Summary
This narrative review (F1000Research, version 4, peer review approved with reservations by one reviewer) synthesizes the sources, health impacts, and mitigation strategies for heavy metal contamination (mercury, cadmium, lead, arsenic, chromium, nickel) with particular attention to Nigerian case studies. The review discusses natural geological sources and anthropogenic inputs (industrial emissions, mining, agricultural practices), reviews health consequences including cardiovascular disease, neurological disorders, and reproductive toxicity, and evaluates mitigation options including chelation therapy and phytoremediation. Nigerian case studies include lead poisoning in Zamfara State and contamination in the Great Kwa River of Cross Rivers State. The review highlights the disproportionate burden of heavy metal pollution in developing nations.
Key numbers
No primary measurements are reported; this is a narrative review of secondary literature. Key toxicological references cited include:
- Mercury in aquatic environments: mercury is primarily a problem in the aquatic environment (p. 5).
- Cadmium is described as toxic, nonessential, and carcinogenic (Group 1 IARC) (p. 6).
- Cadmium exposure linked to 31% increased risk of lung cancer (Farahmandian et al. 2024, cited in review, p. 1 of introduction).
Methods (brief)
Narrative review. F1000Research open peer review platform; version 4 is the latest published version (last updated 29 July 2025). One peer reviewer approved with reservations; two reviewers listed at version 4 have not yet posted approval. No systematic search protocol or PRISMA reported.
Evidence fitness
Context only. This review synthesizes well-established facts about heavy metal toxicology and sources and provides readable background on the Nigerian contamination context. It should not be cited for specific quantitative claims as it does not conduct primary meta-analysis or systematic evidence synthesis. Peer review status at version 4 (one approved with reservations) means this article has not completed full peer review validation at the time of this deposit. It is included for the Nigerian policy and case study context it provides.
Limitations
Narrative review without systematic search or formal risk-of-bias assessment. F1000Research’s open peer review model means the review quality depends on reviewer expertise and independence. Version history (versions 1 to 4, January to July 2025) indicates ongoing revisions. No quantitative synthesis.
Related evidence
- Dietary heavy-metal exposure
- Lead
- Cadmium
- metals/total-mercury
Update history
No substantive edit history is available in this build. The full commit record is available in git.