Plastic debris in oceans -- a growing hazard

Mushfiqur Rahman | Published: June 29, 2018 21:19:02 | Updated: June 29, 2018 21:20:37

An outcry has been growing across the globe in recent times following the rapid increase of plastic wastes in the land and sea. The conservative estimates published in the documents of the United Nations Environment Assembly suggest that the plastic wastes cause damage worth annually $13 billion to the global marine ecosystems. For marine creatures like fishes, dolphins, seabirds and seals, plastic waste can be deadly as they get entangled with or mistake it for food. Plastic particles can be ingested by various marine fishes and organisms. Plastic wastes potentially accumulate and deliver toxins through food chain to other living organisms.

There was a news item covered by Japan-based NHK TV on June 24, 2014 that read "the environment ministers of Japan, China and South Korea have agreed to work together to address ocean pollution caused by microplastics and other wastes."

As per published reports, approximately 8.0 per cent of the world's oil production is used to make plastic products. Estimates suggest that manufacturing of plastic products will consume 20 per cent of world's oil productions within 2050. The world's population was approximately 2.5 billion in 1950 and the plastic manufacturers at that time produced 1.5 million tonnes of plastic annually; the global population in 2016 reached over 7.0 billion and UNEP estimates that approximately 300 million tonnes of  plastic wastes are now being produced annually. As per estimates in 2015, one million plastic beverage bottles are sold every minute around the world. Half of the world's plastics are made in the countries of Asia and nearly 29 per cent of the produced plastics are manufactured in China. Nearly 40 per cent of plastic is used in packaging just for a single use and then discarded. Nearly 18 billion pounds of plastic wastes flow into the oceans every year. One estimate says that there may now be around 5.25 trillion macro and microplastics pieces floating in the open ocean -- weighing up to 269,000 tonnes.

As maritime wastes reach critical levels, South Korea, Japan and China are working together on a solution to abate plastic-related pollution. Officials from the three nations agreed to joint research and cooperation. The ministers met to discuss environment issues in the eastern Chinese city of Suzhou on that day and agreed to discuss the issue the next year at a ministerial meeting on energy and the environment on the sidelines of the G20 summit in Japan. They also said that their countries would step up measures and cooperation to help address the issue of marine pollution in Asia. Japanese Prime Minister Abe earlier said that a large quantity of plastic wastes had been washed ashore along the Japanese coast and the problem of marine pollution could not be solved by a single country. Japanese  government considers that plastic pollution can be effectively addressed if a balanced recycling and reduction strategy is worked out and implemented within a global framework of cooperation. Researchers have been calling for serious international efforts to change the way wastes are managed. Scientists warn that the size of plastic wastes in the oceans could rise 10-fold during the next decade unless effective marine pollution reduction programmes are implemented.

The Science Advances journal (July 2017) published a research paper with a calculation of the total volume (8.3 billion tonnes) of all plastic products so far (over the last 70 years). Of the volume, some 6.3 billion tonnes became wastes and 79 per cent of those are in landfill or in the natural environment, including the world oceans.

The United Nations Environment Programme (UNEP) marking the World Environment Day 2018 published their report on the production and use of plastic products worldwide. Among others, the report contains information that says around 73,000 tonnes of plastic wastes end up in the Bay of Bengal everyday through the Padma, Jamuna and Meghna rivers in Bangladesh. The plastic wastes that fall in the Bay of Bengal contains wastes produced in Bangladesh territory and the same from India, Nepal and China floating down the Ganges, Yamuna and Brahmaputra.

According to UNEP, a significant portion (roughly 8.0 million tonnes) of the world's plastic wastes each year fall into the seas via 10 river basins. Eight of the 10 rivers based in China. Among those, Bangladesh is directly affected by Brahmaputra pollution.

Bangladesh also produces 3,000 tonnes of plastic wastes every day. Of these, a very little portion of the plastic wastes accumulate in the sea. The waste from Bangladesh along with those coming from China, Nepal and India accumulate in domestic rivers, water bodies and pollute the land and cause serious threat to environment and human health.

According to the UN environment authority, Thailand is the sixth-biggest polluter in terms of plastic wastes that end up in the ocean. The world's top four plastic polluters are all in Asia, including China that releases (2.22 million tonnes of plastic wastes every year), Indonesia with 1.29 million tonnes, followed by the Philippines and Vietnam.

"One emerging issue is the increasing use of microplastics directly in consumer products, such as 'microbeads' in toothpaste, gels and facial cleansers," reports the UNEP Year Book. "These microplastics tend not to be filtered out during sewage treatment, but are released directly into rivers, lakes and the ocean." Synthetic clothes also shed microfibers, which are flushed from washing machines into waste water, and into streams, rivers and oceans.

According to one of the foremost researchers in the field Professor Takada, who serves the laboratory of organic geochemistry at Tokyo University, 90 per cent of microplastics come from plastics that we use in our daily life. Plastics decay and break into small pieces when become exposed to ultraviolet rays in strong sunlight. When they break in tiny particles, they are easily carried offshore and accumulate in the oceans.

Microplastics also absorb pollutants from the ocean. Among the chemicals that stick to them are carcinogenic and highly toxic PCBs (polychlorinated biphenyls), industrial chemicals that were widely used in electric appliances until 1970s, and PBDEs (polybrominated diphenyl ethers) that are used as flame retardants and affect thyroid function. Many plastic products contain toxic additives to increase their durability, such as nonylphenol, an endocrine disruptor that can cause breast cancer or endometriosis. Professor Takada, however, considers that 'such chemicals are hard to dissolve in water but are soluble to oil and fat' as plastic is made from petroleum'.

The first step for controlling plastic wastes is to reduce our reliance on plastic items. We may turn down plastic bags at the shopping centres and reduce our consumption of plastic water bottles (for single use). The 3R campaign - reduce, reuse and recycle - should be promoted for waste reduction effectively.

Mushfiqur Rahman, a mining engineer, writes on energy and environment issues.

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