Tons of plastic trash enter the Great Lakes every year – where does it go?

Debris pulled from a Lake Erie marina during a cleanup, June 9, 2012.
NOAA Office of Response and Restoration, CC BY

Matthew J. Hoffman, Rochester Institute of Technology and Christy Tyler, Rochester Institute of Technology

Awareness is rising worldwide about the scourge of ocean plastic pollution, from Earth Day 2018 events to the cover of National Geographic magazine. But few people realize that similar concentrations of plastic pollution are accumulating in lakes and rivers. One recent study found microplastic particles – fragments measuring less then five millimeters – in globally sourced tap water and beer brewed with water from the Great Lakes.

According to recent estimates, over 8 million tons of plastic enter the oceans every year. Using that study’s calculations of how much plastic pollution per person enters the water in coastal regions, one of us (Matthew Hoffman) has estimated that around 10,000 tons of plastic enter the Great Lakes annually. Now we are analyzing where it accumulates and how it may affect aquatic life.

No garbage patches, but lots of scrap on beaches

Plastic enters the Great Lakes in many ways. People on the shore and on boats throw litter in the water. Microplastic pollution also comes from wastewater treatment plants, stormwater and agricultural runoff. Some plastic fibers become airborne – possibly from clothing or building materials weathering outdoors – and are probably deposited into the lakes directly from the air.

Sampling natural water bodies for plastic particles is time-consuming and can be done on only a small fraction of any given river or lake. To augment actual sampling, researchers can use computational models to map how plastic pollution will move once it enters the water. In the ocean, these models show how plastic accumulates in particular locations around the globe, including the Arctic.

When plastic pollution was initially found in the Great Lakes, many observers feared that it could accumulate in large floating garbage patches, like those created by ocean currents. However, when we used our computational models to predict how plastic pollution would move around in the surface waters of Lake Erie, we found that temporary accumulation regions formed but did not persist as they do in the ocean. In Lake Erie and the other Great Lakes, strong winds break up the accumulation regions.

Three-dimensional transport simulations of particle movement in Lake Erie, based on water current models developed by the National Oceanic and Atmospheric Administration.

Subsequent simulations have also found no evidence for a Great Lakes garbage patch. Initially this seems like good news. But we know that a lot of plastic is entering the lakes. If it is not accumulating at their centers, where is it?

Using our models, we created maps that predict the average surface distribution of Great Lakes plastic pollution. They show that most of it ends up closer to shore. This helps to explain why so much plastic is found on Great Lakes beaches: In 2017 alone, volunteers with the Alliance for the Great Lakes collected more than 16 tons of plastic at beach cleanups. If more plastic is ending up near shore, where more wildlife is located and where we obtain our drinking water, is that really a better outcome than a garbage patch?

Average density of simulated particles in the Great Lakes from 2009-2014. Notice that there are no patches in the middle of the Lakes, but more of the particles are concentrated near the shores.
Matthew Hoffman, CC BY-NC-ND

Searching for missing plastic

We estimate that over four tons of microplastic are floating in Lake Erie. This figure is only a small fraction of the approximately 2,500 tons of plastic that we estimate enter the Lake each year. Similarly, researchers have found that their estimates of how much plastic is floating at the ocean’s surface account for only around 1 percent of estimated input. Plastic pollution has adverse effects on many organisms, and to predict which ecosystems and organisms are most affected, it is essential to understand where it is going.

We have begun using more advanced computer models to map the three-dimensional distribution of plastic pollution in the Great Lakes. Assuming that plastic simply moves with currents, we see that a large proportion of it is predicted to sink to lake bottoms. Mapping plastic pollution this way begins to shed light on exposure risks for different species, based on where in the lake they live.

According to our initial simulations, much of the plastic is expected to sink. This prediction is supported by sediment samples collected from the bottom of the Great Lakes, which can contain high concentrations of plastic.

Three-dimensional transport simulation in Lake Erie. Particle color represents depth below the water surface: the bluer the particle, the deeper it is.

In a real lake, plastic does not just move with the current. It also can float or sink, based on its size and density. As a particle floats and is “weathered” by sun and waves, breaks into smaller particles, and becomes colonized by bacteria and other microorganisms, its ability to sink will change.

Better understanding of the processes that affect plastic transport will enable us to generate more accurate models of how it moves through the water. In addition, we know little so far about how plastic is removed from the water as it lands on the bottom or the beach, or is ingested by organisms.

Prediction informs prevention

Developing a complete picture of how plastic pollution travels through waterways, and which habitats are most at risk, is crucial for conceiving and testing possible solutions. If we can accurately track different types of plastic pollution after they enter the water, we can focus on the types that end up in sensitive habitats and predict their ultimate fate.

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Of course, preventing plastic from entering our waterways in the first place is the best way to eliminate the problem. But by determining which plastics are more toxic and also more likely to come into contact with sensitive organisms, or end up in our water supply, we can target the “worst of the worst.” With this information, government agencies and conservation groups can develop specific community education programs, target cleanup efforts and work with industries to develop alternatives to products that contain these materials.

Matthew J. Hoffman, Associate Professor of Mathematical Sciences, Rochester Institute of Technology and Christy Tyler, Associate Professor of Environmental Science, Rochester Institute of Technology

This article was originally published on The Conversation. Read the original article.

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The plastic waste crisis is an opportunity for the US to get serious about recycling at home

Conveyors carry mixed plastic into a device that will shred recycle them at a plastics recycling plant in Vernon, California.
AP Photo/Reed Saxon,File

Kate O’Neill, University of California, Berkeley

A global plastic waste crisis is building, with major implications for health and the environment. Under its so-called “National Sword” policy, China has sharply reduced imports of foreign scrap materials. As a result, piles of plastic waste are building up in ports and recycling facilities across the United States.

In response, support is growing nationally and worldwide for banning or restricting single-use consumer plastics, such as straws and grocery bags. These efforts are also spurred by chilling findings about how micro-plastics travel through oceans and waterways and up the food chain.

I have studied global trade in hazardous wastes for many years and am currently completing a book on the global politics of waste. In my view, today’s unprecedented level of public concern is an opportunity to innovate. There is growing interest in improving plastic recycling in the United States. This means getting consumers to clean and sort recyclables, investing in better technologies for sorting and reusing waste plastics, and creating incentives for producers to buy and use recycled plastic.

Critiques of recycling are not new, and critiques of recycling plastic are many, but I still believe it makes sense to expand, not abandon, the system. This will require large-scale investment and, in the long term, implementing upstream policies, including product bans.

Plastic litter on California beaches has decreased since the state banned single-use plastic bags in 2016.

Easy to use, hard to destroy

Plastics make products lighter, cheaper, easier to assemble and more disposable. They also generate waste, both at the start of their life cycles – the petrochemicals industry is a major source of pollution and greenhouse gas emissions – and after disposal.

The biggest domestic use by far for plastic resin is packaging (34 percent in 2017), followed by consumer and institutional goods (20 percent) and construction (17 percent). Many products’ useful lives can be measured in minutes. Others, especially engineered and industrial plastics, have a longer life – up to 35 years for building and construction products.

After disposal, plastic products take anywhere from five to 600 years to break down. Many degrade into micro-plastic fragments that effectively last forever. Rather like J.R.R. Tolkien’s One Ring, plastics can be permanently destroyed only through incineration at extremely high temperatures.

Why the United States recycles so little plastic

Less than 10 percent of discarded plastics entered the recycling stream in the United States in 2015, compared with 39.1 percent in the European Union and 22 percent in China. Another 15 percent of U.S. plastic waste is burned in waste-to-energy facilities. The remaining 75 percent goes to landfills. These figures do not include any dumping or illegal disposal.

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Even the most easily recyclable plastics have a lengthy journey from the recycling bin to their final destinations. Many barriers have become painfully apparent since China, which until recently accepted half of all U.S. plastic scrap, implemented its crackdown on March 1, 2018.

First, there are many different types of plastics. Of the seven resin identification codes stamped on the bottom of plastic containers, only 1’s and 2’s are easily recyclable. Public education campaigns have lagged, particularly with respect to cleaning and preparing plastics for recycling. Getting consumers to commit to more stringent systems is critical. But scolding can backfire, as experience with food waste shows.

Another factor is U.S. reliance on single-stream recycling systems, in which all recyclables are placed in the same receptacle. This approach is easier for consumers but produces a mixed stream of materials that is difficult and expensive to sort and clean at recycling facilities.

The United States currently has 633 materials recycling facilities, which can clean, sort and bale a total of 100,000 tons of recyclables per day. Today they are under growing pressure as scrap piles up. Even before China’s restrictions went into effect, materials recycling facilities operators threw out around half of what they received because of contamination. Most are not equipped to meet China’s stringent new contamination standards, and their processing rates have slowed – but garbage production rates have not.

Finally, since China was the U.S. plastic scrap market’s main buyer, its ban has eliminated a key revenue stream for municipal governments. As a result, some waste collection agencies are suspending curbside pickup, while others are raising prices. All 50 states have been affected to some extent.

Over 70 percent of U.S. plastic waste goes to landfills.
USEPA

No silver bullets

Numerous public and private entities are working to find a more viable solution for plastics recycling. They include plastics producers and recyclers, corporations such as Coca-Cola, colleges and universities, foundations, international organizations, advocacy groups and state governments.

Upgrading materials recycling facilities and expanding domestic markets for plastic scrap is an obvious priority but will require large-scale investments. Increasing waste-to-energy incineration is another option. Sweden relies on this approach to maintain its zero waste model.

But incineration is deeply controversial in the United States, where it has declined since 2001, partly due to strong opposition from host communities. Zero-waste and anti-incineration advocates have heavily criticized initiatives such as the Hefty EnergyBag Program, a recent pilot initiative in Omaha, Nebraska to divert plastics to energy production. But small companies like Salt Lake City-based Renewlogy are working to develop newer, cleaner ways to convert plastics to energy.

Efforts to cut plastic use in the United States and other wealthy countries are focusing on single-use products. Initiatives such as plastic straw and bag bans build awareness, but may not significantly reduce the problem of plastic trash by themselves. For example, plastic straws account for only 0.03 percent of the plastic that is likely to enter the oceans in any given year.

Industry is starting to push back, with corporations like McDonald’s resisting straw bans. Some U.S. states have passed measures forbidding plastic bag restrictions.

To stem ocean plastic pollution, better waste management on land is critical, including steps to combat illegal dumping and manage hard-to-recycle plastics. Examples include preventing BPA leaching from discarded products, dechlorinating polyvinyl chloride products, on-site recycling of 3D printer waste, and making virgin-quality plastic out of used polypropylene.

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The European Union is developing a circular economy platform that contains a multi-part strategy to increase plastics recycling and control waste. It includes making all plastic packaging recyclable by 2030 and reducing leakage of plastic products into the environment. The United States is unlikely to adopt such sweeping policies at the national level. But for cities and states, especially those where support for environmental protection is strong, it could be a more attainable vision.

Kate O’Neill, Associate Professor, Global Environmental Politics, University of California, Berkeley

This article was originally published on The Conversation. Read the original article.

Curious Kids: What sea creature can attack and win over a blue whale?

Blue whales are the largest creatures to have ever lived on Earth.
Shutterstock

Wally Franklin, Southern Cross University and Trish Franklin, Southern Cross University

This is an article from Curious Kids, a series for children. The Conversation is asking kids to send in questions they’d like an expert to answer. All questions are welcome – serious, weird or wacky! You might also like the podcast Imagine This, a co-production between ABC KIDS listen and The Conversation, based on Curious Kids.

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What sea creature can attack and win over a blue whale? – Drake, age 7, Sydney.

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Hi Drake. That is an interesting question.

As you probably know, blue whales are the largest creatures to have ever lived on Earth – bigger than any dinosaur. They can grow up to 30 metres in length and weigh over 150 tonnes. This is very, very BIG. To give you an idea of how big a blue whale is, it’s the size of a Boeing 737 plane! Because of their size, power and speed, adult blue whales have virtually no natural ocean predators.

The only sea creature known to attack blue whales is the orca whale (scientific name: Orcinus orca) also known as the “killer whale”. They have been known to work in groups to attack blue whales.

However, there are very few reports of orcas actually killing blue whales. We know that orca whales interact with them because many blue whales carry scars from the teeth of orcas. But blue whales probably see orcas as more of a pest than a predator.

Orcas have sharp teeth.
Shutterstock

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Read more:
Curious Kids: Why do sea otters clap?

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Blue whales can grow 30 metres in length and weigh over 150 tonnes.
Kurzon/Wikimedia Commons, CC BY-SA

The human threat

A much more serious problem for blue whales is humans. Humans have caused a lot of trouble for blue whales over the years.

One big problem is what we call “ship strikes”. This is when large ships collide with blue whales causing dreadful wounds and, in many cases, death.

Blue whales migrate freely across all the great oceans of the world to breed. They travel each year to the Antarctic in search of food. Global warming is a major future threat to their way of life. This is because rising sea temperatures and ocean acidification (which are caused by climate change) are likely to cause severe disruption to the production of their main food source, the very small crustacean we call “krill”.

Blue whales were the target of commercial whalers, mainly in Antarctica, between 1900 and the 1970s. During that time, over 330,000 blue whales were killed.

Fortunately – and only just in time – the International Whaling Commission banned commercial whaling in 1966. Blue whales are now a protected species and are recovering from the brink of extinction. People on whale watching trips at various locations around the world can see them, if they are lucky. The risk of whaling still exists in several countries, including Japan, Iceland and Norway. Many people in these countries are seeking to return to commercial whaling. Recently, whalers in Iceland killed a hybrid blue whale.

Blue whales can talk

One of the most interesting things about blue whales is that they use very low frequency sounds to communicate. Through this they can talk to each other over great distances. The low frequency sounds can pass through the earth, so it’s possible to record their songs and sounds from anywhere in the world.

In the 1960s, an American scientist called Chris Clark got permission to use the USA’s submarine listening system across the Atlantic Ocean to listen to blue whales. One day, he heard a blue whale calling from the far northeast Atlantic Ocean and realised another whale many thousands of miles away in the southwest Atlantic Ocean was answering it. Through their calls, he tracked them over the next few weeks moving towards each other. The two blue whales met and spent time together in the middle of the Atlantic. Then they separated and went on their way!

A pair of blue whales swims under the surface in Monterey Bay, California.
Shutterstock

It is important for all who are interested in the conservation and protection of these amazing creatures to remain vigilant and involved in making sure that they remain safe. Whales are part of the international heritage of all people of the Earth.

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Read more:
Curious Kids: How do plastic bags harm our environment and sea life?

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Hello, curious kids! Have you got a question you’d like an expert to answer? Ask an adult to send your question to us. They can:

* Email your question to curiouskids@theconversation.edu.au

* Tell us on Twitter by tagging @ConversationEDU with the hashtag #curiouskids, or

* Tell us on Facebook

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Please tell us your name, age, and which city you live in. You can send an audio recording of your question too, if you want. Send as many questions as you like! We won’t be able to answer every question but we will do our best.

Wally Franklin, Researcher and co-director of the The Oceania Project, Southern Cross University and Trish Franklin, Researcher and co-director of The Oceania Project , Southern Cross University

This article was originally published on The Conversation. Read the original article.