by Zhen Dai
figures by Sean Wilson and Zhen Dai

A deep ripple

It was a typical lab day earlier this year. I planned to install an equipment component that had just arrived in the mail. I unpacked the component and proceeded to recycle the packaging. As I searched through the lab, though, I noticed that our blue recycling bins were nowhere to be found. Asking around, I learned that plastic recycling in the lab had stopped, and it had something to do with China. “We are not sure what exactly is going on. Do you?” said my lab mate.

I did have a faint idea. I had recently learned that China established a policy in 2017 to stop importing plastic waste with a high level of contamination during the director Q&A session of a film screening of Plastic China. This documentary followed families that processed imported plastic waste in an impoverished village in Shandong, China. It depicted the lifecycle of a typical piece of plastic waste generated in US, as it traveled from a recycling bin to a cargo container moving across the Pacific and was finally dumped in an economically-depressed village in China. In this village, plastic was processed by household recycling workshops with poor waste management infrastructure and few safety measures. Kids lived in a literal mountain of garbage. Having few other choices for economic development, their parents traded in their families’ health and pristine homeland to pursue a better life amidst the stench and smoke of shredded plastic.

Of course, the reverberation didn’t stop with the village in the film. Just two months after China’s plastic waste import ban came out, its ripple reached Harvard and swallowed our lab’s blue recycling bins (Figure 1).

Figure 1: Lab recycling sign provided to our lab in the Chemistry building by Harvard’s Office of Sustainability. Based on guidance from Harvard Campus Services Recycling and Waste Management, department labware plastics can no longer be recycled in Harvard labs. Some recycling bins are being removed from certain labs until a solution for more recycling in the lab is found.

Disruption from across the ocean

Why does China’s ban on contaminated plastic import have any impact? Macroscopically, this is because the world has generated an enormous amount of plastic but paid little attention to handling it responsibly after its useful life. According to a recent global analysis on all plastic ever manufactured, roughly 6,300 million tons (Mt) of plastic had been manufactured by 2015. That is roughly 14 times the weight of all human beings alive. Contributing to this large amount is an exponentially-growing rate of plastic generation from a mere 2 Mt per year in 1950 to 380 Mt per year in 2015. The vast majority (79%) of plastic manufactured ended up in landfills and the natural environment, 12% was incinerated, and only 9% was recycled. As such, there has been a large international effort to promote recycling and develop recyclable plastics.

However, as much as the world’s recycling effort falls short, the regional imbalance in the amount of plastic recycled also stands out. Examining international trade data, researchers from the University of Georgia found that the weight of plastic waste (any plastic after its useful life but before it’s factually recycled) exported to foreign countries is roughly 40% of total plastic generated globally. The categories of plastic investigated in their work (polyethylene (PE), polyvinyl chloride (PVC), polystyrene (PS), and others) cover common recyclables in the US (Figure 2). In general, the plastic waste flowed from high-income countries to medium- and low-income countries, and China alone imported nearly half of global plastic waste exports since 1992. On the other end of the spectrum, the US is the largest exporter of plastic waste among all countries in the Organization for Economic Co-operation and Development. In fact, 12% of global waste plastic is exported by the US.

Figure 2: common categories of recyclable plastic in the US and the corresponding recycle codes.

Macroscopically, the rationale behind this regional imbalance is the same one underlying all international trade: both the importing and exporting parties profit from the trade. On the one hand, it’s often more profitable for developed countries to export waste than to pay the higher domestic processing fee. On the other hand, developing countries could also profit from importing plastic waste: lower labor costs and relaxed health and safety rules frequently allow them to recycle plastics cheaply. In addition, in China’s case, the recycled plastic was used largely to satisfy its voracious appetite for plastics as its economy developed.  The economic calculus has stood without properly incorporating the unseen costs related to human health and environmental pollution.

However, the winds of change have been seething from the weeds of disease. As environmental and health concerns grew more salient, and domestic production of plastic waste increased in China, the government has gradually tightened control of plastic waste import. In 2013, in an operation referred to as the “Green Fence,” China introduced a temporary restriction on waste import, requiring imported materials to contain less contamination. Even though that restriction was only imposed on a limited number of waste categories, it still introduced a sizable disruption to the industry: plastic waste export worldwide dropped sharply by 13% the next year.

It shouldn’t come as a surprise, then, that when China instituted a comprehensive ban on import of contaminated plastic in 2017, this decision had a profound impact on the US recycling industry and immediately affected people’s daily lives. A live-updated website hosted by Industry Dive documents the policy’s impact in the US: 13 states are heavily impacted, 28 are noticeably impacted, and only 9 are minimally impacted. Massachusetts, for example, is heavily impacted, with many cities reporting financial losses due to higher contamination removal and recycling costs.

DIY, outsource, or… both?

So far, the recycling industry in the US has struggled to respond to the disruption caused by China’s policy. Efforts are focused on increasing domestic waste-processing capacities and exporting to other developing countries such as Vietnam and Malaysia. Increasing domestic waste processing capacity is costly but might be a viable long-term option. Exporting to developing countries that lack proper waste management facilities, however, could lead to environmental and safety problems similar to those plaguing China. For example, a paper published in the International Journal of Industrial Chemistry in 2013 reviewing the impacts of plastic recycling in developing countries documented an incident where plastic bags allegedly clogged gutters and drains in Mumbai. Local officials claimed that this caused massive flooding during the monsoon season that killed at least 1,000 people. Developing countries could also struggle to process the sudden massive inflow of plastic waste. For example, Vietnam and Malaysia started limiting waste import this June, citing environmental concerns.

The solution to the recycling problem will involve at least two areas of improvement: technological development and more efficient global collaboration. A team of scientists from the US and UK proposed an array of technical solutions aimed at developing a more sustainable plastic manufacturing and recycling industrial system. Other aspects of improvement include more robust decision-making tools that select the best recycling methods and improved capacity for recycling plastic chemically.

Fostering better international collaborations and policy innovations could also have a large positive impact on the recycling problem. For example, one study conducted at United Nations University showed that an eco-friendly way to deal with waste recycling is to divide the tasks between countries with varying capabilities: developing countries can focus on technically simple tasks that require manual labor (e.g. dismantling and manual separation), and developed countries can conduct the more complex and hazardous activities (e.g. toxic treatment) with their better developed and more robust processing facilities. International treaties, such as the Basel Convention that governs the export of hazardous and other wastes, could facilitate the establishment of such a system. These measures must also be supported by domestic governments to provide the proper legal framework and market incentives.

It is unclear whether these solutions are being adopted or will be sufficient to address the lack of recycling capacities in the US. In fact, with recycling costs skyrocketing and mounting recyclables sent to land-fills, our lab’s blue recycling bins seem like only a first casualty. As the University of Georgia researchers pointed out, “without bold new ideas and management strategies, current recycling rates will no longer be met, and ambitious goals and timelines for future recycling growth will be insurmountable.”

Zhen Dai is a graduate student in the Engineering Sciences department. She studies solar geoengineering for her thesis research

Sean Wilson is a fifth-year graduate student in the Department of Molecular and Cellular Biology at Harvard University

For more information:

  • To learn about the fate of all plastic ever manufactures, click on this article published in Science Advances
  • To learn about the impact of China’s ban on import of contaminated plastic, see this study published in Science Advances
  • To track state-level impact of China’s policy, follow this website
  • To learn more about plastic and its impact to our marine environment, check out this SITN article.



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