Microplastic Shedding From Polyester During Washing

ISEF Category: Chemistry

Subcategory: Analytical Chemistry  ·  Difficulty: Intermediate  ·  Setup: School Lab  ·  Time: 1 to 2 Months

The Hook

A single load of laundry can release tiny plastic fibers into water that eventually flows into rivers and oceans. You cannot see most of them by eye, which makes them easy to ignore and hard to count. That is where staining, microscopy, and image analysis come in. You can turn a hidden pollution problem into numbers you can test.

What Is It?

Polyester clothes are made from plastic fibers. When they get washed, some fibers break loose. Those fibers are called microplastics when they are tiny enough to fit into the microplastic range, usually smaller than five millimeters.

Think of the fabric like a rope made from many thin threads. Every wash shakes that rope, and a few threads snap off. Nile red is a dye that sticks to many plastics and glows under the right light, so you can pick plastic particles out from the rest of the debris. A USB microscope lets you photograph the stained particles, and image segmentation software helps you separate each particle from the background so you can measure size, count pieces, and build a distribution.

Why This Is a Good Topic

This project works well because you can measure a real environmental problem with a clear variable, like fabric type, wash condition, or detergent choice. You get both chemistry and data analysis, since you are using a stain, imaging, and a statistical model. You can do meaningful work without a university lab, and the results can connect to pollution, wastewater, and textile design.

Research Questions

• How does fabric weave density affect the number of microplastic fibers released during washing?
• How does wash cycle type affect the size distribution of polyester microplastics collected from rinse water?
• What is the effect of detergent type on the mass and count of stained microplastic particles?
• Does garment age change the total microplastic shedding rate from polyester fabric?
• To what extent does water temperature change the number of detectable polyester fragments after staining?
• Which image segmentation threshold gives the most consistent particle counts across repeated samples?

Basic Materials

• Polyester fabric samples from different garments or textile swatches.
• Access to a shared washing machine or a small controlled wash setup.
• Nile red stain and proper safety gear, including gloves and goggles.
• USB microscope with adjustable magnification.
• Glass slides or clear petri dishes for imaging samples.
• Fine filter paper or membrane filters for collecting particles.
• Digital kitchen scale with 0.1 g accuracy.
• Distilled water for blanks and rinses.
• Tweezers, pipettes, and clean collection containers.
• Dark box or consistent light source for microscope imaging.

Advanced Materials

• Vacuum filtration setup with glass fiber or membrane filters.
• Fluorescence-capable microscope or LED excitation source compatible with Nile red.
• Analytical balance for mass measurements.
• FTIR or Raman access for confirming polymer identity in a subset of particles.
• Certified microplastic reference particles or polymer standards.
• Stereomicroscope for pre-sorting larger fibers.
• Temperature-controlled washer or shaker system for controlled trials.
• Lab software for particle morphometry and image calibration.

Software & Tools

• ImageJ: Measures stained particle area, length, and count from microscope images.
• Python: Automates image processing, threshold testing, and size-distribution analysis.
• R: Fits statistical models and compares shedding rates across treatments.
• Google Sheets: Organizes sample metadata, replicate labels, and basic summaries.
• NIH ImageJ plugins: Adds particle analysis tools and calibration options for microscopy images.

Experiment Steps

1. Define the exact comparison you will make, such as garment age, fabric type, or wash condition.
2. Set up a clean collection plan so you can separate true shedding from background contamination.
3. Choose a staining and imaging workflow that makes polyester fragments easy to detect and measure.
4. Build a calibration process so pixel size becomes real particle size and counts stay comparable across sessions.
5. Plan a size-distribution analysis that treats fiber length, width, or area as your main outcome.
6. Test a control sample and a blank so you can check whether your signal comes from the fabric, not the setup.

Common Pitfalls

• Mixing lint, dust, and true microplastics in the same count, which inflates the shedding estimate.
• Using changing microscope light or focus between samples, which breaks image segmentation consistency.
• Skipping blank controls, which makes background contamination look like fabric shedding.
• Counting only large visible fibers, which misses the smaller particles that dominate the distribution.
• Comparing washed samples with different fabric masses or surface areas, which makes the rate data unfair.

What Makes This Competitive

A stronger project does more than count particles. It tests a clear mechanism, uses matched controls, and reports uncertainty in a clean way. You can raise the level by comparing several fabrics, modeling the full size distribution, and checking whether your image-based counts match a second measurement method. A careful contamination plan also matters a lot, because microplastic work is easy to get wrong.

Project Variations

• Compare new polyester shirts, worn polyester shirts, and polyester fleece to see whether fabric wear changes shedding.
• Test laundry additives, such as detergent type or fabric softener, to see whether they change particle count and particle size.
• Compare image analysis methods, such as manual counting versus automated segmentation, to see how much the analysis step changes your result.

Learn More

• NOAA Marine Debris Program: Background on microplastics and marine pollution, found on the NOAA website.
• USGS Microplastics Research: Government reports and methods on microplastic sampling, found by searching the USGS site.
• PubMed: Search review articles on microplastic shedding, textile fibers, and Nile red staining methods.
• Microplastic Pollution by Mohamed Banati et al.: A widely accessible book for overview concepts, often available through school or public libraries.
• ImageJ Documentation: Free guides for particle analysis, calibration, and thresholding, found on the ImageJ or Fiji website.