The Evolving Problem of Microplastics in a PPE Era
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A plethora of research studies have shown that microplastics are now ubiquitous in our lives and environment. From the depths of our oceans to the top of our mountains and even in some of the most untouched corners of the globe, microplastics are being detected everywhere. To compound the problem, the advent of COVID-19 has seen uptake of single-use plastics in the form of personal protective equipment (PPE) skyrocket.
The potentially damaging impacts of microplastics on health and the environment are still far from fully understood. Therefore, arming scientists with the necessary training, techniques and equipment to be able to interrogate and find answers to these issues will be key.
In part one of this two-part series on the state of microplastics testing and analysis, we’re talking with Kathleen A. Young, environmental market leader, PerkinElmer, Inc., on how the microplastics issue has evolved in light of COVID-19, particularly around PPE waste and what gains are being made in the areas of testing and analysis standards.
Karen Steward (KS): Since the surge in plastic-based single-use PPE as a consequence of COVID-19, what impact is this having on the types, locations and quantities of microplastics being identified? What knock-on effects is this having, or is it still too early to say?
Kathleen A. Young (KY): All anyone has to do is spend a little time outside, walking or in shared and public spaces and you see discarded masks and gloves – on the streets, in parks and along shorelines of surface waters where you live. The negative impact of single-use PPE on the environment in general is easy to see.
Medical and non-medical waste has increased tremendously as a result of the COVID-19 pandemic. Some estimates indicate that the volume of medical PPE generated in a year pre-COVID are now produced in just a couple of months. These plastic pollution sources represent what is commonly referred to as macroplastics and through rain, run off and storm drains, can enter fresh waterways and ultimately the oceans. Over a period of several years, when this waste deteriorates and degrades, it can become microplastics, plastic fragments that are less than 5 mm in length. However, it is important to note that if these macroplastics are removed and properly disposed of, a potential additional source for microplastics release into the environment is eliminated.
Due to the nature and classification of PPE medical waste, it cannot be recycled. Gloves are typically comprised of latex rubber, a polymer of isoprene extracted from rubber trees, and will biodegrade fairly easily with a minimal pollution footprint. However, most other PPE, such as surgical gowns and masks, is not sourced from biodegradable materials, typically comprised of oil-based polymers such as non-woven or melt-blown polypropylene (PP), presenting a pollution challenge.
For consumers who use non-medical masks, there has been inconsistent guidance on disposal practices throughout communities worldwide. A common practice for some households is to include gloves and masks with their recycling trash. However, many disposal facilities are not clear on how to handle and process PPE trash, creating process bottlenecks and a higher likelihood of illegal practices.
Lack of standards and inconsistency in disposal policies on consumer PPE and medical COVID-related PPE waste, along with the tremendous increase in volumes of waste, add a large burden to waste handling and disposal entities. And, in some cases, can lead to improper or illegal disposal which can further negatively impact the environment.
Adding to the PPE issue is the loosening of some regulations or practices around single use plastics generally. Since the start of COVID-19 pandemic in early 2020, several studies have demonstrated that SARS-CoV-2 can spread from person-to-person and through contact with surfaces where droplets and aerosols are deposited. The virus can remain viable and infectious for up to 72 hours (or even longer on certain surfaces). Thus, many countries and state-level governments have rolled back single-use plastic bans and the related financial penalties, out of concern for the potential transmission of the virus through surface contact With the evolution of new mutant strains of SARS-CoV-2, it is reasonable to expect the regulations and scrutiny around single use plastics will continue to be loosened.
The increased generation of waste from PPE, concerns over how contagious SARS-CoV-2 is and the mechanisms that spread it, along with lack of clear guidelines on proper disposal methods, have created the perfect storm, leading to increases in plastic pollution.
It is too soon to tell exactly what the impacts of this increased plastic pollution loading will have on the environment and how much of this waste will contribute to the current microplastics issue; but it is safe to say that the impact will be negative and its full extent not known for years.
On a more positive environmental note, with the various COVID-19 lockdowns that have occurred over the last year, there has been fluctuations in auto usage globally. With synthetic rubber from tire wear contributing up to 28% of the microplastics in the ocean, a major source for microplastics pollution has been reduced, at least in the short-term.
KS: How standardized are detection methods for microplastics? What problems arise from a lack of standardization?
KY: There are volumes of research conducted and underway on microplastics and their impact on the environment reaching back to before one of the first international microplastics conferences, “Workshop on the Fate and Impact of Marine Debris” held in 1984 in Honolulu, Hawaii. However, standardization of analytical methods is still in early development and without standardization you can’t really compare results across various bodies of research.
Today, there is a range of sampling methods, sample preparation and extraction approaches and a diverse set of analytical techniques. These include visual counting with an optical microscope, spectroscopy including Raman and Fourier transform infrared spectroscopy (FTIR) for polymer identification and quantification and hyphenated techniques such as thermogravimetric analyzer-gas chromatography-mass spectrometry (TGA-GC-MS) and pyrolysis-GC-MS methods for qualitative identification and mass quantitation.
For those involved with microplastics –be they providing analytical technologies, performing analytical testing, or developing regulatory frameworks -- standardized methodologies for sampling, testing, and reporting are critical. A microplastics method must address detection, characterization and quantification, as well as provide best practices for quality assurance and guidance for minimizing contamination.
Standardized methods enable consistency, provide robust data, deliver more reliable and repeatable results and provide a framework for assessing analytical data. Without the scientific objectivity and thoroughness of validated methods, supporting technologies and standardization, it is difficult to compare data across the scientific community, accurately measure the impact of microplastics on human health and the environment and ultimately develop regulatory guidance, policies and regulations.
Organizations like the American Society for Testing and Materials (ASTM), International Organization for Standardization (ISO) and European Committee For Standardization (CEN) are working to establish standards across microplastics testing and analysis ranging from sample preparation, analysis matrices for drinking water and groundwaters and building analysis method best practices. PerkinElmer will be on working committees with both ISO and ASTM on microplastics. Japan’s Ministry of Environment is also doing interesting work around standardizing monitoring methods.
While further method development and validation of standard methods is needed, it is extremely encouraging to see the progress regional and international standards organizations have made. Further validation and adoption of methods (such as ASTM D8333, providing a microplastic sample preparation standard) is critical to creating accuracy and consistency in research data and for building the foundation for regulations and policies to mitigate and possibly reverse the impact of microplastics on our environment and human health.
Kathleen A. Young was speaking to Dr Karen Steward, Senior Science Writer for Technology Networks.
Read part two here.