How do plastics impact on our health?
Plastics are abundant in everyday human life. They package the foods we eat, they are in the toys we buy and are even found in the clothes we wear. Plastics, polymers made from crude oil, are renowned for their durability and longevity, and can withstand environmental factors for decades. These characteristics are what make plastics so appealing for commercial uses and why they are found in most everyday items. However, it is this love of plastic that has caused an overproduction of the product. Most plastics contain harmful chemicals that, as the plastic is frequently used and exposed to high temperatures, can leach out and infect animals and humans. Alternatively, the versatility of plastics have also contributed to many benefits of modern living, like allowing foods to be kept for longer, storing and supplying water safely, and making more medical practices possible.
How plastics are made: The formation of plastics began millions of years ago. Organic matter, such as the simple life forms of plankton, died and fell to the seabed, and consequently became covered over the years with layers of sediments. As the matter was continually buried deeper and deeper, it was subject to increasing temperatures and pressures, which converted the plankton remains into crude oil and natural gasses. However, in order to convert this crude oil into different forms, like plastic, it must first undergo a process called fractional distillation. This distillation process involves the separation of the heavier crude oil into lighter groups, called fractions. These fractions are a mixture of hydrocarbon chains, and each differ in size and structure. It is one of these fractions, naphtha, that is crucial for the production of plastics to occur. Naphtha undergoes another splitting process, called cracking, where it is broken down into even smaller hydrocarbon molecules. These hydrocarbons, such as ethylene and propylene, can now be joined through two different processes, either polymerisation or polycondensation, to create different plastics. There are two main groups of plastics; Thermoplastics, and Thermosets. Thermoplastics can be melted and reshaped an infinite number of times, whereas thermosets cannot change shape after their original mould.
Plastics have been a topic of debate over many years because of the harmful chemicals they may contain. One-use plastics, like food packagings, often end up as waste and make their way into our oceans and waterways. Over the years they break down into smaller pieces and act like a sponge to soak up more harmful chemicals. In the oceans, these plastics are mistaken as food by the fish we eat, causing us to ingest dangerous chemicals that can severely impact on our health. Direct toxicity from plastics can come from lead, mercury and cadmium, but some plastics can also leach out carcinogens and chemicals that can harm human development. Bisphenol-A, or BPA, a damaging chemical that is constantly shunned in the news, is the main building block for polycarbonate plastics, like water bottles and food packaging. The bonds in BPA can break down over time from constant stress, pressure and heat, and free the structure of the chemical, which is toxic. BPA has been recognised since the 1940’s as an endocrine (hormonal glands) disruptor, - meaning it can affect normal hormone function and development - and is also linked to cancer, impaired immune function and obesity. Another worrying aspect of plastics and the harmful chemicals within them, is their use in the medical field. Toxic components like di-ethylhexyl phthalate, DEHP, can contribute to up to 50% of the composition of products like IV bags and tubing. Phthalates like these are known to cause adverse health effects like cancer, miscarriage, asthma and abnormal male sexual development, because they aren’t chemically bonded to plastics and can therefore easily filter out and cause harm.
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Future Direction for Chemical Technology
Plastics have greatly contributed to the comfort we experience in modern living and the technologies associated with plastics are continually being developed. 3D printing is a major step forward for the advancement of the uses of plastics. 3D printing allows for plastics to have a wider range of uses in the medical field, such as for developing prosthetic appendages and organs. Scientists have also developed biodegradable plastics, known as bio-plastics, so as to combat the issue of plastics persisting in the environment for centuries. These bioplastics can either be put back into the environment and be composted by microorganisms, or can be recycled. Bio-plastics provide a sustainable alternative to regular, crude-oil based, highly chemical, plastics, and have a promising future as they become more thoroughly integrated into modern living.
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