Quantification of microplastics along the Caribbean Coastline of Colombia: Pollution profile and biological effects on Caenorhabditis elegans

First register of microplastic contamination in oysters (Crassostrea gasar) farmed in Amazonian estuaries

The present study investigated the contamination of oysters farmed in Amazonian estuaries by microplastics (MPs). A total of 120 adult oysters (Crassostrea gasar) were collected from four sites along the Mangrove Coast of Pará/Brazil: S1, S2, S3 and S4, with 30 oyster for each. Overall, 58.33 % of the oyster samples contained microplastics, with mean concentrations of 0.23 MPs/g and 1.9 MPs/ind. The concentration of microplastics varied among the four sites, where S1 and S3 had the highest values while S4 had the lowest. PA fibers were the majority of particles (91 %), followed by PS fragments (9 %). The hepatopancreas and the gonad concentrated more microplastics than the rest of the body. As an important species for aquaculture in Amazon, we recommend additional regulation to reduce human exposure to microplastics, such as the installation of depuration facilities and constant monitoring of the contamination of oysters from farms in the region.

Meso- and microplastic composition, distribution patterns and drivers: A snapshot of plastic pollution on Brazilian beaches

Pollution by plastics is a worldwide problem on par with climatic change and biological invasions. In coastal sediments, plastic particles tend to accumulate and persist over the long term. We assessed the plastic pollution using a standardized surface sediment sampling protocol on 22 sandy beaches along >4600 km of the Brazilian coast. The abundance, size, color, type, and polymeric composition of all meso- and microplastic items found in the surveys were processed to disclose spatial patterns of distribution and pollution associated drivers. A General Linear Model (GLM) was run to investigate how the predictor variables influenced overall beach plastic amounts and by plastic type and size class. Overall, 3114 plastic items were found, with microplastics comprising just over half of all items (54 %). Most items were either white (60 %) or blue (13 %), while polystyrene foam (45 %) and fragments (39 %) comprised the most abundant plastic types. The principal polymers were Polyethylene (40 %) and Polypropylene (32 %). The analyses indicated that the distribution of plastic litter along beaches is determined by three predictive variables: the distance to the nearest estuary (-), tourism (+), and the number of inhabitants in the nearest urban center (+). Tourist (highly-visited) beaches and those near estuarine runoffs or urban centers presented the highest plastic pollution rates. The unveiling of plastic pollution patterns through a large-scale systematic survey is essential for future management guidance and science-based decisions for mitigating and solving the plastic pollution crisis.

Microplastics as contaminants in the Brazilian environment: an updated review

Microplastics have long been present in marine and terrestrial environments and have emerged in recent decades as a global environmental concern. This pollutant has been detected with increasing frequency in Brazilian territory and herein primarily highlights current information and developments about the quantity, distribution, techniques of identification, origins, and sources of microplastics and related pollutants in the Brazilian environment. We evaluated 79 publications from 2018 to December 2022, and some aspects can be highlighted: 27% of studies were published in the Journal Marine Pollution Bulletin; 22% of all studies were conducted in São Paulo city; and 52% of all microplastics found were collected from biota followed by sediment samples. According to the findings given here, microplastics in Brazilian habitats, which can reach concentrations of 4367 to 25,794 items m-2 in sediments, are becoming a serious problem in the Anthropocene age, and some topics regarding the open questions in this area were pointed out in this review.

Microplastic pollution in coastal areas of Colombia: Review

Microplastics are distributed in the environment and are considered emerging pollutants because they are not regulated by legislation. This article aims to know the current state of knowledge regarding microplastic pollution in coastal areas of Colombia. Therefore, a detailed search was carried out in databases such as Scopus, Google Scholar, and university repositories collecting scientific and academic information published between 2000 and March 2022. As a result of the review, the presence of microplastics in coastal areas of Colombia was identified, particularly in the water, sediments, and fish, thus evidencing the contamination in coastal ecosystems, where the Caribbean coast is the area with the highest amount of microplastics in sediments, especially Cartagena (249-1387 particles/m2) and Santa Marta (144-791 particles/m2). It was also found that of 302 species of fish, 7% contained microplastics in the Ciénaga Grande of Santa Marta. In the studies, on the other hand, it was observed that there is no standardized methodology; each researcher chooses a different approach according to the scientific literature. The studies showed that the most abundant microplastics were secondary microplastics, of which polypropylene and polyethylene are predominant due to their different applications in society. This review will serve as a baseline for future research on microplastics in coastal areas of Colombia and will identify the challenges and realities of the country in the face of these emerging pollutants.

Marine Pollution and Advances in Biomonitoring in Cartagena Bay in the Colombian Caribbean

Coastal zones sustain extensive biodiversity, support key processes for ocean dynamics, and influence the balance of the global environment. They also provide resources and services to communities, determine their culture, and are the basis for their economic growth. Cartagena Bay in the Colombian Caribbean is the place of the establishment of one of the country's main cities, which has a great historical and tourist attraction, and it is also the location of the main commercial port and a great variety of industries. Historically, it has been affected by several environmental impacts and intense pollution. This situation has gained the attention of different researchers, so herein is presented a literature review with a systematic approach using RStudio's bibliometrix on the presence of pollutants and the impact on biodiversity in recent decades, providing a critical analysis of the state of Cartagena Bay and its future needs to ensure its recovery and conservation. In addition, the socioeconomic dynamics related to the environmental state of Cartagena Bay are presented from the framework drivers, pressures, status, impacts, and responses (DPSIR). The update and critical understanding of the sources, fate, and effects of pollution are important not only for the knowledge of the status of this singular ecosystem but also to encourage future research and entrench evidence to support decision makers' actions. This review highlights that several pollutants that have been detected exceeding sediment quality guidelines, like As, Cd, Hg, and PAH, are also reported to bioaccumulate and cause damage throughout the trophic levels of the coastal environment. In addition, the potential use of sentinel species and biomarkers for their monitoring is discussed. Finally, the factors that cause pollution and threaten the state of the bay continue to exert pressure and impact; thus, there is a call for the further monitoring of this ecosystem and the strengthening of policies and regulations.

Mercury assessment in invasive Lionfish Pterois (Oken, 1817) from marine protected areas in the Colombian Caribbean

Lionfish (Pterois spp.) are invasive species reported since 2009 in the Corales del Rosario y San Bernardo National Natural Park in the Caribbean. Their capture and consumption are strategies to control their dispersion and limit ecological damage. The natural park is influenced by the vicinity of Cartagena's residential, industrial, and touristic activities, as well as sediments loaded with mercury from the Dique Channel. For the first time, total mercury levels in muscle from 58 lionfish were determined, with values ranging from 0.01 to 0.38 μg/g (mean = 0.11 ± 0.01 μg/g). Fish length ranged from 17.4 to 44.0 cm (mean = 28.0 ± 0.63 cm). Mercury levels did not increase proportionally to fish length for pooled data, but the relationship was significant for specimens from Rosario Island. Mercury levels comply with legislation for fish consumption, but the risk to human health may appear if it occurs daily. Therefore, precautionary approach and a permanent monitoring strategy are strongly advised.

Hydroalcoholic extract of Haematoxylum brasiletto protects Caenorhabditis elegans from cadmium-induced toxicity

Background

H. brasiletto is used in popular culture due to its therapeutic properties, including antioxidant, anti-inflammatory and antiproliferative properties, although little is known about its role as a protector against metal toxicity. This study aimed to investigate the chemical composition and efficacy of the hydroalcoholic extract from H. brasiletto (HAE-Hbrasiletto) collected in northern Colombia to defend against cadmium (Cd)-induced toxicity.

Methods

Phytochemical characterization was performed using HPLC-ESI-QTOF. Caenorhabditis elegans was employed to assess the shielding effect of HAE-Hbrasiletto against Cd toxicity in vivo, and the 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay was utilized to measure radical scavenging activity.

Results

The main secondary metabolites identified by HPLC-ESI-QTOF in the extracts were hematoxylins (brazilein and hematein) and protosappanins (protosappanin A, B and C, 10-O-methylprotosappanin B, and protosappanin A dimethyl acetal). The HAE-Hbrasiletto elicited low lethality in N2 worms and significantly reduced the Cd-induced death of the nematodes. It also improved Cd-induced motility inhibition, as well as body length and reproduction reduction provoked by the heavy metal. The extract displayed a good capacity to halt Cd-induced DAF-16 translocation. As this last process was associated with lethality (r = 0.962, p < 0.01), the antioxidant properties of the extract may contribute to ameliorating tissue damage induced by oxidative stress from Cd exposure.

Conclusion

HAE-Hbrasiletto has remarkable properties to protect against Cd-induced toxicity.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12906-022-03654-6.

Most secondary metabolites tentatively identified in H. brasiletto are homoisoflavones.

Hidroalcoholic extract of H. brasiletto protects C. elegans from Cd toxicity

The extract diminished Cd-induced damage to reproduction, growth, and locomotion.

Cd-induced oxidative stress and translocation of DAF-16 are blocked by the extract.

Where and how? A systematic review of microplastic pollution on beaches in Latin America and the caribbean (LAC)

The dispersion of microplastics (MPs) in coastal and marine environments and their potential harmful effects on organisms and ecosystems makes MPs pollution an emerging problem that has gained increasing attention from the scientific community. Despite the recent increase in the number of studies on MPs presence in different marine environments, investigations in Latin America and the Caribbean (LAC) are still relatively limited. This review presents the spatial distribution (where) and the methods applied (how) in assessing MPs contamination on LAC sandy beaches, identifying the challenges to be faced in advancing the understanding of this emerging contaminant. Most of the 39 papers reviewed were published between 2020 and 2021 (51%) and conducted on Brazilian beaches (43%). The LAC investigations apply spot sampling (69%) on shoreline stretches between 10 and 1000 km (59%). These works used inconsistent sampling methods, incomparable techniques for MPs extraction from sediments, and different measurement units to report their data. The MPs presence on LAC beaches is not negligible, as it varies significantly in its distribution and concentration (0-2457 MP/dw kg and 0-5458 MP/m²). Its highest accumulation is on ocean island beaches; however, there are still large stretches of coastline (Cuba, Venezuela, Argentina) with no data on MPs presence and a small number of studies exploring these contaminants' temporal variability. The lack of standardization in the studies' methodologies, particularly their measurement units, hinders their quantitative comparison and our ability to establish baseline values regarding MPs abundance on LAC beaches. In this sense, future works should direct efforts towards the spatial and temporal expansion of their sampling, as well as protocol standardization to facilitate result comparability on MPs on LAC sandy beaches.

Potential Risks of Microplastic Fomites to Aquatic Organisms with Special Emphasis on Polyethylene-Microplastic-Glyphosate Exposure Case in Aquacultured Shrimp

Plastic litter is increasingly becoming pervasive in aquatic environments, characterized by circulatory patterns between different compartments and continual loading with new debris. Microplastic pollution can cause a variety of effects on aquatic organisms. This review presents the current knowledge of microplastics distribution and sorption capacity, reflecting on possible bioaccumulation and health effects in aquatic organisms. A model case study reveals the fate and toxic effects of glyphosate, focusing on the simultaneous exposure of aquacultured shrimp to polyethylene and glyphosate and their contact route and on the potential effects on their health and the risk for transmission of the contaminants. The toxicity and bioaccumulation of glyphosate-sorbed polyethylene microplastics in shrimp are not well understood, although individual effects have been studied extensively in various organisms. We aim to delineate this knowledge gap by compiling current information regarding the co-exposure to polyethylene microplastic adsorbed with glyphosate to assist in the assessment of the possible health risks to aquacultured shrimp and their consumers.

Microplastics in Latin America and the Caribbean: A review on current status and perspectives

A literature review was carried out to analyze the current status of microplastic research in Latin America and the Caribbean (LAC). Specifically, this work focused on publications pertaining to (1) occurrence and distribution of microplastics in the environment, including water, sediments, and soil and (2) the environmental impact of MPs, particularly their presence and effects on aquatic and terrestrial organisms. The review included peer-reviewed articles from Scopus, Science Direct, Web of Science, Google Scholar and two iberoamerican open access databases (Redalyc and SciELO). It was found that LAC has only contributed to 5% of the global scientific output on microplastics, and overall the highest contributor within the region was Brazil (52%), followed by Chile (16%) and Mexico (13%). An additional section analyzing the barriers to conducting microplastic research in LAC and their exacerbation by the current COVID-19 pandemic was included to provide additional context behind the relatively low scientific production and improve recommendations encouraging research in this region.

The status of marine debris/litter and plastic pollution in the Caribbean Large Marine Ecosystem (CLME): 1980-2020

Plastic pollution is one of several anthropogenic stressors putting pressure on ecosystems of the Caribbean Large Marine Ecosystem (CLME). A 'Clean Ocean' is one of the ambitious goals of the United Nations (UN) Decade of Ocean Science for Sustainable Development. If this is to be realized, it is imperative to build upon the work of the previous decades (1980-2020). The objectives of the present study were to assess the state of knowledge about: (i) the distribution, quantification, sources, transport and fate of marine debris/litter and microplastics in the coastal/marine environment of the CLME and, (ii) the effects of plastics on biodiversity. Snapshots, i.e., peer-reviewed studies and multi-year (1991-2020) marine debris data from International Coastal Cleanup (ICC) events, indicated that plastic debris was a persistent issue in multiple ecosystems and environmental compartments of the CLME. Collectively, a suite of approaches (debris categorization, remote sensing, particle tracking) indicated that plastic debris originated from a combination of land and marine-based sources, with the former more significant than the latter. Rivers were identified as an important means of transporting mismanaged land-based waste to the marine environment. Oceanic currents were important to the transport of plastic debris into, within and out of the region. Plastic debris posed a threat to the biodiversity of the CLME, with specific biological, physical, ecological and chemical effects being identified. Existing data can be used to inform interventions to mitigate the leakage of plastic waste to the marine environment. Given the persistent and transboundary nature of the issue, further elucidation of the problem, its causes and effects must be prioritized, while simultaneously harmonizing regional and international approaches.

Impact of sewer overflow on public health: A comprehensive scientometric analysis and systematic review

Sewer overflow (SO), which has attracted global attention, poses serious threat to public health and ecosystem. SO impacts public health via consumption of contaminated drinking water, aerosolization of pathogens, food-chain transmission, and direct contact with fecally-polluted rivers and beach sediments during recreation. However, no study has attempted to map the linkage between SO and public health including Covid-19 using scientometric analysis and systematic review of literature. Results showed that only few countries were actively involved in SO research in relation to public health. Furthermore, there are renewed calls to scale up environmental surveillance to safeguard public health. To safeguard public health, it is important for public health authorities to optimize water and wastewater treatment plants and improve building ventilation and plumbing systems to minimize pathogen transmission within buildings and transportation systems. In addition, health authorities should formulate appropriate policies that can enhance environmental surveillance and facilitate real-time monitoring of sewer overflow. Increased public awareness on strict personal hygiene and point-of-use-water-treatment such as boiling drinking water will go a long way to safeguard public health. Ecotoxicological studies and health risk assessment of exposure to pathogens via different transmission routes is also required to appropriately inform the use of lockdowns, minimize their socio-economic impact and guide evidence-based welfare/social policy interventions. Soft infrastructures, optimized sewer maintenance and prescreening of sewer overflow are recommended to reduce stormwater burden on wastewater treatment plant, curtail pathogen transmission and marine plastic pollution. Comprehensive, integrated surveillance and global collaborative efforts are important to curtail on-going Covid-19 pandemic and improve resilience against future pandemics.

Source, sea and sink-A holistic approach to understanding plastic pollution in the Southern Caribbean

Marine plastics are considered to be a major threat to the sustainable use of marine and coastal resources of the Caribbean, on which the region relies heavily for tourism and fishing. To date, little work has quantified plastics within the Caribbean marine environment or examined their potential sources. This study aimed to address this by holistically integrating marine (surface water, subsurface water and sediment) and terrestrial sampling and Lagrangian particle tracking to examine the potential origins, flows and quantities of plastics within the Southern Caribbean. Terrestrial litter and the microplastics identified in marine samples may arise from the maritime and tourism industries, both of which are major contributors to the economies of the Caribbean region. The San Blas islands, Panama had the highest abundance of microplastics at a depth of 25 m, and significantly greater quantities in surface water than recorded in the other countries. Modelling indicated the microplastics likely arose from mainland Panama, which has some of the highest levels of mismanaged waste. Antigua had among the lowest quantities of terrestrial and marine plastics, yet the greatest diversity of polymers. Modelling indicated the majority of the microplastics in Antiguan coastal surface were likely to have originated from the wider North Atlantic Ocean. Ocean currents influence the movements of plastics and thus the relative contributions arising from local and distant sources which become distributed within a country's territorial water. These transboundary movements can undermine local or national legislation aimed at reducing plastic pollution. While this study presents a snapshot of plastic pollution, it contributes towards the void of knowledge regarding marine plastic pollution in the Caribbean Sea and highlights the need for international and interdisciplinary collaborative research and solutions to plastic pollution.

Abundance, distribution, and characteristics of microplastics in coastal surface waters of the Colombian Caribbean and Pacific

Microplastic pollution has become a global concern due to its distribution, high abundance, and negative impacts on aquatic ecosystems. These particles enter aquatic systems through the inadequate management of solid waste and wastewater generated from socioeconomic and domestic activities. In Colombia, about 65% of the solid waste generated in coastal populations is improperly managed and discharged into natural water bodies, contributing to microplastic pollution. The present study aimed to determine the abundances, distribution, and physical and chemical characteristics of microplastics in coastal surface waters of the Colombian Caribbean and Pacific. Samplings were carried out at 41 stations distributed across nine study areas during the rainy season of 2017, using a 500-μm mesh plankton net. The microplastic abundances ranged from 0.01 to 8.96 items m^-3, with the coastal waters of the Caribbean areas being the most polluted. Microplastics with shapes of fragments, filaments, and foams, composed of polyethylene, polypropylene, and polystyrene, were the most common. A baseline of microplastic pollution in Colombian coastal water was generated, which will serve to evaluate the effectiveness of the environmental measures implemented to significantly reduce this pollution type, within the sustainable development goals.

Plastics in Porifera: The occurrence of potential microplastics in marine sponges and seawater from Bocas del Toro, Panamá

Microplastics (MP) are now considered ubiquitous across global aquatic environments. The ingestion of MP by fish and other marine vertebrates is well studied, but the ingestion of MP by marine invertebrates is not. Sponges (Phylum Porifera) are particularly understudied when it comes to MP ingestion, even though they are widely distributed across benthic habitats, can process large volumes of seawater, and can retain small particles within their water filtration systems. This study examines the presence of potential MP (PMP) in wild marine sponges and seawater collected in Bocas del Toro, Panamá. Subsurface seawater and tissue from six common Caribbean sponge species was collected in Saigon Bay, a heavily impacted, shallow-water coral reef. Seawater samples were filtered onto glass fiber filters to retain any PMP present and sponge tissue was digested with bleach, heated and filtered. Filters were examined using fluorescence microscopy to quantify PMP. An average of 107 ± 25 PMP L^–1 was detected in seawater from Saigon Bay with particles ranging in size between 10 μm and ~3,000 μm. The number of PMP found in sponge tissue ranged between 6 ± 4 and 169 ± 71 PMP g^–1 of dry tissue. Most particles found in sponge samples were very small (10–20 μm), but fibers greater than 5,000 μm were detected. Our results indicate that PMP exists within the tissues of the sponges we studied, but future studies should confirm the presence of MP in sponges using chemical analysis. Most importantly, the discrepancy between low levels of PMP in our sponge samples and high levels in the surrounding seawater highlights the potential for sponges to resist and/or egest MP. Finally, we provide a critical evaluation of our methods to improve their use in future MP work with benthic marine organisms.

Fecal microbiota transplantation attenuates nano-plastics induced toxicity in Caenorhabditis elegans

Current studies simply focus on the toxicity of nano-plastics, while the correlation between their toxicity and bio-distribution, as well as intestinal microorganisms is still blank. Therefore, we systematically evaluated the toxicity based on the accumulation characteristics of nano-plastics in C. elegans. Meanwhile, for the first time, human fecal microbiota was transplanted into the gut of C. elegans and found that nano-plastics can through the intestinal barrier to the whole body after oral intake and can't be drastically excreted until die, thus causing toxic effects; while human fecal microbiota transplantation can significantly improve the living state via activating PMK-1/SKN-1 pathway to promote the production of intracellular glutathione, and exogenous glutathione addition can also markedly protect nematodes against nano-plastics induced toxicity. Our results not only provide a fully understand between the accumulation characteristic and health risk of nano-plastics, but also take C. elegans and intestinal flora into the field of toxicity evolution of nanomaterials.

An extensive characterization of various environmentally relevant microplastics - Material properties, leaching and ecotoxicity testing

Microplastics in the environment occur in different sizes and shapes and are made of various polymers. Therefore, they also considerably differ in their properties and ecotoxicity. However, the majority of microplastics research uses pre-made spherical microplastics, which practically do not exist in the environment. Our work focused on a comprehensive study of six different types of microplastic that were prepared to simulate common microplastics found in the environment. All types of microplastics where chemically and physically characterized using Fourier-transform infrared spectroscopy, thermal analysis, field-emission scanning electron microscopy, optical microscopy and laser diffraction analysis. The specific surface area was determined using the BET method. Furthermore, effects of microplastics and microplastic leachates on a common duckweed (Lemna minor) were evaluated. All tested microplastics did not affect specific growth rate and chlorophyll a content in duckweed, while microplastics with a rough surface and sharp edges caused a significant reduction of duckweed root length. Microplastics made of Bakelite also showed an intensive leaching, which increased their ecotoxicity potential. Natural particles used as a control did not have any negative effect on duckweed. Overall, microplastic particles have significantly different ecotoxicity profiles depending on their physico-chemical properties. Therefore, the testing of environmentally relevant particles and their proper characterization, as well as the testing of microplastic leaching properties, is crucial for understanding of microplastics ecotoxicological potential.

The aqueous extract of Fridericia chica grown in northern Colombia ameliorates toxicity induced by Tergitol on Caenorhabditis elegans

The aqueous extract of fallen leaves from Fridericia chica (Bonpl.) L.G. Lohmann is utilized as a remedy in communities at northern Colombia. Traditional uses include wound healing, gastrointestinal inflammation, leukemia and psoriasis, among others. The aims of this research were to evaluate the potential of the aqueous extract of fallen leaves of F. chica (AEFchica) to inhibit ethoxylated nonylphenol (Tergitol)-induced toxicity in Caenorhabditis elegans; and to identify its main components. The pharmacological properties of AEFchica was evaluated using a Tergitol-induced toxicity model in Caenorhabditis elegans. Lethality, locomotion, reproduction, and DAF-16 nuclear translocation were quantified. The chemical composition of AEFchica was carried out using ultra-performance liquid chromatography/quadrupole time-of-flight mass spectrometry. AEFchica induced very little lethality on C. elegans (5.6%) even at high concentrations (10,000 μg/mL). The extract had no effect on locomotion impairing induced by ethoxylated nonylphenol. However, AEFchica (1000 μg/mL) abrogated Tergitol-induced mortality, recovering up to 53.3% of the nematodes from lethality induced by 10 mM Tergitol. Similarly, it also blocked Tergitol-dependent reproduction inhibition (82.1% recovery), as well as DAF-16 nuclear translocation (>95%), suggesting a prominent role on oxidative stress control. The chemical analysis indicated the presence of a great variety of molecules with known antioxidant, metabolic and immune modulator properties, such as hydroxylated methoxy flavones, N-methyl-1-deoxynojirimycin, and rehmaionoside A. In short, the aqueous extract of F. chica protects C. elegans from the deleterious effects of Tergitol on lethality, reproduction and oxidative stress involving DAF-16-mediated pathway. This extract is a promising source of bioactive phytochemicals for multi-target pharmacological purposes.

COVID-19 pandemic repercussions on plastic and antiviral polymeric textile causing pollution on beaches and coasts of South America

The propagation of the COVID-19 pandemic worldwide has been alarming in the last months. According to recommendations of the World Health Organization (WHO), the use of face masks is essential for slowing down the transmission rate of COVID-19 in human beings. This pandemic has generated a substantial increase in the use, as well as in the production, of face masks and other elements (gloves, face protectors, protective suits, safety shoes) manufactured with polymeric materials, including antiviral textiles most of which will end as microplastic pools. Focusing on South America, the use and mismanagement of this type of personal protective equipment (PPE) represents an environmental problem. Added to this issue are the increase in the use of single-use plastic, and the reduction of plastic recycling due to the curfew generated by the pandemic, further aggravating plastic pollution on coasts and beaches. Recently, researchers have developed antiviral polymeric textile technology composed of Ag and Cu nanoparticles for PPE to reduce the contagion and spread of COVID-19. Antiviral polymeric textile wastes could also have long-term negative repercussions on aquatic environments, as they are an important emerging class of contaminants. For this reason, this work provides reflections and perspectives on how the COVID-19 pandemic can aggravate plastic pollution on beaches and coastal environments, consequently increasing the damage to marine species in the coming years. In addition, the potential impact of the pandemic on waste management systems is discussed here, as well as future research directions to improve integrated coastal management strategies.

Dysregulated mir-76 mediated a protective response to nanopolystyrene by modulating heme homeostasis related molecular signaling in nematode Caenorhabditis elegans

The underlying mechanisms of microRNAs (miRNAs) in regulating nanoplastic toxicity are still largely unclear in organisms. In nanopolystyrene (NPS) exposed Caenorhabditis elegans, the expression of mir-76 (a neuronal miRNA) was significantly decreased, and the mir-76 mutant was resistant to the toxicity of NPS. The aim of this study was to determine the molecular basis of mir-76 in controlling NPS toxicity in nematodes. The mir-76 mutation increased expression of glb-10 encoding a globin protein in NPS (1 μg/L) exposed nematodes. Exposure to NPS (1-100 μg/L) increased the glb-10 expression, and the glb-10(RNAi) worm was susceptible to NPS toxicity in inducing reactive oxygen species (ROS) production and in decreasing locomotion behavior. Using ROS production and locomotion behavior as endpoints, mutation of glb-10 inhibited resistance of mir-76 mutant to NPS toxicity, and neuronal overexpression of mir-76 inhibited the resistance to NPS toxicity in nematodes overexpressing neuronal glb-10 containing 3' untranslated region (3'UTR). Thus, GLB-10 functioned as a target of mir-76 in the neurons to regulate the NPS toxicity. Moreover, a signaling cascade of HRG-7-HRG-5 required for the control of heme homeostasis was identified to function downstream of neuronal GLB-10 to regulate the NPS toxicity. In this signaling cascade, the neuronal HRG-7 regulated the NPS toxicity by antagonizing function of intestinal HRG-5. Furthermore, in the intestine, HRG-5 controlled NPS toxicity by inhibiting functions of hypoxia-inducible transcriptional factor HIF-1 and transcriptional factor ELT-2. Our results highlight the crucial function of heme homeostasis related signaling in regulating the NPS toxicity in organisms.

Dark-field hyperspectral microscopy for label-free microplastics and nanoplastics detection and identification in vivo: A Caenorhabditis elegans study

Microplastics pollution is a serious ecological threat, severely affecting environments and human health. Tackling microplastics pollution requires an effective methodology to detect minute polymer particles in environmental samples and organisms. Here were report a novel methodology to visualise and identify nanoscale (down to 100 nm) and microscale synthetic commercially-available uniform spherical polymer particles using dark-field hyperspectral microscopy in visible-near infrared (400-1000 nm) wavelength range. Polystyrene particles with diameters between 100 nm-1 μm, polymethacrylate 1 μm and melamine formaldehyde 2 μm microspheres suspended in pure water samples were effectively imaged and chemically identified based on spectral signatures and image-assisted analysis. We succeeded in visualisation and spectral identification of pure and mixed nano- and microplastics in vivo employing optically-transparent Caenorhabditis elegans nematodes as a model to demonstrate the ingestion and tissue distribution of microplastics. As we demonstrate here, dark-field hyperspectral microscopy is capable for differentiating between chemically-different microplastics confined within live invertebrate intestines. Moreover, this optical technology allows for quantitative identification of microplastics ingested by nematodes. We believe that this label-free non-destructive methodology will find numerous applications in environmental nano- and microplastics detection and quantification, investigation of their biodistribution in tissues and organs and nanotoxicology.

Policy responses to reduce single-use plastic marine pollution in the Caribbean

Caribbean economies depend heavily on a healthy marine ecosystem, but the region includes ten of the top global marine polluters per capita. Regional marine pollution is driven by illegal plastic waste dumping due to poor waste management systems with limited recycling, and weak enforcement. Governments recognize the impacts of marine debris on their social and economic well-being and have responded with policies to curb plastic pollution. Most focus on bans of single-use plastic and polystyrene, which comprises ~80% of Caribbean marine litter. However, there is little comparative analysis of policy responses to determine their efficacy. This paper reviews current policies in 13 English-speaking Caribbean countries, exploring tools used and process of implementation. Eleven have introduced legislative policies, with seven including fines and penalties for non-compliance. All successful policies involve multiple tools, including primary stakeholder engagement, sufficient lead time between policy announcement and implementation, and extensive public education campaigns.

Review of current trends, advances and analytical challenges for microplastics contamination in Latin America

Microplastics accumulation is an emerging environmental issue and a threat to marine life and human health. There is a growing number of investigations on the abundance and distribution of microplastics in different water bodies and biota worldwide, with relatively few studies conducted in Latin America, however, the current knowledge of microplastics sources, occurrence, transport, fate and potential impacts remains largely unexplored. This review presents the current trends and advances of microplastics on a lesser known region of the world by compiling the research performed to date in different environmental compartments. The sampling techniques and methods for microplastics extraction in the existing literature data are also summarized. Among 78 published studies reviewed, 34% of studies were from Brazil and 46% of studies have mainly focused on biota. The main findings showed that microplastics are not negligible across Latin America significantly varying in their distribution, with the prevalence of fibers comprising 62% of the total. Polyethylene, polypropylene, polyethylene terephthalate and polystyrene have been identified as the most common polymer types, accounting for 80% of the total. Limited studies and lack of standardized methodologies render difficulties to establish fundamental information on microplastics abundance and types in most countries of this region. Therefore, this review will primarily serve as a baseline when evaluating the environmental relevance of microplastics in Latin America and would stimulate discussions focusing on this topic, calling for more research in future.

Plastic litter pollution along sandy beaches in the Caribbean and Pacific coast of Colombia

Plastic pollution is a global problem that poses a threat to coastal and marine ecosystems and human livelihoods and requires effective solutions adaptable to local conditions. In Colombia, the knowledge about marine plastic pollution is still limited and the development of effective strategies for managing marine and coastal environments is crucial. Therefore, plastic pollution was assessed on 43 Colombian sandy beaches on the Caribbean and Pacific coasts. Amounts of macroplastic ranged from 35 ± 15 to 81 ± 23 items 100 m^-1, being product's packaging the most common. Microplastic densities ranged from 3 to 1387 items m^-2. The highest microplastic concentrations were found on the beaches from Caribbean cities and in rural areas of Pacific municipalities. Fragments and polyethylene were the most commonly observed shape and polymer categories, respectively. Tourism and poor waste management practices are the primary plastic sources on the studied beaches. Plastic litter on Colombian beaches are a problem that requires prevention, mitigation, and control actions to help conserve this ecosystem.

Response of DBL-1/TGF-β signaling-mediated neuron-intestine communication to nanopolystyrene in nematode Caenorhabditis elegans

TGF-β signaling pathway is important for the regulation of stress response in organisms. We here used Caenorhabditis elegans to determine the function of DBL-1/TGF-β signaling pathway in the control of response to nanopolystyrene (100 nm). In DBL-1/TGF-β signaling pathway, exposure to 1-1000 μg/L nanopolystyrene significantly increased the expressions of dbl-1 encoding a TGF-β ligand, sma-6 encoding a TGF-β receptor, sma-4 encoding a Co-Smad, and two genes (mab-31 and sma-9) encoding transcriptional factors. DBL-1 acted in the neurons to control the response to nanopolystyrene. In the neurons, the expression and the function of DBL-1 were under the control of two signaling cascades (SMOC-1-ZAG-1 and SMOC-1-ADT-2). TGF-β receptor SMA-6 acted in the intestine to control the response to nanopolystyrene. The downstream Co-Smad/SMA-4 and two transcriptional factors (MAB-31 and SMA-9) of SMA-6 in the intestine were further identified to be required for the control of response to nanopolystyrene. In nanopolystyrene exposed nematodes, intestinal MAB-31 activated the mitochondrial Mn-SOD/SOD-3 by modulating DAF-16 activity, and intestinal SMA-9 activated the mitochondrial unfolded protein response by affecting ELT-2 activity. Therefore, the DBL-1/TGF-β signaling pathway mediated an important neuron-intestine communication in nanopolystyrene exposed nematodes.

Effects of Different Microplastics on Nematodes in the Soil Environment: Tracking the Extractable Additives Using an Ecotoxicological Approach

With increasing interest in the effects of microplastics on the soil environment, there is a need to thoroughly evaluate the potential adverse effects of these particles as a function of their characteristics (size, shape, and composition). In addition, extractable chemical additives from microplastics have been identified as an important toxicity pathway in the aquatic environment. However, currently, little is known about the effects of such additives on the soil environment. In this study on nematodes (Caenorhabditis elegans), we adopted an ecotoxicological approach to assess the potential effects of 13 different microplastics (0.001-1% of soil dry weight) with different characteristics and extractable additives. We found that poly(ethylene terephthalate) (PET) fragments and polyacrylicnitrile (PAN) fibers show the highest toxicity, while high-density polyethylene (HDPE), polypropylene (PP), and polystyrene (PS) fragments induced relatively less adverse effects on nematodes. In addition, low-density polyethylene (LDPE) induced no toxicity within our test concentration range for the acute period. Acute toxicity was mainly attributed to the extractable additives: when the additives were extracted, the toxic effects of each microplastic disappeared in the acute soil toxicity test. The harmful effects of the LDPE films and PAN fibers increased when the microplastics were maintained in the soil for a long-term period with frequent wet-dry cycles. We here provide clear evidence that microplastic toxicity in the soil is highly related to extractable additives. Our results suggest that future experiments consider extractable additives as key explanatory variables.

The impact of tourism on marine litter pollution on Santa Marta beaches, Colombian Caribbean

Tourism is an important socioeconomic activity in coastal communities, which deteriorates marine-coastal ecosystem quality when poorly managed, increasing litter pollution on beaches during the main tourist seasons. This study aims to assess the tourism impact on litter pollution on eleven Santa Marta beaches, Colombian Caribbean. During high and low tourist seasons, people on the beaches were counted, macrolitter and microplastics were sampled, and perception surveys about litter on beaches were conducted. During the high tourist season, the number of people and macrolitter pollution increased, compared to the low tourist season. Plastics accounted for 30%-77% of macrolitter and microplastics ranged from 1 to 355 items/m². Respondents identified tourism as a main litter source and plastics as the most common litter type. All assessed beaches are impacted by tourism causing litter pollution, therefore, stronger controls, educational, and awareness strategies are needed to reduce litter pollution and prevent ecological and socioeconomic impacts.

Intergenerational toxicity of nonylphenol ethoxylate (NP-9) in Caenorhabditis elegans

The ethoxylated isomers of nonylphenol (NPEs, NP-9) are one of the main active ingredients present in nonionic surfactants employed as herbicides, cosmetics, paints, plastics, disinfectants and detergents. These chemicals and their metabolites are commonly found in environmental matrices. The aim of this work was to evaluate the intergenerational toxicity of NP-9 in Caenorhabditis elegans. The lethality, length, width, locomotion and lifespan were investigated in the larval stage L4 of the wild strain N2. Transgenic green fluorescent protein (GFP) strains were employed to estimate changes in relative gene expression. RT-qPCR was utilized to measure mRNA expression for neurotoxicity-related genes (unc-30, unc-25, dop-3, dat-1, mgl-1, and eat-4). Data were obtained from parent worms (P0) and the first generation (F1). Lethality of the nematode was concentration-dependent, with 48 h-LC₅₀ values of 3215 and 1983 μM in P0 and F1, respectively. Non-lethal concentrations of NP-9 reduced locomotion. Lifespan was also decreased by the xenobiotic, but the negative effect was greater in P0 than in F1. Non-monotonic concentration-response curves were observed for body length and width in both generations. The gene expression profile in P0 was different from that registered in F1, although the expression of sod-4, hsp-70, gpx-6 and mtl-2 increased with the surfactant concentration in both generations. None of the tested genes followed a classical concentration-neurotoxicity relationship. In P0, dopamine presented an inverted-U curve, while GABA and glutamate displayed a bimodal type. However, in F1, inverted U-shaped curves were revealed for these genes. In summary, NP-9 induced intergenerational responses in C. elegans through mechanisms involving ROS, and alterations of the GABA, glutamate, and dopamine pathways.

An environmental concentration of aged microplastics with adsorbed silver significantly affects aquatic organisms

Microplastics are very complex pollutants; they can be made of many polymer types and exist in various shapes and sizes. When they enter the environment they are affected by biotic and abiotic factors that cause their properties to change. In this context, the aim of our study was to evaluate the extent to which biofouling affects the properties and toxicity of microplastics. Cosmetic polyethylene microbeads were incubated in stream water for four weeks resulting in biofouling and aging. Subsequently, the changes in properties (sinking, particle size, adsorption, and leaching of model metal - silver) and the microplastics toxicity to daphnids Daphnia magna and duckweed Lemna minor were evaluated. Pristine microplastics did not affect daphnids but they significantly affected the root growth of duckweed. On the other hand, reference natural particles (beech sawdust) did not show any negative effects. We observed significant differences in the properties of aged versus pristine microplastics. When compared to pristine microplastics, aged microplastics adsorbed more silver and the subsequent leaching of silver was more intensive, especially in the medium with an acidic pH. Microplastics with adsorbed silver had a high ecotoxicological potential and at environmentally relevant concentrations affected both daphnids and duckweed. This study suggests that biofouling is an important parameter that affects microplastics properties, pollutant adsorption and release into the environment, and toxicity. Overall, there are significant alterations of the microplastics properties, behaviour, and fate in the environment.

Prevalence of microplastic contamination in the digestive tract of fishes from mangrove ecosystem in Cispata, Colombian Caribbean

Plastics in Colombian marine-coastal ecosystems are being fragmented by various environmental factors, generating microplastics (size < 5 mm), an emerging pollutant that is ingested by marine organisms, representing a threat to ecosystems and potentially also to humans. This study aims to evaluate the incidence of microplastic ingestion by fishes from mangrove ecosystems in Cispata, Colombian Caribbean. The digestive tract content of 302 specimens of 22 fish species were analyzed using the KOH digestion method (500 g/5 L), stereoscopic visual identification and infrared spectroscopy. A total of 69 microplastics were found in the digestive tract of 7% of the analyzed fishes. 55% of the ingested microplastics were filaments, 23% fragments, 19% films, and 3% foam. The results of this study raised concerns about microplastic contamination in the marine environments, a threat to the fishery resource and to public health, which requires actions to prevent and reduce its negative effects.