Plastic was first discovered in 1907, and it was the first completely synthetic compound with not a hint of natural substances in it. It has since undergone rapid and substantial evolution and found its way into a number of applications to a point where, today, one can barely imagine a world without plastic. Given its myriad uses, we now find ourselves in a practically “plastic-dependent age” where we have come to think of it more as a necessity than as a convenient alternative.

In the recent past, amid the massive efforts to halt climate change, biodegradable plastics have been created. Yet, these are slow to adoption and most plastic used today remains non-biodegradable. Moreover, biodegradable plastics are the product of only the recent past. Over the century that came before, the steadily increasing use of plastic led to its increasing accumulation in the environment. Today, pollution from this accumulated plastic has become a matter of global concern.

A large part of this concern is the fact that plastics in the environment can degrade into miniscule particles known as “microplastics”, which not only remain in the environment for years without completely decomposing, but also find their way into places that plastics otherwise would not, such as in food. This makes microplastics a major threat to not just humans but all living organisms that come in direct contact with them.

Microplastics are also formed of chemical additives used to enhance the durability, ease of manufacturing and uses of plastic. Examples of chemical additives could be pigments, stabilizers, fillers, antioxidants, ingredients in cosmetics, and so on. Most of these materials are toxic in their free state. When our waste eventually finds its way into the oceans (through the sewage system) or landfills and remains there, these additives gradually and constantly leach into the surroundings, reaching hazardous levels. In the oceans, they can also be ingested by marine creatures and travel across the food chain. From landfills, they can leach into the groundwater table or be consumed by scavenging animals. And when they’re small enough, they can diffuse into air and travel considerable distances, to be inhaled or ingested.

Quantifying these minute particles in the environment is a challenge. These additives typically behave differently when free than when bound. Further, different additives in a piece of plastic material leach into the environment at different rates and up to different distances. Thus, their amounts either in residual waste or in the environment at a particular place do not accurately reflect risk of exposure.

This is part of the concern associated with microplastics and plastic additives in the environment and why much research in the field has focused on finding risk assessment and measurement methods. In a breakthrough in this effort, a team of researchers from Incheon National University in Korea has come up with a novel reference index that could change the game. They’ve done this by taking the case of marine pollution by styrene oligomers (SOs), which are components of polystyrene containing materials, one of the most widely used type of material found in disposable plastics to plastics for insulation, and latex. Being estrogenic in nature, SOs can interfere with normal hormone and thyroid functioning, causing adverse effects.

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