Microplastics
The California State Legislature in 2022 tasked the California State Policy Evidence Consortium (CalSPEC) to perform a review of the state of the knowledge of microplastics and report back to the government: (i) What are microplastics and how abundant are they in the environment? (ii) What are the human health effects from microplastics exposure? And (iii) What government actions have addressed microplastics, and to what extent have the policies succeeded in reducing microplastics in the environment? (FPF reported, also here).
CalSPEC published its report in February 2023. Answering the first two questions included information common to similar reports produced by other researchers and groups (FPF reported also here). CalSPEC wrote that “[m]icroplastics research is an emerging field dominated more by studies of occurrence and polymer type than intermediate and long-term environmental and health effects.” They defined the size and shapes of microplastics and where they come from” and found that human exposure to microplastics is suspected to be a hazard to the digestive, reproductive, and likely the respiratory system.
Unique to CalSPEC’s report was the review of laws concerning microplastics around the world. Most of the “51 laws addressing microplastics across various levels of government and jurisdictions” that CalSPEC evaluated were from California itself or the EU. Nearly all of which “are focused on banning microbeads or mandating more research.” Unfortunately there has not yet been much research on the effectiveness of these policies.
Nanoplastics
California leads microplastics regulation in the US (FPF reported and here) but the EU is taking steps beyond microplastics. In February 2023, Science for Environment Policy (SfEP), an independent news and information service published by Directorate General (DG) Environment, released a future brief reviewing the scientific understanding of nanoplastics. Future briefs aim to help decision-makers in the EU anticipate and prepare for potential challenges, opportunities, and impacts from specific issues on policy areas of interest.
There is currently no universally agreed upon definition of nanoplastics but according to SfEP, “a particle measuring no more than 1 micrometer (0.001mm) across in any one dimension is widely accepted as a guiding definition,” i.e., in the nanometer range. The report covers current quantification and assessment methods, occurrence of nanoplastics in the environment, their ecotoxicity, and impacts on human health.
Nanoplastics are “a behaviorally distinct type of environmental contaminant,” because they are capable of penetrating “more and different biological barriers,” are difficult to quantify, can “adsorb significant amounts of other pollutants,” are more reactive, and can slip through filters, SfEP explained.
Measuring nanoplastics and assessing effects in humans is difficult and therefore “to date there have been few studies that specifically assess the impacts of nanoplastic particles on human health.” However, in vitro and in vivo studies have demonstrated that by increasing concentrations of nanoplastics, the genotoxic, inflammatory, and cytotoxic responses increase and studies in mice show adverse effects on fetal brain development (FPF reported).
Due to the current lack of knowledge the authors compare the arguments of a purely evidence-based versus a precautionary approach to the management of micro- and nanoplastics. Here, they quote Martin Wagner (a microplastic researcher at the Norwegian University of Science and Technology) who supports the precautionary principle: “Based on my values, I favor a precautionary approach to microplastics, not because I consider them doomsday devices but because I believe in positive change.” Additionally, the European Environment Agency proposed regulators should consider “early warning signs… when considering materials and substances.” Human biomonitoring studies of plastic-associated chemicals and metabolites may also play a role in studying plastic exposure effects (FPF reported, also here).
SfEP concludes that “despite the challenges… we know that microplastics degrade into nanoplastics, so we know they are there even if we cannot yet detect them. There is abundant evidence of significant detrimental effects of microplastics – and of plastics at any scale.” The authors continue, “regulatory response is lagging behind.” Some of that lag is due to debates about enforcement and size cutoffs when nanoplastics are so difficult to detect. But they emphasize, “scientific evidence does not support a cut-off point for the environmental and human effects of plastics at a particular size limit; indeed… the smaller the plastic particles, the more likely they can cross biological membranes and the more thoroughly they can permeate organisms.”
In 2021 scientists argued that plastic pollution fulfills the criteria of a planetary boundary threat due to its ubiquity, irreversibility, and its disruption of natural processes (FPF reported). The micro- and nanoplastics that develop have been measured in every environment tested (FPF reported), in foods and beverages (FPF reported and here), and increasingly are also detected in human bodies (FPF reported also here and here).
A Dutch study published in 2022 found that through the cooperation of industry, consumers, government bodies, NGOs, and knowledge institutions implementing a series of mitigation strategies it would be possible to reduce microplastics generation by 70% by 2050 (FPF reported). Even in a time of increasing plastic use (FPF reported).
References
Science for Environment Policy (February 14, 2023). “Nanoplastics : state of knowledge and environmental and human health impacts.” Publications Office of the European Union
CalSPEC (January 2023). “Microplastics occurrence, health effects, and mitigation policies: An evidence review for the California State Legislature.” (pdf)
ChatGPT (February 20, 2023).,”How is a Future Brief used in the European Union?” message to author, openai.com.
