Dorte Herzke ↗, senior researcher at the Norwegian Institute of Public Health ↗, has dedicated her career to understanding how pollutants travel from the environment into our bodies. Her pioneering work on persistent organic pollutants and human biomonitoring has naturally led her to one of today’s most complex challenges: microplastics. From ocean plastic patches to traces of microplastics in human blood, Herzke explains why understanding exposure and health risks remains so difficult – and how initiatives like PARC are paving the way to harmonised monitoring methods that can finally turn emerging science into reliable protection for people.

You’ve been at the forefront of environmental chemistry for years. What first sparked your interest in microplastics, and how did your focus shift toward human health impacts?

My interest began when I read Kara Lavender’s early reports about plastic patches in the Atlantic Ocean. I contacted her and analysed chemicals on some of the plastic samples she collected. We found surprisingly high concentrations of certain pollutants, which sparked my curiosity as an environmental chemist. Over time, I realised that since humans are producing, emitting, and using these plastics, understanding human exposure had to become a key part of my research.

Microplastics have been detected in drinking water, food, air, even in human blood. From your perspective, how widespread is human exposure today?

We are exposed to microplastics everywhere. However, we still know very little about how much we actually absorb and where these particles may travel within the body.

But is this something the general public is truly aware of?

Yes, awareness has certainly increased. However, our understanding of the full extent and impact of exposure is still very limited.

Based on research, which exposure routes are currently the most critical — or perhaps the most underestimated?

The research community currently sees food (including water) and air as major exposure routes. However, due to the challenges in detecting very small mictoplastics and especially nanoplastics, we may be underestimating their presence and overlooking other exposure pathways altogether.

Research on the health effects of microplastics is still emerging. What do we know so far about how these particles interact with the human body?

We know very little. In particular, the role of the chemicals that are part of or associated with each plastic particle is not well understood. I hope PARC can help close some of these important knowledge gaps.

Should we be more concerned about vulnerable groups, such as children or pregnant women?

Protecting vulnerable groups should always be a priority. But currently, the data is insufficient to identify who these groups are or what measures should be taken.

One of your major projects focuses on harmonising methods. Why is it still so difficult to generate comparable data on microplastics?

Compared to other pollutants, there are still major gaps. We lack widely accepted commercially available standards, internal standards, and harmonised analytical methods for human samples. Quality assurance is another area that needs strengthening.

What are the main challenges in translating lab findings into real-world risk assessments?

Most polymer standards used in labs differ from those found in the environment or in humans. They are often virgin materials, not exposed to weathering processes like sunlight or seawater. This means their chemical composition, size, shape, and surface characteristics differ significantly. Furthermore, the range of particle sizes used in lab studies doesn't fully represent real-world exposures, and detecting the smallest particles remains a technical challenge.

How is the PARC partnership supporting more robust and harmonised monitoring of microplastics?

PARC plays a key role in identifying gaps in the current research landscape and has committed to supporting the development of harmonised, robust, and sensitive methods for microplastic measurement, particularly in human health research.

While the science is still catching up, what actions should regulators or citizens take now to reduce exposure?

That’s a tough question. Because our understanding of exposure pathways and what happens after uptake is still so limited, it’s hard to make concrete recommendations at this point.

How do you see your role as a chemical leader, and what are PARC’s current priorities?

My role is to help connect ongoing microplastics research across PARC and identify areas where the partnership can contribute with its wealth of expertise and infrastructure. Advancing method development and fostering collaboration are top priorities.