Gholami et al. 2025 — Heavy metals in corn, Khuzestan Province, Iran
This study assessed Pb, As, and Cr contamination in corn (Zea mays) and associated soils from two agricultural cities in Khuzestan Province, Iran — Dezful and Behbahan — with particular attention to human health risk. Fifty corn and fifty soil samples were collected across 10 farms during summer and autumn 2022. Mean Pb concentration in corn exceeded the safety limit used by the authors (likely Codex/FAO standard), with the total hazard quotient (THQ) indicating non-carcinogenic risk. Carcinogenic risk indices for As and Cr were elevated.
Key numbers
Mean concentrations in corn (mg/kg, presumably wet weight):
- Pb: 1.84 mg/kg (1,840 ppb)
- As: 1.57 mg/kg (1,570 ppb)
- Cr: 4.92 mg/kg (4,920 ppb)
Mean concentrations in soil (mg/kg):
- Pb: 11.91 mg/kg
- As: 4.02 mg/kg
- Cr: 76.86 mg/kg
Transfer Factors (TF = corn/soil) — highest values:
- Pb TF max: 0.256
- As TF max: 0.762
- Cr TF max: 0.128
Carcinogenic risk index (CR), highest values reported:
- Pb: 0.05
- As: 8.40
- Cr: 9.27
THQ for Cr: does not cause problems for adults and children per authors’ assessment. THQ for Pb and As: exceeds acceptable limits at the observed concentrations.
Note: These are total arsenic (tAs) values; speciation to inorganic arsenic was not performed. The wiki treats total As (tAs) and inorganic As (iAs) as non-substitutable; tAs values are recorded here.
Methods (brief)
ICP analysis for Pb, As, and Cr. Samples from 5 farms per city (Dezful and Behbahan), 5 soil and 5 corn samples per farm, collected summer and autumn 2022. Health risk assessed using THQ (non-carcinogenic) and CR (carcinogenic) indices per US EPA methodology. The paper is published in Scientific Reports (OPEN access, CC BY).
Implications
Certification: Corn in this Iranian agricultural zone shows Pb at 1,840 ppb mean — far above Codex Alimentarius Pb limits for grain (typically 200 ppb for cereal grains as placed on market). Also well above EU limits. These are contaminated agricultural zone values, not representative of global commercial corn.
Courses: Good example of heavy metal uptake from contaminated soils into corn; Transfer Factor data useful for illustrating the soil-to-plant pathway. Khuzestan Province is industrialized (oil industry) and results reflect anthropogenic contamination.
App: Corn contamination profile note — these concentrations are atypical for global commercial corn. Representative commercial corn values for Pb, As, and Cr will be much lower. Flag as regional-contamination-zone data point.
Microbiome: Not addressed.