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Microplastics: The ever present contaminant

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By Watershed Protection Program Co-Op Vincent Liu

Large-scale plastic production has been around since the 1950s, and while plastics existed prior, it was not until this time where plastics began making their way into many aspects of life. With the rise of plastic as a popular material, microplastics emerged as a new contaminant. Microplastics are small pieces of plastic, less than 5mm in size, and they are everywhere. In even the most remote waters of Earth, microplastics can be found. Microplastics are not a recent environmental concern as they have been extensively studied in the marine environment. The presence and impact of microplastics on freshwater ecosystems, however, has been a topic of interest in recent years. With its ability to persist in the environment and being incredibly difficult to remove efficiently, microplastics have established themselves as a worrying pollutant.

Microplastics are formed when larger pieces of plastic break apart into smaller ones. They can come from a wide variety of sources, such as textiles, industry, and packaging. Single-use plastics that reach the environment gradually break into microplastics that can then wash into a stream from a storm event. Plastic fibers are easily shed in the washing machine and then end up in wastewater that enters streams and rivers. These are just some of the many ways that microplastics are released into water. The biological effects of microplastics are yet to be clearly defined, but harmful impacts have been found in studies involving freshwater fish and bottom-dwelling macroinvertebrates. Macroinvertebrates are small animals that lack a backbone, and some species are often used by scientists as indicators of stream health. A study by Redondo-Hasselerharm et. al in 2018 showed that the impact of microplastics on macroinvertebrates is species dependent, with some species being highly sensitive to microplastics and others not being affected at all. Specific health effects were also found in fish including liver damage and reduced growth.

I did my senior project on observing microplastics in Pennsylvanian streams while working with the environmental policy organization, PennEnvironment, on their citizen science microplastic project. PennEnvironment staff collected samples while I assisted in processing samples and analyzing the data. The samples were collected in glass jars, to help reduce the plastic contamination, and were run through a filtration system that draws the water sample through a filter, leaving just the suspended solid material from the water. The filter is placed under a microscope to detect the presence of microplastics within the sample. The 4 categories of microplastics that this project looked for were fibers, fragments, films, and beads. Fibers are long, thin strands of plastic that usually come from textiles. Films are flat, wide, and typically transparent. Beads are round spheres, often found in personal care products prior to 2015. Fragments are plastics that do not fit any of the other categories. A microplastic was distinguished from a natural material by using the squish test, which is a simple test done by poking the suspected microplastic with tweezers. Plastic will not break. It will either maintain its shape or mold into a different shape. 

Example of a microfiber viewed under a microscope. Photo by Caitlin Wessel

The results of the project confirmed the presence of microplastics in every stream that was sampled. What was particularly interesting was the low amount of microbeads compared to every other category of plastic. Beads were by far the least common category of microplastic. This can most likely be attributed to the Microbead-Free Waters Act in 2015, which banned plastic microbeads in rinse-off cosmetics. It was also notable that samples had wildly varying amounts of microplastic, though concentration was not calculated for this project. The site photos from where the samples were collected often told a story as well. In one of the sites, there was a blue tarp that was hanging from a tree into the stream just upstream of the collection site. During microplastic analysis for that sample, there was a noticeably high count of blue microfibers. 

Filtration system used to filter microplastic from water and the jars that samples are stored in

Finding ways to remediate microplastic already existing in the environment is an ongoing pursuit, but policy changes can reduce microplastic output from the source. The microbead ban leading to almost a complete disappearance of microbeads in waterways is an example of how legislation can lead to reductions of microplastic contamination. Policy changes in reducing unnecessary plastic usage and encouraging the use of alternative materials will reduce the amount of microplastics entering the streams. After over 70 years of mass plastic production, it may be time to switch gears and look for alternatives. 

— By Watershed Protection Program Co-Op Vincent Liu

References

Parker, B., Andreou, D., Green, I. D., & Britton, J. R. (2021). Microplastics in freshwater fishes: Occurrence, impacts and future perspectives. Fish and Fisheries, 22(3), 467–488. https://doi.org/10.1111/faf.12528

Redondo-Hasselerharm, Paula E., et al. “Microplastic Effect Thresholds for Freshwater Benthic Macroinvertebrates.” Environmental Science & Technology, vol. 52, no. 4, 30 Jan. 2018, pp. 2278–2286, https://pubs.acs.org/doi/10.1021/acs.est.7b05367 

Eerkes-Medrano, D., Thompson, R. C., & Aldridge, D. C. (2015). Microplastics in freshwater systems: A review of the emerging threats, identification of knowledge gaps and prioritisation of research needs. Water Research, 75, 63–82. https://doi.org/10.1016/j.watres.2015.02.012

Birch, Q. T., Potter, P. M., Pinto, P. X., Dionysiou, D. D., & Al-Abed, S. R. (2020). Sources, transport, measurement and impact of nano and microplastics in urban watersheds. Reviews in Environmental Science and Bio/Technology, 19(2), 275–336. https://doi.org/10.1007/s11157-020-09529-x

Geyer, R., Jambeck, J. R., & Law, K. L. (2017). Production, use, and fate of all plastics ever made. Science Advances, 3(7). https://doi.org/10.1126/sciadv.1700782

Center for Food Safety and Applied Nutrition. “The Microbead-Free Waters Act.” U.S. Food and Drug Administration, 2018, www.fda.gov/cosmetics/cosmetics-laws-regulations/microbead-free-waters-act-faqs.b 

The Burden of Expanding Plastic Production and Use: A Great Product or a Horrific Product? Your Choice

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By Carol L. Armstrong, Ph.D., ABN, Friends of Heinz Refuge, Board of Directors
Cover Photo by Jennifer Mathes

Did you know that right here in our region, we have a wildland that supports over 300 species of birds, of which you will see and hear over 40 on any day? The marshes at the John Heinz National Wildlife Refuge spanned almost 6,000 acres in the time of Lenape stewardship of the land, and now it consists of 1,000 acres where massive biodiversity exists, some endangered species survive, and beautiful streams flow into tidal wetlands. It is a place where you can feel you can get lost, all the time being but a stone’s throw from Philadelphia and the dense suburbs of Delaware County. But there is a hidden problem: plastic debris is inundating the Refuge (Photo copyright: Kim Sheridan).

Darby Creek. Photo Copyright: Kim Sheridan

To manage the plastic debris, the Refuge has both public and non-public clean-ups throughout the year. Volunteers help Refuge staff to remove the hundreds of tires, layers of plastic debris on flood plains, plastic stuck in the riparian trees and shrubs after a storm, and thick accumulation of plastics in coves, marsh, and aquatic plants. The problem is most apparent at low tide (photo copyright: Mary Trzeciak). 

Plastics found during low tide. Photo Copyright: Mary Trzeciak

How do we prevent this sort of pollution? Personal evolution comes from reading about the problem, watching the webinars from the Friends of Heinz Refuge (see videos on our Facebook), reading the Friends of Heinz Refuge e-Newsletter, and joining our Plastics Working Group meetings, held monthly. 

One of our Board members, whose career was in business and not involved in environmental restoration, recently admitted that his view of plastic had changed completely since he joined the Board, and now he “can’t stand plastic.” He is horrified at the stuff, and now refuses to purchase plastic drinking containers. 

In three of the public cleanups at the Refuge, volunteers sorted the types and number of debris using the Ocean Conservancy’s data form. Of plastics, metal, glass, and paper debris, more than 99% were some form of plastic, which, over the next hundreds of years, will flake off microplastics and leach into the water the chemicals that make plastic have the features producers want (e.g., color, flexibility, weight, heat/light resistance), long before the plastic actually decomposes back into organic matter. Plastics begin to break down into microplastics and leach chemicals as soon as they are in the environment.

It’s difficult to make the paradigm shift that this board member made, because we are so accustomed to thinking that we cannot live without plastics. The 4% increase in the production of plastics each year means that it is increasing due to supply and not due to demand. The increasing number of items that are packaged in plastic can be witnessed in any store, often in multiple layers of plastic. For example, cheeses are sold in see-through plastic boxes rather than wrapped in paper, bakery items are all packaged in some amount of plastic, condiments and drinks leave few choices in glass rather than plastic, and organic produce is difficult to find without plastic packaging. There are zero waste businesses dedicated to transforming industries to reusable containers or alternate materials, and they find the uphill road very steep. 

In the U.S., plastic that is recycled has declined from 7 to 9% to 5 to 6%, according to the most recent reports from the EPA and the U. S. Department of Energy. 100% of plastic waste is incinerated in some towns such as Harrisburg, and this practice is  increasing in many cities. Some “chemical recycling” is emerging from burning plastics for energy, which increases the demand for plastic waste, results in more toxic air pollution, and increases greenhouse gas emissions. By 2050, humans will have produced more than 28.5 billion tons of plastic, and we will be dealing with four times more plastic production than currently exists. Borrowing from L-M Miranda’s Hamilton: “Do you support this Earth? Of course. Then defend it.”

The key is to remember that there is always something that each person can do: 

  1. Make purchasing decisions based on the presence or relative amount of plastic in the packaging; 
  2. Do your own home assessment of the sources and amounts of your waste versus recycling (now in Pennsylvania mainly limited to clear or white #1 and #2). The EPA and California provide online instructions for zero waste practices, and a simple site for home is: https://www.thezerowastecollective.com/post/how-to-do-a-trash-audit-at-home;
  3. Work towards cutting in half (or more) the amount that you put out in trash and recyclables;
  4. Avoid plastic sheeting and synthetic textiles used in landscaping, sediment/erosion control, blankets and rugs, and personal clothing as these plastics are filling our air, soil, and water, and there are alternatives for all.  The presence of plastics in our indoor air is disturbing at estimates of 30% of dust;
  5. Give up thin, single-use plastic bags and drinking containers forever; and
  6. Ask your town to ban single-use plastics. 

— By Carol L. Armstrong, Ph.D., ABN, Friends of Heinz Refuge, Board of Directors

A Cycle of Give and Take

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By Watershed Protection Program Co-Op Sarah Busby

Within our streams, there are many players that work to create a functioning, thriving ecosystem. From the tall trees that hang overhead at the bank’s edge, providing cooling shade and abundant habitat, to charismatic animals like the beaver that literally shape the movement of the stream, some species play a more visible role than others. However, there are plenty more individuals hard at work behind the scenes, — or rather, below the surface of the stream. One such character is the freshwater mussel. Sometimes mistaken for a stone, this unassuming animal quietly resides at the bottom of our streams, often going unnoticed. While an individual mussel may be overlooked, their dramatic impact on a stream is impossible to miss when they work together.

One of many Elliptio complanata mussels found in our very own Crum Creek during a recent mussel survey. Photo by Sarah Busby

Freshwater mussels begin their life in a curious fashion, highly dependent on the fish in their communities. During reproduction, female mussels release packets of larval mussels, or glochidia, carefully timed with the encounter of a suitable host fish. After release, the larval mussels must attach to the gills of their host to survive. Once the larvae have secured a ride, they will travel with their host until they grow big enough to go off on their own, which may take up to a few weeks. When ready to depart, the mussels drop off and settle down into the riverbed. Host fish not only provide a safe haven for the larval mussels to develop in, but also allow for them to disperse much greater distances than freshwater mussels could ever go on their own. While glochidia do not cause harm to their host in most cases, the obligate parasite owes much to the hosts they grow up in. Though freshwater mussels are quick to give back to their neighbors once they come into adulthood.

Freshwater mussels are constantly filtering through water to breathe and feed. Typically, they sit partially buried into the substrate, siphoning in water. As water flows through their gills, they filter out bacteria, algae, phytoplankton, detritus, and other small organic particles to feed on. In this process, they also filter out pollutants from the water, accumulating the contaminants into their own bodies.

The filter-feeding activities of mussel populations greatly improves the water quality of the bodies of water they inhabit. This is beneficial to the rest of their local community. The fecal pellets they expel provide food for other invertebrates, and the mussels themselves are consumed by fish, birds, and mammals alike. Additionally, their shells provide shelter and habitat for aquatic invertebrates like caddisflies, midges, and other insects that fish rely on for sources of food. Much like the fish who sheltered them in their vulnerable state, an adult mussel provides for its community throughout its entire lifetime of up to a century, and even beyond when only its shell remains.

Mussel by Sarah Busby

Freshwater mussels have a long history of providing not only for their aquatic communities, but for humans as well. These mussels were a major food source for many prehistoric [1] and pre-colonial people in North America. Multiple Native American tribes have mussel harvests that date back to over 10,000 years ago. The shells were used for creating tools and jewelry. Before the invention of plastic, buttons were also made from the shells of mussels. The mentioned uses were in addition to the ecological service mussels provide by improving the quality of our water sources. While the cultural use of mussels has shifted over time, this critical service upholds its relevance.

Now in modern times, freshwater mussels are more vulnerable than ever before. From habitat degradation, pollution and impaired water quality, mussels face threats on multiple fronts — many of which are human imposed. As many native host fish species decline, the mussels follow close behind.

Currently, freshwater mussels are considered the most endangered group of organisms in [2] the country. It is our turn to provide for the mussels and the communities that come with them. Protecting the mussels means protecting our rivers and streams. Current efforts are being made to reintroduce [3] freshwater mussels into our streams and foster their growth through research and restoration. But success of these efforts is brought to fruition through community support. It starts with appreciating the role mussels play in a thriving ecosystem and follows by embracing our own part in it.[4] 

— By Watershed Protection Program Co-Op Sarah Busby

Sources:

About freshwater mussels. Pacific Northwest Native Freshwater Mussel Workgroup. (n.d.). Retrieved June 6, 2022, from https://pnwmussels.org/about-freshwater-mussels/

Freshwater Mussels. Center for Biological Diversity. (n.d.). Retrieved June 6, 2022, from https://www.biologicaldiversity.org/campaigns/freshwater_mussels/

Freshwater mussels. Partnership for the Delaware Estuary. (2020, July 17). Retrieved June 6, 2022, from https://delawareestuary.org/science-and-research/freshwater-mussels/

Jaramillo, C. (2018, May 2). With nation’s first city-owned Mussel Hatchery, Philly employing bivalves in battle to improve water quality. WHYY. Retrieved June 6, 2022, from https://whyy.org/articles/with-nations-first-city-owned-mussel-hatchery-philly-employing-bivalves-in-battle-to-improve-water-quality/

Mussels and Us Prehistory. FMCS – Freshwater Mussels. (n.d.). Retrieved June 6, 2022, from https://molluskconservation.org/MUSSELS/Prehistory.html

Strayer, D. L. (2017). What are freshwater mussels worth? Freshwater Mollusk Biology and Conservation, 20(2), 103–113. https://doi.org/10.31931/fmbc.v20i2.2017.103-113

Wimberly, B. (2021, August 26). The “mussel” Behind the delaware river watershed’s clean water. Audubon Pennsylvania. Retrieved June 6, 2022, from https://pa.audubon.org/news/%E2%80%9Cmussel%E2%80%9D-behind-delaware-river-watershed%E2%80%99s-clean-water

Beavers Beyond the Dam

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By Watershed Protection Program Co-Op Catherine Quinn

Beavers are known and loved as one of North America’s favorite stream architects. With historic removals of these lovely creatures, we are only just now grasping how important they are in shaping our freshwater ecosystems, which encompasses all streams, rivers, lakes, and ponds, as well as the surrounding land. In food chains, removing any level will alter populations of other levels. For instance, if a species of fish is removed from a stream, populations of macro-invertebrates (which are aquatic, typically early development forms of insects) will grow as there are fewer predators to keep their populations in check. In turn, with large numbers of macro-invertebrates, algae will decrease in population size as there is a higher demand for them as food.

Beaver by Andrew Patrick

With beavers, their impact extends beyond these food chain alterations when they are introduced to a new stream ecosystem. As ecosystem engineers, beavers actively change the physical features of freshwater environments by building their dams. Even failed or abandoned dams continue to affect the environment. Dams are incredibly capable of storing nutrients and groundwater. They affect water flow to varying degrees and can alter water temperatures. These alterations of physical qualities change the quality of life for other organisms. For example, certain organisms rely on food flowing straight into their mouth, habitat, or home and therefore thrive in fast-flowing areas of water. If that water slows down, they may not be able to survive!

In terms of understanding our streams, we already have a considerable grasp of the macro-invertebrates that inhabit them. Freshwater macro-invertebrates typically live on rocks in fast-flowing environments, like streams. They play an integral role in food chains as they consume much of the plant matter in streams and are an excellent food source for predators, both in water and on land. With the introduction of a significant change to an ecosystem, such as a beaver dam, the conditions macro-invertebrates are used to may be impacted, which will either improve or worsen their ability to survive and reproduce in the environment.

Beaver Dam by WCT Watershed Protection Program

Macro-invertebrates play an important role in regulating nutrients as they enter and leave the water. They are also incredible bioindicators, meaning their presence alone can tell us about the health of the water they are living in. Each macro-invertebrate lies on a scale of pollution tolerance, from sensitive to tolerant. In healthy freshwater systems, we see sensitive groups and a variety of species. This biodiversity tells us that the ecosystem is healthy enough to keep the maximum number of organisms happy. With this application of macro-invertebrates, we can use them to understand how beaver dams are affecting freshwater systems entirely.

The jury is still out on how beaver dams impact the existence of macro-invertebrates, but one thing is certain: beaver dams are indeed affecting them. One study by Clifford et al. (1983), found that in an Alberta, Canada stream, macro-invertebrates increased in both abundance (the number of species) and biodiversity (the variety of species) after the introduction of beavers. The study concluded that sections of the stream flowing from the beaver dam are healthier than sections flowing into the dam. On the other hand, in Utah, Washko et al. (2019) found that beaver ponds (areas completely blocked by beaver dams, creating a pond-like environment) showed lower levels of biodiversity and significantly lower populations of macro-invertebrates. The effects of beaver activity on macro-invertebrates likely depend on a variety of factors. Further research will help us better understand the overall impact beavers have on our waters.

Caddisfly by Catherine Quinn

— By Watershed Protection Program Co-Op Catherine Quinn

[1] 

Sources:

Clifford, H. F., Wiley, G. M., & Casey, R. J. (1993). Macroinvertebrates of a beaver-altered

boreal stream of Alberta, Canada, with special reference to the fauna on the dams.

Canadian Journal of Zoology, 71(7), 1439–1447. https://doi.org/10.1139/z93-199

Hood, G. A., McIntosh, A. C. S., & Hvenegaard, G. T. (2021). Ecological Compromise: Can

Alternative Beaver Management Maintain Aquatic Macroinvertebrate Biodiversity?

Wetlands, 41(8), 112. https://doi.org/10.1007/s13157-021-01494-7

Robinson, C. T., Schweizer, P., Larsen, A., Schubert, C. J., & Siebers, A. R. (2020). Beaver

effects on macroinvertebrate assemblages in two streams with contrasting morphology.

Science of The Total Environment, 722, 137899.

Shampain, A. (2017, December). The impact of beaver dams on aquatic macroinvertebrate

communities | WALPA.

macroinvertebrate-communities/

Washko, S., Roper, B., & Atwood, T. B. (2020). Beavers alter stream macroinvertebrate

communities in north-eastern Utah. Freshwater Biology, 65(3), 579–591.

Wetlands & Bogs: Aquatic Ecosystems Undercover

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By Watershed Protection Program Co-Op Catherine Quinn

Wetlands are a critical ecosystem in the protection of our watersheds. But what are wetlands exactly? They are just as they sound — land that is wet. How are they critical? In the realm of watersheds, they have many beneficial roles. For instance, the watershed areas protected by the Willistown Conservation Trust make up the headwaters of the Darby, Crum, and Ridley creeks. Their role as headwaters means they have a significant impact on downstream areas of these creeks.

The wetlands surrounding these headwaters help filter the water feeding into them, which in turn helps reduce flooding and pollution. Sphagnum moss, a characteristic plant of bogs, is unique compared to other land plants because it works like a sponge. When precipitation occurs, vegetation normally acts as a barrier from much of the water reaching the ground. However, sphagnum moss, with its sponge-like abilities, will absorb water from precipitation and release it into the ground below, helping maintain that wetland habitat.

Sphagnum Moss by Lorraine Boissoneault

Now, how do wetland ecosystems come to be in the first place? Most can be explained by groundwater! Groundwater is also exactly as it sounds — water that exists in the ground. Groundwater can be explained in more detail by the water table, which is a term used to describe the boundary between soil that is completely wet (below the water table), and soil that can hold more water (above the water table). When the ground’s surface is below the water table boundary, or when the surface-level ground is consistently saturated with water (which can also occur with persistent rain), a wetland ecosystem occurs. It is important to distinguish ecosystems like wetlands versus woodlands from one another, particularly in conservation, because of their varying functions, populations, and dynamics. Within wetlands, there is a further multitude of habitat types.

Wetland at Rushton Woods Preserve by Catherine Quinn

A common subset of a wetland is a bog. You have likely heard of bogs before, particularly in relation to where cranberries come from. Bogs are characterized by the makeup of their soil. These wetlands have had at least hundreds of years to develop by means of decaying plant matter. Bogs form from plant matter decaying into what we call peat, which is known for its significant amounts of stored carbon, otherwise known as a carbon sink. Carbon sinks are hugely important ecosystems in terms of the global climate. Human-caused climate change is primarily attributed to the amount of carbon dioxide in the atmosphere. The deterioration of carbon sinks is a contributor to this problem; a common example of this is deforestation.

Many wetlands in our region likely contained bogs, which is a discovery made through finding layers of peat. In our conservation efforts, it is incredibly beneficial to understand the ecosystems we are working in as well as we can. For example, bog turtles are the smallest turtle in North America and are critically endangered due to poaching and habitat loss. Being able to identify their habitat is critical to their protection as an individual will know to look out for them.

Bog Turtle by The Nature Conservancy

The Watershed Protection Program had the opportunity to shadow George Gress, a bog turtle pro from the Nature Conservancy, on a bog turtle habitat assessment. We discovered that while many wetlands do not contain the habitat that bog turtles look for, that does not necessarily mean they are not there. In ecology, it is quite difficult, and sometimes impossible, to prove the complete absence of a species, especially when it comes to our smaller friends. In addition to bog turtles and sphagnum moss, bog habitats have several other characterizing species. Another common type of bog plant is sedges. Sedges are grass-like plants that grow in clumps and help provide ideal habitat to bog turtles by allowing for muddy, particularly wetter depressions in the ground.

— By Watershed Protection Program Co-Op Catherine Quinn

Sources:

https://education.nationalgeographic.org/resource/bog
https://www.epa.gov/wetlands/what-wetland
https://www.nature.org/en-us/get-involved/how-to-help/animals-we-protect/bog-turtle/
https://en.wikipedia.org/wiki/Peat
https://en.wikipedia.org/wiki/Sphagnum