flags for watermelon and muskmelon when declared origin is Ganga-Yamuna basin agricultural region of Northern India.