KEY TAKEAWAYS:

1. Plastics are non-biodegradable and may progressively break down into smaller particles (micro and nano plastics) that can be trapped in water and foods without visible traces. 

2. Plastics can persist in the environment for 1000 years with only 15% of discarded plastics being recycled globally, highlighting inefficiencies in waste management.

3. Nigeria generates over 2.5 million tonnes of plastic waste annually, and Lagos alone accounts for over 34% (870,000 tonnes) of this. Given the significant threat posed by plastic waste, the Lagos State Government has been most aggressive in managing plastic waste and plans to enforce a ban on specific single-use plastics (SUPs) by January 2025.

4. Most plastic waste eventually ends up in the ocean posing a threat to marine ecosystems. It is estimated that by 2035, plastic waste in the ocean could equal or surpass the total biomass of fish.

5. Plastics contribute to global warming by releasing methane when disintegrating under heat and sunlight and reducing the ability of phytoplanktons to absorb CO₂ and produce oxygen.  Methane is more than 25-28 times a more potent greenhouse gas than CO₂. 

6. Plastics have both physical and toxic impacts on animals within the ecosystem. Depending on the size and shape of the plastic, the physical impact may include Suffocation, trapping, entanglement, and ulceration of the gut of ingesting animals, etc. 

7. Toxic impacts include endocrine disruption, reproductive issues, carcinogenic effects, etc. Toxic impacts of plastics result from pollutants adsorbed on plastic particles, monomers of plastic polymers, and nano-plastics.

1. INTRODUCTION 

Plastic, a versatile material with numerous applications, has become deeply linked to the comforts of modern life. Since the creation of nitrocellulose, the first semi-synthetic plastic, in 1862 (9), a variety of plastics with expanding properties and uses have been developed. Compared to traditional materials such as glass, wood, and metal, the appeal of plastic lies in its unique characteristics: it is relatively inexpensive to produce, lightweight, tough, stiff, easily fabricated, and offers good insulation for electricity and heat. These attributes have led to its widespread use in sectors like agriculture, construction, transportation, heat insulation, packaging, manufacturing, electronics, furniture, toys, automobiles, and medicine. From 2000 to 2019, rapid population growth and economic advancements have driven global plastic production to nearly double, increasing from 234 million tons to 460 million tons (18). Approximately two-thirds of plastic production consists of single-use plastics, which typically have a lifespan of less than a month. This growing prevalence of plastic waste is a significant concern, particularly in the absence of targeted strategies to address and reduce the issue. Approximately 20 to million metric tons of plastic waste are estimated to enter the environment annually, with projections indicating a substantial rise by 2040 (8).  Nigeria is estimated to produce approximately 2.5 million tonnes of plastic waste each year, with Lagos, its commercial hub, contributing 870,000 tonnes (over 34%) annually. Alarmingly, only about 15% of discarded plastics are recycled, leaving vast quantities to accumulate in landfills and ecosystems causing various health, ecological, and climate crises (4).  

2. THE PLASTIC WASTE CRISIS

Despite its many advantages, synthetic plastics face a significant drawback: they are non-biodegradable due to their structure (long polymer chains) and the presence of additives such as antioxidants. For this reason,  discarded plastics may remain in the environment for 1000 years (21). The ocean is the ultimate destination for most plastic waste, which threatens marine biodiversity and ecological balance. By 2035 the amount of plastic waste in the ocean is projected to be equal to or surpass the total biomass of fish, highlighting a severe environmental crisis (20). 

When exposed to ultraviolet radiation, plastics undergo photo-oxidation, making them brittle and causing them to break into smaller pieces typically classified as macroplastics (>5 mm) and microplastics <1mm). These small plastic pieces are particularly more difficult to manage and pose significant health and ecological threats to aquatic and terrestrial animals. In 2019, microplastics of <0.5mm accounted for 88% of global plastic pollution, contributing to the contamination of ecosystems worldwide (8). In a study conducted recently in Osun River, Nigeria, 22,079 plastic microparticles in 1 liter of water were reported making it the highest reported for any river globally. In the same study, between 407 to 1691.7 microplastic particles were found in the gastrointestinal tract (GIT) of six fish species analyzed. Microplastic has also been recovered in several other rivers in Nigeria including Nwangele River in Imo State, Kaduna River, and Elechi Creek, in Port Harcourt. 

3. ADVERSE EFFECTS OF PLASTIC WASTE ON THE ECOLOGY, HUMAN HEALTH, AND GLOBAL CLIMATE

• Ecological impact of plastic waste 

Plastics disrupt aquatic ecosystems in multiple ways, every organism in an ecosystem has a distinct and essential role contributing to the overall ecological balance and functions. Plastic has various adverse effects on different classes of aquatic animals in the ecosystem. These effects may have physical or toxic impacts 

1. Physical Impact: Plastic particles of varying shapes and sizes physically harm small and large aquatic animals including such as seabirds, turtles, fish, crustaceans, etc. These harms are typically caused by suffocation, entrapment, entanglement, and ingestion of plastic particles (5). Entrapped or entangled animals may lose their ability to hunt, evade prey, or drown. Ingested plastics may block digestive tracts, damage stomach linings and give a false sense of satiation to the animals. 
2. Toxic Impact: Plastics have direct and indirect toxic impacts on aquatic life plants and animals. Direct impacts include toxic impacts from nanoplastic particles as well as monomers and hazardous additives like plasticizers and flame retardants leaching from the plastic polymers. Indirect toxic impact results when plastic serves as a vector for other organic pollutants, heavy metals, and pathogens attached to plastics. In animals, toxic impacts include early mortality, inflammatory responses, inhibited growth and development, reduced energy, low feeding activity, oxidative damage, immunity and neurotransmission dysfunction, and even behavioral abnormality, etc. Plastic particulates can cause unfavorable changes to plant growth, germination, and oxidative stress in plants (7). 

Studies have shown microplastics in rivers and aquatic animals. This poses significant health to humans that rely on such rivers for cooking and drinking especially in where municipal water treatment plants have not been updated to remove microplastic. Similarly, plastic may also, as well as those that eat such aquatic animals. As humans occupy the highest levels of the trophic chain, they are exposed to elevated concentrations of plastic and organic pollutants that accumulate through the trophic levels. Due to their small size, the nanoparticles (19) can easily pass through biological barriers and accumulate in tissues and organs. Studies have also revealed the presence of microplastics in human blood (11), semen, and placenta (16) highlighting the potentially toxic impact on adult humans and fetuses.

 The following details on several pathological outcomes that have been associated with plastics: 

1. Endocrine Disruption: Chemicals like bisphenol A (BPA) interfere with hormonal functions.
2. Reproductive Issues: Phthalates and other additives have been associated with infertility and developmental abnormalities.
3. Carcinogenic Effects: Long-term exposure to certain plastic-related toxins increases cancer risk.
4. Neurological Disorders: Plastics’ impact on neurotransmission can lead to cognitive and behavioral impairments.

• Global Environmental impact

Although the impact of discarded plastic waste on aesthetics and land use is very obvious. Its contribution to climate is not frequently highlighted. Discarded plastics produce methane when exposed to solar radiation (17). Methane, in particular, is 25 times more potent than greenhouse gas CO₂. Microplastics (12) have become a major threat to ocean carbon sequestration (15) affecting phytoplankton, which are crucial for absorbing carbon dioxide and producing oxygen (20) MPs in the soil have also been demonstrated to increase soil CO2 emission (1). 

4. REGULATORY FRAMEWORK FOR PLASTIC WASTE MANAGEMENT IN NIGERIA

Nigeria’s regulatory framework for plastic waste management relies on a combination of general environmental laws and sector-specific policies. Key provisions include the Constitution of Nigeria (1999), which obligates the government to protect the environment, though this is non-justiciable. The National Environmental Standards and Regulation Enforcement Agency (NESREA) Act (2007) empowers NESREA to enforce compliance with environmental regulations, while the Environmental Impact Assessment (EIA) Act, CAP E12 LFN 2004 mandates assessments for projects that could harm the environment, including waste facilities. Other regulations, such as the National Environmental (Sanitation and Wastes Control) Regulations (2009) and the Plastic, Rubber, and Foam Sector Regulations (2011), target indiscriminate waste disposal and promote practices like recycling and Extended Producer Responsibility (EPR). Policies like the National Policy on Plastic Waste Management (2020) and the National Policy on Solid Waste Management (2020) emphasize sustainable waste management through recycling, limiting single-use plastics, and adopting circular economy principles. Additionally, laws like the Harmful Waste Act (1988) and the Import Prohibition Act address harmful waste dumping and restrict certain plastic imports (14).

Despite these measures, the framework is criticized for being fragmented, lacking a dedicated national law for plastic pollution, and showing weak enforcement. Key gaps include inadequate roles for stakeholders like customs and maritime authorities, limited monitoring, and insufficient bans on single-use plastics. 

5. WAY FORWARD

To curtail the nuisance of plastic entails a concerted and multi-pronged approach. These include:  

Promote research on the adverse impact of plastic: Detailed and locally relevant studies on the impact of plastic waste on human health, ecosystem, and climate should be in our research institutions, and universities should be encouraged and funded by various levels of government in Nigeria. This will bring the adverse effect of plastic waste in high relief to local communities and in turn serve as a pressure point to elicit action from the concerned stakeholders (11). More locally relevant studies on the health and environmental hazards associated with  plastic waste in Maiduguri should be encouraged

Waste treatment and standards should be updated to include micro and nano plastic: Current waste treatment technology in Nigeria and drinking water standards do not address the nano and microplastic problem. Given the frequent isolation of microplastic in water bodies within Nigeria, public health crises might ensue. For this reason, regulatory agencies in Nigeria such as NESREA should update their standard to set a safe limit for plastic particles in our drinking water.

Industrial fishing companies in Nigeria should be mandated to measure and keep records of plastic particles in fish and crustaceans caught within Nigeria. Similarly, incidences of entrapment and entangles of aquatic animals caused by abandoned dragnets should be adequately reported and sanctions implemented where possible.

Establish strict regulation to curtail the use of plastic: national and subnational governments should as a matter of urgency enact laws to curtail the use of plastics. The Lagos State Government is leading the charge in this direction with its plan to enforce a state-wide ban on specific categories of single-use plastics (SUP) starting in January 2025. The banned items include Styrofoam (plates and cups), straws, single-use plastic cutlery, and nylon bags less than 40 microns thick (10).   

Discourage the use of virgin plastic while encouraging recycling: Enacting policies that discourage the use of virgin plastic while encouraging recycled plastic will reduce the quantity of plastic waste in the environment. The Lagos state government has developed a policy that encourages the recycling of plastic such as PET bottles, sachets, and carrier bags with a minimum thickness of 40 microns will be managed under a mandatory Extended Producer Responsibility (EPR) program. This initiative will be supported by the Plastics Waste Management Fund, a collaboration between the Lagos State Government, producers, and Producer Responsibility Organizations (PROs), jointly managed and funded by contributions from producers and importers to ensure efficient plastic waste management statewide (10). 

Enacting a comprehensive national plastic waste law, enforcing stricter penalties, promoting recycling through incentives, and enhancing public awareness would improve plastic waste management. Integrating international standards like the Basel Convention and strengthening institutional collaboration could significantly improve Nigeria’s plastic waste management efforts. 

6. CONCLUSION

Plastic waste poses profound and multifaceted challenges, ranging from ecosystem disruption to human health risks and contributions to climate change. Its impacts are direct and indirect, such as physical harm to organisms, and the release of toxic chemicals and greenhouse gasses.

To address this crisis, global and local actions are essential. Strategies such as reducing single-use plastics, improving recycling rates, promoting biodegradable alternatives, and enforcing stricter plastic production and waste management regulations are critical. Without immediate intervention, plastic waste will continue to threaten the ecological balance, human health, and the stability of our planet’s climate systems. This is a call to action for civil society groups, industries, and government agencies to work together to mitigate the ever-growing plastic pollution crisis.

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