Can a ‘Sustainability Metric’ Curb Our Plastic Pollution?

Plastics, which primarily consist of polymers, are a broad category of synthetic or semi-synthetic organic compounds. It is their plasticity that makes it possible for plastics to be molded into different shapes and have many valuable uses. 

Given that plastic is cheap, versatile, and sterile, it finds many applications, including home appliances, food packaging, construction, and medical instruments, adding value to our lives.

Plastic usage over the last many decades has grown substantially and now results in about 450 million tonnes of plastic waste every year. In fact, it accounts for at least 85% of total marine waste. A vast majority of plastic waste (46%) is landfilled, with only 15% collected for recycling and less than 9% being recycled. The rest either turns into smaller fragments or is incinerated. 

As plastics become part of the Earth's fossil record, they carry severe environmental, health, social, and economic consequences. Moreover, recent studies reveal an increasing presence of minuscule particles in our water and food, further exacerbating these problems.

A new study by researchers at Columbia University has found that bottled water sold in stores may actually contain ten to a hundred times more plastic than previously estimated. Plastics found in the water were in the form of nanoparticles, which are 1,000th the average width of a human hair. These nanoparticles are so tiny that they can't be seen under a microscope and can migrate into the bloodstream through the tissues of the digestive tract or lungs. Once in our bloodstream, these minuscule particles can distribute harmful synthetic chemicals throughout our bodies and into cells.

The study notes that, on average, 240,000 plastic particles have been detected in one liter of water, equivalent to two standard-size bottled waters. These particles originated from seven types of plastics, with 90% being nanoplastics and the remaining 10% microplastics.

Microplastics are polymer fragments ranging from less than 0.2 inches down to 1/25,000th of an inch. Anything smaller than this is categorized as a nanoplastic, measured in billionths of a meter.

This finding illustrates that plastics constantly shed, akin to how we shed skin cells. The continual shedding of tiny plastic bits, which then break off, underscores the importance of using stainless steel or glass containers to reduce exposure.

Calling the study “exceedingly impressive,” Sherri “Sam” Mason, director of sustainability at the Pennsylvania State University at Erie, who was not involved in the study, said: 

“The body of work that they put into this was really quite profound … I would call it groundbreaking.”

Studying the Chemical Structure & Risks of Nanoparticles

Back in 2018, Mason co-authored a study that first found the existence of microplastics and nanoplastics in the vast majority (93%) of bottled water samples. In her study, she discovered that each polluted liter of water contained an average of 300 smaller particles as well as ten particles of plastic that were wider than a human hair. 

So, while it was already known that nanoplastics existed, at the time, it wasn't possible to assess these particles, let alone discover if there were more.

Now, according to a new study published in the journal Proceedings of the National Academy of Sciences in the third week of Jan. 2024, a new technology has been demonstrated that can not just see but also count and analyze the chemical structure of nanoparticles in bottled water.

The new approach, which relies on the modified version of the laser-based technique known as Raman spectroscopy, will be able to help with that. Stimulated Raman scattering microscopy, or SRS, measures how molecules vibrate in response to light and amplify the signal by a great magnitude that allows the nanoparticle to be detected. It is expected to help understand whether polymers, “the plastic part of plastic,” harm the body.

This study was the first one to make use of microscopy in the nanoplastic world. The research team took three unnamed popular brands of water sold in the US and found that they contained 110,000 to 370,000 plastic bits instead of 300 per liter. 

“These particles can be inorganic nanoparticles, organic particles, and some other plastic particles not among the seven major plastic types we studied.” 

– Beizhan Yan, who was part of the research and is the associate research professor at the Earth Observatory of the Columbia University

The ability of this technology to see and analyze the nanoparticles presents the opportunity to better understand the potential risks to human health, especially infants and young children whose brains and bodies are in the developing phase and more vulnerable to toxic exposures.

Among different plastic pollution types, nanoplastics are the most alarming due to the fact that they are very small in size and can enter the cells and tissues of our major organs. Once there, these bits of plastics can potentially deposit chemicals like heavy metals, phthalates, bisphenols, flame retardants, and PFAS (per- and polyfluorinated substances). These endocrine-disrupting chemicals (EDCs) have resulted in a dramatic increase in US health costs, about $250 billion in 2018 alone, according to research.

Already, it has been observed that the small size of microplastics enables them to absorb toxic materials from the environment and enter the food chain. Additionally, all the chemicals used in the production of plastic not only enter our bodies along with the plastics but also migrate out of the plastics into our bodies, which have a higher temperature than the external environment.

These chemicals then enter your kidneys, liver, and brain. Subsequently, they are found in unborn children's brains, hearts, livers, kidneys, and lungs, as observed in studies on pregnant mice just 24 hours after the mother ingested or inhaled plastic particles.

“Micro and nanoplastics have been found in the human placenta at this point. They've been found in human lung tissues. They've been found in human feces; they've been found in human blood.”  

– Phoebe Stapleton, the study co-author and an associate professor at the pharmacy school of Rutgers University 

The durability of microplastics indicates that they pose long-term ecological and health risks. Moreover, recent findings suggest that natural events like hurricanes also contribute to this pollution by acting as powerful distribution mechanisms. This represents a growing threat to ecosystems and human health globally.

Solving the Problem of Plastic Pollution via Sustainability Metric

While new technology and approaches are being utilized to analyze previously unseen nanoparticles, progress is also being made in tackling the problem of plastic pollution. In a recent study, researchers from the non-profit organization dedicated to marine research, the Woods Hole Oceanographic Institution (WHOI), developed a sustainability metric for the ecological design of plastic products with low environmental persistence. Adhering to this metric is expected to yield environmental and societal benefits.

The new study compared indices for the environmental impact of plastics as well as their substitutes, which demonstrated that accounting for the environmental persistence of plastics could lead to the benefits of hundreds of millions of dollars for a single consumer product. 

Such products are generally designed by balancing the trade-offs between resource depletion and environmental concerns. This balance is necessary because, although frameworks exist for estimating these impacts, none so far have been developed for material selection or quantifying environmental persistence. The latest study aims to address this gap by introducing metrics and methods to assist designers, engineers, and scientists in making informed design decisions and setting research priorities.

For this, a new study published in the journal ACS Sustainable Chemistry & Engineering has developed a sustainability metric for the ecological design of plastic products with low environmental persistence.

Despite the risks that plastic pollution poses to human health and ecosystems, the use of plastic products continues to rise. Therefore, limiting its harm requires design strategies for plastic products that are informed by the threats plastics pose to the environment, as stated in the study. 

To this end, a sustainability metric has been developed for the eco-design of plastic products, which aims to maintain performance while ensuring low environmental persistence. The analysis identifies materials and their properties that merit development, adoption, and investment for manufacturing plastic products that are less environmentally impactful yet functional.

“What's important to determine is how can we design functional, sustainable, and benign materials, products, and processes that embody all of the principles of green materials engineering into the future world that we are going to live in.” 

– said lead author Bryan James, a materials scientist and engineer

He added:

“What are the next set of strategies and tools that engineers, product designers, and even the average consumer can use to make the best choices for the environment while not having to sacrifice product performance?” 

To create this metric, the study utilized the environmental degradation rate of plastic alongside established material selection strategies. This approach focused on the environmental impact and characteristics of different materials, providing a guide based on their persistence in the environment.

Implementing a sustainability metric for persistence has been challenging due to the historical lack of comprehensive data on the various types of plastics used in consumer goods. However, with recent access to sufficient data on the realistic environmental degradation rates of a wide array of plastics, researchers can now illustrate how switching one material for another in the design process can reduce both the cost of the product and its greenhouse gas emissions.

By considering the properties of different types of plastics and utilizing them strategically, switches can be made to minimize environmental persistence, offering substantial benefits.

For example, the study applied this metric to switch to alternative materials like cellulose diacetate and polyhydroxyalkanoates for single-use coffee cup lids. This switch could reduce the environmental costs to society by hundreds of millions of dollars. These lids, currently made from materials like polylactic acid, polypropylene, and polystyrene, contribute to about 5% of all plastic debris collected in coastal cleanups globally. Cellulose diacetate and polyhydroxyalkanoates, while slightly more expensive, have lower greenhouse gas emissions than polylactic acid and do not persist in the ocean.

In determining which material to switch to, the study considered whether it is better to use a material with lower greenhouse gas emissions that persists longer, or one with slightly higher emissions but less persistence. To this end, the study assigned a dollar value to the environmental cost of each material.

“Simply making products that persist less by virtue of not being there, or going away faster, reduces that cost to society tremendously.” 

– said lead author Jame, a postdoctoral at WHOI's Marine Chemistry & Geochemistry Department

By taking into account the lid's persistence, which designers are not considering currently, co-advisor Christopher Reddy, who's the senior scientist in WHOI's Marine Chemistry & Geochemistry Department, said this metric has been “groundbreaking,” as it shifts the narrative from defining the problem to arriving at solutions.

As co-author and co-advisor Collin Ward, associate scientist in WHOI's Marine Chemistry & Geochemistry Department, noted, given the fact that plastics have high utility, “they're not going anywhere anytime soon.” However, everyone agrees with the problem of plastic pollution and how much it is leaking into the environment. Ward said:

“The framework presented in this study represents an important first step towards solving this problem by designing materials that simultaneously meet the needs of consumers and do not persist if incidentally leaked into the environment.” 

Click here to learn how from fetus to adult, microplastics are polluting our bodies.

Companies Developing Novel Solutions to Remove Plastic Waste

With plastic pollution becoming a critical issue, many companies worldwide are working on solutions to removing plastic waste from waterways, such as:

1. SUEZ Group

This European company focuses on water cycle management and waste recycling and recovery solutions globally. SUEZ Group has nearly 1700 patents and ten research centers to protect the environment.

The company shares are listed on the Euronext exchanges in Paris and Brussels and are currently trading at EUR 19.83. In September 2023, it signed two new contracts for water and waste projects to support China's 2060 carbon neutrality ambition further.

2. Clearwater Mills

The company built Trash Wheels to address river waste and has so far picked up a total of about 2,000 tons of trash. The way it works is that containment booms are configured in a V-shape across the river with rubber skirts just under the water's surface to catch the trash and channel it to the rotating water wheel that lifts trash out of the river.

Conclusion

To address the serious issue of plastic pollution, it is crucial to both understand the problem and discover new approaches to tackle it. As we have seen, studies are being conducted to examine plastics at the microscopic level and assess the threat they pose to ecosystems and human health. Additionally, scientists are working on various strategies to reduce plastic production and enhance the design and materials of plastic items. Collectively, these efforts assist designers, scientists, and companies in making a significant impact on the plastic pollution crisis.

Click here to learn about recent dive surveys that show a need for innovative waste collection solutions.