Islam et al. 2024 — Systematic review of heavy metals in Bangladeshi fruits
This systematic review synthesized findings from 10 primary studies (2012–2022) measuring heavy metal concentrations in locally produced fruits in Bangladesh. The review compiled concentration ranges across 22 fruit varieties for As, Cd, Pb, Cr, Mn, Ni, Cu, Zn, and Hg, then estimated carcinogenic and non-carcinogenic health risks using estimated daily intake (EDI), target hazard quotient (THQ), and target cancer risk (TR). Several fruits — banana, mango, guava, litchi, blackberry, lemon, and tamarind — contained Pb and Cd above WHO/FAO maximum allowable concentrations, and As exceeded the safety threshold in mango and guava (up to 1.3 mg/kg FW). Cancer risk (TR) from As, Cd, Cr, and Ni exceeded acceptable levels for most fruit types, indicating potential long-term carcinogenic risk for regular consumers of Bangladeshi fruits.
Key numbers
| Metal | Matrix | Range (mg/kg FW) | WHO/FAO MAC (mg/kg) | Highest fruit |
|---|---|---|---|---|
| As | fresh fruit | ND–1.3 | 0.1 | Mango, guava |
| Cd | fresh fruit | ND–0.64 | 0.05 | Stone apple |
| Pb | fresh fruit | ND–2.4 | 0.1 | Mango (0.75 max) |
| Cr | fresh fruit | ND–2.5 | 1.0 | Lemon |
| Ni | fresh fruit | ND–9.0 | 0.8 | Guava |
| Hg | fresh fruit | ND–0.006 | — | Elephant apple |
| Mn | fresh fruit | ND–570 | — | Papaya (570 max) |
| Cu | fresh fruit | 0.5–32 | 4.5 | Guava |
| Zn | fresh fruit | 0.24–134 | — | Banana (134 max) |
All metals reported on fresh weight (FW) basis. Analytical methods across included studies: ICP-MS (n=4), ICP-OES (n=1), AAS (n=4), FAAS (n=1). Quality assurance reported in 8 of 10 studies (IQCs, CRMs, or accuracy/precision analysis).
Total target hazard quotient (TTHQ) exceeded 1 for 7 fruits (banana, mango, jackfruit, papaya, guava, pineapple, strawberry), with guava (9.43), mango (8.25), and papaya (8.04) highest. Combined hazard index (HI) across all fruits = 45.93. Total cancer risk for Cd ranked highest (0.037) followed by Ni (0.024) and As (0.013); only Pb was within the acceptable TR level.
Methods (brief)
Systematic review following PRISMA guidelines. Databases: PubMed, Google Scholar, and manual Google searching. Inclusion criteria: cross-sectional studies in Bangladesh, 2012–2022, reporting heavy metal concentrations in edible fruit portions in English. Of 1,458 retrieved articles, 10 were included after screening. Highest metal concentrations per fruit used for risk calculations, which the authors acknowledge may overestimate risk. The review used EDI, THQ (using EPA RfDs), and TR (using IRIS oral carcinogenic slope factors) for As, Cd, Pb, Cr, and Ni. All EDI values were below MTDI for all fruits.
Implications
Certification: Confirms elevated Pb and Cd in tropical fruits from Bangladesh relative to WHO/FAO MACs; relevant for any product formulations using Bangladeshi-sourced mango, guava, jackfruit, or banana. Cd in stone apple (0.64 mg/kg FW) is ~12x the WHO MAC.
Courses: Illustrates the soil-to-crop pathway for arsenic from groundwater irrigation in Bangladesh; also demonstrates the THQ/TR framework for health risk communication.
App: Supports elevated contamination flags for tropical fruits (mango, guava, banana) when declared country-of-origin is Bangladesh. As, Cd, Pb, Cr all exceeded MACs in multiple fruits.