Microplastics in Lakes: Human Health Risks

published on 07 February 2024

We can all agree that microplastics in our lakes are concerning when it comes to human health.

In this article, I will analyze the potential risks microplastics pose through drinking water and recreation, reviewing toxicity mechanisms and health correlations.

You'll discover the exposure pathways, at-risk groups, and strategies to mitigate risks through policy, technology, and public education.

Introduction to Microplastics in Lakes and Their Human Health Risks

Understanding Microplastics and Limnology

Microplastics are small plastic pieces less than 5 mm in size that come from the breakdown of larger plastic items or are manufactured to be that small. They are commonly found in freshwater lakes and studied as an emerging pollutant within the field of limnology - the study of inland aquatic ecosystems. Major types of microplastics detected in lakes include fibers from clothing, plastic microbeads from cosmetics, and fragments of larger plastic waste.

Global Distribution of Microplastics in Lakes

Recent studies have detected microplastics in lakes across North America, Europe, Asia, Africa, and Antarctica. While less research has been conducted on lake microplastics compared to marine environments, scientists have found high concentrations in some major lakes. For example, one study found over 1.9 million particles per square kilometer in Lake Erie. The composition varies by region but commonly includes polyethylene, polypropylene, and polystyrene.

Microplastics as a Source of Plastic Pollution

Microplastics enter lakes through wastewater treatment plant effluent, urban runoff, degraded plastic litter, atmospheric deposition, and more. They contribute to the broader plastic pollution issue as they absorb toxins, are ingested by aquatic life, and spread further through water cycles. Their small size also makes them difficult to remove with standard plastic cleanup methods.

Initial Concerns Over Health Effects from Microplastics

Early toxicology studies have prompted worries over potential human health issues like inflammation, oxidative stress, and even cancer from ingesting microplastics through drinking water or recreational activities. However, research is still emerging and risk assessments remain inconclusive on safe exposure thresholds for humans. Still, scientists agree microplastic pollution presents an environmental risk warranting further study and preventative action.

Are there microplastics in lakes?

Microplastics are increasingly being found in lakes around the world. Recent studies have detected microplastics in lakes across North America, Europe, Asia, Africa, and Antarctica. Sources of microplastics entering lakes include:

  • Plastic waste and litter from shorelines and recreational activities that get broken down into smaller pieces
  • Effluent from wastewater treatment plants that discharge into lakes
  • Atmospheric fallout of fibers and fragments from synthetic textiles
  • Runoff from urban areas carrying bits of plastic from streets and storm drains

Once in lake systems, microplastics tend to accumulate along shorelines and get ingested by aquatic life. Their small size allows them to be consumed by zooplankton, fish, birds, and other organisms. Over time, microplastics accumulate up the food chain, impacting entire lake ecosystems.

The presence of microplastics in lakes poses potential risks:

  • Physical harm to wildlife from ingestion
  • Toxic chemical transfer from plastics to animals
  • Bioaccumulation of plastics over generations
  • Spread of invasive species clinging to floating plastic

Further research is still needed to fully gauge the effects of microplastics on lake ecology. But their widespread distribution underscores the need for plastic waste reduction efforts to prevent plastic pollution from degrading water quality.

Are microplastics in water harmful to humans?

Microplastics in lakes and other water bodies can pose potential risks to human health, primarily through contamination of drinking water and exposure during recreational activities.

The main concerns around microplastics and human health include:

  • Physical effects: Microplastics small enough to be ingested can accumulate in the digestive system, potentially causing inflammation, ulceration, and even cancer over time with repeated exposure. Their small size also enables them to cross cell membranes.

  • Leaching chemicals: Many microplastics contain chemical additives like plasticizers that can leach out. These chemicals may disrupt hormones, metabolism, reproduction, and development.

  • Accumulating contaminants: Microplastics tend to absorb other toxins from the environment like heavy metals and pesticides. Consuming microplastics introduces these contaminants into the body.

  • Spreading pathogens: Microplastics can transport microbes that cause diseases in water supplies. One study found antibiotic-resistant bacteria on microplastics in a lake used for drinking water.

While research is still ongoing, these potential effects highlight the need to limit microplastic pollution entering water bodies, especially those used for municipal water or recreation. Implementing better waste management systems and reducing single-use plastics can help achieve this goal.

How do you remove microplastics from a lake?

Removing microplastics from lakes can be challenging due to their small size, but there are some potential methods.

Filtration Systems

One of the most direct ways is to install filtration systems that can physically filter out microplastics at water intake pipes or at key locations along a lake. Ideal filters would have pore sizes of 0.1 microns or less to capture most microplastics. This could significantly reduce microplastics entering the water supply. However, such systems would likely be expensive to install and maintain.

Natural Remediation

Another option is utilizing natural remediation processes within the lake. Installing floating treatment wetlands along the perimeter can help filter some microplastics while also absorbing nutrients and improving water quality. The plants' roots provide surface area for microplastic particles to adhere to. This method may be more cost-effective but less comprehensive than filtration systems.

In some cases, manually removing microplastic accumulation zones could also help. Areas with low water flow tend to accumulate more plastics. Dredging or skimming these areas could reduce microplastic density. However, this would likely need to be an ongoing process.

Ultimately, the most effective solution involves preventing microplastics from entering lakes to begin with. But when contamination does occur, a combination of filtration systems, natural remediation, and manual removal may help mitigate risks.


How do microplastics get into the Great Lakes?

Microplastics enter the Great Lakes through various sources, posing risks to human health and the environment. Major sources include:

  • Microfibers from textiles: Washing synthetic fabrics like polyester releases microfibers into wastewater. These fibers pass through water treatment plants and enter waterways that connect to the Great Lakes.

  • Plastic pellets: Small plastic pellets used in manufacturing and known as nurdles are spilled or leaked into the environment during production and transport. Rain and wind carries them into rivers and lakes.

  • Tire wear particles: As tires degrade from friction on roads, tiny rubber particles are produced. These get washed by rain into storm drains and make their way into lakes.

  • Plastic foam: Polystyrene foam used in building insulation and packaging breaks down into small pieces that are blown or washed into waterways during construction projects near lakes.

Once microplastics enter, they persist and accumulate in lake ecosystems. Researchers urge policy changes to prevent plastic pollution at the source before it reaches vulnerable freshwater habitats like the Great Lakes. Simple daily choices to reduce plastic use also helps mitigate this emerging threat.

Microplastic Pollution and Exposure Pathways to Humans

Microplastics from lakes can enter the human body through various exposure pathways, primarily water consumption and participation in recreational activities. As lakes are used for drinking water and leisure, understanding microplastic contamination levels and associated health implications is an important public health issue.

Assessment of Microplastics in Drinking Water Resources

Recent studies have detected microplastics in tap and bottled water sourced from lakes in Europe and North America. While current research shows microplastic levels below established risk thresholds, findings indicate the potential for cumulative exposure over a lifetime of consumption. Monitoring programs and improved treatment solutions will be vital for ensuring the safety of drinking water resources.

Additional research should further clarify potential human health outcomes from ingesting microplastics through drinking water over time. Effects could range from inflammation to the transport of chemical contaminants into body tissues. Ongoing efforts to limit microplastic pollution entering lakes will help safeguard water quality.

Recreational Activities as Exposure Points

Swimming, boating, and fishing in contaminated lakes can facilitate microplastic ingestion and inhalation as well as absorption through the skin. Microfibers shed from sportswear could also directly enter lake water during recreational usage.

While research is still emerging, initial studies found microplastic levels in wild fish from various lakes to be low. Further assessments of bioaccumulation across lake food chains will clarify potential human exposures from eating contaminated seafood.

Understanding differences in microplastic exposures across activities can promote safer public health guidelines. Proper usage of protective gear may help mitigate exposures during water sports.

Identifying At-Risk Groups for Microplastic Exposure

Children and communities lacking water treatment systems face higher risks from microplastic contaminated drinking water. Children's developing bodies are more vulnerable to chemical additives and they consume more water relative to their body weight. Low-income areas often draw drinking water directly from lakes without microplastic removal processing, increasing their contaminant levels.

Targeted outreach, infrastructure improvements, and subsidies may help provide at-risk groups additional protections from microplastics entering local water supplies. Ongoing research can also clarify health outcomes across different exposure levels and demographics.

Environmental Impact of Microplastics on Lake Ecosystems

Studies show microplastics accumulating in lakebed sediments, aquatic plants, and diverse organisms from plankton to fish. Documented effects include inflammation, inhibited growth, liver damage, and potentially altered behaviors. These ecological impacts may indirectly affect human communities relying on local species for food, recreation, and cultural practices.

While further research is needed, initial evidence indicates microplastics could threaten the biodiversity and resilience of freshwater habitats. Preventing additional contamination and developing cleanup solutions may help restore environmental health. In turn, conservation efforts can help safeguard water resources and public health.

Assessing the Human Health Risks of Microplastic Pollution

Investigating Toxicity Mechanisms of Microplastics

Microplastics could potentially cause harm through several proposed mechanisms:

  • Leaching of chemicals: Additives and environmental pollutants can leach out of microplastics. These chemicals may be toxic to human cells and organs.
  • Intestinal damage: The sharp edges of some microplastics could physically damage intestinal tissue, especially smaller microplastics that cross the gut barrier.
  • Inflammation: Microplastics may trigger inflammatory responses. Chronic inflammation is linked to diseases like cancer, diabetes, and autoimmune disorders.
  • Oxidative stress: Microplastics can induce reactive oxygen species that damage cells through oxidative stress. This can disrupt normal cellular signaling.

Further research is critically needed to clarify microplastic toxicity mechanisms and determine relative contribution to human health risks.

Systemic Effects of Microplastics on Human Health

Early research shows potential links between microplastic exposure and:

  • Gastrointestinal issues: Changes to gut microbiome, intestinal permeability, inflammatory bowel diseases.
  • Liver dysfunction: Fatty liver disease, impaired metabolism of toxins, oxidative stress.
  • Kidney disorders: Reduced filtration capacity, kidney stone formation, tissue damage.
  • Respiratory effects: Lung inflammation and fibrosis, asthma, allergies.
  • Cardiovascular disease: Arterial plaque buildup, hypertension, blood clots.
  • Neurological effects: Impaired development, neuroinflammation, Alzheimer's disease.
  • Reproductive issues: Endocrine disruption, reduced fertility, pregnancy complications.

However, human epidemiological data remains limited. More research is urgently needed to clarify health consequences, especially for vulnerable groups like children.

Correlation Between Microplastics and Cancer Risks

A few rodent studies reveal worrying correlations between microplastic exposure and indicators of carcinogenic effects like cell mutations and tumor formation.

However, evidence directly linking microplastics to human cancers is still lacking. Future research should investigate relationships between microplastic pollution and cancer risks. Tracking rates of cancers such as lymphoma, leukemia, and breast cancer in areas with high microplastic exposure could reveal valuable insights.

Reviewing the Evidence: Microplastics and Human Health

In summary, microplastics likely pose health risks through several mechanisms such as leaching hazardous chemicals, inducing inflammation, and disrupting organ function. But considerable uncertainty remains regarding the magnitude of risks for human populations.

More extensive, long-term epidemiological studies tracking health outcomes of people exposed to high levels of microplastics are critically needed. Future research should focus on vulnerable groups, effects of early life exposures, and combined impacts of complex mixtures of plastic additives and environmental pollutants.

Clarifying microplastic health consequences is an urgent public health priority to inform environmental policy-making and prevention strategies worldwide.

Strategies and Recommendations to Mitigate Microplastic Health Risks

Policy Interventions to Address Microplastic Pollution

Policy interventions are critical to reducing the amount of plastic waste entering waterways and improving standards for microplastic removal from drinking water. Some recommendations include:

  • Implementing extended producer responsibility programs to incentivize companies to design less wasteful plastic products and packaging
  • Banning certain unnecessary single-use plastics that frequently end up as water contamination
  • Establishing watershed-level plastic waste reduction targets
  • Improving waste management infrastructure to prevent plastic leakage into waterways
  • Updating drinking water quality standards to specifically target microplastic removal with advanced filtration methods

Advancements in Water Treatment for Microplastic Removal

Water treatment plant upgrades focused on optimizing microplastic removal would substantially lower health risks. Priority areas include:

  • Installing membrane bioreactor systems with ultrafiltration for small microplastic capture
  • Using coagulant and flocculant aids to improve microplastic aggregation and separation
  • Incorporating advanced oxidation processes to degrade microplastics during treatment
  • Implementing tertiary filtration methods (sand, granular activated carbon) to extract residual microplastics

Personal Protective Measures Against Microplastics

Individuals concerned about microplastic exposure from recreational activities in contaminated lakes can take protective steps such as:

  • Consuming only fillet fish meat rather than whole fish to reduce microplastic ingestion
  • Using designated swimming areas away from plastic waste accumulation zones
  • Washing thoroughly after swimming to remove any microplastic residue
  • Drinking bottled or filtered water instead of directly from the lake

Educational Outreach on Microplastics and Human Health

Greater public awareness of microplastic health effects is vital for driving action across sectors. Education should highlight:

  • Major sources and distribution mechanisms of lake microplastic pollution
  • Potential human health consequences from microplastic contaminated water
  • Practical mitigation strategies individuals and communities can implement
  • Ongoing research needs and opportunities for public involvement

Targeted outreach to healthcare providers and policymakers can also help prioritize this emerging health issue.

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