This study systematically reviewed research on heavy metal contamination in environmental and food systems in Uganda using the PRISMA 2020 data reporting method and the PICOS framework. An extensive literature search of published papers on heavy metal contamination in Uganda's environment and food systems was conducted in PubMed, Web of Science, and Scopus databases up to May 21, 2024. Boolean operators (AND/OR/NOT) were applied to develop search strategies tailored to each database. Following duplicate removal, title and abstract screening, and full-text assessment using the Rayyan platform, 39 articles were included in the final review. Data were extracted from each study using a standardized template that captured metal type, contamination source, concentration levels, affected food or environmental matrix, geographic location, and toxicological impact. Data were synthesized using a descriptive and narrative approach. Key sources of contamination include industrial and municipal waste, agricultural practices, and emissions from transport and manufacturing. Among the metals, lead was the most mentioned across studies. Regional analysis revealed that Central Uganda had the highest reports on heavy metals, while Northern Uganda remains critically understudied. Ecologically, heavy metals threaten soil fertility, aquatic biodiversity, and agricultural sustainability. Contamination of staple foods with lead, cadmium, and mercury poses significant public health risks, particularly for children and pregnant women. Strengthened environmental monitoring, targeted regional investigations, and improved food safety surveillance within a One Health framework are urgently recommended.
This systematic review examined heavy metal contamination in drinking water, soil, and edible vegetables in Nigeria, along with the associated human health risks. Heavy metal pollution from mining, oil exploration, and wastewater irrigation poses serious threats to food safety and public health; however, comprehensive synthesis of contamination levels and risk assessments across the country remains limited. This systematic review, guided by PRISMA 2020, assessed contamination patterns and health risks across Nigeria. Comprehensive searches were conducted in PubMed, Scopus, Web of Science, ScienceDirect, African Journals Online (AJOL), and Google Scholar for studies published between 1 January 2011 and 30 April 2026. From 1,248 records, 18 unique studies (derived from 21 references after duplicate removal) were included. These comprised cross-sectional surveys and contamination analyses reporting quantitative heavy metal concentrations in water, soil, and/or edible vegetables together with standard health risk indices (EDI, THQ, HI, TLCR, BAF, or TF).Findings revealed widespread exceedance of FAO/WHO permissible limits, particularly for cadmium and lead in leafy vegetables such as spinach, lettuce, cabbage, and amaranth. Hazard indices (HI) exceeded 1 in the majority of studies, while lifetime cancer risks (TLCR) for arsenic frequently surpassed the acceptable threshold of 10⁻⁴, especially in northern mining zones (Kano, Jos, Kaduna) and the Niger Delta. Nigerian studies showed higher exceedance rates (Pb: 83%, Cd: 78%) and elevated risk levels compared with some other West African contexts. Leafy vegetables consistently demonstrated the highest bioaccumulation. Interventions and monitoring efforts remain limited, and systemic challenges such as unregulated irrigation and weak enforcement of environmental standards continue to exacerbate exposure risks, particularly for children and frequent consumers of locally grown produce. Urgent, context-specific interventions are required, including stricter regulation of irrigation water and soil quality, targeted remediation in high-risk zones, safer agricultural practices, and enhanced public awareness. These measures are essential to reduce dietary heavy metal exposure, protect public health, and support sustainable food safety in Nigeria.
M. R. Madugu, H. Suleiman, A. Akyala et al.· International Journal of Med...· 0 citations
Mercury presents a significant environmental health hazard due to its ability to bioaccumulate in the food chain, posing risks through the consumption of contaminated fish. This systematic review aims to analyze and compare mercury levels in human populations, specifically focusing on the health risks associated with fish consumption in urban versus rural areas. The review followed PRISMA guidelines and included articles published between January 1, 2020 and March 15, 2025 from PubMed, Scopus, and ScienceDirect. A total of 768 articles were identified, and seven studies met the inclusion criteria. Data extraction was performed, and study quality was assessed using the JBI checklist and risk of bias assessment with ROBINS-E. Data were extracted and synthesized using RevMan 5.4 for the meta-analysis. The meta-analysis showed substantially higher mercury levels in rural populations (SMD 2.76; 95% CI: 2.63–2.89), largely influenced by dietary patterns, predominant fish species, and environmental contamination levels. Health effects associated with elevated mercury exposure included neurodevelopmental risks, elevated mercury levels in pregnant women, and increased vulnerability among populations with high reliance on freshwater fish. These findings highlight the need for targeted public health strategies to mitigate mercury exposure while maintaining the nutritional benefits of fish consumption.
A. A. S. Sadana, Tanthowi Jauhari, John Ringo et al.· Journal of Public Health and...· 0 citations
Environmental contamination of water systems and food products by radionuclides, heavy metals, and pathogenic microorganisms poses significant public health and environmental challenges in Nigeria. However, comprehensive evidence integrating these contaminants across water and food systems remains limited. This study systematically reviewed the occurrence, distribution, and health implications of radiological, chemical, and microbiological contaminants in Nigerian water systems and food products. A systematic review was conducted following PRISMA 2020 guidelines. Literature searches covering 2000–2025 identified 2,483 records from major databases. After duplicate removal and screening, 238 full-text articles were assessed, and 72 studies were included in the final synthesis, comprising radiological (n = 21), chemical (n = 27), food microbiology (n = 20), and water microbiology (n = 24) investigations. Annual effective doses from drinking water generally ranged from 0.02 to 0.09 mSv/year and remained below the WHO reference level of 0.1 mSv/year, although localized studies reported doses of 2.48–6.01 mSv/year and infant exposures of approximately 4.63 mSv/year. Radionuclide concentrations ranged from 0.41 to 8.78 Bq/L for ²³²Th and 4.29–376 Bq/L for ⁴⁰K. Heavy metal studies reported Pb concentrations of 0.021–0.145 mg/L and Cd concentrations of 0.002–0.008 mg/L, with hazard indices frequently exceeding unity and lifetime cancer risks ranging from 2.1 × 10⁻⁴ to 4.7 × 10⁻³. Microbiological contamination was widespread, with bacterial loads reaching 10⁶ CFU/mL in water and 1.06 × 10⁷ CFU/g in food products. Escherichia coli concentrations reached 98–106 CFU/100 mL, while total coliform prevalence and E. coli prevalence were 53.3% and 12.4%, respectively. Multidrug-resistant bacteria were reported in 94–99% of isolates from ready-to-eat foods. Radiological contamination in Nigeria is generally localized and mostly within international safety limits, whereas heavy metal and microbiological contamination represent persistent and widespread public health hazards. The findings highlight the need for integrated environmental surveillance, strengthened regulatory enforcement, routine monitoring of food and water systems, and implementation of One Health strategies to reduce environmental exposure and associated health risks. Not applicable.
B. Samaila, A. Shehu· Discover Hazards· 0 citations
Heavy metal contamination remains a major global environmental and public health issue because of the persistence, bioaccumulation, and toxicity of metals including lead, mercury, cadmium, arsenic, and chromium. This study combines bibliometric and qualitative reviews to evaluate research trends and health hazards associated with heavy metal pollution. Data retrieved from the Scopus database (2014–2025) produced 18,930 documents, refined to 7,768English-language research articles after excluding conference papers, reviews, and errata. VOSviewer, MapPlot, and OriginPro were used to analyze publication trends, research productivity, citation impact, and keyword networks.Contributions came from 174 countries, with 22 meeting the threshold of at least 50 publications and 5,000 citations. China and the United States recorded the highest outputs and citation impacts, while Nigeria contributed about 205 publications with over 5,000 citations, reflecting growing but limited African participation. Among 552 publication outlets, 12 major journals met productivity thresholds and accumulated more than 50,000 citations. Keyword analysis identified 41,618 terms, with 918 significant keywords grouped into seven thematic clusters that guided the qualitative review. The synthesis showed that heavy metals cause toxicity through oxidative stress, enzyme inhibition, mitochondrial dysfunction, genotoxicity, endocrine disruption, and imbalance of essential metal homeostasis,resulting in neurological, renal, hepatic, cardiovascular, reproductive, immune, and carcinogenic disorders. A Nigerian case study highlighted persistent exposure risks and regulatory challenges. Overall, the study provides an integrated evidence base to support environmental monitoring, risk assessment, policy formulation, and sustainable mitigation of heavy metal pollution.
A. F. Ajeboriogbon, B. O. Adewuyi, O. O. Daramola· Communication in Physical Sc...· 0 citations
It is confirmed that pharmaceutical pollutants represent a multidimensional One Health challenge and primary recommendations include strengthening pharmaceutical waste management systems and medication take-back programs and implementing advanced wastewater treatment technologies.
Benjamin Oritsemuelebi, E. O. Chidebe, G. Udom et al.· Discover Environment· 0 citations
Pharmaceutical quality and safety are critical to public health, yet low- and middle-income countries such as Nigeria remain vulnerable to medicine safety challenges due to weak regulatory enforcement and limited market surveillance. A major concern is contamination of pharmaceutical products with toxic heavy metals, including lead, cadmium, mercury, arsenic, nickel, and chromium. These metals can bioaccumulate and cause adverse health effects even at low concentrations, such as neurodevelopmental impairment, renal and hepatic dysfunction, reproductive toxicity, and cardiovascular complications. This narrative review synthesised evidence on the prevalence of heavy metal contamination in pharmaceuticals marketed in Nigeria, associated health risks, and the adequacy of existing regulatory frameworks.Relevant literature published between 2005 and 2025 was identified through a comprehensive literature search of major databases such as PubMed, Google Scholar, African Journals Online, and Scopus, supplemented with reports from the National Agency for Food and Drug Administration and Control, the World Health Organisation, and grey literature. Studies assessing industrially manufactured or over-the-counter medicines for heavy metal contamination in Nigeria were included.The findings reveal recurrent contamination across several pharmaceutical categories, particularly syrups, locally manufactured analgesics, and herbal preparations. Lead and cadmium were the most frequently reported contaminants, with some products containing multiple metals and exceeding pharmacopeial limits. Heavy metal exposure induces oxidative stress and cellular damage, contributing to kidney injury, neurotoxicity, haematological effects, and endocrine disruption. Children, pregnant women, individuals with renal impairment, and frequent users of herbal medicines were identified as particularly vulnerable. Overall, heavy metal contamination remains a significant medicine safety concern in Nigeria, highlighting the need for stronger regulation, improved analytical capacity, and risk-based surveillance.
Blessing Abraham Ogungbe, David Ololade Atanda, Janet Adedoyin Bepo et al.· International Journal of Ris...· 0 citations
