Polythene bags are everywhere – literally – and the world is not sure how to deal with them. Shopping bags made from polythene have become ubiquitous, showing up everywhere from the summit of Mount Everest to the deep ocean floors to polar ice caps.
The main concern is the environmental challenge they pose. There have been attempts to create environment-friendly alternatives but nothing has worked – until now. A Bangladeshi scientist says the South Asian country has the answer.
Professor Dr Mubarak Ahmed Khan and his team have created a type of polythene from jute cellulose that looks and feels like plastic but – according to him – is ‘completely’ biodegradable.
“This means, the bag will not cause any harm to the environment when it decomposes,” Dr Mubarak, a scientific adviser to Bangladesh Jute Mills Corporation, told UNB. “The colour used in the bag is extracted from vegetables and the binder is the same edible one used in capsules.”
The bag, named ‘Sonali’ after the moniker of jute, can support more weight than conventional polythene bags, he says. It can survive about five hours in water and gradually melts after this period. It takes the bag five to six months to decompose on land.
“If the bag is thrown into water, it’ll decompose and become food for fish because it has cellulose. Burn it, you’ll get ashes that can be used as fertiliser,” he says. “It’s compostable and biodegradable.”
Dr Mubarak says the so-called biodegradable polythene bags that are coming to the market are mostly made from starch and they contain plastic. “What makes our biopolymer stand out is that it doesn’t have any plastic in it,” he says.
A lasting affair
Polythene bags are cheap to make and durable. By 1979, shortly after they became available, polythene bags controlled 80% of Europe’s bag market, according to UN Environment. In the following years, they replaced almost all paper bags around the world.
Last year, the UN estimated that polythene shopping bags were being produced at a rate of one trillion a year.
But they take hundreds of years to decompose. After breaking down, polythene bags turn into microplastics and nanoparticles that contaminate the soil and water. Scientist Jacquie McGlade told a UN conference that microplastics had been detected in environments as remote as a Mongolian mountain lake and deep sea sediments.
Humans are affected when these particles enter the food chain. The adverse effect of polythene on the marine life is well documented. They are said to have the same effect on human beings just as they have on the environment.
A 2016 UN report called Frontiers noted that the presence of microplastic in foodstuffs could potentially increase direct exposure of plastic-associated chemicals to humans and may present an attributable risk to human health.
Last year, scientists found microplastics in human stools for the first time. The finding suggests that they may be widespread in our food chain.
“Polythene is like poison,” Dr Mubarak says. “One should not drink it even if it is given for free.”
The ‘Golden’ Hope
There is no data on the daily or annual demand and production of polythene bags in Bangladesh. An environmental organisation estimated last year that the residents of capital Dhaka use 14-15 million pieces of polythene bags every day.
Polythene is considered to be one of the main reasons for the clogging of drains. In 2002, Bangladesh banned thin polythene, becoming the first country in the world to do so.
Eight years later, the government formulated the Mandatory Jute Packaging Act making the use of jute bags compulsory instead of plastic sacks for packing paddy, rice, wheat, maize, sugar and fertiliser.
But lax implementation of the law means polythene bags are still widely available and used throughout the country.
Dr Mubarak says he chose jute because of its abundance in Bangladesh. Only 30% cellulose can be extracted from a full-grown tree but jute has 70% cellulose and needs about three months to mature.
It took the scientist and his team about a decade to invent Sonali Bag.
“We started around 2008 and had a breakthrough about seven years later. We finally made it in 2017,” he says. The research was government funded.
Bangladesh is in talks with a foreign company for sourcing machines to start commercial production. Dr Mubarak says cost is one of the barriers to the bag’s popularity. “The price will come down when we go into mass production,” he says.
“But if you consider the environmental cost, then a Tk-10 Sonali Bag is cheap,” the scientist says. “Because of its properties, it can be a substitute not just for traditional polythene bags, but also other plastics.
This report is produced by United, News of Bangladesh (UNB) and, Inter Press Service (IPS)