Heavy metal contamination in riverine fish from the Lilongwe River, Malawi: Implications for human health risk
Concern about environmental pollution of rivers from heavy metal contamination has increased significantly in recent years due to rapid urbanization and industrialization, which pose risks to human health. Lilongwe River is vulnerable to such pollution but offers an important fish source to rural an...
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| Main Authors: | , , |
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| Format: | Article |
| Language: | English |
| Published: |
KeAi Communications Co., Ltd.
2025-12-01
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| Series: | Environmental Pollution and Management |
| Subjects: | |
| Online Access: | http://www.sciencedirect.com/science/article/pii/S2950305125000142 |
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| Summary: | Concern about environmental pollution of rivers from heavy metal contamination has increased significantly in recent years due to rapid urbanization and industrialization, which pose risks to human health. Lilongwe River is vulnerable to such pollution but offers an important fish source to rural and urban Malawians. Hence, a study was conducted to assess heavy metal contamination in six commonly consumed fish species: Oreochromis shiranus, Opsaridium microlepis, Astatotilapia calliptera, Labeo mesops, Labeo cylindricus, and Enteromius paludinosus. The levels of Zinc (Zn), Manganese (Mn), Chromium (Cr), Nickel (Ni), Mercury (Hg), Lead (Pb), Cobalt (Co), Cadmium (Cd), and Arsenic (As) were analyzed in fish muscles and gills. The concentration ranges for Zn (0.114–0.407 mg/kg), Mn (0.053–0.376 mg/kg), Cr (0.005–0.607 mg/kg), and Ni (0.045–0.117 mg/kg) were below the limits recommended by Food and Agriculture Organization (FAO) and U.S. Environmental Protection Agency (USEPA). Heavy metals were higher in urban (Likuni) compared to rural area (Malingunde), and were consistently higher in gills than in muscles across all species. Among species, heavy metal concentration followed the trend: O. shiranus (1.207 mg/kg) > L. mesops (1.009 mg/kg) > A. calliptera (0.843 mg/kg) > L. cylindricus (0.858 mg/kg) > O. microlepis (0.865 mg/kg) > E. paludinosus (0.588 mg/kg). Risk assessment showed no significant non-carcinogenic health risks to fish consumers. However, the concentration, bioavailability, and spatial distribution of heavy metals in rivers can vary with river hydrodynamics and seasonal variations. Hence, there is a need for systematic monitoring of heavy metals to guarantee safe consumption of fish from Lilongwe River. |
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| ISSN: | 2950-3051 |