Category: research

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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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How can Illinois address the problem of PFAS pollution?

John Scott - senior analytical chemist, Illinois Sustainable Technology Center Photo by L. Brian Stauffer
John Scott, a senior chemist with the Illinois Sustainable Technology Center, says per- and polyfluoroalkyl substances are widespread, long-lasting and extremely difficult to remove from the environment. Photo by L. Brian Stauffer

by Diana Yates, Life Sciences Editor, U of I News Bureau

Editor’s note: Following action by the federal Environmental Protection Agency, the state of Illinois is investigating the occurrence of per- and polyfluoroalkyl substances in community water supplies across the state, with an eye toward developing policies to reduce their use. Exposure to PFAS has been linked to increased risk of certain cancers and potential developmental problems in children. News Bureau life sciences editor Diana Yates spoke about the issue with John Scott, a senior chemist with the Illinois Sustainable Technology Center.

Why are PFAS used in so many products?

PFAS are used in packaging, nonstick cookware, water-resistant carpeting, construction materials, firefighting foam, and personal-use products like shampoos and dental floss.

PFAS have unique properties. They are very resistant to water, oil and most things that would stain surfaces. They also are thermally stable, resistant to degradation and great friction reducers.

Why are they so problematic?

There are more than 5,000 compounds classified as PFAS, and the list seems to be growing every day. This makes monitoring, regulating and treating them a much more difficult task.

What makes PFAS so useful is also what makes them so problematic. For starters, they are very water soluble, which means they can reach very high concentrations in surface and groundwaters contaminated by them. This also makes them very mobile in the environment, so they can readily move from soil to water to organisms. PFAS also are known to bioaccumulate. This means they can be present at higher concentrations in wildlife and humans than in the surrounding environment.

Since PFAS are so stable, they are extremely persistent in the environment. Carbon-fluorine bonds are some of the strongest chemical bonds known. This is why these compounds are so hard to break down. Once they get into the environment, they pretty much stick around forever. This is also why treatment of PFAS is so difficult. We can readily get PFAS to adsorb to many materials, but it isn’t clear what to do with those materials afterward. It requires a great deal of energy and cost to destroy PFAS, and the process may create even more potentially toxic degradation products or hazardous air pollutants. The only alternative is to landfill these materials, but that gives them the potential to be released back into the environment.

How widespread is the problem in Illinois?

In reference to PFAS, one will typically hear the word “ubiquitous.” It seems that everywhere we look for PFAS, they turn up. This is true in Illinois.

Illinois does have some “PFAS hot spots” that I am aware of. These sites are typically where fires have been treated with aqueous firefighting foams, locations where training with these foams has occurred and air force bases. These hot spots usually have very high concentrations of PFAS in their soils and nearby groundwaters and surface waters. Michigan has many sites where illegal dumping of PFAS occurred, but I am unaware of any sites like that in Illinois. That doesn’t mean they don’t exist.

Many PFAS-laden materials are dumped in landfills and, as a result, high concentrations of PFAS can end up in landfill leachates. These leachates are commonly sent to wastewater treatment plants, which are not currently designed to treat PFAS. This means the PFAS are either directly discharged to the environment via effluent or they contaminate the sewage sludge, commonly referred to as biosolids. Because biosolids from wastewater treatment plants are sometimes used as fertilizer on agricultural crops, the PFAS are then released back into the environment. When considering the potential impact, it’s good to keep in mind that Illinois has 37 active landfills and many more that are inactive or closed.

Are there safer alternatives to PFAS?

Many alternative chemicals have been developed and implemented to replace the traditional PFAS. However, the consensus of the scientific community is that they are just as problematic as the compounds they replaced. The Department of Defense is aggressively looking for fluorine-free alternatives.

How might the state of Illinois address the problem?

In the hierarchy of pollution prevention, source reduction is the most efficient approach. We need to reduce the amount of PFAS we produce and the amount of PFAS we use, and find safer alternatives that have minimal environmental impact. Education is an essential part of this process. Making the public aware of the issue would be a great place to start.

I suspect that many people purchasing materials containing PFAS are not even aware of it. A requirement for labeling of materials that contain PFAS may provide consumers with a means to make the right decision with their purchasing power. This also could provide a way for solid waste managers to divert these materials so that they are not released back into the environment. Even if we stopped all use of PFAS tomorrow, however, I suspect that we will be dealing with their legacy for decades to come.

Editor’s note:  To contact John Scott, email zhewang@illinois.edu.

This story was originally published by the U of I News Bureau. View the original article  on their website.

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Scientists study ways to reduce PPCPs transferred from soils to food plants

Plant growing in soil

The debate continues: how much risk to human health is the transfer of pharmaceuticals and personal care products (PPCPs) through soils to food plants when biosolids, sewage effluents, and animal wastes are applied to fields? As scientists speculate and study the factors that affect risk, researchers at the Illinois Sustainable Technology Center (ISTC) are finding innovative solutions to remove PPCPs before they contaminate the vegetables and fruits we consume.

PPCPs are the chemicals that make up fragrances, cosmetics, over-the-counter drugs, and veterinary medicines. These chemical residues in the environments are considered emerging contaminants because they are not yet regulated by state and federal agencies.

Organic wastes like biosolids, sewage effluent, and animal waste contain PPCP residues. When these are applied to farm fields, some of the chemicals may degrade, while others may transfer from soils to roots of vegetables and fruits, and then possibly accumulate in edible plant tissues.

Field studies have shown that pharmaceutical concentrations in soils were lower than predicted because PPCPs may degrade in soils, latch on to soil particles, or run off/leach into surface and groundwater. Yet continued and long-term application of PPCP-containing biosolids, animal wastes, and wastewater effluents may increase their concentration levels in plants, according to Wei Zheng, ISTC scientist.

“There has been much argument and debate if PPCPs derived from organic waste application in crop fields can cause risks on public health,” Zheng said. “This issue will become even more at the forefront as the use of biosolids and sewage effluents in crop production systems increases. More studies are necessary because PPCPs vary in their toxicity and physicochemical properties in the environment. In particular, the compounds that are highly persistent and toxic will be a concern.”

Zheng reviewed the literature, summarized the research findings, and made recommendations for future research in a recent article published in Current Pollution Reports.

Factors affecting PPCP transfer

In his review, Zheng reiterated that the factors that have the greatest effect on PPCP transfer are the properties of the PPCPs and soils as well as plant species. Plants grown in sandy soils have higher levels of PPCPs than those grown in high organic matter and clay soils. For certain PPCPs that are destroyed in soils, the process breaks down the original compound into metabolites that may be more toxic and mobile. Metabolites with lower molecular weights could be taken up by plant roots more readily.

Studies have also found that leafy vegetables, such as lettuce and cabbage, tend to have a higher potential to take in PPCPs than root vegetables. Furthermore, certain chemicals accumulate in the roots and have little effect on human health, while others can be transferred to leaves. Further research is needed to develop thresholds for accumulations of PPCPs in food crops when biosolids, effluents, and animal manure are used on fields.

Mitigation efforts

At ISTC, Wei and colleagues are studying several technologies to remove PPCPs, either before they reach the soils or after sewage waste application. The study is being supported by a project funded by the U.S. Department of Agriculture (USDA).

In the project, Wei is studying the feasibility of using inexpensive oils to capture hydrophobic PPCPs from wastewater effluents. The treatment, which would be used at water treatment plants, is especially low cost when applying used cooking oils, such as those from restaurants.

One advantage of this process is that oils remove PPCPs from rural sewage water while leaving behind the nutrients that fertilize crops. After capturing PPCPs, the spent oils can be used as fuel for diesel engines. The process can eliminate the captured contaminants.

Carbon-rich biochar produced from forest and agricultural residues can be used as a filter to absorb PPCPs from sewage water.  Biochar can also be directly applied to soils.

Studies found that the average PPCP concentrations in lettuce leaves decreased by 23 to 55 percent when biochar was used in the soil compared with the soils without biochar. Biochar can also be composted with solid waste to immobilize PPCPs and reduce their transfer in soil-plant systems.

In the USDA project, scientists will conduct laboratory, field, and numerical modeling studies to better understand the transfer of PPCPs to crops when rural sewage effluents are applied to agricultural lands. The results will help federal and state agencies and farmers evaluate their current nutrient management and nontraditional water-use practices, inform science-based regulatory programs, and suggest best management strategies to minimize risks and promote the safe and beneficial use of nontraditional water in agriculture.

Media contact: Wei Zheng, 217-333-7276, weizheng@illinois.edu
news@prairie.illinois.edu

This story originally appeared on the PRI News Blog. Read the original story.

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US EPA releases report on environmental impacts of US food waste

EPA infographic on environmental impacts of US food waste
Image from US EPA Office of Research and Development.

On November 30, 2021, the US Environmental Protection Agency (EPA) released a new report entitled “From Farm to Kitchen: The Environmental Impacts of U.S. Food Waste (Part 1).”

This report reveals the climate and environmental impacts of producing, processing, distributing, and retailing food that is ultimately wasted and projects the environmental benefits of meeting the US goal to prevent 50 percent of food waste by 2030. The report was prepared to inform domestic policymakers, researchers, and the public, and focuses primarily on five inputs to the US cradle-to-consumer food supply chain — agricultural land use, water use, application of pesticides and fertilizers, and energy use — plus one environmental impact — greenhouse gas emissions.

This report provides estimates of the environmental footprint of current levels of food loss and waste to assist stakeholders in clearly communicating the significance; decision-making among competing environmental priorities; and designing tailored reduction strategies that maximize environmental benefits. The report also identifies key knowledge gaps where new research could improve our understanding of US food loss and waste and help shape successful strategies to reduce its environmental impact.

The new report reveals that each year, the resources attributed to US food loss and waste are equivalent to:

  • 140 million acres agricultural land – an area the size of California and New York combined;
  • 5.9 trillion gallons blue water – equal to the annual water use of 50 million American homes;
  • 778 million pounds pesticides;
  • 14 billion pounds fertilizer – enough to grow all the plant-based foods produced each year in the United States for domestic consumption;
  • 664 billion kWh energy – enough to power more than 50 million US homes for a year; and
  • 170 million MTCO2e greenhouse gas emissions (excluding landfill emissions) – equal to the annual CO2 emissions of 42 coal-fired power plants

In short, significant resources go into growing, processing, packaging, storing, and distributing food. Thus, the most important action we can take to reduce the environmental impacts of uneaten food is to prevent that food from becoming waste in the first place.

A companion report, “The Environmental Impacts of U.S. Food Waste: Part 2,” will examine and compare the environmental impacts of a range of management pathways for food waste, such as landfilling, composting, and anaerobic digestion. EPA plans to complete and release this second report in Spring 2022. Together, these two reports will encompass the net environmental footprint of US food loss and waste.

Read the full report at https://www.epa.gov/system/files/documents/2021-11/from-farm-to-kitchen-the-environmental-impacts-of-u.s.-food-waste_508-tagged.pdf.  (PDF document, 113 pages)

For questions, contact Shannon Kenny, Senior Advisor, Food Loss and Food Waste, US EPA Office of Research and Development.

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UIUC research shows smaller plates reduce food waste in dining halls

UI dining hall

Research conducted by University of Illinois at Urbana-Champaign scientists from two departments within the College of Agricultural, Consumer, and Environmental Sciences (ACES) demonstrates that the simple act of changing plate size and shape can have a significant impact on food waste in university dining halls.

In an article published in May 2021 in the journal Resources, Conservation & Recycling, authors Rachel Richardson [former graduate student in the Department of Agricultural and Consumer Economics (ACE)], Melissa Pflugh Prescott (assistant professor in the Department of Food Science and Human Nutrition), and Brenna Ellison (associate professor in the associate professor in ACE) describe data collected at two dining halls on the Illinois campus in the Fall of 2018. The researchers and dining hall staff monitored and limited the dishware available for patron use.  The only intervention in this study was a change in plate size and shape. Traditionally, the university dining facilities used round plates (9″x9”). In this study, the round plates were replaced with oval platters (9.75″x7.75″), decreasing the plate’s surface area by 6.76%. Both the round and oval plates were tested at each dining hall, and the menu offered was the same for both plate types.

After diners selected their food, but before they sat down at a table, researchers approached them and asked permission to take a picture of their plates and to weigh the plate of food. Participation was incentivized with an entry in a later drawing for a $50 Amazon gift card. Participating diners additionally filled out a survey, and when their plates were brought to the dish return, the researchers took a post-consumption picture and weight measurement. The survey included a question about whether diners went back for seconds; in that circumstance, a post-consumption weight was not recorded.

A total of 1825 observations were collected with 1285 observations retained for analysis. Observations were excluded if the participant: only selected food using non-standard dishware (e.g., only eating a bowl of soup); submitted an incomplete survey; was missing a pre- or post-consumption photo; did not return their plate; or returned plates with different food on them than selected.

Overall, food waste went down from 15.8% of food selected for round plates to 11.8% for oval plates. This amounts to nearly 20 grams (0.7 oz) less food waste per plate. In a setting where thousands of meals are served, this seemingly small reduction could quickly add up. The researchers concluded that changing plate type is a viable strategy to reduce food waste, though dining hall managers need to weigh the cost of purchasing new plates against the potential savings. They speculate that combining the direct-nudge approach of smaller plates with an education campaign could be even more effective.

Read the full article at https://doi.org/10.1016/j.resconrec.2020.105293.

Learn more

Note: This post was originally published on the ISTC Green Lunchroom Challenge blog, which is maintained by Technical Assistance Program staff. Check out that blog for more news, resources, and tips on preventing food waste and diverting food from landfills via rescue, repurposing, composting, and other strategies.

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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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DOE-funded project to find beneficial uses for coal combustion wastes

"Ash lagoon, West Pans" by Richard Webb is licensed under CC BY-SA 2.0
“Ash lagoon, West Pans” by Richard Webb is licensed under CC BY-SA 2.0

Scientists at the Illinois Sustainable Technology Center (ISTC) are beginning a $1 million, two-year project to find new and value-added uses for fly ash, a powdery remnant of burning coal. Confining the ash in vegetable oil will potentially reduce the amount of fly ash waste and lessen the risk of heavy metals from waste piles leaching into surface and groundwater.

Although fly ash is used in concrete, construction materials, and other products, a significant amount is stored in ash ponds and sent to landfills. Fly ash contains arsenic, lead, mercury, and other harmful chemicals, posing human health and environmental risks when rainwater causes contaminants to leach underground.

“Our biggest motivation for the project is to investigate new, beneficial uses of fly ash, particularly in encapsulating ash into vegetable oils, to help eliminate exposure of heavy metals to the environment,” said BK Sharma, principal investigator of the project.

In this new approach, the scientists will use their expertise in modifying vegetable oils to coat fly ash particles with oil so that the contaminants are fully contained. The challenge will be identifying the appropriate vegetable oil and the right operating conditions to ensure a uniform coating, according to Sriraam Chandrasekaran, co-principal investigator.

The smallest fly ash particles contain the highest concentration of toxic elements. The project targets removing these fine fractions to reduce contamination while also developing a marketable product for commercial use.

“Because of their small size, the ash particles are ideally suited for use as fillers in plastics,” Chandrasekaran said. “The project will not only provide a value-added coated fly ash product but will also help us identify ways to use other fractions in different applications.”

 When fly ash is used in concrete and other materials, its economic value is particularly low. So, it’s not economical to transport the material from power plants to other states or regions.

If ISTC scientists can develop a new technology to develop fillers and toughening agents in products for a booming market—in this case, estimated to be $10 billion a year in the U.S.—the vegetable oil encapsulated fly ash will command a much higher price than unmodified fly ash while also increasing beneficial uses, Sharma said.

In addition, a successful project will make transporting fly ash long distances more economically feasible, provide incentives to develop technologies to size and store fly ash, and create non-seasonal product demand.

The ISTC team is partnering with The Ohio State University, where scientists will investigate the use of coated fly ash materials to replace carbon black filler materials in rubber, particularly for use in tires. Funding is provided by the U.S. Department of Energy.

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Media contacts: BK Sharma, 217-265-6810, bksharma@illinois.edu, Sriraam Chandrasekaran, 217-300-1477, schandr@illinois.edu; news@prairie.illinois.edu

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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.