Category: microplastics

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Study tracks emerging contaminants from landfill to treatment plant to application

Aerial photo of a wastewater treatment plant.
Photo credit: Amine KM/Pexels

Treatment plants can effectively remove microplastics and per- and polyfluoroalkyl substances (PFAS) from wastewater before they’re discharged to lakes and rivers, but large amounts of contaminants end up in solid waste, called biosolids, often used on agricultural fields as soil nutrients. By land applying this material, these contaminants then are re-released back into the environment.  

In a recent study published in an Illinois Sustainable Technology Center report, John Scott, analytical chemist at ISTC in the University of Illinois, studied the fate of microplastics and PFAS as they moved from landfill leachate, or water that filters though the mound of trash, to wastewater treatment plants and beyond. As health concerns about PFAS in water continue to grow, Scott predicts that state and federal regulatory agencies will set rules limiting these contaminants in water.

“I expect regulations concerning PFAS will be coming soon, but the big question is that nobody knows where to set the limits because the toxicity of PFAS hasn’t been established yet,” Scott said.   

To date, wastewater treatment plants are not required to monitor for PFAS and microplastics, so studies on these contaminants provide a better understanding of their major sources and how they can end up in the environment.

Eighty percent of plastics are destined for landfills. Among the castaways are food packaging, furniture, clothing, and other textiles that shed microplastics and PFAS contaminants. Scott noted that while all samples contained both microplastics and PFAS, PFAS concentrations in landfill leachate were found to be much greater than in wastewater influent.  

After wastewater treatment, the highest levels of microplastics and PFAS were in the biosolids, of which 50% are applied back to the land. If farmers stop using biosolids in fields due to regulatory and liability issues, the only option is to send them to landfills where the cycle from landfill to wastewater treatment plant will continue.

“Once in landfills, the stuff moves into the leachate, which is headed back to the wastewater treatment plant,” Scott said. “We’re just moving them from one environmental compartment to the next without addressing the problem. We never get rid of them; we’re just shifting them back and forth.”

To manage this problem, which is increasing over time because plastics and PFAS take so long to break down, consumers have some responsibility, he said.

“People have the perception that when you throw something away and it goes to a landfill, then it’s gone forever, when it’s not,” Scott said. “A landfill is just a holding place, and actually, the contaminants will end up fugitive in our environment.”

If the use of PFAS is regulated, PFAS in raw sewage will decrease, but contamination in landfill leachate will continue to rise, Scott said. Similarly, as plastics are added to landfills, they breakdown to smaller sizes, increasing contamination levels in leachate. Over time, landfills will become an even more significant sources of these contaminants, as well as many others. 

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Media Contact: John Scott, 217-333-8407, zhewang@illinois.edu

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Celebrate Plastic-Free July: Atypical tips to reduce your use of single-use plastics

Plastic Free July Badge

In a 2017 article in the journal Science Advances, researchers Roland Geyer, Jenna R. Jambeck, and Kara Lavender Law estimated that as of 2015 “approximately 6300 Mt of plastic waste had been generated, around 9% of which had been recycled, 12% was incinerated, and 79% was accumulated in landfills or the natural environment. If current production and waste management trends continue, roughly 12,000 Mt of plastic waste will be in landfills or in the natural environment by 2050.” With microplastics having been detected in virtually every habitat on Earth, including the ocean floor, and in a variety of organisms, including humans, it’s easy to understand why the U.S. Environmental Protection Agency (EPA) recently released a draft National Strategy to Prevent Plastic Pollution, as described in a previous post (Note: The deadline for the public comment period has been extended to July 31, 2023, so don’t miss out on the chance to read the strategy and provide feedback). It’s also easy to understand why delegates from nearly 180 countries came together in Paris recently, to discuss what would be the first legally binding global treaty to reduce plastic pollution. The first draft of that treaty is scheduled to be developed by November 2023, with a goal of having a final agreement in force by 2025.

For a dozen years now, people have taken time in July to consider ways they might help stem the tide of plastic pollution. Plastic Free July is an initiative of the Plastic Free Foundation which began in 2011 and has grown into a global movement to reduce single-use plastic consumption and pollution. You can sign up to take the Plastic Free July Challenge, and receive weekly emails in July to inspire and motivate your plastic reduction efforts. To help get you started the Plastic Free July website offers tips on ways to reduce single-use plastic. You can probably guess some of the tips which have become common mantras among those interested in waste reduction, such as using a refillable mug instead of accepting single-use coffee cups or bringing reusable bags when you go grocery shopping instead of packing your items home in plastic carrier bags. But the tips below might surprise you and inspire you to think about just how ubiquitous single-use plastic has become.

Note: ISTC does not endorse, either explicitly or implicitly, any particular manufacturer, vendor, product, or service. Information about specific products, manufacturers or vendors is provided for reference only.

  • Chew less gum and/or opt for plastic-free alternatives. It may surprise you to know that chewing gum, based on the indigenous tradition of chewing natural rubber called chicle, involves single-use plastic in its actual substance and not just in its packaging. According to the website Plastic Free Shopper, “Most modern chewing gums have what’s known as a gum base which makes up the majority of the chewing gum. This synthetic rubbery substance is commonly made from ingredients including: Butadiene-styrene rubber Isobutylene-isoprene copolymer (butyl rubber); Paraffin (via the Fischer-Tropsch process); Petroleum wax; Polyethylene; Polyisobutylene; Polyvinyl acetate. This synthetic plastic/rubber gum base is mixed with sweeteners and flavourings to make up regular chewing gum as we know it. Ingredients such as Polyethylene and Polyvinyl acetate are both common forms of plastic. Polyethylene is found in items such as plastic bottles and food containers, and Polyvinyl acetate is used in glues and adhesives.” So, when people spit their gum out on the sidewalk, they’re not just littering and setting the innocent up for sticky shoes–they’re also contributing to plastic pollution. If you enjoy chewing gum, a simple way to reduce your single-use plastic consumption is to opt for brands made with natural chicle, such as Simply Gum or Glee, among others.
  • Take plastic out of your water filtration equation. If you’re avoiding water in disposable plastic bottles, odds are you might be using a reusable bottle or pitcher with a filter. However, the more popular units for this purpose still incorporate plastic in the filters. In October 2022, editors of The Good Trade shared their top five plastic-free water filtration options. It should be noted that most of these are pretty pricey and the filter cartridges for the plastic-free vessels still tend to incorporate some small amount of plastic. But the Kishu charcoal stick option is quite affordable, completely plastic-free, and after its days as a water filter are over, the sticks can be composted, put out in your garden, or reused to absorb odors in your refrigerator.
  • Quit smoking—or encourage a friend or family member to do so if you’re a non-smoker. There are obvious health-related reasons to do this, but did you know that cigarette butts are the most common form of plastic pollution? A 2019 review article in Environmental Research explained that “Cigarette butts (CB) are the most frequent form of personal item found on beaches. Yearly, 6 trillion cigarettes are smoked worldwide, and 4.5 trillion cigarettes are littered in the environment.” Once they have become litter, cigarette butts degrade into microplastics. E-cigarettes and plastic vape cartridges also contribute to the plastic pollution problem, as well as contributing to the burgeoning tide of e-waste (that’s another post for another day). Learn more at “Plastics, the Environment, and the Tobacco Industry,” an online resource from the University of Bath.
  • Dispose of pet poo without plastics. If you have a dog, or a cat whose litter box needs to be scooped, disposable plastic bags are probably a commonly used tool. It’s definitely important to pick up your dog’s poo during a walk (see this article from The Guardian and this page from the Dooloop website for more on the environmental impacts of your best friend’s excrement), but there are ways to take care of this business with less petroleum-based plastic. The Dog People list their choices for plant-based pet waste bags that are “compostable under the right conditions.” If you have a yard with available space, you might also consider a separate compost pile or bin for pet waste (avoid using this compost on your fruit or vegetable garden to prevent the spread of parasites, but feel free to fertilize your flowers and other ornamental plants). Doogie Dooley offers in-ground digester systems for breaking down dog waste (they’re not compatible with cat waste, sadly), and though all incorporate plastic lids, there is a model with a steel tank. I Love a Clean San Diego also highlights some pooper scoopers and disposal tips that allow you to pick up waste without using a dedicated plastic bag.
  • Reduce your use of laser printers and copiers when possible. We all know that printer ink and toner cartridges contribute to the plastic waste stream, so many of us recycle our spent cartridges and purchase remanufactured ones to reduce consumption of virgin plastics. But did you ever stop to think about what laser printer and copier toner is made of? Spoiler alert—toner is mostly made of plastic. We’ve all seen reminders to print documents or emails only when necessary to save paper, but it turns out, this is a good tip to avoid plastic consumption too. If you’ve ever added shredded office paper or junk mail printed on non-slick paper to your compost bin, you might reconsider and put those in the paper recycling bin instead. Toner starts out as a collection of microplastics, so when that printed paper breaks down in a compost pile, you might be inadvertently releasing those into your environment. This Federal Electronics Challenge resource from the US EPA includes tips for reducing paper and ink usage. See this post from CDW on the differences between ink and toner, and you might also consider bio-based toner options available in your country. Some of these reduce the amount of petroleum-based plastic involved by using powder made from soybean oil. Some bio-based toners also use a percentage of bio-plastics for the cartridges themselves, such as https://pelikan-printing.com/biobased and https://www.union-tec.com/print-rite-bio-based-toner-cartridges/.

This post is already quite long, so we’ll stop at five tips, but there are many more ways to reduce single-use plastics. What are your favorites? Share your thoughts on social media.

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ISTC/University of Birmingham exchange fosters collaboration

l-r: Perry Akrie (ISTC), Jim Best (UIUC Dept. of Geology), John Scott (ISTC), Stefan Krause (UB Ecohydrology and Biogeochemistry), and Rafael Omar Tinoco Lopez (UIUC Civil Engineering), with University of Birmingham students.

ISTC researchers recently visited the University of Plymouth and the University of Birmingham to learn more about their contaminants research. Perry Akrie, a visiting scientific specialist at ISTC, shares his impressions of the trip.

Our journey began with a trip to Plymouth to visit with Dr. Andrew Turner, Professor of Environmental Sciences at the University of Plymouth, and a group of his students. John Scott gave a short talk about his research on microplastics at ISTC over the past several years and the students from Dr. Turner’s lab group presented their current research. Topics included polymer identification, additives and contaminants, adsorption of pollutants, fate and transport, weathering and degradation, and occurrence of microplastics.

John Scott (top) addresses Andrew Turner (bottom) and his students (not pictured). Photo credit: Perry Akrie

We also met with Rob Arnold, a colleague of Dr. Turner’s. Rob is an artist and activist on the topic of ocean pollution. He brought some of his collection of plastics that he has found washed up on the shore. This included a collection of vintage toothbrushes, assorted toys, and food wrappers, as well as a collection he affectionately refers to as “wedgies,” bits of plastic which have had other bits of plastic wedged into them in their travels through the ocean. Some of his most well-known art includes a 5.5-foot sculpture in the shape of the Moai statues of Easter Island that is made entirely of plastic waste. You see more of his art on Instagram (@rob.arnold.art).

Rob Turner displays his collection of microplastics found on beaches around England. Photo credit: Perry Akrie

We then traveled to the University of Birmingham to meet with members of the BRIDGE Birmingham-Illinois Partnership. This partnership has been in place since 2014. It allows both universities to exchange knowledge across disciplines through face-to-face meetings between faculty, staff, and students. As part of this program, Kate Rowley and Sophie Comer-Warner, students from the University of Birmingham, will be visiting ISTC to further their research.

The group from the University of Illinois included ISTC chemist John Scott, geology professor Jim Best, assistant professor of civil engineering Rafael Omar Tinoco Lopez, and and myself. We met with ecohydrology and biogeochemistry professor Stefan Krause and hydrology professor David Hannah from the University of Birmingham. We gave feedback on short presentations made by the students from Birmingham on topics that included transport of tire wear particles, biodegradation of microplastics in soils, and microplastics response to rainfall events.

BRIDGE meeting with researchers from the University of Illinois Urbana-Champaign and the University of Birmingham. Photo credit: Perry Akrie
BRIDGE meeting with researchers from the University of Illinois Urbana-Champaign and the University of Birmingham. Photo credit: Perry Akrie

The next day, we were taken on a tour of the preparation and analysis labs. Some of the most impressive facilities there were EcoLab and the National Buried Infrastructure Facility (NBIF).

EcoLab is a versatile open-air facility that hosts an array of experiments from many disciplines. Researchers in our host lab group have used it to study how microplastics are transported through water.

EcoLab includes a series of flumes that facilitate studies on the interaction between water, soils, plants, and other contaminants.
EcoLab includes a series of flumes that facilitate studies on the interaction between water, soils, plants, and other contaminants. Photo credit: Perry Akrie

The NBIF’s main feature is a 25m x 10m x 5m pit that can be split into smaller sections and filled with various structures, soils, and sensors related to several potential research questions. The sky is the limit for this one-of-a-kind facility.

The blocks at the far end of the NBIF pit are for building partitions
The blocks at the far end of the NBIF pit are for building partitions. Photo credit: Perry Akrie
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Help #BeatPlasticPollution on World Environment Day June 5th

World Environment Day 2023 banner

World Environment Day (WED) is an annual event celebrated on June 5th which raises awareness of environmental issues and encourages people across the globe to take action to protect our shared environment. The United Nations (UN) General Assembly designated June 5th as World Environment Day in 1972, marking the first day of the Stockholm Conference on the Human Environment. That same day, they adopted another resolution creating the United Nations Environment Programme (UNEP). UNEP coordinated the first celebration of WED in 1973, and it has led celebrations ever since. This year’s theme is #BeatPlasticPollution, shining a light on this worldwide issue (see past themes at https://www.worldenvironmentday.global/about/history). This year’s host country is Côte d’Ivoire in partnership with the Netherlands. Since 2014, Côte d’Ivoire has banned the use of plastic bags, supporting a shift to reusable packaging, and the country’s largest city, Abidjan, has also become a hub for environmentally minded start-ups.

As described in a previous post, plastics, including micro- and nanoplastics, are ubiquitous in our environment, even leaking from plastic recycling facilities. Microplastics are found in a variety of organisms, including humans. Recognizing the need for action, the U.S. Environmental Protection Agency released a draft National Strategy to Prevent Plastic Pollution in April and is seeking public comment through June 16, 2023.

On its WED website, UNEP provides a Beat Plastic Pollution Practical Guide, with recommendations for individuals; non-governmental organizations, faith organizations, and community groups; science and education organizations; governments; cities, towns, and local authorities; investors; and businesses and industry. The guide outlines how plastic pollution affects us, the sources of plastic pollution, what progress is being made, and what more needs to be done to address the situation.

Cover page of UNEP "Turning off the Tap" reportThe WED website also links to an interactive lesson on the plastic pollution problem and the UNEP report, Turning off the Tap: How the world can end plastic pollution and create a circular economy, which was released on May 16, 2023. This report examines the economic and business models needed to address the impacts of the plastics economy. UNEP suggests “a systems change to address the causes of plastic pollution, combining reducing problematic and unnecessary plastic use with a market transformation towards circularity in plastics. This can be achieved by accelerating three key shifts – reuse, recycle, and reorient and diversify – and actions to deal with the legacy of plastic pollution.” They explain that “reorient and diversify” “refers to shifting the market towards sustainable plastic alternatives, which will require a shift in consumer demand, regulatory frameworks and costs.”

Finally, the WED site provides relevant news, updates related to this year’s celebration, an opportunity to register your organization’s relevant events or activities, and links to other UNEP reports related to the global plastic pollution problem.

What strategies do you use to reduce plastic consumption and pollution? Share your thoughts on social media this June 5th with the hashtag #BeatPlasticPollution. You can connect with UNEP on Facebook, Twitter, LinkedIn, or Instagram.

Learn More

 

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U.S. EPA seeks feedback on draft National Strategy to Prevent Plastic Pollution

Plastic debris on a beach with water in the background.
Debris at Magee Wildlife Area near Oak Harbor, OH. (Credit: NOAA)

Although plastics have led to many positive innovations that have benefitted human society (e.g. less expensive medical devices, more portable electronic devices, increased fuel efficiency of vehicles made with plastic incorporated in their bodies, etc.), it is clear that plastic pollution is an ever-growing problem that threatens human and environmental health. When considering the fate of all plastic ever produced, Geyer et al. estimated that as of 2015, “approximately 6300 Mt of plastic waste had been generated, around 9% of which had been recycled, 12% was incinerated, and 79% was accumulated in landfills or the natural environment. If current production and waste management trends continue, roughly 12,000 Mt of plastic waste will be in landfills or in the natural environment by 2050.” [Note: Mt=million metric tons] In its 2022 report, Global Plastics Outlook: Economic Drivers, Environmental Impacts and Policy Options, the Organisation for Economic Co-operation and Development (OECD) stated that “Widespread plastics use and inadequate prevention measures have led to persistent plastic leakage. In 2019 an estimated 22 Mt of plastics leaked into the environment. The largest leakage source (82%) is mismanaged waste, i.e. waste that is inadequately disposed of. Other sources are abrasion and losses of microplastics (12%), littering (5%) and marine activities (1%).” They define “mismanaged waste” as “Waste that is not captured by any state-of-the-art waste collection or treatment facilities. It includes waste that is burned in open pits, dumped into seas or open waters, or disposed of in unsanitary landfills and dumpsites.” Even when plastics are collected and processed at a recycling facility, there is still potential for pollution. A study published this month in the Journal of Hazardous Materials Advances describes the analysis of wastewater from a UK plastics recycling facility before and after filters were installed. While filters decreased the discharge of microplastics, even with the filters in place, the total discharge from the multiple washes used in processing could produce up to 75 billion particles per cubic meter of wastewater. If these findings are extrapolated across the whole of the plastics recycling industry, the potential pollution from plastic recycling facilities alone is mind-boggling.

Plastics in the environment break down into smaller and smaller pieces over time. The full extent of the impacts of micro- and nano-plastics on Earth’s ecosystems is unknown, but we do know that wildlife may ingest plastic accidentally when eating food waste contained in plastic, because of visual similarities of plastics to their food sources, and in some cases because the plastic smells like food. When prey animals consume plastic, their predators ingest the plastic along with the prey. Even humans can ingest plastic in this way, and microplastics can also be inhaled. Microplastics are found worldwide, even in protected areas. They have been found in sea ice in the Arctic and on the ocean floor. They’ve even been found in human breast milk.

Given the scale and ubiquity of plastic pollution, in April 2023 the U.S. Environmental Protection Agency (EPA) released a Draft National Strategy to Prevent Plastic Pollution.  This builds upon EPA’s National Recycling Strategy, focusing on means to reduce, reuse, collect, and capture plastic waste.

image of national strategy cover pageEPA has identified three key objectives for the strategy. The draft strategy document lists proposed actions associated with each objective.

  • Objective A: Reduce pollution during plastic production. This entails designing products for reuse and recycling, using less impactful materials, phasing out unnecessary products, and ensuring proper controls at plastic production facilities.
  • Objective B: Improve post-use materials management. This involves the pursuit of circularity through pathways susch as reuse, refilling, and composting.
  • Objective C: Prevent trash and micro/nanoplastics from entering waterways and remove escaped trash from the environment. The pursuit of this objective may involve policy, programs, technical assistance, compliance assurance efforts, improved water management, improved measurement, increased public awareness, and further research.

Read the full draft strategy at https://www.epa.gov/system/files/documents/2023-04/Draft_National_Strategy_to_Prevent_Plastic_Pollution.pdf. An executive summary is also available.

EPA has opened a public comment period on this draft national strategy. Comments are due on or before June 16, 2023. EPA is asking the public to consider several key questions when reviewing and commenting on the draft strategy. To see these questions and learn more about how to submit your comments, see https://www.epa.gov/circulareconomy/draft-national-strategy-prevent-plastic-pollution#feedback.

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Microplastics on the move: Research projects detect microplastics in water and on land

Microplastics

The mind-boggling amount of microplastics in the environment is becoming a greater concern as early studies suggest serious health effects from human exposure to the plastic particles. Taking these effects seriously, the United Nations recently endorsed a historic resolution to end global plastic pollution, including microplastics.

At the Illinois Sustainable Technology Center (ISTC), researcher John Scott is studying microplastics in landfills, rural streams, and city drinking water to further understand where they are coming from and how they move in the environment.

Illinois landfills and microplastics

Since about 80 percent of all plastic waste is destined for landfills, they are a logical place to look for microplastics. Landfills that use plastic liners underneath the waste piles routinely pump out leachate, the waste “soup” that has drained into the liners. The leachate is sent to wastewater treatment plants, which are not designed to handle plastic waste.

As a result, plastic entering water treatment plants can end up either in the treated wastewater, where it is ultimately discharged to rivers or lakes, or in the sludge, called biosolids. Scott’s team has found that 99 percent of microplastics are in the biosolids, which are typically applied to agricultural lands as fertilizer. This means that microplastics taken from landfills are released back into the environment.

In this project, the researchers hypothesized that landfill leachate is the most significant source of microplastics taken to wastewater treatment plants. They compared the contribution of microplastics in leachate with other potential sources.

Although the study is still ongoing, the significance of this finding is that, although it is not feasible to treat the enormous amount of wastewater that comes into a treatment plant every day, treating the smaller amount of leachate may be an option.

“If our hypothesis is correct, then addressing plastic pollution in landfill leachate may be a more efficient and cost-effective way to reduce its environmental loading,” Scott said. “It’s better to treat the waste further upstream.”

The project has been funded by the Illinois Hazardous Research Fund.

Rural Iowa streams

ISTC is partnering with the University of Iowa and the U.S. Geological Survey in the first statewide assessment of microplastics and co-contaminants in rural Iowa streams. Most research studies to date have focused on microplastics in ocean habitats. In contrast, the research team sampled stream water, fish tissues, and rural sediments for this study. They also examined the samples for other contaminants, such as herbicides and insecticides, pharmaceuticals, and per- and polyfluoroalkyl substances (PFAS).

Some of the sediment samples have the highest concentrations of microplastics that they’ve ever seen, said Scott. With the methodology they designed in 2020, they can detect microplastics as small as 20 micrometers, while other researchers are limited to 100-micrometer sizes.

More microplastics appeared in the soil sediments than in the streams and fish tissues.

“Some of the concentrations of microplastics we found in samples were astronomical,” Scott said. “If concentrations for other contaminants approached that percentage level in the soil, it would raise an alarm. Microplastics may not be as toxic as other contaminants, but when there is this much stuff loading into out sediments, the concentrations will get worse over time.”

These findings support the theory that most of the microplastics that go to the wastewater treatment plants end up in biosolids and are released into soils in agricultural areas.

One objective of the study is to investigate the relationship of microplastics to sediments and other contaminants, such as PFAS. Microplastics can harbor exotic bacteria that are much different from that in the surrounding environment. Previous studies have shown that contaminants concentrate on these materials at hundreds of times the background levels.

In addition, studies have shown that microplastics as small as 20 micrometers can be taken up by plants.

“We don’t know if microplastics affect agricultural land, but if we load enough into our soils, it’s going to have some adverse effects, like trying to grow plants in plastic,” Scott said.

St. Louis city and county drinking water  

In a new three-year project, ISTC researchers’ role will be to investigate micro- and nano-plastics and other contaminants in surface waters, water treatment plants, and in tap water samples from residential households in St. Louis. Nanoplastics are particles that are even smaller than microplastics and are not visible to the naked eye or even under a simple optical microscope.

It is known that surface waters contain microplastics, but less is known about water distribution systems in the home and from water treatment facilities. Scott plans to trace microplastics found at water supply plants back to water distribution systems to determine if water softeners, dishwashers, and household plumbing can also be sources of microplastics.

Scott said he doesn’t expect to find microplastics originating from these sources, implying that in terms of microplastics, tap water is safer than bottled water, which contains large amounts of the plastic specks.

These efforts will be part of a larger project to determine an impact baseline for those contaminants in St. Louis city and county water systems, to survey community members to obtain their perceptions of drinking water quality, and to provide hot-spot mapping and policy recommendations for clean water investments and regulations.

Findings from the project will be provided to local water utility companies to begin to address micro- and nanoplastics in city water systems. Project partners also hope to promote equitable investments in clean water infrastructure.

The project is funded by the Missouri Foundation for Health. ISTC’s partners are Mixte Communications, Waterkeeper Alliance, and LH Consulting.

Because roadways are suspected to be another major contributor to microplastics pollution, Scott will soon begin another project, this one focused on microplastics in Michigan lakes that are highly affected by road salt.

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Media contact: John Scott, 217-333-8407, zhewang@illinois.edu
news@prairie.illinois.edu

This story originally appeared on the Prairie Research Institute News Blog. Read the original story.

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Article on microplastic contamination in karst groundwater systems co-authored by ISTC researchers among journal’s most cited

The University of Illinois-led study included researchers from the Prairie Research Institute. Pictured, from left: Walton R. Kelly, John Scott, Nancy Holm, Wei Zheng and lead author Samuel V. Panno. Photo by Fred Zwicky
The University of Illinois-led study included researchers from the Prairie Research Institute. Pictured, from left: Walton R. Kelly, John Scott, Nancy Holm, Wei Zheng and lead author Samuel V. Panno. Photo by Fred Zwicky

An article co-authored by ISTC’s John Scott, Wei Zheng, and Nancy Holm is among the top cited research in Groundwater.

“Microplastic Contamination in Karst Groundwater Systems” was a collaborative effort of researchers from ISTC, ISWS, and ISGS. Published in 2019, it was the first to report microplastics in fractured limestone aquifers – a groundwater source that accounts for 25 percent of the global drinking water supply.

Read more about the research from the University of Illinois News Bureau.

 

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‘Plastics don’t ever go away’—ISTC scientist John Scott studies impact of microplastics

Discarded disposable masks on sidewalk
The COVID-19 pandemic has worsened the plastic waste problem with increased use of single-use products like masks.

Plastic products permeate our environment and over time they break down. The microscopic size of particles, how long they last, and what is associated with them raise health concerns.

Although the health effects are still largely uncertain, recent research at the Illinois Sustainability Technology Center (ISTC) has provided some insight into what happens to plastics once they’re used and thrown away.

Microplastics are everywhere: in what we eat, drink, and breathe, according to ISTC senior chemist John Scott. They’re found in surface water, sediments and soils, air and dust, wildlife, and everywhere else scientists look.

“Plastics don’t ever go away, they just break down to smaller and smaller sizes,” Scott said. “They’re always out there. If I analyze something that doesn’t have microplastics in it, I think there’s something wrong.”

Plastics have been mass-produced since the 1950s, with an estimated 8.3 billion metric tons produced globally. Nearly 80 percent of plastic waste ends up in landfills and in the environment. The COVID-19 pandemic has exacerbated the plastic waste problem with more shipping and packaging and the worldwide use of single-use products, such as gloves, gowns, and booties.

Since plastics have been engineered to last, the breakdown rates are incredibly long. Nylon fishing line lasts some 600 years, plastic bottles last 400 years, and plastic straws last 200 years.

“A child’s diaper can be around for 400 to 500 years—five to six times the child’s lifespan,” Scott said. “Even if we stopped producing plastics now, because of these legacy products, we would still have a plastic waste problem for many decades.”

What they absorb

Plastics act as sponges, absorbing all kinds of contaminants in the environment. In 2020, Scott and collaborators at the Annis Water Resources Institute submerged samples of different types of plastic for three months in Muskegon Lake in Michigan.

Findings showed that many pollutants such as polyaromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), and even pesticides concentrate on these materials at hundreds of times the background levels.

The group also found a group of chemicals, per- and polyfluoroalkyl substances (PFAS), can stick to microplastics submerged in lake water. PFASs are human-made chemicals used in products such as non-stick cookware, cleaning supplies, and food packaging. Their stability and water and oil resistance are useful for various products, but the PFASs don’t break down readily in the environment or in humans, causing potential adverse health effects.

Scott’s team also tested PFAS adsorption on plastic in the laboratory, without the presence of organic matter such as biofilms. In the laboratory, the amount of PFASs that was absorbed into the microplastics was small (about 25%), yet the lake-exposed samples showed 600 times more PFASs were attached to the microplastics compared with those in the laboratory tests.

“We found only small concentrations of PFASs, but what was interesting was the discovery that they don’t stick to the plastic,” Scott said. “We believe that they stick to a biofilm of organic material that develops over time on the plastic from the lake environment.”

The initial findings are published in the Journal of Great Lakes Research. A second paper reporting PFAS in currently in draft.

How to measure them

To understand microplastics and make accurate comparisons of plastic size and concentrations, researchers need to use a standardized method of detection limits. The National Oceanic and Atmospheric Administration (NOAA) developed a method in 2015, which was designed to measure large plastic debris in surface water and on beaches.

The smallest size detected through this process is 300 micrometers, which does not account for microplastics that are small enough to cross biological membranes.

“We needed to push the detection limits to measure smaller microplastics,” Scott said. “If we use the NOAA method, we’ll underestimate the amount of microplastics in a sample.

In 2020, Scott and Lee Green, ISTC chemist, developed a way to count microplastics down to the size of 20 micrometers, sizes that would have been missed by the NOAA standard.

Another challenge was to find a standardized way to report findings. Estimating the number of plastic particles per liter wasn’t accurate because the particles can further break down during the estimation process. Instead, Scott and his team applied a detailed analysis of particle dimensions to estimate its mass.

More study details are available at http://hdl.handle.net/2142/107799.

What happens to them from the landfill to the treatment plant

Microplastics might be everywhere, but the hotspots are landfills. Plastic breaks down in landfills and becomes more mobile. Leachate, or water and waste from the landfill, is piped to wastewater treatment plants (WWTP), which are not designed to handle microplastics.

The sludge produced by WWTPs is commonly used on crop fields since the biosolids are high in nutrients. Once applied, the sludge material—and microplastics—is taken up by plants and runs into surface water and groundwater.

Scott plans a pilot study to examine the feasibility of treating wastewater to remove microplastics that come into plants before sludge is pumped back out into the environment.

Ideally, though, keeping plastics out of the landfills by reducing the amount produced, using fewer single-use plastic products, and better plastic recycling would be the way to go, Scott said.

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Media contact: John Scott, 217-333-8407, zhewang@illinois.edu
news@prairie.illinois.edu

This story originally appeared on the Prairie Research Institute News Blog. View the original story.

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ISTC researchers develop improved method for microplastics analysis

Since the emergence of mass-produced plastics in the 1940s, the global appetite for these materials has rapidly increased. Estimates of cumulative plastic waste generated are as much as 6.3 billion metric tons. Less than 10% of this material is recycled, while nearly 80% is sent to landfills or released into the natural environment. Because of this, microplastics are now ubiquitous in the environment. Their presence has been detected in surface waters, groundwater sources such as Karst waters, sediments, wildlife, and even consumer products.

The major drawback with current microplastic sample preparation and counting is that researchers use different methods. The National Oceanic and Atmospheric Administration (NOAA) was the first to publish a standard method to measure these materials. However, it only addressed large plastic debris in surface water and beach samples. Furthermore, it can only isolate and account for materials with a density less than 1.2 g/cm3. Many microplastics, including polyvinyl chloride, polyesters, and fluoropolymers, have a density greater than 1.3 g/cm3 and are unaccounted for in preparation by NOAA’s method.

When the researchers analysed samples from the Lake Muskegon and Missouri surface waters, they discovered that they would have missed the most abundant microplastics, those less than 300 µm, if they had processed them using the standard NOAA method. Their new method achieves a lower size detection limit and greater microplastic density limit.

The researchers also designed an innovative reporting method that uses detailed size measurements of the microplastic in the sample. This new approach for data reporting allows researchers to estimate the mass of microplastics present. This measurement is important because although particle sizes can change in a sample, the overall mass remains the same.

Following development, the researchers demonstrated the method with surface waters collected from three locations and fish larvae samples archived by the Illinois Natural History Survey.

The work is detailed in ISTC’s new research report, Development and Demonstration of a Superior Method for Microplastics Analysis: Improved Size Detection Limits, Greater Density Limits, and More Informative Reporting.