Microplastics are small bits of plastic, 5 millimeters or less, and either engineered for end-products, or the result of environmental degradation of polymer-based trash.

Researchers have found microplastics in marine and terrestrial life. It invades the food chain, and it’s even been found in salt, sugar, beer, alcohol, and honey. Not to mention glaciers and rainwater.

Primary microplastics are directly released into the environment as small plastic particles. These are intentionally engineered particles, like those found in some consumer and industrial products. Cosmetics have used microplastics as abrasives.

Secondary microplastics are the result of the degradation of large plastic waste, like plastic bags and bottles, into smaller plastic fragments when exposed to our environment.

Why produce microplastics?

Manufacturers engineer primary microplastics because of the unique physical and chemical properties created by its small scale. Those properties include durability, rigidity and abrasiveness. Density, size, shape and composition influence its properties.

Scientists use microplastics in many areas, including cosmetics, personal care, detergents, paints/coatings/inks, industrial abrasives, agriculture, pharmaceuticals, wastewater treatment and construction.

But these particles often weather, degrade or abrade from environmental or physical events, ending up in our oceans and elsewhere.

Where do primary microplastics come from?

Ordinary consumer products are the source of most of the ocean’s primary microplastics, according to a study by the International Union for Conservation of Nature (IUCN). That includes synthetic textiles, city dust, tires, road markings, marine coatings, personal care products and engineered plastic pellets.

What are the health risks of microplastics?

Microplastics can be toxic, depending on its composition. It can also act as a carrier of other molecules that cling to it. Some of those clinging molecules are bacterial, and others, viral.

Scientists fear the cumulative buildup of these toxins might affect the health of living organisms. Yet researchers are unsure about the volume of microplastics a body can tolerate or the damage it may cause.

What we do know is this - consuming microplastics can physically damage organs and leech hazardous chemicals like pesticides. Scientists have shown that these substances can weaken immune function and hinder growth and reproduction.

The World Health Organization reported in 2019 that the current level of microplastics in drinking water doesn't pose a health risk—yet. But the group said we need to know more.

Researchers from Johns Hopkins looked at the impact of eating seafood contaminated with microplastics. Their conclusion? The accumulated plastic we take in could damage the immune system and upset a gut's balance.

Still, the research on health effects are slim. Recent research, through particle analysis and Raman spectroscopy has begun to identify various microplastic types. Scientist are developing sampling, extraction and analysis methods so we can trace these particles back to its sources. That way, we can create public policy to address this potential threat.

A typical analysis workflow for Microplastics separation, counting and identification by means of spectroscopic techniques requires five main steps: sampling, sample preparation or sample pretreatment, filtration, measurement/data acquisition, and finally, analysis/report.

1. Sampling
   The Sampling step involves the collection of a matrix and/or different matrices where the Microplastics presence must be investigated.
    
2. Sample Preparation
   Sample pretreatment is one of the most important steps, since it can influence the accurate identification of the Microplastics during the measurement step. Indeed, the contribution of the matrices (and all the organic contaminants within them) that can interfere with the Microplastics identification must be eliminated.
    
3. Filtration
   Filters must be carefully selected, considering the wide variety available. Three main characteristics must be considered: Filter size (microplastic concentration, analysis time etc… are driving the choice), filter material (the measurement technique that is tuning this) and pore sizes (which microplastic size we want to analyze).
    
4. Measure/Data Acquisition
   This is the Chemical/Morphological Identification of the microplastics by the technique of choice. We propose Raman Microscopy, which allows the identification of organic and inorganic particles and assures the analysis of particles from the macro (1 to 5 mm), down to the micron and sub micron ranges.
    
5. Analysis & Reporting
   Software is a key point for data manipulation and for presenting the results. HORIBA provides fully automated ease-of-use particle analysis software called ParticleFinder, combined with IDFinder, a particle identification software.