Confronting the Toxic Threat: Addressing Heavy Metal Poisoning and Pollution in Nigeria

The rising incidence of heavy metal poisoning-related deaths in Nigeria is an alarming public health issue ^{[1 , 2]} . Heavy metals such as lead (Pb), cadmium (Cd), and mercury (Hg) pose significant health risks due to their toxicity and persistence in the environment ^[3]. This problem is exacerbated in low- and middle-income countries (LMICs) like Nigeria, which, despite using a quarter of the world’s pesticides, account for nearly all global deaths from pesticide exposure. Key factors contributing to heavy metal poisoning in Nigeria include unsafe mining activities, the use of leaded gasoline, and contaminated traditional medicines ^{[4 , 5]} . This article highlights the health impacts of heavy metal pollution and provides evidence-based feasible and practicable comprehensive strategies to mitigate this issue.

Heavy metal pollution in Nigeria is widespread, with significant contamination reported in various regions ^[6] The 2010 lead outbreak in Zamfara State, Northern Nigeria, is a notable example, where over 400 children died and more than 2,000 were left with disabilities due to lead poisoning from illegal gold mining ^{[7 , 8, 9].} Studies have shown soil lead levels and blood lead levels exceeding 100,000 parts per million (ppm) and 70ug/dL in children under five years of age respectively in affected areas, far surpassing the recommended upper limit of 400 ppm and the recommended BLL of 5 ug/dL ^{[10, 11, 12].} The historical use of leaded gasoline and reliance on traditional medicines further contribute to the legacy of heavy metal contamination in Nigeria.

Heavy metal poisoning has severe health implications, particularly for vulnerable populations such as children. While, there is no safe blood lead levels (BLLs), any value above 5µg/dl is deemed lead poisoning ^[6]. . Lead poisoning, for example, is linked to anemia, hypertension, renal injury, cognitive deficits, and behavioral problems ^[10]. . The Zamfara lead outbreak exemplifies the devastating effects of heavy metal exposure, with young children bearing the brunt of the health consequences. The recent incident in Sokoto State, where individuals were poisoned by contaminated herbal preparations, underscores the ongoing risk posed by heavy metal-laden traditional medicines ^[13]. .

The drivers of heavy metal pollution in Nigeria are multifaceted and deeply rooted in the country's developmental challenges. Inadequate waste management practices, particularly in urban areas, lead to the release of heavy metals into the environment. Only about 30% of solid waste is properly collected and disposed of ^[14]. , with the remainder often ending up in open dumpsites or water bodies leading to the release of heavy metals into the environment ^[15]. . Furthermore, the widespread historical use of lead gasoline and the reliance on traditional medicines, which may be contaminated with heavy metals has left a legacy of lead contamination in Nigeria ^{[16], [17].}

To address the issue of heavy metal pollution, the Nigerian government must implement stricter regulations on industrial waste management and mining practices ^[18]. . This includes enforcing the use of cleaner production methods and ensuring the correct disposal of hazardous materials. Providing subsidies or tax incentives for environmentally friendly techniques in the mining sector can also encourage safer practices. National regulations for monitoring and managing heavy metals in traditional medicines are essential to prevent poisoning cases from contaminated products ^[19]. . The risks associated with herbal preparations suspected to be contaminated with heavy metals also highlight the urgent need for prompt regulatory intervention and widespread public awareness.

The risks associated with herbal preparations suspected to be contaminated with heavy metals also highlight the urgent need for prompt regulatory intervention and widespread public awareness. Healthcare providers need specialized training to recognize and treat heavy metal poisoning ^[20]. . The swift response to the Sokoto incident, marked by the rapid mobilization of health workers, is a promising development ^[13]. . Establishing diagnostic procedures and patient monitoring systems for screening high-risk groups is crucial. The recent launch of the National Genomics Sequencing Consortium by the Nigeria Centre for Disease Control (NCDC) in May 2024 underscores Nigeria's dedication to advancing public health ^[21]. . This center is pivotal for enhancing preparedness against emerging threats by improving the connectivity between disease control programs and surveillance networks and leveraging the underutilized laboratory capacities bolstered during the pandemic, this new strategy represents a significant step forward. However, while these efforts are commendable, more proactive measures are urgently needed to address not only infectious disease threats, but also the silent epidemic of heavy metal poisoning that continues to devastate the nation, particularly its children. Increasing the availability of rapid point-of-care devices can help detect heavy metal poisoning promptly ^[22]. , allowing for immediate medical intervention. In southwestern Nigeria, a study by Ojekunle in Ogun State have detected alarmingly high levels of lead and cadmium in surface water samples collected from mining communities ^[23]. . Community organizations play a vital role in raising awareness and facilitating localized solutions, such as community-led water purification initiatives.

There is a critical need for longitudinal studies to understand the extent and impact of heavy metal exposure in Nigeria. Epidemiological studies should map the prevalence, distribution, and risk factors associated with heavy metal poisoning, identifying vulnerable populations and environmental determinants. Research on the long-term effects of treatment and the development of affordable diagnostic tools is essential. Exploring innovative remediation techniques, such as phytoremediation, can provide sustainable solutions tailored to the Nigerian context. Interdisciplinary collaboration with policymakers, practitioners, and community organizations is essential to translate research findings into evidence-based, actionable strategies. This comprehensive research agenda can contribute significantly to Nigeria's efforts to address the heavy metal crisis and improve the health and well-being of its citizens.

The increasing incidence of heavy metal poisoning and pollution in Nigeria demands immediate and comprehensive actions. Implementing stricter regulations on industrial waste management, mining practices, and traditional medicines is vital. Efforts to raise awareness, improve healthcare provider training, make available testing devices, and conduct extensive research are crucial for developing targeted interventions. By adopting these multifaceted strategies, Nigeria can effectively combat this public health crisis and safeguard the well-being of its citizens.

Not applicable This research received no specific grants from any funding agency in the public, commercial, or not-for-profit sectors. The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper. None. The datasets generated during and/or analyzed during the current study are available from the corresponding author upon reasonable request.