Microplastics Newsletter: Q2 2025

Study Identifies Methodology to Detect Microplastics Concentrations (<20 μm) in Potable Water Sources

A study published by Hagelskjaer et al. developed an analytical method based on automated Raman microspectroscopy and computer‐vision processing to quantify microplastics concentrations down to 1 micrometer (μm) in ten brands of polyethylene terephthalate (PET) bottled water and one municipal tap water sample.  Concentrations ranged from 19 to 1,154 particles per liter, with 98% and 94% of particles measuring less than 20 μm and 10 μm, respectively. Although these sizes have the potential to cross biological barriers and accumulate in human tissues, this microplastic size range is currently not incorporated into regulations within the European Union or the United States.  This study shows the importance of integrating particles in the 1- to 20-μm range for microplastics detection into robust analytical protocols.

Microplastics Identified Entering the Food Chain Through Plant Leaf Absorption 

A recent study published by Li et al. demonstrated that atmospheric microplastics can be directly absorbed by plant leaves through foliar uptake.  Concentrations of polyethylene terephthalate (PET) and polystyrene (PS) were measured in plant samples collected from five sampling sites in Tianjin, China.  Microplastic concentrations were highest in areas with significant air pollution.  Imaging techniques confirmed the presence and movement of PET MPs in the < 0.3 μm to 10 μm and PS nano-sized plastics (< 100 nm) within leaf tissues, including entry through stomata and translocation to vascular structures. This study documents foliar absorption as a pathway for microplastic accumulation in terrestrial plants, which is important for assessing exposures to humans and animals that consume plants.  

Microplastic Distribution in the Oceanic Water Columns

Researchers evaluated microplastics data collected from different ocean depths to better understand the distribution and transport mechanisms of microplastics within oceans. The study concluded that particle size affects distribution in the water column. Larger particles (100 to 5,000 µm) accumulate in stratified layers, while smaller particles (1 to 100 µm) were more evenly distributed throughout the water column.  Although the study establishes a global benchmark of microplastics distribution within oceanic environments, it does highlight the need for standardizing sampling and analysis of microplastics to ensure comparability across similar studies, ultimately enhancing understanding of microplastics concentrations throughout the water column.

The Transport and Retention of Microplastic Fibers in Streams  

Berg et al. (2025) investigated the impacts of benthic algae, substrate material, and stream discharge on the deposition of polyester fibers in experimental streams. The researchers found that the presence of benthic algae and larger substrates (i.e., cobbles and pea gravel instead of sand) correlated with higher microplastic deposition. High stream discharges were also associated with higher microplastic deposition, which may demonstrate that microplastics have unique retention pathways compared to other particulates. Microplastic resuspension/release from the experimental streams was observed after a simulated storm event, suggesting weather events such as flash foods can mobilize trapped microplastics. These findings provide further understanding of stream-scale microplastic dynamics and may enhance modeling of plastic transport and retention in freshwater ecosystems.  

Microplastic and Nanoplastic Contamination Identified in Bird Lungs

A recent study conducted by Wang et al. (2025) is the first study providing multi-species evidence of micro(nano)plastics (MNPs) detected in bird lung tissues. A total of 56 birds were collected, representing 51 bird species, including a variety of trophic levels, sizes, and environments. MNPs were detected in the lung tissues of all specimens collected.  Higher MNP counts were found in the tissues of carnivorous and omnivorous birds, and more MNPs were identified in the tissues of terrestrial birds than when compared to marine birds. The most abundant shapes were plastic films and pellets ranging from 20 µm to 50 µm. Though the mechanism for how MNPs reached the lung tissue is unknown, the study demonstrated the detection of MNPs in bird lung tissues.

Study Identified Phytoremediation Capabilities Using Water Hyacinth to Remove Microplastics  

A recent study aimed to understand the phytoremediation capabilities of Eichhornia crassipes (water hyacinth) to remove microplastics from microplastic-impacted water.  In the study, hyacinth removed 55-69% of 0.5-, 1-, and 2-μm microplastics from contaminated water after two days, and up to 78% of the microplastics in the water after five days. Further, hyacinths have a vascular ring connected to the roots of the plants, which filters out the microplastics such that it does not enter the other parts of the plant. This study shows the ability for the water hyacinth to sequester microplastics in a way that could be used for phytoremediation. 

Research Triangle Environmental Health Collaborative Summit Focused on Microplastics in North Carolina Occurred in January 2025 in Durham, North Carolina  

A two-day summit meeting in Durham, NC of 100+ experts from government, industry, and academia explored the current state of knowledge regarding the source and fate of microplastics and  environmental and human health impacts. The summit consisted of technical presentations and breakout sessions focused on Exploring Solutions and Turning Ideas into Actionable Strategies. Common themes were a shared emphasis on behavior changes and reuse models that would encourage marketing, education, and incentive systems to shift away from single-use plastics. There was also overall support for Extended Producer Responsibility (EPR) policies which make producers responsible for the end-of-life management of their products. The summit also identified a need for collaborative innovation platforms that link basic research, market testing, and public funding to accelerate adoption of innovative technologies. Interventions such as pilot programs, communication strategies, and policy reviews were not seen as transformational, but were widely acknowledged as necessary stepping stones. 

Regulatory Roundup

U.S. Federal and State

• The California Department of Toxic Substances Control’s (DTSC) Safer Consumer Products Program (SCP) proposed adding microplastics to the Candidate Chemicals List.  If added, it would allow SCP to evaluate potential “Priority Products” that may contain or release microplastics and manufacturers would need to conduct an Alternatives Analysis to evaluate possible safer alternatives.

International

• The EU has reached a provisional agreement between the Council and Parliament on the first-ever regulation aimed at preventing the loss of plastic pellets across the entire supply chain, including maritime transport. Each facility handling pellets must now implement a risk-management plan covering packaging, loading/unloading, staff training, and spill response; larger operators will require third-party certification while smaller firms may use self-declarations. Once formally adopted and published, the regulation is expected to go into effect within two years. 

Litigation

• On April 25, 2025, a class-action lawsuit was filed by a consumer alleging that a major household goods manufacturer falsely marketed certain plastic storage products as “microwave safe” and “freezer safe.” The complaint claims that under normal conditions such as heating and freezing, these products release harmful microplastics—specifically polyethylene and polypropylene—which may pose health risks. The plaintiff argues that the company’s failure to disclose this information amounts to false advertising and violates California’s consumer protection laws. The lawsuit seeks class certification for both California and broader U.S. consumers, as well as monetary damages, restitution, and injunctive relief, including revisions to product labeling and marketing practices.