Microplastics, a latent threat

Nestor Pinacho

Plastic is used almost universally in all aspects of daily life, but over the past decade, concern about its contaminating effects took on a new dimension when it was discovered that the degradation of this material, due to environmental conditions and even UV rays, produced small particles that were virtually ubiquitous in the environment.

These tiny particles, less than 5 millimeters in size, are called microplastics, which are composed of polymers and additives that, according to the Pan American Health Organization (PAHO), are potentially toxic. In addition to being present in air, water, and soil, research led by Gurusamy Kutralam Muniasamy and Shruti Venkata Chari, researchers from the Centro de Investigación y de Estudios Avanzados (Cinvestav) of the IPN, has revealed the presence of microplastics, even in charales intended for human consumption.

For this research – published in the journal Environmental Pollution and involving scientists from the Mexican Center for Cleaner Production (CMP+L) of the IPN, and the Institute of Geology of UNAM – charales were acquired from four supermarkets, as well as from three street vendors and 18 traditional markets. The results in the analyzed product were significant: 4 to 80 microplastics per gram of dried fish.

Most of the plastics found in the samples were polyester, polystyrene, viscose, and nylon, many of which correspond to materials used in clothing manufacturing, thus being associated with the pollution of the lakes where this fish is obtained, one of them being Lake Pátzcuaro, and others located in the states of Guerrero and Jalisco.

"Our results reveal two aspects: one, the range [of microplastic presence in the charales] means that something is already being ingested, and two, the region is contaminated. That is a concern because this lake has been contaminated for years, and fish are cultivated and acquired there. Additionally, the level found is a little higher compared to other studies conducted around the world," said Gurusamy Kutralam Muniasamy.

He emphasized that the microplastics that have shown indications of causing more harm are those in fiber form, as well as irregular fragments, although they also exist in spherical form.

"Irregular fragments and those fibers have very fine edges and when they come into contact with tissue, they can cause injuries and inflammation. We are talking about a very invisible level and damage where we don't know what happens," explained Dr. Kutralam Muniasamy.

The major danger of microplastics explained by Dr. Shruti Venkata Chari, actually lies in the fact that once they enter the environment and fragment, smaller particles can adhere to other pollutants, such as heavy metals, insecticides, or fertilizers.

Necessary Reduction of Plastic Use

The health threat posed by microplastics has led the Pan American Health Organization to place them on the list of environmental determinants of health, to promote studies on their impacts on human and environmental well-being, as well as their relationship with other pollutants.

Microplastics, Dr. Venkata Chari reported, are even present in the atmosphere of Mexico City, and previous research conducted demonstrates that these particles increase in quantity during the dry season.

Microplastics are tiny particles less than 5 millimeters in size and can be in fiber or sphere form.

From 150 microns (a micron being one-thousandth of a millimeter) onwards, microplastics can already enter the human body, transported in the air, and due to the substances they carry, they can cause harm.

The presence of these microplastics is virtually total, and while pertinent research is underway to determine their specific effects on humans, scientists recommend avoiding the use of plastics as much as possible and considering that using them will have repercussions later on in their degradation and release into the environment.

Damage Yet to Be Discovered

Research on microplastics is still in its early stages, both scientists noted, and the first phase of studies, that is, detecting their presence in the environment worldwide, has already yielded results. Now, the focus will be on discovering the level of toxicity or damage they cause to humans.

However, the outlook is not encouraging, as studies with rodents have revealed effects on fertility and lung damage. Despite this, a direct relationship between health effects and microplastics cannot be established due to all the substances they can transport.

Selección Gaceta Politécnica #171. (February 29th, 2024). IPN Imagen Institucional: Read the full magazine in Spanish here.