A Journey Through Plastic Waste

Imagine strolling through a busy open-air market and shops in Kenya or Ghana. Customers haggle over fresh produce; vendors call out their prices, and in the background, plastic packaging rustles in the wind. It's everywhere—in nicely stacked snack packs, bottled drinks, and thin bags used for wrapping grains. Not always does the plastic from these transactions find a proper waste disposal. Instead, it usually ends up in rivers, streets, and the ocean. In addition to localized harm like clogged urban storm drains and impacts on wildlife, mismanaged plastic waste can bio-accumulate in marine life and finally in human tissue like breast milk and placentas as plastic debris deteriorates into microplastics.

Following the Trail of Plastic

People's shopping habits tell a story. Over the years, how consumers purchase goods has evolved greatly, especially in rapidly urbanizing regions. Convenience and food safety have become key, and with it, the prevalence of plastic packaging has soared. However, many cities in low- and middle-income countries (LMICs) lack adequate waste management services, so most plastic of their waste is mismanaged.

In a previous study, we used household expenditure surveys to estimate the amount of mismanaged plastic waste from particular products such as disposable diapers (which contain a plastic layer) or water sold in plastic bottles or bags.  Such surveys and implemented in many countries and ask a representative household sample about the products that they buy and how their waste is collected. This enabled us to monitor products sold in plastic packaging to populations lacking waste disposal services and so identify hot-spots of mismanaged plastics. However, we wondered about the big picture: could the same surveys be used to assess the entire basket of goods purchased by a household, not just particular products like diapers or bottled water? 

To answer this question, we looked at the NOVA classification, which distinguishes ultra-processed and processed foods from minimally or unprocessed foods. Using real-life market observations in Greater Accra, Ghana, and Kisumu, Kenya, we assessed whether ultra-processed or processed foods more frequently came packaged in plastics than minimally or unprocessed foods.  As an alternative, we also asked local residents in both cities to identify those food products commonly sold in plastics.

What We Discovered

The results were striking. In Greater Accra, nearly every food or beverage purchase—94%—came with plastic packaging. In contrast, Kisumu had a lower rate of 57%. Kenya's ban on single-use plastic bags may have played a role in reducing waste, but plastic packaging was still common there, especially in processed foods and beverages.

Interestingly, we found that where people shopped made a big difference. Supermarket purchases more often generated plastic waste, as their products came prepackaged. Smaller vendors, such as kiosks and market stalls, often repackaged items into smaller quantities, sometimes using less plastic or allowing customers to bring their own containers. In Kisumu, this practice was more common, reducing plastic waste at the household level.

Food type also played a role. Using the internationally recognized NOVA classification system, we confirmed that highly processed foods—like snacks, sugary drinks, and ready-to-eat meals—were far more likely to come in plastic than fresh produce or staple ingredients. When local residents categorized foods based on their own experience, the results were similar to using NOVA, suggesting that local knowledge is valuable in waste monitoring.

Why This Matters

Understanding waste generation patterns is key to improving waste management strategies. If household expenditure surveys can be used to track mismanaged waste, policymakers and environmental groups can identify areas where plastic waste is most mismanaged and take targeted action by analyzing household spending habits.

For example, governments could introduce better regulations to hold manufacturers accountable for the plastic waste they produce, a concept known as Extended Producer Responsibility (EPR). Businesses could be encouraged to switch to eco-friendly packaging or support consumer habits that reduce plastic use. On a local level, efforts to promote reusable packaging and proper waste disposal could significantly reduce plastic pollution.

The Bigger Picture: Addressing Plastic Waste Beyond Consumption

The challenges of plastic waste management extend beyond consumer habits. Policy interventions must address the entire lifecycle of plastic, from production and distribution to disposal and recycling. Countries like Kenya, which have implemented partial bans on single-use plastics, demonstrate that regulatory measures can influence waste generation patterns. However, enforcement and waste management infrastructure must be strengthened to ensure long-term impact.

Collaboration between governments, businesses, and communities is essential. Retailers could be incentivized to reduce unnecessary plastic packaging, while consumers can be encouraged to adopt more sustainable shopping habits. Meanwhile, investments in waste separation initiatives and recycling systems can create jobs for informal collectors and reduce plastic’s environmental harms.

Looking Ahead

There's still much work to be done. Future research should refine classification methods, explore additional waste sources like takeaway food containers, and examine how seasonal trends impact plastic consumption. Understanding plastic waste at the household level is a crucial step in creating sustainable cities, and by linking consumer behavior with waste management strategies, we can move toward a more responsible and sustainable future.

The study was undertaken through the 'Expanding safe water and waste management service access to off-grid populations in Africa' project (ref: ES/T008121/1), funded through the UKRI Collective Fund award via the Global Challenges Research Fund (GCRF) under the 'Rethinking the Off-grid City' program. The support of the UK Economic and Social Research Council (ESRC) is gratefully acknowledged. The project team comprises the University of Southampton, the University of Ghana, Jaramogi Oginga Odinga University of Science and Technology (JOOUST), and VIRED International, with expertise in water resources, sanitation, and public health.

You can access the entire research paper here to dive deeper into our findings and methodology.