A recent 2023 study published in Polymers tested different household water filters for their ability to remove microplastics from drinking water.
Main Takeaway:
Specific at-home water filters can remove up to 100% of microplastics from drinking water, according to a new study.
Definitions:
- Microplastics: Small plastic pieces less than 5mm in size (about the size of a sesame seed). Think of how a plastic water bottle breaks down into smaller and smaller pieces over many years. These tiny plastic fragments can pollute our water sources.
- Point-of-use filters (POU): Filters that are attached right at the point water comes out of your tap, like those Brita pitcher filters or filters attached to kitchen faucets. It’s like a final “strainer” for your water before you drink it.
- Granular Activated Carbon (GAC) – Filtration using activated carbon particles to absorb contaminants
- Ion Exchange (IX) – filtration using resins to attract and remove charged particles
- Non-woven Membrane (MEM) – A porous, permeable membrane made of continuous, interlocked fibers
- Microfiltration (MF) – Filtration using a membrane with microscopic pores to remove particles
Introduction:
Have you ever wondered if those plastic water bottles you recycle might end up back in your drinking water? Microplastics from broken down plastics are increasingly found in drinking water sources. But new research shows promise for removing these tiny plastics using special at-home water filters.
Study Overview:
- Lab-based study by researchers at the University of Toronto
- Tested 3 commercially available POU filters for microplastic removal efficiency
- Spiked tap water samples with plastic microbeads and fibers to mimic real-world conditions
Key Findings:
- POU filters with membrane filtration removed 78-100% of plastic microbeads
- Filters using just carbon filtration showed lower removal rates
- Smaller membrane pore sizes (0.2 vs 1 μm) increased removal efficiency
- Filters continued to remove microplastics even after rated capacity
Significance:
This suggests POU filters with membrane filtration could provide an accessible method to reduce human consumption of microplastics from drinking water. This is important as health impacts of ingesting microplastics are still not fully known.
Limitations:
- Limited to 3 POU filter types in lab setting
- Larger field study needed to confirm results
Study Details
- Published January 2023 in Polymers
- Conducted by researchers at the University of Toronto Department of Civil and Mineral Engineering
- Lab-based study that spiked tap water samples with plastic microbeads and fibers
- Tested 3 commercially available pour-through point-of-use water filters
Conclusions:
- The POU water filters containing membrane filtration tested in this study show promise for removing potentially harmful microplastics from home drinking water.
- Membrane filtration was key, using a specialized polymer filter to physically block particles. Carbon filtration alone was less effective.
- Further research on a wider range of filter types is needed, but these membrane filtration methods could help reduce microplastic ingestion from tap water based on this initial study.
Have you noticed microplastics in your home’s tap water? Do you use any at-home filters that help reduce this? Share your experiences in the comments below!
Frequently Asked Questions:
Q1: How much microplastic contamination is in my tap water?
A: The amount can vary greatly depending on your geographic location and drinking water source. Some studies have found microplastic levels ranging from just a couple pieces per liter to over 10,000 pieces per liter. Check with your local water utility to inquire about microplastic testing.
Q2: Couldn’t plastic from the filters themselves contaminate my water?
A: That’s a good point. Proper maintenance and replacement of filters is important to reduce plastic shedding from the filter materials themselves. Always follow manufacturer guidelines on maintenance and lifespans.
Q3: What’s the easiest way I can start filtering microplastics at home?
A: If your tap water source contains microplastics, a faucet-mounted or pitcher style filter containing membrane filtration would be the easiest way to filter directly at the point of use. Be sure to pick one with a pore size of 1 micron or less.
Q4: How exactly does membrane filtration work to remove microplastics?
A: Membrane filtration uses a specialized type of filter that acts like an extra-fine mesh screen. It contains tiny pores that allow water to pass through but block particles bigger than the pore size.
The pore sizes of the membranes tested in this study were 0.2 and 1 micron (1 micron is 1/1000 of a millimeter). To put that into perspective, a human hair is around 50 microns wide. So these pores are small enough to block microplastics and other particles, while still allowing pure water to flow through.
The membranes are made of materials like polymers that can be produced with precise pore sizes. As water passes through the membrane, any particles or contaminants bigger than the pores get trapped on the surface, unable to fit through. This physical filtration process removes particulates down to the size of the pore openings.
Q5: Are microplastics found in bottled water as well?
A: Yes, studies have detected microplastics in bottled water. The point-of-use filters discussed here could provide an alternative with potentially less plastic contamination.
Reference:
Cherian AG, Liu Z, McKie MJ, Almuhtaram H, Andrews RC. Microplastic Removal from Drinking Water Using Point-of-Use Devices. Polymers (Basel). 2023 Mar 7;15(6):1331. doi: 10.3390/polym15061331. PMID: 36987112; PMCID: PMC10054062.
