For the past 30 years, the Ocean Conservancy has been organising coastal clean-ups every September, involving half a million volunteers in 100 countries. The volunteers pick up trash in beaches, waterways and oceans and this gives an annual global snapshot of the most persistent and proliferating form of marine debris.
“What we’ve seen in the past three decades is an exorbitant amount of trash being picked up, over 200 million pounds (90 million kilos). The collected items span a wide variety of ordinary and extraordinary things, but what is clear is that the bulk of it is disposable plastic packaging,” says Nicholas Mallos at a symposium on marine litter held during the United Nations Environment Assembly in Nairobi in late May.
The director of the NGO’s Trash Free Seas programme says research in 2010 estimated that some eight million tonnes of plastic leaked into the ocean. If this trend continues, the ocean could contain a tonne of plastic for every three tonnes of fish by 2025. Over 150 million tonnes of plastic debris are fouling the seas, based on estimated leaks per year since 1950.
A study by Ocean Conservancy, as detailed in its report Stemming the tide, shows that the bulk of the plastic waste in the ocean comes from five countries – China, Indonesia, Vietnam, Thailand and the Philippines.
“All this plastic is a consequence of rapid development in these countries, where we see the economy booming and an emerging middle class with increasing consumption of plastic and consumer goods. But what we’re not seeing is a similar amount of waste management taking place in these countries. This mismatch has been highlighted by various research as a reason why plastic is ending up in the ocean,” says Mallos.
He says it is mostly uncollected waste and low-value plastics that end up in the sea. At dump sites, scavengers retrieve PET water bottles and rigid plastics as these have recycling value, but not low-value waste like food wrappers, cling films, shopping bags and composites (food packaging made up of plastic and aluminium layers).
Mallos says lots of waste originate from city outskirts, where people consume goods just like in urban areas but where there is no waste collection. Dumps sited near waterways and coastlines also lead to waste flowing into the sea, especially lightweight flyaway plastics.
Waste that is collected can still find its way to the ocean because of illegal dumping. This happens when haulers are paid upon picking up the trash. “After that, they have no incentive to drive for kilometres to transfer the waste to a proper landfill. They simply dispose the waste in ditches and canals.” The solution in this case, Mallos says, is to pay haulers at the disposal site so that they complete the trip.
After three decades of clean-up efforts, Ocean Conservancy concludes that they are not the cure-all. “We need to look upstream for solutions,” says Mallos. He says just by focusing efforts on improving waste management in the five countries can curtail plastic leakage into the ocean by half in 10 years’ time.
What is needed are better waste collection and plugging of post-collection leakage, followed by the development of recovery and treatment technologies. In the long term, we need to design materials and products that facilitate reuse or recycling, for instance, creating a value for lightweight plastic.
The industry responds
Keith Christman of the World Plastic Council says efforts by the industry to divert plastic waste from oceans include anti-littering and recycling campaigns, promoting reusable water bottles, encouraging good waste management practices, and enhancing recycling efforts.
To deal with the problem of plastic films and bags which are often not collected, the group is working with retail stores. There is now a network of 1,800 sites in the United States that accept plastic films for recycling. The industry also adheres to best management practices to keep raw materials such as plastic pellets out of the environment, through proper storage and recovery.
Christman says substituting plastic with other materials is not the solution to marine litter. “We need to look at what the impact of plastic and alternative materials are and make sure that we design them to be recovered, reused, recycled or used for energy recovery. It’s also important to look at the life cycle so that as we’re looking at new plastics, we’re not creating other challenges such as increasing greenhouse gases and other waste.”
He says the industry is looking at developing alternative materials that are biodegradable or bio-based but it is a daunting challenge as they will have to design something that can hold liquids, yet degrade in a reasonable amount of time in the highly variable marine environment, be it at the water surface or seabed, and areas with different temperatures.
“So it isn’t one environment to degrade in, and finding one material that meets all those challenges, yet is economical, and can be recovered in existing systems, is very challenging. We would not want to put in place a material that can become a contaminant in existing recycling programmes,” says Christman.