What does the public think about microplastics? Insights from an empirical analysis of mental models elicited through free associations

Twenty years of microplastic pollution research-what have we learned?

Twenty years after the first publication that used the term microplastic, we review current understanding, refine definitions, and consider future prospects. Microplastics arise from multiple sources, including tires, textiles, cosmetics, paint, and the fragmentation of larger items. They are widely distributed throughout the natural environment, with evidence of harm at multiple levels of biological organization. They are pervasive in food and drink and have been detected throughout the human body, with emerging evidence of negative effects. Environmental contamination could double by 2040, and wide-scale harm has been predicted. Public concern is increasing, and diverse measures to address microplastic pollution are being considered in international negotiations. Clear evidence on the efficacy of potential solutions is now needed to address the issue and to minimize the risks of unintended consequences.

Decadal changes in microplastic accumulation in freshwater sediments: Evaluating influencing factors

Microplastics are small plastic particles with sizes ranging between 1 μm and 5 mm. Microplastics can originate from macro plastics and degrade to a smaller size or be produced directly by manufacturers. Few studies have examined microplastic contamination in freshwater sediment cores to estimate changes in microplastic contamination over time. We present the results of a study that examined sediment cores from four watersheds, Kiskiminetas River, Blacklick Creek, Raystown Lake, and Darby Creek, in Pennsylvania, USA to reveal the history of microplastic accumulation and factors that contribute to microplastic distribution. The abundance and morphology of microplastics varied over time and between these four locations. The highest microplastic abundance was found in Raystown Lake, ranging from 704 to 5397 particles kg-1 with fiber as the dominant microplastic type, while Darby Creek (0-3000 particles kg-1), Kiskiminetas River (0-448 particles kg-1), and Blacklick Creek (0-156 particles kg-1) had lower microplastic concentration. Moreover, Darby Creek had the most diverse microplastic morphology and a trend of decreasing concentration with depth. Although the Darby Creek watershed has the most developed area and highest population density, it did not have the highest microplastic concentration. Averaged over the four cores, microplastic abundance increased as global plastics production increased from the 1950s-2010s. Our findings provide insights into the fate and transport of microplastic contamination in freshwater environments, which is vital to establishing sustainable mitigation strategies.

Exploring public risk perceptions of microplastics: Findings from a cross-national qualitative interview study among German and Italian citizens

Microplastics are receiving growing attention in the public debate, while the scientific assessment of risks of microplastics to ecological and human health is still ongoing. Previous studies suggest concerns among the general public with country-specific differences. However, little is known about the reasoning underlying these concerns. By conducting qualitative interviews with German (n = 15) and Italian citizens (n = 15), this study adopted a cross-national perspective to investigate which concepts shape citizens' perceptions of microplastics. A qualitative content analysis was used, with coding categories and subcategories developed inductively. Results showed that interviewees formed assumptions around microplastics despite own uncertainties, transferred knowledge from macro- to microplastics, and used the concepts of accumulation and dose-response relationship to make sense of the topic. Moreover, they saw the domains of human health and the environment as intertwined and expressed helplessness when discussing solutions to the microplastics issue. Many themes on the topic were similar in both samples, but there were also some differences. For instance, whereas Italian participants talked about marine-related microplastics, German participants talked about airborne sources; also, German participants tended to recognize more strongly the actions their country was putting in place to address the problem. These findings underscore the need for proactive risk communication despite remaining gaps in scientific risk assessment. Beyond providing technical information, communicators should consider the reasoning behind risk perception on microplastics and address scientific uncertainty as well as the interconnectedness between the domains of human health and the environment.

The influence of media narratives on microplastics risk perception

Background

Media are the interface between scientists and citizens, communicating and interpreting the risk message and powerfully influencing individual awareness, public debate, and, hence, people's behavior. Pollution by microplastics (MPs), a threat to public health and terrestrial and marine ecosystems, has received research, media, and public interest. However, how MPs environmental and health risks are reflected in the media and assessed in the scientific literature does not find consensus over time. To date, few studies have examined social aspects around MPs, such as, for example, factors that influence awareness and perception of the risk of MPs. In this context, the objective of this study is twofold. First, we determined if media narratives influenced Romanians' awareness of MPs, and second, we investigated if media narratives influenced Romanians' perceptions of MPs health and environmental risk.

Method

An online survey was conducted among 417 Romanian respondents. The questionnaire had 21 questions. The questions were related to the awareness of MPs, the perceived health risk of MPs, the perceived environmental risk of MPs, the intensity of exposure to media narratives about the MPs impact on health and the environment, and the demographics. Binary logistic regression was run to identify what media narratives influenced MPs awareness and risk perception. In recent times, mass media has shaped perceptions of health and environmental risks, driven by events like COVID-19 and global climate change. Our study relies on media narratives as its foundation.

Results

Binary logistic regression showed that the awareness of MPs is influenced by the media narrative "Microplastics in the sea threaten fish stocks" (p = 0.001). When the frequency of exposure to this media narrative increases, the probability of reporting awareness of MPs increases. Likewise, an increase in age represents a higher probability of reporting awareness of MPs. The perceived health risk of MPs, with the highest weighting, was related to the dependent variable "Leakage of harmful chemicals from MPs affects the soil" (p = 0.014).

Conclusions

Media narratives about plastic and MPs pollution have increased over time, influencing the perception of this risk. The study argues the need for accurate and balanced media reporting on MPs to prevent the spread of misinformation and ensure that people clearly understand MPs risks. Furthermore, a closer examination of people's perceptions supports the design of appropriate interventions to reduce plastic consumption, thereby decreasing the risks of MPs pollution with benefits for human health and the environment.

Investigating nanoplastics toxicity using advanced stem cell-based intestinal and lung in vitro models

Plastic particles in the nanometer range-called nanoplastics-are environmental contaminants with growing public health concern. As plastic particles are present in water, soil, air and food, human exposure via intestine and lung is unavoidable, but possible health effects are still to be elucidated. To better understand the Mode of Action of plastic particles, it is key to use experimental models that best reflect human physiology. Novel assessment methods like advanced cell models and several alternative approaches are currently used and developed in the scientific community. So far, the use of cancer cell line-based models is the standard approach regarding in vitro nanotoxicology. However, among the many advantages of the use of cancer cell lines, there are also disadvantages that might favor other approaches. In this review, we compare cell line-based models with stem cell-based in vitro models of the human intestine and lung. In the context of nanoplastics research, we highlight the advantages that come with the use of stem cells. Further, the specific challenges of testing nanoplastics in vitro are discussed. Although the use of stem cell-based models can be demanding, we conclude that, depending on the research question, stem cells in combination with advanced exposure strategies might be a more suitable approach than cancer cell lines when it comes to toxicological investigation of nanoplastics.