New research suggests that the very gloves used by scientists can contaminate samples and bias study results.
It seems like every day a new study finds tiny plastic particlescalled microplastics, where they shouldn’t be: in our bodies, in our food, in the water and in the air.
However, finding and identifying microplastics is extremely challenging, especially due to its small size. A single microplastic can range from the size of a ladybug to the size of an eighth of a red blood cell.
Furthermore, it may be difficult for investigators prevent accidental contamination of your samples, because these plastics are practically everywhere. As a result, much of this research may be overestimating the number of microplastics.
In a new published in March 2026, a team found that even following established protocols, using certain methods to measure environmental microplastics can potentially contaminate the results.
The study
The goal was to understand how much microplastics Michigan residents inhaled outdoors and whether this depended on where they lived.
When preparing the samples, the authors followed all standard protocols during the investigation – they avoided the use of plastic in the laboratory, used plastic-free clothing and even a specialized chamber for reduce possible air contamination of the laboratory.
Despite these precautions, they found concentrations of plastic in the air more than 1000 times higher to those previously reported. You knew these numbers didn’t look right, so what happened?
The Culprit: Lab Gloves
After a long search for the source of contamination, they discovered that laboratory gloves, the use of which is recommended by the scientific community, can transfer particles to the surface of samples – in this case, small metal plates used to collect deposited material from the air. Furthermore, the particles led to an overestimation of the abundance of microplastics in the study.
Here’s how: The particles, which we identify as stearate salts, are used to facilitate removal of gloves from the mold during the manufacturing process. When gloves are used to handle laboratory equipment, the particles are transferred to everything they touch. Stearate salts are similar to soap molecules – if ingested in large quantities, they are probably not good for your health, but they are not harmful to the environment in the same way as microplastics.
Although they are not microplastics per se, stearate salts are structurally similar to polyethylenethe type of plastic most frequently found in the environment. This structural similarity makes it difficult to distinguish between them using the most common tools that scientists use to determine whether a particle is plastic.
Researchers use vibrational spectroscopy to identify microplastics, which involves measure how the particle interacts with light to produce what scientists call a chemical fingerprint.
Because polyethylene and stearate salts have very similar structures, they also interact with light in a similar way.
As a result, at least in some cases, particles from gloves are incorrectly identified as microplastics. As more researchers rely on automated methods to speed up their analyses, glove waste may increasingly be mistaken for microplastics, leading to more reports of microplastics in the environment than are actually the case.
How extensive is this contamination?
To investigate the prevalence of this contamination, they analyzed different types of gloves. They simulated contact between seven types of gloves when handling laboratory equipment and counted the number of microplastics that would be erroneously attributed to the environment if the most common approaches were followed.
They found that gloves can contribute to more than 7000 particles per millimeter square that are wrongly identified as microplastics. This finding means that researchers may be unknowingly overestimating the abundance of microplastics in the environment by handling their samples with gloves.
Even more worrying, scientists found that the particles were mostly less than 5 micrometers in size. Microplastics in this size range have greater impacts on human health and ecosystems, as they can enter cells more easily. By inflating microplastic counts in this size range, the use of laboratory gloves could compromise studies that inform future policies and regulations.
For the future
To avoid contamination, the authors suggest that scientists avoid using gloves when carrying out research on microplastics. If this is not possible – for example, with biological samples where researchers have to wear gloves to protect themselves – using stearate-free gloves, such as those used in electronics manufacturing, will be better. To recover old, potentially contaminated data sets, scientists recommend methods that help differentiate chemical fingerprints.
Science is an iterative process. New areas of research, including environmental microplastics, bring new challenges for the scientific community. As we deal with these new challenges, we will encounter setbacks such as unforeseen contamination.
It is important to highlight that, even if the abundance of microplastics in the environment is lower than researchers initially thought, any amount of microplastics can be problematic, given their negative effects on human health and ecosystems.
