A recent study by researchers at the Department of Wood Science and Technology, Kwame Nkrumah University of Science and Technology (KNUST), has found that older mangrove wood used for smoking fish contains high levels of cancer-causing agents.
The 2026 study revealed that older mangrove wood had alarming concentrations of polycyclic aromatic hydrocarbons (PAHs), a group of organic compounds known to alter genes, cause cancer, and harm human health.
Led by Dr. Kwadwo Boakye Boadu, the research assessed PAH toxicity in three age categories of mangrove wood collected from Salo Market in Keta, Volta Region: 8 years (early), 11 years (mid-rotation), and 14 years (late-rotation), within the typical harvesting cycle of 6 to 15 years.
The study, published by Elsevier B.V., detected 18 PAHs in the wood, with concentrations increasing with age. Four of these—Chrysene, Benzo[a]anthracene, Benzo[b]fluoranthene, and Benzo[a]pyrene—are classified by the European Commission as probable cancer-causing agents. While Benzo[a]pyrene levels remained within EU limits (1.0 microgram/kilogram), the combined concentration of the four PAHs exceeded the 12.0 microgram/kilogram limit in fish smoked with 14-year-old wood, reaching 12.5 microgram/kilogram.
Dr. Boakye explained, “If you wait until the wood is around 14 years old before harvesting, burning it to smoke fish produces high amounts of PAHs. This results in significant deposits in the fish, making it unhealthy.”
The study also found elevated levels of heavy metals, including cadmium and lead, exceeding EU thresholds.
While the use of mangrove wood for smoking fish remains popular among fishmongers due to its slow burning, strong flavor, and availability, the researchers recommend improved smoking practices and guidelines on selecting wood age, ideally favoring younger mangrove wood to reduce health risks.
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