Heavy metals in lettuce and cabbage from one Iranian city
What it found
Lettuce and cabbage from Behbahan, Iran, contained lead, chromium, cadmium and nickel at levels linked to an unacceptable cancer risk in calculations.
The estimated risk for other health problems was low.
What they found
Metal levels found
Average total metal levels were 0.820 mg/kg wet weight in lettuce and 1.720 mg/kg wet weight in cabbage. Chromium was highest, followed by nickel, lead and cadmium. Lead levels averaged 3.28 times higher than cadmium.
Lead and chromium above guidelines
In cabbage, average lead and chromium levels were higher than health guidelines of 0.3 and 0.5 mg/kg. All four metals in lettuce fell below those same guideline limits.
Non-cancer risk estimates
The calculated hazard index was 4.58E-01 for lettuce and 1.52E-01 for cabbage. Because both numbers are under 1, the authors say there is no significant non-cancer risk for shoppers.
Cancer risk estimates
The modelled lifetime cancer risk was 4.14E-03 for lettuce and 1.40E-03 for cabbage. Both numbers sit above the 10^-4 limit the authors use to flag an unacceptable cancer risk. Lettuce carried a higher risk partly because people eat more of it.
Heart risk from lead
The authors calculated a margin of exposure for lead linked to heart problems in adults. The values were 6.22 for cabbage and 2.79 for lettuce, which they interpret as a concern.
What the authors conclude
- They say that industrial growth and city expansion have raised heavy metal pollution in food, creating a health risk for shoppers in developing countries like Iran.
- They recommend that local officials control sources of pollution such as sewage and solid waste to keep metals out of farm soil and water.
- They suggest future work should look at processed foods made with these vegetables.
How it was done
People are eating more vegetables, but farming near growing cities and industries can leave heavy metals in the soil. The authors wanted to measure these metals in popular vegetables and estimate the health risk for shoppers in a developing region of southern Iran.
They bought 20 samples each of lettuce and cabbage from 10 shops in Behbahan, Iran, over two visits four weeks apart. They measured lead, chromium, cadmium and nickel in the washed and dried vegetables. They then used computer models to estimate the health risk for people eating them.
What it can’t tell you
- These results come from one city in Iran and cannot show what metal levels are in lettuce or cabbage sold elsewhere.
- The cancer and heart risks are based on computer models using averages, not on tracking real shoppers over time to see who became ill.
Who paid
- Funding
- Funded by Behbahan Faculty of Medical Sciences (from the PubMed record).
- Conflicts
- Declarations. Competing interests: The authors declare no competing interests.
- Authors work at
- Behbahan Faculty of Medical Sciences, Iran; Hamadan University of Medical Sciences, Iran; Torbat Jam Faculty of Medical Sciences, Iran
The paper
- Title
- Probabilistic carcinogenic and health risk assessment of heavy metals in lettuce and cabbage from Behbahan, Iran, using Monte Carlo simulation
- Type
- Study
- Summarised from
- Full text
- Cite
- Armand R, Rafati L, Mohammadi H, Armand N (2026). Probabilistic carcinogenic and health risk assessment of heavy metals in lettuce and cabbage from Behbahan, Iran, using Monte Carlo simulation. Scientific reports. doi:10.1038/s41598-026-40958-wFree full textPubMed 41741540DOI
Summary written 30 Sep 2026. Check it against the paper before it changes what you eat. How we summarise papers · Report an error