Preliminary Assessment of Plastic Litter and Microplastic Contamination in Freshwater Depositional Areas: The Case Study of Puerto Misahualli, Ecuadorian Amazonia

Microplastic pollution in the Amazon Basin: Current scenario, advances and perspectives

The presence of microplastics (MPs) has been reported in ecosystems in the most different regions of the world and rivers have been identified as one of the main means of transporting this debris to oceans. Recent research shows microplastic deposition and accumulation in the Amazon Basin and, despite being scarce, microplastic pollution is ubiquitous in the region. Of the 9 countries that make up the Amazon Basin, only Brazil, Guyana, Ecuador and Peru have published on the topic, with the main focus on biota (58 %). Several Amazon regions such as Northern Amazon in the Far North of Brazil still have no evidence of microplastic pollution with published data. MP abundance ranges from 5 to 74,500 MPs m-3 for waters, 0 to 8178 MPs kg-1 for sediment and 0.34 to 38.3 MPs individual-1 for biota, with nanoplastic scale (<100 μm) in the sediment. Blue and colorless are the predominant colors, mainly from secondary sources (fibers and fragments). The most commonly found polymers are polyamide, polyethyleneterephthalate and polypropylene. Microplastic abundance in aquatic systems is higher than that found in other rivers, such as the Guayas in Ecuador, the Magdalena, in Colombia and the Surabaya in Indonesia and are similar to regions with intense anthropogenic activity such as the Guanabara Bay - Brazil and the Yellow River in China. The precarious basic sanitation structure, urban planning, waste management, combined with the extensive network of navigable waters, are aggravating factors for the increase in plastic pollution in the region. It is necessary to increase research investment on the topic, considering MP quantification, impacts and the relationship with the hydrosedimentological dynamics of the Amazon Basin. The creation and enforcement of laws that minimize the accumulation of these materials is emerging, besides the development of the bioeconomy and sustainable proposals to minimize plastic pollution in the Amazon.

Marine litter along the Peruvian coast: spatiotemporal composition, sources, hazard, and human modification relations

Marine litter (ML) represents an escalating environmental issue, particularly in Latin America, where comprehensive studies are scarce despite critical solid waste management challenges and continuous human modification occurring on the coasts. To contribute to the knowledge of ML in the southeast Pacific, this study examined contamination across 10 beaches on Peru's extensive coast. Overall, ML contamination was categorized as moderate (with an ML concentration of 0.49 ± 0.64 items∙m-2), while significantly differing between summer (dirty with an ML concentration of 0.56 ± 0.66 items∙m-2) and winter (moderate with an ML concentration of 0.47 ± 0.60 items∙m-2). Three beaches were extremely dirty (concentrations of ML exceeded 1.0 items∙m-2). Predominant materials, items, and sources were plastic, cigarette butts (CBs), and mixed packaging. The Peruvian coast faced CB leachate impact (CBPI = 3.5 ± 3.5), reaching severe levels on two beaches, with considerable hazardous litter (HALI = 3.0 ± 2.9). Additionally, a higher degree of human modification was associated with higher ML levels along the coast.

Microplastics in the Amazon biome: State of the art and future priorities

Microplastics (MPs) have been identified as a major potential threat to the biota and human health. Despite the exponential increase in MP research worldwide, few studies have focused on the extensive Amazon biome. To assess research priorities, the present study reviewed and summarized the available scientific knowledge on MPs in the Amazon, in addition to analyzing population and waste-management data, to evaluate potential sources of MPs in the hydrographic system. Poor sanitation conditions are a main source of MPs for the vast hydrographic basin, and, consequently, for the adjacent ocean. Secondary MPs predominated, mostly fibers (96% of debris), composed of polyamide (32%). Mean MP concentrations ranged from 0.34 to 38.3 particles.individual-1 in biota, 5 to 476,000 particles.m-3 in water, and 492.5 to 1.30848 × 107 particles.m-3 in sediment, values in close comparison with those found in areas profoundly affected by anthropogenic pollution. MPs were widespread in a range of Amazonian environments and species, and negative effects are probably occurring at various ecological levels. However, limited research, methodological constraints, flaws and the lack of standardization, combined with the continental dimensions of the Amazon, hampers the collection of the fundamental knowledge needed to reliably evaluate the impacts and implement effective mitigation measures. There is an urgent need to expand scientific data available for the region, improving local research infrastructure, and training and deploying local researchers.

Microplastics in Ecuador: A review of environmental and health-risk assessment challenges

Pollution from plastic debris and microplastics (MPs) is a worldwide issue. Classified as emerging contaminants, MPs have become widespread and have been found not only in terrestrial and aquatic ecosystems but also within the food chain, which affects both the environment and human health. Since the outbreak of COVID-19, the consumption of single-use plastics has drastically increased, intensifying mismanaged plastic waste in countries such as Ecuador. Therefore, the aim of this review is to 1) summarize the state of MP-related knowledge, focusing on studies conducted with environmental matrices, biota, and food, and 2) analyze the efforts by different national authorities and entities in Ecuador to control MP contamination. Results showed a limited number of studies have been done in Ecuador, which have mainly focused on the surface water of coastal areas, followed by studies on sediment and food. MPs were identified in all samples, indicating the lack of wastewater management policies, deficient management of solid wastes, and the contribution of anthropogenic activities such as artisanal fishing and aquaculture to water ecosystem pollution, which affects food webs. Moreover, studies have shown that food contamination can occur through atmospheric deposition of MPs; however, ingredients and inputs from food production, processing, and packaging, as well as food containers, contribute to MP occurrence in food. Further research is needed to develop more sensitive, precise, and reliable detection methods and assess MPs' impact on terrestrial and aquatic ecosystems, biota, and human health. In Ecuador specifically, implementing wastewater treatment plants in major cities, continuously monitoring MP coastal contamination, and establishing environmental and food safety regulations are crucial. Additionally, national authorities need to develop programs to raise public awareness of plastic use and its environmental effects, as well as MP exposure's effects on human health.

Human health risk assessment of metals and metalloids in mining areas of the Northeast Andean foothills of the Ecuadorian Amazon

Gold mining (GM) is a major source of metals and metalloids in rivers, causing severe environmental pollution and increasing the exposure risks to the residents of surrounding areas. Mining in Ecuadorian Amazonia has dramatically increased in recent years, but its impacts on Indigenous local populations that make use of rivers are still unknown. The aim of this study was to assess the risks to adults and children caused by the exposure to metals and metalloids in freshwater ecosystems contaminated with tailings released by GM activities in 11 sites of the upper Napo River basin, Ecuador. We selected a carcinogenic and a noncarcinogenic risk assessment method to estimate the hazard index (HI) and total cancer risk (TCR). The concentration of Ag, Al, As, Cd, Cu, Fe, Mn, Pb, Zn, B, and V in water and sediment samples was considered to assess the risks to human health. The calculated HI was 23-352 times greater than the acceptable limits in all sites for both children and adults. Mn and Fe were the main contributors (75% in water and 99% in sediment) to the total calculated risk based on the HI. The calculated TCR for children and adults exceeded approximately one to three times the permissible threshold in all sites. As and Pb contributed up to 93% of the total calculated risk based on TCR for both children and adults. This study demonstrates that the emission and mobilization of metals and metalloids caused by mining activities increase the risk to human health, to which we recommend further monitoring of freshwater contamination in the area and the implementation of preventive health management measures. Integr Environ Assess Manag 2023;19:706-716. © 2022 The Authors. Integrated Environmental Assessment and Management published by Wiley Periodicals LLC on behalf of Society of Environmental Toxicology & Chemistry (SETAC).

Large-scale monitoring and risk assessment of microplastics in the Amazon River

Microplastics (MPs) are one of the most widespread contaminants worldwide, yet their risks for freshwater ecosystems have seldom been investigated. In this study, we performed a large monitoring campaign to assess the presence and risks of MPs in Amazonian freshwater ecosystems. We investigated MP pollution in 40 samples collected along 1500 km in the Brazilian Amazon, including the Amazon River, three major tributaries, and several streams next to the most important urban areas. MPs in the 55-5000 µm size range were characterized (size, shape, color) by microscopy and identified (polymer composition) by infrared spectroscopy. Ecotoxicological risks were assessed using chronic Species Sensitivity Distributions for effects triggered by food dilution and tissue translocation using data alignment methods that correct for polydispersity of environmental MPs and bioaccessibility. This study shows that MPs are ubiquitous contaminants in Amazonian freshwater ecosystems, with measured concentrations (55-5000 µm) ranging between 5 and 152 MPs/m³ in the Amazon River and its main tributaries, and between 23 and 74,550 MPs/m³ in urban streams. The calculated Hazardous Concentration for the 5% of species (HC₅) derived from the SSDs for the entire MP range (1-5000 µm) were 1.6 × 10⁷ MPs/m³ (95% CI: 1.2 × 10⁶ - 4.0 × 10⁸) for food dilution, and 1.8 × 10⁷ MPs/m³ (95% CI: 1.5 × 10⁶ - 4.3 × 10⁸) for translocation. Rescaled exposure concentrations (1-5000 µm) in the Amazon River and tributaries ranged between 6.0 × 10³ and 1.8 × 10⁵ MPs/m³, and were significantly lower than the calculated HC₅ values. Rescaled concentrations in urban streams ranged between 1.7 × 10⁵ and 5.7 × 10⁸ MPs/m³, and exceeded both calculated HC₅ values in 20% of the locations. This study shows that ecological impacts by MP contamination are not likely to happen in the Amazon River and its major tributaries. However, risks for freshwater organisms may be expected in near densely populated areas, such as the cities of Manaus or Belem, which have limited wastewater treatment facilities.

What Are Lake Beaches Made of? An Assessment of Plastic Beach Litter on the Shores of Como Bay (Italy)

Plastic waste dispersion is a well-recognized environmental threat, despite continuous efforts towards improving waste disposal management over the last few decades. Plastic litter is known to strongly impact upon water bodies and shorelines, affecting the health of ecosystems and impacting upon the aesthetic value of sites. Moreover, plastic waste that is abandoned on beaches contributes towards different degradation processes that potentially lead to the formation of secondary microplastics (MPs), with likely cascade effects upon the whole ecosystem. In this view, this study aims to characterize the plastic beach litter found on the shores of the western basin of Como Lake (Italy) to better understand the origin of MPs in littoral sediments, including the recognition of object typologies and the chemical characterization of polymers using Fourier-transformed infrared analysis (FTIR). The results highlighted that the most abundant polymers on beaches are polypropylene (PP) and polyethylene (PE), representing 73% of the collected polymers. This confirms that floating, low-density polymers are more likely to accumulate on beaches. Moreover, almost 66% of litter is represented by commonly used manufactured items (disposable objects, packaging, and everyday items). This evidence, combined with the analysis of the main environmental features of the sampling sites (the main winds, distance to urban areas, and the presence of tributaries) indicate that abundance of beached litter is mainly linked to beach accessibility and the local winds. These results highlight that multiple factors affect the environmental fate of plastic litter and give insights into the assessment of secondary microplastics in beach sediments.

Emerging Contaminants in the Northeast Andean Foothills of Amazonia: The Case of Study of the City of Tena, Napo, Ecuador

This work is a study on the occurrence of emerging pollutants in the northeast Ecuadorian Amazon. Emerging contaminants (ECs)-caffeine, triclosan, estradiol, acetaminophen, nicotine, and ibuprofen-were quantified by gas chromatography-mass spectrometry in rivers and streams of the Amazon basin near the city of Tena, Ecuador. For that, a total of 16 natural water samples were taken in 8 locations. Sampling sites included areas impacted by discharges from inefficient sewage networks in urban areas, wastes from fish farming and non-functional landfill, a stream with few threats, tap water, and treated sewage. Caffeine was found in the 38% of the samples studied while trimethoprim and acetaminophen had an occurrence of 13%. Caffeine was detected at two sites receiving untreated sewage and one site receiving treated sewage with mean concentrations that ranged between 19 and 31.5 μg L^-1. Acetaminophen (50.4 μg L^-1) and trimethoprim (2 μg L^-1) were only detected in the river receiving treated sewage effluent. This is the first assessment of emerging contaminants in the upper Ecuadorian Amazon basin, and our observations highlight the need for better sewage treatment and water quality monitoring in Amazonian cities.

Moulatlet G. An Integrative Approach to Assess the Environmental Impacts of Gold Mining Contamination in the Amazon

As the number of legal and illegal gold mining sites increases in the Andes-Amazonia region, integrative methods to evaluate the effects of mining pollution on freshwater ecosystems are of paramount importance. Here, we sampled water and sediments in 11 sites potentially affected by gold mining activities in the Napo province (Ecuador). The environmental impacts were evaluated using the following lines of evidence (LOEs): water physicochemical parameters, metal exposure concentrations, macroinvertebrate community response (AAMBI), and toxicity by conducting bioassays with Lactuca sativa and Daphnia magna. Dissolved oxygen and total suspended solids were under (<80%) and above (>130 mg/Ls) quality standards 65% of the sites. Ag, Al, As, Cd, Cu, Fe, Mn, Pb, and Zn in water and V, B, and Cr in sediments were detected above quality standards at sampled sites. Nine out of eleven sites were classified as having bad environmental quality based on the AAMBI. L. sativa seed germination in both water (37% to 70%) and sediment (0% to 65%) indicate significant toxicity. In five sites, neonates of D. magna showed a 25% reduction in survival compared to the control. Our integrated LOEs index ranked sites regarding their environmental degradation. We recommend environmental impact monitoring of the mining expansion at the Andes-Amazonia region using multiple LOEs.