Microplastics’ Hidden Contribution to Snow Melting - Eos (2022)

Black carbon particles, produced by combustion of gasoline, diesel fuel, coal, and other organics, have been found to be the second-largest driver of climate warming, after carbon dioxide (CO2), since the Industrial Revolution [Myhre et al., 2013]. Much of black carbon’s role in this warming results from the fact that it contributes to the melting of snow and ice and thus to darkening of Earth’s surface, reducing the amount of sunlight the planet reflects and increasing the amount it absorbs.

These processes have been thoroughly studied, yet measurements made in the past of black carbon particles in snow and determinations of their effects on melting may be inaccurate. To date, most studies have overlooked a major and potentially complicating factor: microplastics. Here we address the possible implications of this issue and offer recommendations to promote more accurate assessments of the effects of both black carbon and microplastics on snow and climate.

Massive Amounts of Uncounted Microplastics

Microplastics (MPs) are tiny plastic particles, fibers, or fragments smaller than 5 millimeters across—and they are everywhere. They have been implicated in a range of environmental effects, including bioaccumulation in fish and in human blood and feces. These particles have reached Earth’s least populated areas, including in the High Alps, the Arctic [Bergmann et al., 2019], and even Antarctica [Kelly et al., 2020]—in fact, everywhere scientists look, they find microplastic particles. MPs and black carbon (BC) have been depositing together in snow since the 1950s, when plastics and petroleum products came into widespread use.

Today the mass of microplastic particles in the environment is very likely more than that of black carbon (BC).

Today the mass of MP particles in the environment is very likely more than that of BC. Dubaish and Liebezeit [2013] found 5 times more MP particles than visible BC particles in a microscope slide count of particles in water samples from Jade Bay along the northwestern coast of Germany. This is the only study to date that has reported simultaneous measurements of MP and BC particles, and it did not address the coexistence of MPs and BC in snow.

Wind can loft MP particles above the ground and carry them onto snow surfaces [Evangeliou et al., 2020], where, calculations have shown, they can remain for hundreds of years before they completely decompose. MPs are now believed to have spread to every human-reached corner of Earth [Brahney et al., 2020; Pabortsava and Lampitt, 2020]. So when field researchers sample snow for BC laboratory measurements, they inevitably bottle or bag MPs together with BC—and both types of particles may be counted together during measurement and analysis.

Very few studies of BC in snow have tried to separate out MPs before making instrumental measurements. This long-term neglect of MPs in snow in past studies may have resulted in overestimations of the BC content in snow and of its effects on glaciers, snow cover, ice sheets, and climate. Unfortunately, climate change assessments, so far, also have not included the role of MPs in snow.

(Video) Microplastics discovered in freshly fallen Antarctic snow

It’s All the Same to the Instruments…

The risk in not separating MPs from BC before conducting lab measurements is that the effects of the two types of particles could be confounded, impairing our understanding of the true effects of each on snow and climate. Why is this? MPs and BC may be indistinguishable in the results of thermal-optical and pyrolysis-based laboratory tests (Figure 1).

The most-used plastics include polyethylene, polypropylene, polystyrene, and polyvinyl chloride, along with smaller amounts of other plastics. Combustion experiments demonstrate that plastics ignite and burn in oxygen at temperatures between 500°C and 1,000°C. Because the main elements composing plastics are carbon (roughly 85%), hydrogen (roughly 14%), and oxygen (less than 1%), the gases released when these plastics are completely combusted are CO2 and H2O [Zevenhoven et al., 1997].

Until recently, light-absorbing constituents in snow samples were implicitly presumed to be BC, organic carbon, or dust, while the probable coexistence of MPs was overlooked.

BC particles, which consist mostly of carbon, oxidize in air between 500°C and 700°C and form CO2 if combustion goes to completion [Andreae and Gelencsér, 2006]. The overlap in the oxidation temperature ranges of BC and MPs implies that pyrolysis-related techniques may produce results in which the BC signal is contaminated by MPs in a sample.

Likewise, optical absorption techniques such as aethalometry (light absorption by aerosol particles collected on filters) and laser-induced incandescence (light absorption by nebulized samples) may also combine signals from MPs and BC. Many types of MPs are brightly colored or black and absorb light in the visible and near-infrared wavelengths [Alexander et al., 2008], just as BC particles do.

Until recently, light-absorbing constituents in snow samples measured using the above methods were implicitly presumed to be BC, organic carbon, or dust, while the probable coexistence of MPs was overlooked.

(Video) Microplastics, Mega Impact

But the Environment Knows the Difference

Almost all “clear” plastics are nearly transparent in the UV–visible wavelengths [Ishaq, 2019]. These plastics, deposited on snow, do not perturb the solar radiation balance. However, most plastic products are dyed or painted, which causes them to absorb light. For example, red plastics absorb green light, blue plastics absorb yellow light, and black plastics absorb a wide range of wavelengths. In addition, as plastics weather and break down, partly because of sunlight absorption, the resulting MPs can turn from transparent to translucent. Tearing, scratching, and aging processes such as these cause MP particles to absorb more light.

Increased light absorption by MPs may contaminate assessments of BC’s impacts on snow albedo (the fraction of sunlight that snow reflects), and thus on its contribution to calculations of radiative balance, in two ways. One is that MPs may be responsible for part of the reduced snow albedo that current lab tests ascribe entirely to BC. The other is that measured amounts of equivalent BC (a value determined using a mass absorption coefficient that may include substances other than BC) can overestimate the amount of actual BC if the equivalent BC amounts include significant contributions from MPs.

Although natural environmental temperatures never get high enough to convert BC and MP particles to CO2 (except perhaps near active wildfires or volcanoes), laboratory analyses using pyrolysis methods are another matter. In such analyses, both BC and MPs are oxidized to CO2, and measurements reflect contributions from both species. Calculations of BC thermally converted to CO2 in instruments may thus be inflated by unrecognized contributions from MPs in current instrument analyses.

A Work-Around to Measure BC and MPs in Snow

Considering the potentially significant complications that MPs pose for our understanding of BC’s effects on snow melting and climate, it is clear that research is urgently needed to determine the extent—or lack thereof—to which scientists can distinguish these particles using different analytical methods. It is also very important to quantify the co-occurrence of MPs and BC in snow samples collected for lab measurements.

In light of potential interference from MPs, previous measurements of BC in snow may need to be reviewed and the radiative effects of BC and MPs in snow co-assessed.

So far, no protocols have been applied to separate these particles prior to instrumental analysis of BC in snow or ice. We thus suggest the following simple preprocessing protocol to separate MPs and BC in snow samples before testing:

  • Use glass bottles instead of plastic ones when collecting field samples to avoid plastic contamination from sampling bottles.
  • Filter melted snow samples through filters with micrometer-sized pores to remove relatively large MP particles.
  • Centrifuge samples to separate smaller MP particles. (The density of BC particles is greater than 1.8 grams per cubic centimeter, whereas most plastics have a density of less than 1.4 grams per cubic centimeter.)

In light of potential interference from MPs, we also suggest that previous measurements of BC in snow may need to be reviewed and the radiative effects of BC and MPs in snow co-assessed. Such a reassessment could assist in identifying the true sources of particle pollution and melting in snow and increase the effectiveness of remediation efforts.

(Video) Microplastics from 3D Printing (how to detect them and risk management)

References

Alexander, D. L. T., P. A. Crozier, and J. R. Anderson (2008), Brown carbon spheres in East Asian outflow and their optical properties, Science, 321(5890), 833–836, https://doi.org/10.1126/science.1155296.

Andreae, M. O., and A. Gelencsér (2006), Black carbon or brown carbon? The nature of light-absorbing carbonaceous aerosols, Atmos. Chem. Phys., 6, 3,419–3,463, https://doi.org/10.5194/acp-6-3131-2006.

Bergmann, M., et al. (2019), White and wonderful? Microplastics prevail in snow from the Alps to the Arctic, Sci. Adv., 5(8), eaax1157, https://doi.org/10.1126/sciadv.aax1157.

Brahney, J., et al. (2020), Plastic rain in protected areas of the United States, Science, 368(6496), 1,257–1,260, https://doi.org/10.1126/science.aaz5819.

Dubaish, F., and G. Liebezeit (2013), Suspended microplastics and black carbon particles in the Jade system, southern North Sea, Water Air Soil Pollut., 224(2), 1352, https://doi.org/10.1007/s11270-012-1352-9.

Evangeliou, N., et al. (2020), Atmospheric transport is a major pathway of microplastics to remote regions, Nat. Commun., 11(1), 3381, https://doi.org/10.1038/s41467-020-17201-9.

Ishaq, M. U. (2019), On optical properties of transparent micro-and nanoplastics, MS thesis, 40 pp., Dep. of Phys. and Math., Univ. of East. Finland, Joensuu, https://urn.fi/urn:nbn:fi:uef-20190313.

(Video) The world is on the alert: Microplastic sleet fell on Antarctica for the first time

Kelly, A., et al. (2020), Microplastic contamination in east Antarctic sea ice, Mar. Pollut. Bull., 154, 111130, https://doi.org/10.1016/j.marpolbul.2020.111130.

Myhre, G., et al. (2013), Anthropogenic and natural radiative forcing, in Climate Change 2013: The Physical Science Basis—Contribution of Working Group I to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change, pp. 659–740, Cambridge Univ. Press, Cambridge, U.K.

Pabortsava, K., and R. S. Lampitt (2020), High concentrations of plastic hidden beneath the surface of the Atlantic Ocean, Nat. Commun., 11(1), 4073, https://doi.org/10.1038/s41467-020-17932-9.

Zevenhoven, R., et al. (1997), Combustion and gasification properties of plastics particles, J. Air Waste Manage. Assoc., 47(8), 861–870, https://doi.org/10.1080/10473289.1997.10464461.

Author Information

Jing Ming (petermingjing@hotmail.com), Beacon Science & Consulting, Malvern, S.A., Australia; and Feiteng Wang, State Key Laboratory of Cryospheric Science/Tien Shan Glaciological Station, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou, China

Citation:

Ming, J.,Wang, F. (2021), Microplastics’ hidden contribution to snow melting, Eos, 102, https://doi.org/10.1029/2021EO155631. Published on 08 March 2021.

(Video) North Cascades National Park on Understanding Microplastics

Text © 2021. The authors. CC BY-NC-ND 3.0
Except where otherwise noted, images are subject to copyright. Any reuse without express permission from the copyright owner is prohibited.

FAQs

Is there microplastic in snow? ›

Scientists have found microplastics—small plastic debris about the size of a sesame seed—in freshly fallen snow in Antarctica for the first time. They published their findings in The Cryosphere.

How do microplastics get into snow? ›

Snow that fell on a remote Antarctic island in 2019 contained tiny pieces of plastic — probably pollution from nearby research bases1. Plastic materials break down over time to form microplastics, small fragments that can be carried long distances by wind and water.

What is the biggest contributor to microplastics? ›

Particles of paint account for more than half (58%) of all the microplastics that end up in the world's oceans and waterways every year, according to a new study.

What are 3 sources of microplastics? ›

Seven major sources of primary microplastics are identified and evaluated in this report: Tyres, Synthetic Textiles, Marine Coatings, Road Markings, Personal Care Products, Plastic Pellets and City Dust.

Does snow contain plastic? ›

Most of the particles were from a type of plastic called polyethylene terephthalate, which is found in clothing and water bottles. The study found an average of 29 particles per liter of melted snow, higher than marine concentrations previously reported from the surrounding Ross Sea and in Antarctic sea ice.

Can you avoid eating microplastics? ›

Exposure to microplastics through food is high, but you can minimize it by limiting your consumption of highly processed foods, choosing eco-friendly food packaging, and replacing plastic water bottles with glass or stainless steel ones.

Do microplastics cause autism? ›

In common with the increase in environmental pollution in the past 10 years, there has also been a recent increase in the prevalence of autism spectrum disorder (ASD). In this regard, we hypothesized that exposure to microplastics is a potential risk factor for ASD.

How can we avoid microplastics? ›

Tips on how to avoid microplastics in food
  1. Consume less processed foods. ...
  2. Drink filtered tap water. ...
  3. Use eco-friendly bottles such as glass or stainless steel bottles. ...
  4. Use eco-friendly packaging. ...
  5. Do not microwave food in plastic containers. ...
  6. Substitute takeaway cups with refillable and eco-friendly ones.
Sep 5, 2022

Where are microplastics most commonly found? ›

Microplastics are found globally in the marine environment at all depths, in coastal areas and remote locations such as Arctic sea ice. Microplastics can float in the water column, settle into marine sediments, or be consumed by organisms and enter the marine food web.

What are the three main routes of exposure to microplastics in humans? ›

Currently, four major routes of exposure have been identified including entanglement, contact, ingestion and inhalation. Humans maybe the most exposed organism because they are at the peak of the food chain.

What foods are high in microplastics? ›

Apples and carrots have the highest levels of microplastic particles. However, microplastics appeared in other crops such as pears, broccoli, lettuce, potatoes, radishes, and turnips. Contamination in fruit and vegetables is thought to occur when plants suck water that contains microplastics up through their roots.

Can your body get rid of microplastics? ›

‌There is not much research about how microplastics affect the body. It is known that larger pieces of plastic are eliminated through fecal matter and that absorption of smaller pieces is rare.

Does canned tuna have microplastics? ›

Highlights. Occurrence of microplastics (MPs) in tuna and mackerel canned fish was investigated. 80% of the analyzed samples had at least one MP particle. The most abundant MPs were polyethylene terephthalate, polystyrene, and polypropylene.

Do apples have microplastics? ›

Researchers at a university in Italy discovered tiny plastic particles in things like lettuce, broccoli, potatoes, and pears. The study, published in the Environmental Research journal, discovered that Apples and carrots were found to have the highest levels of plastic particles in them.

What chemicals are in fake snow? ›

Artificial snow is made of a polyacrylate polymer, such as sodium polyacrylate, which is shredded to produce flakes of a similar size and colour to real snow. Sodium polyacrylate is a superabsorbent polymer, also known as a hydrogel, and can absorb up to 800 times its own weight in water.

Are there chemicals in artificial snow? ›

Fake snow, which is made with surfactants and bacteria as “seeds” (see related article on the next page), keeps our ski resorts busy, and gives winter Olympic athletes adequate surfaces to compete on.

What chemical is pure snow made of? ›

There are two chemical elements in snow; hydrogen and oxygen. Snow is the solid form of water, better known as ice. A single water molecule is made of two atoms of hydrogen and one atom of oxygen, giving it a chemical formula of H2O H 2 O .

Do Brita filters remove microplastics? ›

Basic water filters that rely on simple carbon (like Brita®) or charcoal are only effective at removing unpleasant odors and taste. These filters are not capable of stopping microplastics and instead allows them to pass right through the filter into the water you're drinking.

Does tap water have microplastics? ›

Microplastics are ubiquitous in the environment and have been detected in a broad range of concentrations in marine water, wastewater, fresh water, food, air and drinking-water, both bottled and tap water.

Do organic apples have microplastics? ›

Apples had one of the highest microplastic counts in fruit, with an average of 195,500 plastic particles per gram, while pears averaged around 189,500 plastic particles per gram.

What particles are in snow? ›

A: A snowflake begins to form when an extremely cold water droplet freezes onto a pollen or dust particle in the sky. This creates an ice crystal. As the ice crystal falls to the ground, water vapor freezes onto the primary crystal, building new crystals – the six arms of the snowflake.

Where are microplastic found? ›

Primary microplastics are tiny particles designed for commercial use, such as cosmetics, as well as microfibers shed from clothing and other textiles, such as fishing nets. Secondarymicroplastics are particles that result from the breakdown of larger plastic items, such as water bottles.

Are microplastics found in rain? ›

'It is raining plastic': Scientists find microplastic in rain in Rocky Mountains. A recent rainfall survey conducted by scientists at the US Department of the Interior and US Geological Survey concludes that 'it is raining plastic' after microplastics were found in over 90 per cent of the samples in the study.

What items contain microplastics? ›

We call them “stealth microplastics”, and they include:
  • Tyres. Mussel meal. ...
  • Synthetic clothing. ...
  • Tennis balls. ...
  • Laundry and dishwasher pods/tablets. ...
  • Cigarette butts. ...
  • Glitter. ...
  • Wet wipes. ...
  • Tea bags.
Jan 17, 2018

Videos

1. Science Tonight🌙 Microplastics in our Air, Water, and Bodies
(North Carolina Museum of Natural Sciences)
2. Scientist's Terrifying New Discovery Under Antarctica's Ice
(Future Byte)
3. Eco-Leaders 2.0 Training: Microplastics
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4. Nature in Your Classroom - Microplastics | Grade 8
(Toronto and Region Conservation Authority)
5. STORE SAUSAGE UNDER A MICROSCOPE
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6. Global Plastic Pollution Reaches Juneau
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