Plastic Peril (DownToEarth)

Waste management is key to keeping the oceans free of plastic waste, new research suggests

Marine debris and plastic pollution along Haiti's coastline (Courtesy: Timothy Townsend)

The ocean is the final receptacle of a substantial amount of waste generated on land. Plastic pollution in the ocean was first reported in the scientific literature of the early 1970s. In just four decades, it has become a pressing environmental problem and has been found even in the most remote corners of the earth. The amount of plastic entering the oceans is up to 2,000 times more than earlier estimates.

A study published in the February 13, 2015 issue of the journal, Science, estimated the amount of plastic that could enter the oceans based on the amount of unmanaged waste. The researchers found that anything between 4.8 and 12.7 million tonnes (MT) of plastic enters the oceans each year (see ‘More data collection needed’).

The researchers estimated the quantity of plastic entering the oceans by using 2010 data on solid waste produced, population density and economic status of 192 countries that have a coastline. They found that 275 MT of plastic waste was generated in these countries. They then used a model to estimate the amount of plastic that is likely to enter the oceans every year, depending on the country’s ability to manage waste. The team found that the top 20 countries accounted for 83 per cent of the mismanaged plastic waste entering the ocean. China tops the list and throws 1.32 MT to 3.53 MT of plastic waste in the sea. India is 12th, contributing 0.09 MT to 0.24 MT plastic waste to oceans every year. America is 20th, throwing 0.04 MT to 0.11 MT of plastic trash into the sea every year. However, the amount of waste generated by a person in India is very low compared to that produced by a person in the US. In India, 0.34 kg of waste is produced per day by a person compared to as much as 2.58 kg by a person in the US. In India, only 3 per cent of the waste produced per day by a person is plastic compared to 13 per cent in the US.

The findings are staggering, says Nick Mallos, director, Trash Free Sea programme of Ocean Conservancy, a US-based advocacy group. If things continue unchecked, in 10 years we could see one pound of plastic for every three pounds of finfish, adds Mallos. The concerns are justified considering that global plastic resin production is growing at a fast pace. It registered a 620 per cent increase between 1975 and 2012. Most of this plastic resin is used for packaging, is quickly disposed of and could end up in the sea. In December, 2014, a study published in PLoS ONE revealed that there are 5.25 trillion plastic particles floating around in the sea.

As it would be difficult and expensive to remove plastic from the sea, researchers suggest it would be better to start managing waste. They suggest reduction of waste, expanded recovery systems and extended producer responsibility. The researchers also suggest that while infrastructure is being built in developing nations, industrialised countries can take immediate action by reducing waste and curbing the growth of disposable plastic. If per capita waste generation were reduced to the 2010 average (1.7 kg/day) in the 91 coastal countries that exceed it, and the per cent plastic in the waste streams were capped at 11 per cent (the 192-country average in 2010), a 26 per cent decrease could be achieved by 2025. This strategy would target higher-income countries and might require smaller global investments.

The study underscores the need to shift the ocean conservation dialogue from beach cleanup to waste management to ultimately preventing plastics from entering our oceans. There is evidence that this waste is detrimental to ocean wildlife. “We know that plastic is bad for ocean wildlife and habitats-animals ingest it or can get entangled in it; it litters beaches and can degrade sensitive reef systems. In lab studies, we have seen that plastic has negative impacts on animals that ingest it, and scientists have seen plastic’s impact on more than 660 species of ocean wildlife, including every type of sea turtle, as well as the majority of other marine species like whales, dolphins, seals, and seabirds,” says Mallos. “As far as human health goes, we don’t yet know the full extent of how plastics affect the ocean food chain. However, each new study makes us more, not less concerned,” he adds.

`More data collection needed'

Jenna Jambeck, assistant professor in the College of Engineering at the University of Georgia and lead author of the paper says more data collection would be her next step

How reliable is the model you developed? In India, substantial plastic waste is recycled. Has this been factored in to the model?

Our goal was to make a global estimate of plastic entering the ocean and we used the best available global dataset we could find, which came from the World Bank. Based upon our work, we do feel this global quantification is robust. The paper states that we could not include imports/exports and informal waste management. I have been to India, visiting waste management facilities and landfills and witnessed recycling activity, which is not always reported to the government or World Bank, or quantified at the country level. I think more data collection and quantification for India would be a great next step in this analysis.

You have developed the Marine Debris Tracker app which can track waste. Has this contributed to this study?

The app did not contribute to this work. But it is an action that people can take once they hear about the problem. Marine Debris Tracker is a tool that people can use to report litter anywhere in the world and it will build a global database as more people use it.

How are you planning to take your study forward?

We are trying to add more data from the materials flow standpoint.

Tags: Science & Technology, China, Down to earth, Global, Hazardous Waste, India, Marine Ecosystems, Oceans and Seas, Plastics, Scientists, United States Of America (US), Waste Disposal, Waste Management,