Plastic is present in the environment from our stockings to space crafts, from peaks of the Mount Everest to the deepest parts of the oceans. The wonder substance of the twentieth century has not only dramatically changed our lives but deteriorated the ecological health of Planet Earth. Plastic was invented in 1907 by a Belgian chemist, Leo Baekeland and since then the annual global plastic production has detonated from 1.5 million metric tons in 1950 to 359 million metric tons in 2018. Globally, one million plastic bottles are bought every minute, while up to five trillion plastic bags are used around the world in a year. In total, half of the all plastic produced is designed for single-use purposes to meet our daily life habits where many of the things we utilize regularly are disposable plastic items. A plastic cup to enjoy a hot or cold beverage for five minutes that we use just once and then throw away, may end up in the marine environment where it will last for 500-700 years. According to United Nation Environment Program, seven billion tonnes of plastic waste generated globally so far, less than 10 percent has been recycled. Today, we produce about 4 million tonnes of plastic waste every year. Cigarette butts, food packaging wrappers, plastic bottles, plastic bags, plastic straws are the most common items in plastic waste. We use these goods daily, without being thoughtful about where they might end up. Our modern-day life style of using disposable containers is deadly for other life forms on this planet. We need to remind ourselves that we share this biosphere with millions of other life forms and our existence is associated with the sustainability of all the inhabitants of this planet we depend on directly or indirectly.
It is estimated that 75 to 199 million tonnes of plastic is presently found in our oceans and with global trend of plastic production and utilization, the amount of plastic waste entering aquatic ecosystems could nearly triple from 9-14 million tonnes per year in 2016 to a projected 23-37 million tonnes per year by 2040. Plastics in environment get converted into tiny plastic particles known as microplastics by photochemical, thermal and biological degradation. Microplastics known as plastic particles usually smaller than 5 mm in length, are present in oceans worldwide and can be divided into two types on the bases of their origin; primary and secondary microplastics. Primary microplastics can be made directly from sources such as scrubbers, commercial cleaning abrasives, and plastic pellets whereas secondary microplastics are obtained from breakdown of larger plastic debris through environmental weathering processes. Degradation of synthetic products can also produce secondary microplastics, for example, clothing and carpets. The knowledge about distribution of microplastic has increased greatly over the past two tanners. Microplastics are even seen on populated coastlines, rivers, lakes, deep-sea sediments, sea ice and even inside tissues of marine fauna.
A wide range of marine organisms are in danger due to presence of microplastic pollution, such as zooplankton, benthic invertebrates, fishes, marine mammals and marine birds. Microplastics fall within the size range of prey ingested by zooplankton and planktivorous from where they enter the marine food web. Microplastic pellets with rough edges cause internal scrapping of tissues of the digestive tract, and/or accumulate in the gastrointestinal tract of an organism. Microplastics also serve as vectors of hydrophobic persistent organic pollutants, besides its physical harm caused to marine biota. Students and faculty of Institute of Marine Science, University of Karachi have analyzed microplastics in commercially valuable fishes of 15 different species collected from the Karachi coast. Microplastics of a variety of sizes and forms are recorded in all fishes at an alarming rate. Despite a number of health benefits of fish consumption, accumulation of microplastics and other persistent bio accumulative toxins, raise questions about consuming fishes coming from contaminated environments. Underprivileged fisherman communities in Pakistan who use seafood as their primary food, are more prone to adverse effects of these contaminants.
Whatever is present on this planet is in a continuous perpetual circulation, changing its form from one form to another. Whatever amount of plastic we have discarded, is coming back to us in the form of microplastics in our food. It is high time we change our lifestyle of carelessly using disposable plastic items, otherwise we will have more plastic in our oceans than fish.