Editorial: Microplastics and the delicate balance

Searching for evidence of microplastic contamination, scientists at the University of New Mexico analyzed 23 human testis samples from the New Mexico Office of the Medical Investigator that were earmarked for disposal. They also obtained tissue from 47 recently neutered dogs.

All the samples contained microplastics. In humans, the average concentration was 328.44 μg/g; in dogs, it was 122.63. The researchers found all the most industrially significant polymers. In both species, the most predominant polymer was polyethylene, the polymer sold around the world at the highest volume. The study also noted a negative correlation between some of the plastics and testis weight, an indication, possibly, of lower sperm counts.

In recent years, study after study has detected the presence of microplastics in sensitive tissues. For example, in February, a team consisting of many of the same University of New Mexico researchers reported finding microplastics in all 62 placentas it sampled. In 2022, scientists at Dutch institutions found quantifiable levels of microplastics in 17 of 22 blood samples they analyzed.

The media picked up both landmark studies. But it is perhaps a testament to how patriarchal our world still is that the testicle study garnered levels of attention that even the placenta study could not. In May, when the University of New Mexico researchers published the testicle study, Google searches for “microplastics” rose to their highest levels since Google started tracking such data

The reality is the public’s interest in microplastics has been climbing steadily because of the growing curiosity about studies on microplastic prevalence. People are increasingly anxious about the effects the microplastics swirling around in their bloodstreams might have on their health. As scientists hone their detection techniques, they will add to their portfolio of alarming studies. And the public will want action from governments and industry.

Such inflection points should be familiar to the chemical industry. In the mid-2010s, images showing trash piling up on the beach, bobbing in the ocean, and ensnaring turtles, shocked the public. Industry rushed recycling schemes to quell mass outrage. Governments started limiting single-use plastics and imposed recycling mandates. The United Nations Environment Programme is currently negotiating an international treaty that could even impose limits on polymer production.

An earlier generation had some success in mobilizing to meet environmental challenges. The 1984 Bhopal disaster led directly to the chemical industry’s Responsible Care initiative of voluntary chemical-handling standards. The big pollution issue of the 1970s and ’80s was the hole in the ozone layer. The public clamor helped usher in the Montreal Protocol on Substances That Deplete the Ozone Layer in 1987, which phased out chlorofluorocarbons, and the ozone layer started to heal.

But history might not offer a precise model for responding to environmental crises, as the solution to microplastics won’t be as simple as banning a few industrial chemicals. Microplastics aren’t just one problem—they are many problems added together. They are created whenever we drive our cars, wash our clothes, or lose a candy wrapper on the sidewalk. Regulators and businesses will need to chase down the sources of microplastics emissions one at a time and devise a plan to reduce, though probably not halt, those emissions.

Even if officials manage to significantly stem the rate of microplastic pollution, policy treaties cannot remove the microplastics already emitted. Microbes are apparently evolving to eat the plastics showing up in the ecosystem, much to the fascination of biologically inspired engineers, but removal is not likely within our lifetimes.

Solving the problem of microplastics requires a delicate balance of ambitious, proactive policies, technological creativity, and patient insistence from society. That’s a big ask.

But the alternative is that the store of microplastics in the ecosystem and in our own bodies will continue to grow. As will the public’s agitation.

This editorial is the result of collective deliberation in C&EN. For this week’s editorial, the lead contributor is Alex Tullo.

Views expressed on this page are not necessarily those of ACS.