Lake Erie Treatment Plants Cut Micro- and Nanoplastics But Treated Water Still Averaged About 2 Million Particles Per Liter, Study Finds

Conventional drinking water treatment cuts a large share of micro- and nanoplastics from Lake Erie source water — but treated water still carried millions of particles per liter in a new plant-scale study.

The paper, “From Source to Sip: Evaluating the Removal of Micro- and Nanoplastics in Conventional Drinking Water Treatment Plants,” was published online July 9, 2026 in ACS ES&T Water (DOI: 10.1021/acsestwater.6c00258; issue date August 14, 2026). Lenhart and colleagues sampled four conventional drinking water treatment plants that use Lake Erie as their source and that differ in unit-operation design.

What the team measured

• They quantified micro- and nanoplastics (MNPs) down to 0.5 μm using scanning electron microscopy paired with optical photothermal infrared spectroscopy.
• They compared raw and treated water across the four plants.

What they found

• Raw water was heavily loaded. Particle counts ranged from about 2 million to 12 million particles per liter; mass concentrations ranged from about 1.8 to 14.5 μg/L.
• Treatment cut both counts and mass — incompletely. Removal averaged about 54% by particle count and about 75% by mass.
• Treated water still averaged roughly 2 million particles per liter (about 1.5 μg/L by mass). The authors reported no significant difference among the four plants in treated-water concentrations.
• Nanoparticles dominated the count. Particles in the nano size range accounted for about 47% to 70% of measured particles in all samples.
• Polymers differed. The most prevalent polymers were polyamide, polyesters and rubber. The team also noted notable differences in removal of polyester and rubber MNPs smaller than 5 μm at three of the four plants.

Why it matters

The study is a drinking-water treatment finding about particle and mass removal at conventional plants — not a health study, and not a claim about any home device. Even after average removals of about half the particles and three-quarters of the mass, treated Lake Erie water in this sample set still averaged on the order of 2 million particles per liter.

A note on scope: this post summarises a peer-reviewed ACS ES&T Water study. It is not medical advice, and WaterVO was not involved in the research.

Sources

• Lenhart, J. J.; et al. “From Source to Sip: Evaluating the Removal of Micro- and Nanoplastics in Conventional Drinking Water Treatment Plants.” ACS ES&T Water, published online July 9, 2026 (issue August 14, 2026). DOI: 10.1021/acsestwater.6c00258

Photo: Cleveland water intake crib on Lake Erie (public domain via Wikimedia Commons). Illustration of Great Lakes drinking-water infrastructure; not one of the four study plants.

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