The Age of Plastics
This could be our future! Let’s take this pledge to reduce our carbon footprint today!
(This image is from a project called Plastic Ocean where an Austrian artist named Andreas Franke submerged 24 portraits (for a period of 4 months) into the sea off the coast of Key West to raise awareness about how plastics are suffocating our oceans!)
We are in the middle of a pandemic where a minuscule virus has reminded us that we are not as invincible as we delude ourselves into thinking. Indeed, we have nobody but us to blame for it. It is quite tragic how easily we deny that we are just one species out of millions of other species on this planet and like each one of those species, our survival depends on the preservation of a fragile and intricate balance between opposing forces present in our ecosystem.
Yet, like recidivists, we keep repeating this crime over and over again. It is quite obvious that COVID-19 is just one of the many symptoms of our planet’s ailing health. Incidents of extreme weather events like cyclones, wildfires and floods caused due to climate change are rising globally and impacting millions of lives all over the world.
The great lockdown has done something unthinkable and like an unbalanced force, it has caused a sudden change in our quotidian “motion”. For the past several months we have been left with no choice but to sit in front of our TV screens and witness the consequences of our cumulative actions. I am hoping that each one of us would have spared at least a moment, to reflect over what we have done and how can we bring a change?
Out of the numerous ways we harm our planet every day, one that is literally choking up our environment is something that was considered an engineering triumph at the time. I am talking about plastics. Just look around you for a moment, from your laptops to credit cards, from your toys to cars, from your eyeglasses to earphones, from your footwear to furniture, plastics are everywhere! If you step outside of your house, from top of the mountains (including the highest peak on Earth, Mount Everest) to the depths of the ocean (including the deepest point on Earth, Mariana Trench), plastic materials have reached places where even humans usually can’t. Microplastics (extremely small pieces (< 5 millimeters) of plastic which results from the breakdown of plastic commodities) have been found in the most unlikely places like the gut of seabirds, the core of Arctic ice and even human lungs!
As someone who claims to be a lover of nature, I feel uncomfortable every time I use something made of plastic. Only, it seems like a Hobson’s choice! Is it even possible to live without plastics? I am sure most of you share these feelings with me. But in this fast-moving world, since almost everything we consume comes wrapped up in plastic, the idea of living a plastic-free life seems unfathomable. In the following paragraphs, we will try to find out if it is possible to save our planet from drowning in plastic and how?
What are plastics?
Plastics are a family of synthetic or semi-synthetic high molecular weight organic polymers, mostly derived from petroleum derivatives (obtained from coal, crude oil, or natural gas), which are capable of being molded into various shapes. In fact, the word plastic is derived from a Greek word plastikos which means “fit for molding”. Due to this unique property, plastics are extremely versatile and therefore, have ubiquitous applications.
A polymer is a substance which is composed of a network of smaller subunits called monomers which are bound together in chain-like structures. They are not some strange compounds brewed in laboratories. In fact, polymers are commonly found in nature. Cellulose, the material that enables the tree trunks strong enough to hold up the tallest trees, is one of the most abundant polymers present in nature.
Depending on the subunits that they are composed of, and the way these subunits are organized structurally, plastics can be of many different types. However, the main types of plastics that are manufactured are low density polyethylene (LDPE) or linear LDPE (LLPDE), polyethylene terephthalate (PET), high density polyethylene (HDPE), polypropylene (PP), polystyrene (PS), polyvinyl chloride (PVC), polyurethane (PUR), high performance polyamide (PPA). However, plenty of other types of plastics are also produced in great variety. The fractions of total plastic waste generated due to each of these types divided based on their application sector is shown in Fig. 1.
Fig. 1 : Global plastics use by polymer and sector (data based on a 2015 study).
Plastics last forever!
The mass production of plastics started in the 1940s without a proper deliberation over their long-term effects on the environment. Even with what we know now, they continue to be produced in unprecedented amounts. Since the 1940s, the global production of plastics has increased nearly 200 times and now more than 300 million tonnes of plastics are being produced every year. We generated a total of 6.3 billion tonnes of plastic waste between 1950 and 2015 of which only 9 % was recycled, only 12 % was incinerated but the rest 79 % of it is either being stored in a landfill somewhere or worse, has escaped into our natural environment. Just in the year 2015, primary plastic production (newly produced plastic) was 407 million tonnes of which, around 75 % (302 million tonnes) ended up as waste. This massive scale of production and wastage becomes a nightmare since plastics are non-biodegradable materials. Since plastics are not a product of nature, micro-organisms that can easily breakdown complex natural polymers like cellulose and silk, simply can’t recognize plastic as food material (However, it is well known that micro-organisms have highly adaptive nature. Therefore, researchers are on a lookout to find out if a bacterium/yeast have evolved the ability to degrade plastic). As a result, the same properties that make plastics so versatile and useful also make it extremely resistant to biodegradation. Depending upon its structure and the process of manufacturing, a piece of plastic can last up to several hundred years’ in our environment (see Fig. 2).
Biodegradation is a process where a substance is broken down by living organisms into their constituent parts which are then recycled through natural cycles to act as new building blocks for life. Since most living organisms require oxygen to survive, therefore, biodegradation is effective under oxygen-rich conditions.
By these estimates, every single piece of plastic ever made is still lying around somewhere on our planet! Let me put it this way, the pacifiers that you used as an infant, your diapers, even your first toothbrush, they are probably piled up somewhere in a landfill or on the seabed. The amount of plastic we consume in a single day, add thousands of years’ worth of garbage in our environment. Biodegradation of plastics is slowed down even further due to the highly compacted and ergo, oxygen-deficient conditions present in landfills. Therefore, it becomes important for us to (a) be mindful of the amount of plastics generated and (b) make sure that the amount of plastic produced is not mismanaged which increases its probability of entering our environment. The current state of plastic production and waste mismanagement is evident from Fig. 3 and Table 1.
Should we ban them?
The question is, if they are so bad for the environment, shouldn’t we just stop using them? The answer is, we can’t, or we probably shouldn’t! It might sound ridiculous now, but plastics were actually invented to save wildlife from human exploitation. Despite the fact, that they are a growing environmental catastrophe, it can’t be denied that they made the modern world possible.
Plastics have innumerable benefits. They are lightweight, tough, transparent, waterproof, corrosion-resistant and so forth. No wonder they have permeated into all facets of modern life. They prevent food wastage by keeping agricultural produce fresh for a longer period, prevent spread of infections through single-use disposable syringes and healthcare supplies, they are used as biocompatible materials for surgical implants and medical procedures like tissue engineering. Being light-weight, they are also less fuel-intensive which results in reduced greenhouse gas emissions. They are even required to manufacture PPE (personal protective equipment) like gloves, masks and Hazmat suits, and therefore, are indispensable in fighting the current COVID-19 pandemic.
But we should have other substances that can provide these benefits, right? Ummm…the answer is trickier than you probably might imagine. Alternative materials like glass and metal aren’t as energy-efficient, cheap, versatile or durable as plastic. Another alternate, paper, comes with its own set of problems. According to the British Plastics Federation, the use of these alternative materials against plastic would result in 2.7 times more greenhouse gas emissions over their complete lifecycle. So, it seems that the solution doesn’t lie in eliminating plastics from our lives but rather in finding a sustainable way of utilizing their amazing properties.
How can we solve this conundrum?
Is there a way we can continue using plastics without damaging our environment? Well, there is, but it will require us to redesign the complete product cycle of plastics from its production to disposal. Basically, we can divide this plastic problem into three categories:
a. Plastics are produced mainly using fossil fuels which are already rapidly depleting (Production problem)
b. Massive production of plastic globally which creates logistic problems regarding its proper management (Consumption problem)
c. Escape of plastic material into the environment and its resistance to biodegradation (Disposal problem)
Fortunately, we can turn the tide by implementing a three-part solution as shown in Fig. 4 which is explained further below.
Fig. 4: New approaches to Life Cycle Assessment (from production to disposal) of plastics are required
a. Abstinence from fossil feedstocks
In order to achieve the envisaged aim of circular economy, researchers have been looking for alternate renewable resources that can replace petrochemicals as raw materials for plastic production. Studies are being conducted to test the potential of non-conventional feedstocks like methanol/formate (easily produced from CO2 via electrochemical catalysis), glycerol (a by-product of biodiesel synthesis) and even plastic hydrolysates to abstain from using fossil fuels as raw materials. Harnessing anthropogenically produced CO2 as the feedstock is being considered as the future of the carbon-reduced chemical industry.
The progress in this area is evident from the fact that several of these bio-based plastics such as thermoplastic starch and polylactic acid are already being produced commercially. These bio-based plastics are relatively easy to compost and are gaining more and more attraction.
b. Ethical consumerism
There is no challenging the fact that it’s time to rethink the way we manufacture, use and dispose of plastic items. We need to understand that just dollar voting won’t make a significant impact unless we make conscious changes in our lifestyle to reduce our carbon footprint on a daily basis. This will require a shift from “produce-consume-dispose” approach to a “reduce-reuse-recycle” culture. Besides policy changes like national level bans on single-use plastics (at least for non-essential items like carrier bags), as a society we need to put pressure on governing bodies/corporate giants to incentivize sustainable innovation and green economy.
This starts with improving waste collection systems and addressing the full plastics value chain so that plastics can be redesigned, replaced, recovered, and recycled. Establishment of better waste management systems by improving source segregation; designing effective municipal solid waste plans; ensuring collection and transportation of segregated waste, would allow waste plastics to be captured before they begin creating problems in the natural environment.
Researchers from all over the world have been working on improving the ways we handle our plastic waste by designing new waste management programs especially in developing countries like Kenya, India and Bangladesh.
c. Biodegradable plastics coupled with efficient waste management programs
The fact that conventional plastic materials display great resistance to biodegradation, is a major factor in making plastic pollution a huge global catastrophe. Keeping this in mind, chemists are trying to modify these organic polymers such that they become compostable. For instance, a group of scientists have developed processes to convert non-biodegradable plastics such as PET, post-consumer polyethylene and polystyrene into their biodegradable counterparts, polyhydroxyalkanoates, using a combination of chemical and biotechnological methods.
Although, if we replace all the petrochemical-based plastics with bio-based plastics (synthesized using biomass) that are still non-biodegradable or on the other hand, by conventional plastics that have been modified to become biodegradable, we will still solve only half of the problem. Therefore, researchers are now coming up with new plastic materials that are not only produced using renewable biological materials but are also easily degraded by the micro-organisms present in our environment.
Bioplastics is a term that is often used for plastics that are produced using biological material. However, they are not necessarily biodegradable as well (Not all bioplastics are biodegradable and also, not all biodegradable plastics are bioplastics). Therefore, plastics that are made using biomass and are also biodegradable constitutes a fraction of bioplastics (see Fig. 5) (the interested reader is also referred to check out this paper on various types of bioplastics: http://www.biomed.cas.cz/mbu/folia/).
Fig. 5: Schematic representation of various types of bioplastics and the different approaches that are generally used to produce them. As is clear from this figure, bioplastics can also no non-biodegradable. (Source: https://doi.org/10.1016/j.cogsc.2019.12.005)
It is important to understand the difference between a biodegradable plastic and a bio-based biodegradable plastic because only the latter can be essentially called truly eco-friendly. Although they are already being produced commercially, the biodegradable plastics like polylactic acid often lack the desired properties. This limitation is usually overcome by blending them with other non-biodegradable polymers, partially defeating the original purpose.
Novel innovations like production of compostable plastics using potato peels, microalgae, cactus, mushrooms will hopefully become the norm in near future. However, all these innovative ideas won’t be enough to save our planet, if we do not change the way we treat our environment. COVID-19 should be a lesson for humanity that viruses, pollution and climate change know no borders. These are global problems and each one of us will be affected by them irrespective of the colors of our skin or the countries we live in. Therefore, the future should be envisioned with a sustainable and resilient whole-system based approach where technological innovations are made while keeping our environment’s health in mind, always!