NEW DELHI : The dread has come true. Plastic has entered the food chain and human beings are practically eating plastic inadvertently. The scenario is as such – plastic waste in rivers and oceans gradually breaks into tiny pieces called ‘micro plastics’. These tiny particles enter the food chain, from tiny plankton to fish larvae to fish, including the fish we eat. How this plastic effects human body, it is still being researched.
Chelsea Rochman, an ecologist at the University of Toronto is working on how micro-plastics enter the food chain. As a graduate student, Rochman landed a spot on the research vessel to visit the “infamous Floating Garbage Patch” in the Pacific Ocean. She and other scientists on board were supposed to count the plastic as it drifted by. So, once they sailed into the patch everybody started counting the trash, but soon enough realized that it is a soup of confetti, of tiny little plastic bits andthus stopped counting with a realization that it is not an island of trash that can be picked up. That’s when she decided to make a career in studying this stuff. For further study in this, she picked up Lake Ontario as her spot. It is the area from where she generally collects her specimens.
To demonstrate how plastics get into fish’s system, Bucci, Rocham’s student prepared micro plastics from morning’s collection. She took postage stamp size piece of black plastic and grinded it to particles and then pushed this into a beaker containing fish larvae. Then, she drew out certain larvae and it was observed that the larva’s gut was translucent and weirdly shaped black things could be seen on the inside. This plastic can also penetrate the fish’s tissues.
Most plastic is inert, i.e. does not react chemically with other substances and thus is resilient, durable and also doesn’t degrade easily. But, over time, plastic can break down and shed the chemicals that make it useful; such as Phthalates and Biphenyl A. These substances are common in the environment and their effects on human health are of concern.
Plastic also attracts other chemicals present in the water that latch onto it, including toxic compounds like polychlorinated biphenyls and etc. Thus, it functions as a chemical Trojan horse. Tracking chemicals is the job of researcher Clara Thaysens. Since it is in nascent stages they studied only common types of plastic like polyethylene, polypropylene, and polystyrene. Sincethe chemical
composition of plastics varies considerably, what happens to it cannot be stated clearly.
Bane of Plastic
From the times when plastic was first mass-produced, till now 8 billion tons has been manufactured.It is used rampantly but nobody gives a thought to what happens to it once it is discarded. Whether it completely degrades or remains in the environment though in a form which is not discernible from its previous form. Much of it crumbles into small pieces over time.
Scientists called these tiny pieces “Micro plastics” and define them as objects smaller than 5 millimeters. Scientist started paying serious attention to micro plastics about 15 years ago when it was realized that they were everywhere; in the oceans, rivers, lakes, soil, food chain and etc.