Greenpeace researcher on microplastics: 'The more visible the problem, the greater the chance that we will take action'

Dr. David Santillo works in Exeter, the county seat of Devon, England. He has been a senior scientist at the Greenpeace Research Laboratories, based at the University of Exeter, since 1994. Santillo has more than twenty years of experience in environmental forensics and is closely involved in research into microplastics. Santilloo: “I have worked on many environmental issues and have represented Greenpeace at the interface between science and policy at a number of international conferences focused on environmental protection.”

By: Dimitri Reijerman

His current research focuses on detecting microplastics. During the LabAnalysis event, on Thursday, November 7, 2019 in Congrescentrum 1931 in Den Bosch, Santillo will important keynote entitled 'FT-IR as a tool in environmental forensic investigations: some advances and challenges in the characterization of microplastics as environmental pollutants'.

The problems surrounding microplastics are well known. These tiny plastic particles – less than 5 mm long – are a huge environmental problem floating around the world’s oceans, seas and rivers. More scientific data is needed and Greenpeace is focusing on specific research into microplastics in the lab.

Santillo explains his research: “Our efforts are focused on documenting the presence of microplastics and contaminants in our environment in general, but also in the foods, drinks and other consumer products to which we are exposed every day. We analyze biological samples, for example to study the presence of microplastics in the stomachs of dead turtles or dolphins that wash up on beaches, or in the feces of freshwater mammals and birds. But we do not study the direct biological effects of microplastics. There are many academic research groups worldwide that study the effects of microplastics once they are ingested by animals. And in some cases, also in humans.”

But identifying plastic microfibers is far from easy, says the researcher: “Microplastics, as environmental pollutants, pose a number of analytical challenges. First of all, their separation in environmental matrices – especially from biological tissues and sediments – can confound identification.”

He continues: “Microfibers present additional challenges due to their low density, small cross-sectional area, and potential for contamination, even in carefully controlled laboratory environments. In all cases, given the inconspicuous nature of contamination by microplastic fragments and fibers, it can be particularly difficult to determine which samples and subsamples are representative.”

Applying FT-IR

Greenpeace researchers use Infrared Spectroscopy (FT-IR) for the identification process, along with a high-powered microscope. “Generally, we use our PerkinElmer Spectrum 2 and Frontier spectrometers with an ATR attachment to identify microplastics down to a size of about 1 mm. These are fast and can provide good spectral quality,” says Santillo. “For smaller fragments and fibers, we use the Spotlight 400 microscope system, either in reflection mode (for microplastics collected on silver-coated filters) or in transmission mode (for fibers using a diamond compression cell). We complement those techniques with the use of a micro-ATR attachment when necessary.”

But there are more techniques available for microfiber detection: “The use of the diamond compression cell has significantly improved the quality of spectra we can obtain for microfibers because it holds the fibers in place, ensures that the sample area for analysis is in a single plane, and that the sample is thin enough for FT-IR,” says Santillo. “It is a relatively slow process to go from one fiber to another, but the improvements in spectral quality often make it worthwhile. However, it is important to consider FT-IR as only one part of the identification. You need to combine it with the physical characterization of the appearance, structure, uniformity and surface properties of the fiber to make the distinction. We are currently investigating the use of other standard histological techniques to further complement the identification methods, as well as the application of micro-pyrolysis GC-MS.”

A long way to go

Identification of microfibers using FT-IR, or any of the other techniques mentioned, is just one step in the analysis of the environmental contaminating fibers. The Greenpeace researcher explains: “Before we reach that final stage, a lot of attention is paid to experimental design and decontamination of equipment, representative sampling, safe transport and storage, and ultimately reliable and reproducible separation of microplastics from the environmental matrix in which they are contained, whether that is water, sediment, consumer products or biological tissues. Quality control, and specifically prevention of contamination, must run as a central theme throughout the protocols to ensure that what we find really came from the environment.”

To truly tackle the microplastic problem, much work remains to be done. Santillo: “The environmental forensics we do in our research group is just one contribution to a better understanding of the ubiquity and complexity of plastics, in particular microplastics, pollution, and the chemical additives and contaminants associated with plastics. With this greater scientific understanding comes the opportunity to raise awareness among the public, the media, and decision-makers in governments, regulators, and businesses. The more visible the problem, the more likely we are to take action to prevent it from getting worse. This can be done by tackling the problem at its source, reducing plastic use in general, avoiding single-use plastics, and designing product packaging in a more sustainable way. Ultimately, we also need to address the long-term problem of overconsumption, of which plastic pollution is just one symptom.”