Plastics are ubiquitous in our society. Demand for plastic has skyrocketed since the 1950s due its inexpensive, strong, durable, and lightweight properties (Thompson et al., 2009). As a result, plastic pollution is now found all across the planet, including along coastlines (Kwon et al., 2014; Courtene-Jones et al., 2021), in the open ocean (Eriksen et al., 2013; Cózar et al., 2014), the deep sea (Bergmann et al., 2017; Barrett et al., 2020), soils (Fuller and Gautam, 2016), and the atmosphere (González-Pleiter et al., 2021). Current estimates suggest that a minimum of 5.25 trillion plastic particles are present in the world’s oceans, a number that is expected to grow (Eriksen et al., 2014). Indeed, the amount of plastic pollution entering the terrestrial and aquatic environment is predicted to grow by an additional 710 million metric tons between 2016 and 2040, even if immediate action is taken to reduce waste (Lau et al., 2020). These plastics are degraded by biotic and abiotic processes in the environment, such as bacterial activity, UV light, temperature, and abrasion, resulting in smaller fragments with altered surface properties. These smaller plastics, classified as microplastics (<5 mm) and nanoplastics (<1 µm), are the most prevalent type of solid waste, especially in the aquatic environment (Jambeck et al., 2015; Gigault et al., 2018). Additionally, both types of small plastics (referred to as micro- and nanoplastics) can be found in commercial and industrial items.

The ubiquity of plastics in the biosphere has made interactions with animals and humans inevitable. Vast numbers of marine species are impacted by plastics (Gall and Thompson, 2015). Microplastics are found in fish, clams, mussels, oysters, and crabs destined for human consumption (Van Cauwenberghe and Janssen, 2014; Li et al., 2015; Rochman et al., 2015; Karami et al., 2017; Su et al., 2018; Waite et al., 2018), as well as table and sea salt (Yang et al., 2015; Zarus et al., 2021), seaweed (Baini et al., 2017), honey (Liebezeit and Liebezeit, 2013; Liebezeit and Liebezeit, 2015), tea (Hernandez et al., 2019), beer (Kosuth et al., 2018), and tap and bottled water (Kosuth et al., 2018; Zuccarello et al., 2019; Kankanige and Babel, 2020). Microplastics have also been documented in the human body, (e.g., in lung tissues (Amato-Lourenço et al., 2021), stool (Schwabl et al., 2019; Ibrahim et al., 2021), blood (Leslie et al., 2022), and even placentas (Ragusa et al., 2021).

There is perhaps no other single anthropogenic contaminant that has had such a wide spectrum of direct exposure ranging across all levels of biology. Plastics disrupt homeostasis at the individual organismal level via ingestion of plastic debris (Gall and Thompson, 2015). Plastic pollution can also disrupt ecosystem functioning by changing and damaging habitats (Aloy et al., 2011; Carson et al., 2011; Richards and Beger, 2011) and altering the balance of species across ecosystems (Barnes and Milner, 2005; Goldstein et al., 2012). Such changes, in turn, inevitably have unknown effects upon health. Mitigating plastic impacts on the health of people, animals, and ecosystems requires an approach that transcends traditional species-level risk assessments. One such framework is the concept of One Health ( Figure 1 ). One Health recognizes the interconnectedness of people, animals, and plants, and how their individual health is itself dependent on the health of their shared environment (One Health, 2021). The One Health perspective calls for a multi-sectoral, transdisciplinary, and collaborative approach to solving health issues at the local, national, and global levels (One Health, 2022). While the origins of One Health research stem from the study of zoonotic diseases, this framework provides a transdisciplinary lens to (i) examine the imminent threat to human, animal, and ecosystem health imposed by plastic pollution, (ii) elucidate socio-economic ramifications of plastic pollution and (iii) implement mitigation strategies interlining with the public and private sectors.

To establish the need for an integrated assessment, here, we focus on routes of exposure and the health threats at the cellular, individual organismal, population, and ecosystem levels to highlight plastic pollution impacts across layers of biological organization. The goals of this review are to i) summarize our understanding of how plastic affects layers of biological organization, ii) provide rationale for the use of a One Health paradigm to understand and investigate plastic’s consequences on health, and iii) illuminate gaps in existing knowledge and research on the impacts of plastics within the One Health paradigm.

Humans and other organisms encounter plastics in a variety of ways, including ingestion, inhalation, and physical contact with plastics and plastic additive chemicals (Cox et al., 2020; World Health Organization, 2022). Humans in the United States are estimated to consume between 39,000 to 52,000 microplastic particles per year from food and beverages alone (Cox et al., 2020) or an average of 0.1-5g of microplastics weekly (Senathirajah et al., 2021). Plastic ingestion is also well documented in other species, including zooplankton (Desforges et al., 2015), fish (Barboza et al., 2020), turtles (Duncan et al., 2019), seabirds (Wilcox et al., 2015), and marine mammals (Nelms et al., 2019).

In addition to ingestion, humans and other terrestrial organisms can also inhale plastics. Micro- and nanoplastics (MNPs) and plastic fibers are released into the atmosphere via the washing of synthetic textiles, rubber tires, dried sludge, agriculture, and city and household dust (Wright and Kelly, 2017; Karbalaei et al., 2018; World Health Organization, 2022). MNPs can even be generated through simple tasks, such as opening and cutting plastic packaging and containers (Sobhani et al., 2020). While the fate of inhaled MNPs and their subsequent uptake in lung tissue is currently unknown (Amato-Lourenço et al., 2021), airborne exposures can occur both indoors, via household items and clothing, as well as outdoors from particulate matter (Kasirajan and Ngouajio, 2012; Wright and Kelly, 2017; Catarino et al., 2018). Occupational exposure, exposure to medical devices, and contact exposure to items such as personal care products and plastic toys also contribute to human exposures (Karbalaei et al., 2018; Zarus et al., 2021).

Exposure to plastics is inexorably associated with exposure to plastic additives—compounds added to plastic to improve the functionality of the polymers (Hahladakis et al., 2018; Wiesinger et al., 2021). Additives include plasticizers, flame retardants, heat and light stabilizers, antioxidants, lubricants, pigments, antistatic agents, slip agents, biocides, and thermal stabilizers (Groh et al., 2019). While these additives are helpful to enhance the performance of plastics, there is great potential for additives to contaminate soil, air, water, and food (Hahladakis et al., 2018), with poorly-understood consequences to the environment and to health.

In addition to the chemicals intentionally added, plastics can carry environmental pollutants and microbes. Collected plastic litter has been associated with diverse bacterial species, including human pathogens, suggesting that plastic may lead to transmission of infectious diseases and may contribute to antimicrobial resistance (Rasool et al., 2021). Plastics accumulate persistent organic pollutants and heavy metals (Thompson et al., 2009; Rochman et al., 2014), though more work is needed to understand if these “Trojan horse” or “vector” effects of adsorption are physiologically relevant (Koelmans et al., 2016). In addition to plastic polymers, we must also consider the potential exposure to a variety of chemicals and microbes, when evaluating impacts of plastics on health.

Ecosystem health, function, and services are critically linked with human physical health as well as societal, cultural, and economic well-being (Summers et al., 2012). The various consequences of plastic across all levels of biological organization from cells to populations portend a grim future with respect to the constitution of the natural world, inclusive of humans, and can be exemplified by sentinel species. Among these sentinel species, many marine apex predators, such as marine mammals, have long life spans, amplify trophic information across multiple spatiotemporal scales, and share food resources of commercial and subsistence importance to humans, making them efficacious harbingers of negative impacts to both individual- and population-level animal and human well-being (Bossart, 2011; Hazen et al., 2019). Trophic transfer of microplastic particles to marine mammals from contaminated prey who have consumed microplastics is thought to be the primary route of microplastic exposure for both filter and raptorial predators (Zantis et al., 2022). The direct link between humans and marine mammals is self-evident: as top predators with shared resources, exposure to microplastics in humans via consumption is concerning. However, a larger question of indirect consequences looms: does plastic pollution threaten whole ecosystem collapse?

Whether or not plastic threatens the functionality of whole ecosystems is poorly studied (Bucci et al., 2020); however, the potential downstream consequences of plastic to marine mammals and the ecosystems they inhabit are not difficult to imagine, particularly when contextualized through a framework of population consequences of disturbance (Ocean Studies Board et al., 2017; Bucci et al., 2020). Interaction with macroplastic, such as ingestion or entanglement, can lead to physiological and behavioral changes that induce acute or lethal consequences impacting vital rates and subsequently population dynamics (Ocean Studies Board et al., 2017). Similarly, both micro and macroplastics may have chronic, sublethal impacts on individual health, which may also lead to alterations in vital rates (Ocean Studies Board et al., 2017). As instrumental players in nutrient cycling (Roman et al., 2016), the reduction of a whale population, for example, may result in a catastrophic depletion of energy at lower trophic levels that rely on whale excrement and carcasses. This disruption to energy availability at the lower trophic levels could potentially reverberate up each trophic level, including those with cultural, subsistence, and commercial importance to humans, resulting in whole ecosystem remodeling or collapse. Indeed, marine mammals are of great cultural and subsistence importance to indigenous communities (Huntington et al., 2016). For most of the contemporary global human population, marine mammals serve as clear sentinels for a variety of environmental and ecological threats (Bossart, 2011; Hazen et al., 2019). But for some native peoples who consume them, the meat from contaminated marine mammals may have direct consequences to users’ health. Ingestion of plastic by whales, seals, sea lions, and polar bears is well documented and may either translocate to, or leach toxic substances into, consumable tissues (Law, 2017; Zantis et al., 2021). Plastic consumed by marine mammals therefore threatens a critical life line, and a way of life, for several indigenous communities world-wide.

Of course, many factors influence the proper functioning of an ecosystem, and processes like emigration/immigration, prey-switching, shifts in species assemblages and niche partitioning among others may all affect the ultimate ecosystem-level consequence of disturbances resulting from plastic exposure. In addition, ecosystems contend with many anthropogenic stressors apart from plastic. Consequently, the interactions between exposure to plastic and climate change, habitat loss/degradation, exploitation, etc. need to be explored, and safeguarding regular and proper functioning of ecosystems from plastic pollution is critical to optimal human, organism, and environmental vitality.

As human demand for plastic continues, new solutions will be needed that span the entirety of societal structure, including novel technological innovations to degrade or recycle plastic, campaigns directed at consumer behavior, and implementation of bold policies at all levels of government. These solutions must be implemented across the entire lifecycle of plastic, from reducing the amount of new plastic entering the environment to removing existing plastic pollution. Technological innovations that are underway for clean-up and remediation efforts include a variety of plastic capture approaches. These tools are summarized in “The Inventory,” a summary of 52 inventions, such as ocean plastic skimmers, beach cleaning robots, and river and ocean debris filters, that are focused on preventing plastic leakage or collecting marine plastics (Schmaltz et al., 2020). Although these technologies are a necessary component of our efforts to mitigate plastic pollution, their scalability and effectiveness to date does not match the enormity of the plastic pollution problem.

Another novel approach to prevent plastic pollution is the utilization of plastic-degrading bacteria as a mechanism to create a “circular economy of plastic”. As plastic has increased in the environment over the past century, microorganisms have evolved enzymes to degrade plastic [reviewed in (Sheth et al., 2019)]. While there may be hundreds of bacterial strains that have evolved plastic-degrading properties, none have been able to do so rapidly; however, further refinement of these naturally-evolved enzymes has led to increasingly-efficient microbially-mediated plastic bioremediation systems (Tournier et al., 2020; Lu et al., 2022). In addition to these substantial improvements in bacterially-mediated degradation of plastic, it will be important to process plastic waste into forms that are readily and fully biodegradable, such as through amorphization of micronization.

Concomitant with the development of new technologies, governments around the world are increasingly using policy, laws, and ordinances to target the plastic pollution issue. Policies can target plastic pollution in a variety of ways through the implementation of regulatory, economic, and educational instruments. A recent review of plastic policies around the world found that international policies primarily focus on plans and future actions, while national and subnational policies most frequently use plastic bans to achieve a reduction in plastic pollution (Diana et al., 2022). Despite this increasing trend, substantial gaps still remain across the policy space, including the types of plastic targeted by these policies. For example, within national policies throughout the world, macroplastics were the most common plastic type targeted, followed by plastic bags (Diana et al., 2022), while only 3 of the 147 national policies to date solely target microplastics. Furthermore, only 5% of national policies have effectiveness studies in the peer-reviewed literature, highlighting the need for more evidenced-based policy development in the future (Diana et al., 2022). Finally, notably lacking from global policy is a binding global treaty targeting plastic pollution (Karasik et al., 2020). Despite an increasing trend of policy implementation to combat plastic waste, progress has been stymied by the COVID-19 pandemic, which prompted a pause in many policies around the world due to safety concerns regarding reusable materials (Karasik et al., 2020). Existing policy limitations, compounded by COVID-19 impacts, call for improved and coordinated policy efforts globally.

To help guide global policy efforts, a planetary boundaries approach has been proposed to first define the limits of waste production that ensure that Earth remains a “safe operating space” for humanity (Folke et al., 2021). To date, planetary boundaries have been defined for climate change, genetic diversity, land-system change, freshwater use, biochemical flows (phosphorus and nitrogen), ocean acidification, and the depletion of stratospheric ozone depletion (Steffen et al., 2015). However, experts have not yet defined planetary boundaries for plastics or other novel entities. Quantifying the planetary boundary for plastic pollution can help society to understand whether or not plastic pollution is driving large-scale and irreversible harm to the planet and identify measures to prevent exceeding the boundary. By changing ecosystems, generating greenhouse gasses, and impacting the health of people and animals, it remains unclear whether plastic pollution could reach levels that would render the planet inhospitable. Recent efforts have sought to characterize the dangerous pathways that plastic could lead to such irreversible impacts in order to better understand the cumulative and planetary impacts of plastic pollution (Diana et al., 2022). These efforts are the first step towards defining a limit for plastic pollution, which can then facilitate the development of global policy to keep society within the identified boundary.

Finally, in addition to improved technologies and policies that target plastic pollution, increased research on the impacts of plastic are also needed. A recent review of studies examining impacts of plastic pollution highlighted several important gaps in research to date (Bucci et al., 2020). Observational or manipulative field experiments have largely focused on macroplastics (97%), while manipulative laboratory experiments have largely focused on microplastics (96%). Of the experiments that researched microplastics, the majority used polyethylene and polystyrene, and only a few investigated other polymer types such as PVC, PET, polypropylene, and others. Finally, 76% of all studies focused only on the marine environment, whereas relatively little research has been conducted on freshwater and terrestrial ecosystems. Understanding the effects of different plastic types, different sizes and shapes of plastics, as well as the effects in different ecosystems is critical to gaining a complete understanding of the health impacts of plastic pollution globally.

Mounting evidence suggests that plastic can impact multiple layers of biological organization, from molecular and cellular to organismal and population levels. These impacts are wide-ranging, inducing alterations to inflammation and oxidative stress, metabolic function, neurologic function, behavior, reproduction and development, and the microbiome. These effects are mediated both by the physical impacts of ingested or absorbed plastic particles and by the chemicals and microbes present in or on the plastics.

Despite the growing body of research on the impacts of plastics on global human, animal, plant, and overall ecosystem health, many questions remain. For one, more systematic and comprehensive studies are needed to account for the widespread differences in polymer type, plastic particle size, and additive mixtures. Additionally, there is a notable lack of research that integrates cell, organismal, population- and ecosystem-level impacts of plastic pollution, and little is understood about the cumulative exposure to plastics and additives over time across these levels of biology. Furthermore, the pace of global policy response and the adoption of plastic-reducing technologies is lagging substantially behind the rate of plastic consumption and production. A One Health approach can help address these knowledge gaps by providing a framework in which to integrate across biological scales, promote transdisciplinary partnerships, and engage stakeholders from diverse perspectives in an effort to mitigate and prevent the accelerating global plastic pollution crisis for the protection of all life on Earth.

MM, RT, PR, GM, JS, NJ, WE and AH each wrote sections of the manuscript. JS, NJ and WE helped supervise the project. All authors contributed to the article and approved the submitted version.

The authors acknowledge funding support from the Nicholas Institute for Environmental Policy Solutions (pre-catalyst grant to JAS) and the Duke Bass Connections program (JAS). The authors thank members of the Duke Plastic Pollution Working Group, particularly Zoie Diana and Dr. Meagan Dunphy-Daly, for helpful discussions. The authors acknowledge Uko Gorter for providing figure illustrations.

The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.

All claims expressed in this article are solely those of the authors and do not necessarily represent those of their affiliated organizations, or those of the publisher, the editors and the reviewers. Any product that may be evaluated in this article, or claim that may be made by its manufacturer, is not guaranteed or endorsed by the publisher.