The global production of plastics has dramatically increased over the last decade, reaching over 380 million tons per year (Geyer et al., 2017). Every year, millions of tons of plastics enter the oceans. Despite extensive efforts invested in recycling plastics, these figures are predicted to increase over the next decade, leading to severe and irreversible damage to the environment (Law and Thompson, 2014; Bornscheuer, 2016).

In terms of plastic fragments, Hartmann et al. (2019) defined the following sizes: macroplastics (greater than 1 cm), mesoplastics (between 1 and 10 mm), microplastics (between 1 and 1,000 µm) and nanoplastics (between 1 and 1,000 nm). However, the larger scientific community has continued to conceptualize microplastics as those that are less than 5 mm in length. Microplastics are classified as primary when they are originally designed to such a small size, such as for use in facial cleansers, cosmetic preparations, air blast cleaning media, etc. (De Falco et al., 2020). Secondary microplastics are derived from larger plastic items as a result of the weathering process (Gouin et al., 2011). Boucher and Friot (2017), concluded that, globally, between 0,8 and 2,5 million tons of microplastics are released into the ocean each year. Therefore, there is a concern regarding their ubiquitous presence and accumulation through the food webs.

Microplastics have been detected in seafood (Andrade and Ovando, 2017), honey and alcohol (Cox et al., 2019), plastic teabags (Hernandez et al., 2019), beer (Liebezeit and Liebezeit, 2014), milk (Kutralam-Muniasamy et al., 2020), different types of salts (Karami et al., 2017), and food and water on plastic containers (Fadare et al., 2020). In fact, Cox et al. (2019), estimate that a person could ingest annually between 39,000 and 52,000 microplastic particles through food. These numbers increase to 74,000 and 121,000 when breathing is included. Several efforts have been devoted to evaluate microplastics in terrestrial and marine fauna UNEP (2016). However, research is still needed to assess the effect of microplastics on human and environmental health (Wang et al., 2019). The latest report from the World Health Organization (WHO, 2017) makes an important call to study the physical hazards, chemical agents and microbial pathogens associated with microplastics in water for human consumption, in order to better understand their health risks.

Globally, 44 countries are actively conducting research on the impact of microplastic pollution (Ajith et al., 2020). This represents only 23% of the total number of countries in the world, and most of these are from Europe and Asia. In Latin America, research in this area is just starting with emerging efforts in Chile, Argentina, Brazil, Colombia and Mexico (Kutralam-Muniasamy et al., 2020). Chile is a country of multiple environments. Continental Chile has a long latitudinal gradient (>4,000 km) between 17°30S and 56°30S. Briefly, Valdés-Pineda et al. (2014) described a wide range of landscapes, with arid and semi-arid climates in northern regions, temperate climates in central Chile, humid climates in southern regions, and tundra and polar climates in the Andes Mountains. Moreover, Chile also has several oceanic currents that shape the landscape. Part of the West Drift current meets the continent (40 a 45°S) to form the Humboldt current system (HCS) that flows predominantly northward and the Cape Horn current that flows southward. Thus, taking into consideration the biogeographic landscape that defines the Chilean territory, it is paramount to engage the scientific and governmental communities in order to investigate the scope of microplastic pollution in Chilean environments. Increasing scientific knowledge, developing research capacity, and transferring marine technology, will be compulsory for the country.

The plastic problem has been a matter of concern for the Chilean government and some efforts towards mitigation have been put in place. The degradation of plastics bags in the environment is a major contributor to microplastic pollution (Tziourrou et al., 2021). In November 2018, Chile was the first country in Latin America to eliminate single-use plastic bags from commerce, and now single-use plastic containers will be prohibited as well, as a national strategy to reduce the impact of plastic on the environment. Currently, there is a national strategy for marine and microplastic waste management proposed by the Ministry of the Chilean Environment, maritime authorities (Directemar) and Circular economy division (MMA, 2021–https://mma.gob.cl/publicaciones-destacadas/). Despite these endeavors, the scientific literature about microplastics in Chile remains limited. The goal of this review is to synthesize the existing information regarding microplastics pollution in Chilean environments, identify critical scientific gaps and suggest future research directions.

Chile is a country with diverse environments and biota that borders the South Pacific Ocean. Given Chile’s close relationship and reliance on the sea, it is critical to continue promoting research regarding the distribution and bioaccumulation of microplastics in Chilean waters. It is also important to start investigating the detrimental effects of the microplastics’ interactions with contaminants and microbial communities. Unfortunately, there is a paucity of microplastic research in Chile. To date, there has not been a systematic study of microplastic occurrence, fate and distribution in either marine or terrestrial environments. Research on the bioaccumulation of microplastics in Chilean environments is also limited. Efforts have been made to study the bioaccumulation of microplastics in fish (Figure 1B) from Easter Island (D. muroadsi, C. rapanouiensis and T. albacares, Chagnon et al., 2018) and in intertidal fish from central Chile (G. laevifrons, S. viridis, G. nigra, H. chilensis and A. microcirrhis, Thiel et al., 2018). Microplastics have also been detected in commercial fish from central Chile including E. maclovinus, A. punctatus, B. australis, T. murphyi, S. bentincki and M. gayi (Pozo et al., 2019). Marine mammals in Chilean coasts have been particularly underexplored with only two reports showing the presence of microplastics in scat from American fur seals (A. australis) (Perez-Venegas et al., 2018, 2020).

Figure 2 summarizes the microplastic generation process as well as current knowledge and gaps concerning microplastic pollution in Chile. Plastic waste accumulates in landfills and aquatic environments via wastewater effluents. A weathering process then induces fragmentation of the plastic waste, leading to the formation of microplastics. A large body of work has been devoted to studying the distribution and bioaccumulation of microplastics. However, there are major areas that remain poorly explored and that need to be addressed, including: 1) microplastic-microorganism association, 2) microplastic-gene transport, and 3) microplastic-organic pollutant interactions (Figure 2).

Fortunately, Chile’s society actions on this topic are heading in a positive direction (Figure 2). Since 2015, Chile is officially committed to the UN’s SDGs. As a consequence, in 2018, Chile was the first country in Latin America to eliminate single-use plastic bags from commerce. Also, the Chilean government has agreed to develop a National Strategy on marine litter together with an Action Plan, for the period 2021–2030. However, reaching these environmental goals will be a challenging task. According to the data obtained from the “International Beach Cleaning Day” in Chile, the largest amount of waste collected were pieces of plumage (45%), cigarette butts (21%), plastic bottle caps (6.3%), food wrappers (5.6%), plastic bags (4.3%), pieces of plastic, pieces of glass, drink bottles, drink cans and glass bottles (17.8%) (Directemar, 2017). Considering this information, the education of the population will be a key factor in the reduction of pollution on the shared local places which are being constantly damaged by littering. Public policies will be necessary to reach these goals and the government will need the support of the public and private sectors.

It has been well established that microplastics can serve as vehicles to transport harmful chemicals and metals (referred to as the Trojan effect; Godoy et al., 2019; Hildebrandt et al., 2021). In Chile, reports have shown the ability of microplastics to adsorb contaminants including PCBs, PAHs, petroleum hydrocarbons, DDTs, HCHs, PBDEs, alkylphenols and BPA. However, there are no studies regarding metal adsorption in microplastics (Figure 2). This is an important line of research in Chile due to the strong metal industry in the north. The Trojan effect of microplastics have also been observed in bacteria and antibiotics. To date and to the best of our knowledge, there are no reported studies about the ability of microplastics to transport bacteria and antibiotics in Chile (Figure 2), where the use of antibiotics in salmon farming is excessive (Ahumada-Rudolph et al., 2021) and could potentially lead to the development of antibiotic resistance (Cabrera-Pardo et al., 2019). Thus, it is paramount to understand the dynamics of antibiotics transport by microplastics in Chile, especially in salmon farming areas. Recently, a potential link between microplastics and antibiotic-resistance was proposed. In this context, it has been demonstrated that microplastics are able to accumulate antibiotic-resistance genes (ARGs), which can mediate their dissemination through the environment (Liu et al., 2021). This phenomenon may be even more critical since bacterial biofilms are present on the surfaces of microplastics as reported by Pham et al. (2021). These processes could play an important role in the dissemination of antibiotic-resistant bacteria and ARGs (Bank et al., 2020), aggravating this crisis. Unfortunately, scientific reports on this line of research are, to this date, unexplored in Chile (Figure 2).

Chile needs to invest more scientific efforts to combat this environmental and human threat. Future endeavors should be focused on systematic study of the distribution of microplastics across the country as well as the association of toxic chemicals, metals and bacteria on their surfaces. This information will be crucial to determine the risk of Trojan effect of microplastics in Chilean environments. Special attention should be put on the adsorption of antibiotics and multi-resistant bacteria, both of which heavily contribute to the antibiotic resistance crisis. These studies would be particularly relevant in areas where antibiotic abuse is a constant threat (i.e. salmon farming industry, Miranda et al., 2018). Finally, as a country Chile needs increased education programs to create awareness of the problem of microplastic pollution and to develop strategies that address it in the future.