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Abstract

Estuarine pollution imposes rapid, increasing and lasting environmental modifications. In the present review, especial attention is given to estuaries in South America (SA), where legislation, policies and actions to guarantee environmental quality remain ineffective. There, the majority of estuaries face uncontrolled occupation of its margins by urban and industrial centres, agriculture and aquaculture expansion, water extraction and flow control. The lack of basic sanitation and poor environmental management (including territories within Marine Protected Areas) often lead to hydrological alterations, high nutrient loads, and the presence and dynamics of pollutants (nutrient loads, persistent organic pollutants (POPs), metals and plastic debris) along the entire estuarine ecocline.Organic enrichment has increased dissolved oxygen consumption, withwide spatio-temporal variability along latitudes and estuarine gradients. The toxicity, biogeochemistry and availability of metals and POPs depend on the annual fluctuations of salinity, water renewal, dissolved oxygen levels, suspended particulate loads, sediment mobility, grain size and composition at the sink. Plastic debris from land sources are widespread in estuaries,where they continue to fragment into microplastics. River basins are themain contributors of plastics to estuaries, whose transportation and accumulation are subjected to interannual water flow variations. Although some systems seems to be in a better condition in relation to others around the world (e.g. Goiana and Negro estuaries), many others are among the most modified worldwide (e.g. Guanabara Bay and Estero Salado System).We propose that, estuarine conservation plans should consider year-round fluctuations of the ecocline and the resulting cycles of retention and flush of environmental signals and their influence on trophic webs over the whole extent of estuarine gradients.

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... (Iqbal et al., 2017). De ce fait, les environnements côtiers et estuariens sont très impactés par ces polluants Barletta, Lima et Costa, 2019) car ils reçoivent les flux de contaminations de sources anthropiques en amont depuis les bassins versants . Ces environnements sensibles sont également soumis à des transferts entre le milieu et les organismes (bioaccumulation) (Mackay et Fraser, 2000;You et al., 2011;Borgå et al., 2012) ou dans les réseaux trophiques (bioamplification) (Gobas et Morrison, 2000;Mackay et Fraser, 2000). ...
... Estuaries are located at the interface between watersheds and the open ocean, representing transition areas with commonly high contamination levels Barletta, Lima and Costa, 2019). Therefore, estuarine environments are, on the one hand, rich ecosystems with a high level of biodiversity and major ecological role (e.g., as nurseries for numerous fish species) and, on the other hand, areas potentially subjected to intense chemical inputs. ...
... These factors may promote sorption to suspended sediments and, thus, subsequent accumulation in bed sediments . As the transition zone between watersheds and the open sea, estuaries may receive large pollutant loads and may exhibit high contamination levels Thierry Burgeot et al., 2017;Barletta, Lima and Costa, 2019). In addition, estuaries shelter rich ecosystems in which a large biodiversity can develop. ...
Thesis
Dans un contexte de changement global, les effets de la pollution d'origine anthropique sont importants. Cette pollution est liée à l'urbanisation, l'activité industrielle ou encore l'agriculture intensive. Ces multiples sources génèrent de nombreuses catégories de pollution, dont la pollution chimique. Afin de mieux comprendre l'écodynamique de certains polluants ubiquistes, toxiques et bioaccumulables, l'estuaire de Seine a été choisi car il constitue le réceptacle final d'un bassin versant soumis à une forte pression anthropique. Plusieurs compartiments y ont été étudiés. Quatre espèces d'oiseaux marins (goéland argenté : Larus argentatus ; goéland brun : Larus fuscus ; goéland marin : Larus marinus ; cormoran huppé : Phalacrocorax aristotelis) sentinelles, bioindicatrices, représentatives d’un niveau trophique élevé et ayant des habitats et des habitudes d'alimentation variés et caractéristiques des milieux estuariens ont été choisies afin de suivre leur imprégnation en différentes classes de contaminants historiques tels que les polychlorobiphényles (PCB), les pesticides organochlorés (OCP) et les polybromodiphényléthers (PBDE) et de contaminants d’intérêt plus émergents comme les composés per- et poly-fluoroalkylés (PFAS). Les PCB, l'hexabromocyclododécane (HBCDD) et les PFAS ont été également suivis dans le milieu de vie et le réseau trophique de la sole commune (Solea solea) afin d’appréhender les transferts du sédiment vers le biote, au sein du réseau trophique benthique, mais aussi entre les stades juvéniles d'un organisme d’intérêt halieutique et écologique majeur.
... Plastic has recently been identified as a pollutant in the context of the international economic and environmental crisis, owing to its ability to last for several decades (Worm et al. 2017). According to research, the aquatic environment in several regions has been polluted by plastic debris (Barletta et al. 2019;Wagner et al. 2014). Large plastic particles have long been known to interact with a variety of aquatic species via processes such as entanglement and ingestion (Duncan et al. 2017). ...
... Plastic accounts for approximately 85% of marine litter. Plastics and microplastics are persistent pollutants that are increasingly found in the littering of every environmental niche on a global scale (Barletta et al. 2019;Jambeck et al. 2015). Plastic waste is becoming a major concern due to its persistent nature and impact on aquatic organisms as well as humans (Thompson et al. 2009). ...
... Plastic particle aggregation in the ecosystem has toxic effects on biodiversity (Dawson et al. 2018;Gall and Thompson, 2015;Lu et al. 2016). As a result, immediate management strategies are required to reduce or eliminate potential threats to organism life (Barletta et al. 2019;Bour et al. 2018;Daiwile et al. 2015). ...
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Plastic trash dumped into water bodies degrade over time into small fragments. These plastic fragments, which come under the category of micro-plastics (MPs), are generally 0.05–5 mm in size, and due to their small size they are frequently consumed by aquatic organisms. As a result, widespread MPs infiltration is a global concern for the aquatic environment, posing a threat to existing life forms. MPs easily bind to other toxic chemicals or metals, acting as vector for such toxic substances and introducing them into life forms. Polyethylene, polypropylene, polystyrene, and other polymers are emerging pollutants that are detrimental to all types of organisms. The main route for MPs into the aquatic ecosystems is through the flushing of urban wastewater. The current paper investigates the origin, environmental fate, and toxicity of MPs, shedding light on their sustainable remediation.
... These particles pose numerous risks to aquatic biota and human health. Due to their high surface-to-volume ratio, MPs act as vectors for plastic additives, persistent organic pollutants (POPs), and heavy metals that cause ecotoxicological impacts upon leaching (Barletta et al., 2019;Woods et al., 2021;Zaki et al., 2021b). One exposure pathway of biota to MPs is through ingestion (Woods et al., 2021). ...
... The water exchange in such environments is a factor of river discharge on the continental side (upper estuary) and tidal cycles on the marine side (lower estuary) (Dris et al., 2020). The multiple water inputs cause a high nutrient content, making estuaries among the most biologically productive ecosystems in the world (Barletta et al., 2019;Lourenço et al., 2017). They act as habitats for countless species of flora and fauna. ...
... They act as habitats for countless species of flora and fauna. In fact, numerous commercial fish species utilize estuaries as nursery areas due to the availability of food and sheltered waters (Barletta et al., 2019;Rodrigues et al., 2019). In addition, the economic value of such ecosystems attracted anthropogenic structures such as fisheries (Anderson et al., 2018), wastewater treatment plants (WWTP) (Sousa et al., 2021), harbors (Frère et al., 2017), ports (Preston-Whyte et al., 2021), and residential properties (Willis et al., 2017). ...
Article
Despite the importance of estuaries as transition zones between freshwater and marine compartments, their role in the transport of microplastics is still unclear. This review analyzes the findings pertaining to the transport mechanisms and other factors that influence the fate of microplastics in estuaries. It was found that the concentration of microplastics temporally varies under daily tides, monthly tides, and seasonal flows. Moreover, it spatially varies due to density effects, biofouling, aggregation, and salinity. Wind direction and intensity impact the spatiotemporal distribution of microplastics in the water column. Some of these processes transport microplastics to the estuarine sediments. Thereafter, microplastics are prone to resuspension by turbulence and bioturbation. Hence, estuaries act as temporary sinks that retain microplastics before being flushed to the ocean. Finally, a review of highly plastic-emitting rivers shows differences in the factors affecting the transport mechanisms of microplastics, which calls for regionalization when modelling their fate henceforward.
... The composition, diversity, biomass, and distribution of species of the phytoplankton community constantly change due to seasonal and temporal variations (Córdoba-Mena et al. 2020). Furthermore, algae overgrows when nutrients are in excess and there are ideal light and temperature conditions (Smith et al. 1999;Van Beusekom 2018; Barletta et al. 2019). This can result in reduced water quality, decreasing the quantity of dissolved oxygen by bacterial action (Halliday et al. 2014), which can affect many organisms in the trophic chain (Douglas et al. 2016;Lecher and Mackey 2018). ...
... The overgrowth of algae, caused by eutrophication (Coffey et al. 2018;Barletta et al. 2019;Córdoba-Mena et al. 2020), was investigated on Central Beach in Balneário Camboriú, Santa Catarina. There was an increase in concentrations of nutrients in the water column in the summer that promoted considerable growth of bryozoans and phytobenthos (Rörig et al. 2017), which are an important source of food for the polychaete T. furcifera (Otegui et al. 2012). ...
Article
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Urban expansion in Brazilian coastal zones has caused various anthropic impacts on coastal marine ecosystems that have resulted from unorganized use and the lack of infrastructure projects. The inadequate disposal of domestic and industrial effluents in coastal waterbodies is notable, which can cause severe environmental problems. For sandy beaches, the relationships between the contamination of groundwater with domestic sewage and the possible effects on spatial and temporal variations in the density and composition of benthic infauna are still poorly understood. This work aimed to relate variations in benthic infaunal associations with the concentrations of groundwater nutrients in summer and winter on Enseada Beach. The greater concentrations of nutrients in water percolating through the sediment in the summer, increasing of domestic effluents, and periods of intense precipitation increased the contamination of the surface and groundwater. This contributes to an increase in the population density of Thoracophelia furcifera, demonstrating its use as an indicator of eutrophication of the groundwater, allowing monitoring and contribution to actions aimed at improving the environmental quality of sandy beaches.
... Este bajo suministro de sedimentos resulta en una morfología costera dominada por procesos marinos y eólicos, y cambios significativos con la geomorfología descripta en el siglo pasado Además del agua y los sedimentos, la agricultura y la acuicultura contribuyen significativamente con contaminantes y nutrientes tanto a la cuenca baja del río, así como también lo hace la infraestructura de las zonas urbanas, fundamentalmente en relación con la eliminación de residuos sólidos y aguas residuales no tratadas (Marins et al., 2011). La presencia de bosques de manglares relativamente extensos actúa como barreras para el transporte de contaminantes como metales pesados, pesticidas, hidrocarburos y otros (Barletta et al., 2019), y la capacidad de retención de contaminantes depende del contenido de materia orgánica del suelo. Sin embargo, este sumidero natural se ve amenazado actualmente por el desarrollo de áreas para el turismo y la acuicultura en la región estuarial, así como por el cambio climático. ...
... Nutrient pollution is responsible for an array of problems in many aquatic bodies causing a range of debilitating effects in humans and with substantial health, economic, with ecological implications (Camargo & Alonso, 2006;Cloern et al., 2020). Some of the identified effects include eutrophication, harmful algal blooms, dead zones, fish kills, shellfish poisoning, loss of seagrasses and kelp beds, coral reef destruction and diseases, destruction of spawning grounds for aquatic life, and deaths of some marine mammals and seabirds (Barletta et al., 2019;Dougan et al., 2020;Ferreira et al., 2011;Johnson et al., 2010;Silbiger et al., 2018). ...
Article
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Surface water and sediment from Bonny Estuary, Nigeria, were assessed to determine the nutrient dynamics. Nutrients (nitrates, phosphates, and total organic carbon (TOC)) and some physicochemical parameters of water samples are collected from three sampling stations along the Bonny Estuary during wet seasons (April 2017, 2018, and 2019) and dry seasons (November 2017, 2018, and 2019). Physicochemical parameters analyses were conducted in situ using Horiba water checker (Model U-10). Surface water nitrate and phosphate were analysed by APHA 4500-NO3-B Colorimetric method, while sediment nitrates and phosphate by Chemical Analysis for Ecological Matter CAEM/APHA 4500-NO3-E Colorimetric method and TOC by CAEM-Wet-Oxidation Titration method. There was no significant seasonal variation in pH, temperature, dissolved oxygen, biological oxygen demand, conductivity, and turbidity nor across the sampling stations. TDS values showed significant seasonal variation with higher values in the wet seasons. Surface water nitrate and phosphate had higher concentrations in wet seasons though within recommended limits. Conversely, nitrate, phosphate, and TOC in the sediments were quite high, with higher values in wet seasons, especially the downstream of the estuary. The high levels of nutrients in the sediments as opposed to surface water could be a result of rapid deposition of nutrients which could lead to possible nutrient enrichment of the sediment. Nutrient levels in the sediment have increased fourfold over the study period. This suggests an influx of nutrients into the estuary, due to human activities. Nutrient enrichment could result in deterioration in aquatic water quality and pose a threat to the ecology of the estuary.
... In aquatic environments, non-essential metals consist of water-soluble species, colloids, suspended forms, and sedimentary phases (Peng et al., 2009). Metals generally tend to be more soluble and mobile in water sources at neutral to low pH values (Joseph et al., 2019); however, sediments are a major sink for metals (Barletta et al., 2019;Maurice et al., 2019). Non-essential metals exhibit widely different solubilities in the presence of oxygen and under reducing conditions. ...
Article
Non-essential metal contamination is a common issue worldwide. In the last decades, the primary contamination sources have been associated mainly with anthropogenic activities, but non-essential metals are also naturally present in the ecosystem. The latter applies to the Andean region, where various "contaminant" elements from volcanic and subsoil sources are present. In Ecuador, non-essential metal contamination in crops has gained attention in the last three decades and has been the focus of both domestic and international studies on agricultural products. Because of globalized commerce and demand for healthier products, international regulations regarding maximum permissible limits for certain metallic elements are becoming increasingly rigorous, requiring production systems that guarantee food safety. While Ecuador has specific regulations, they are not comprehensive for all non-essential metal contaminants that are harmful in certain amounts. Further, existing regulations are not fully enforced, and government control systems are inefficient, which increases the pop-ulation's possibility of exposure to pollutants. This review compiles and discusses results from studies on metal contamination, their availability in the environment, translocation in vegetables, and consumption-related health problems to evaluate whether current Ecuadorian agricultural product regulations ensure food quality and safety in terms of non-essential metal pollution.
... In an urban area, high conductivity values are indirect measures of the concentration of pollutants in the water, derived from ions from effluents and decomposition of organic matter (Esteves, 1998;Rosa et al., 2014). Changes and oscillations in abiotic variables over the years in aquatic ecosystems can result from oscillations in the fluviometric level, seasonal variations, human activities and especially increased pollution (Barletta et al., 2019). The pollution of aquatic environments can affect important limnological variables that structure aquatic communities. ...
Article
Aquatic environments in urban centers suffer constantly from changes in limnological variables, mainly due to increased pollution in these systems. Aquatic Oligochaeta are bioindicators of environmental change. The Iguaçu River is the second most polluted river in Brazil and in the Middle Iguaçu region is used for the public water supply. Efforts to understand the dynamics and conservation of this river are necessary, since this region has a gap in studies with aquatic invertebrates. Thus, the aim of this study was to investigate temporally the Oligochaeta species composition and the beta diversity of an anthropized stretch of a subtropical urban river, predicting that changes in abiotic variables cause changes in species composition and decrease the beta diversity over the years. We measured abiotic variables (water temperature, dissolved oxygen, electrical conductivity, pH, organic matter, aluminum and lead) and collected sediment samples using a grab in a stretch of the Iguaçu River over three years. We recorded 35 species of Oligochaeta and observed that changes in abiotic variables caused changes in species composition and beta diversity over the years, corroborating our prediction. The abiotic variables electrical conductivity, organic matter and aluminum were negatively related to species composition. In conclusion, the stretch studied in the middle Iguaçu showed an evident inter-annual variation in the Oligochaeta species composition, with a tendency to decrease the beta diversity, probably caused by changes in the abiotic variables.
... The CH 4 fluxes show a declining tendency with increasing salinity, according to Shiau and Chiu [63]. The Sundarban estuary receives a significant amount of nutrients from a variety of sources, including mining wastes, land runoff during the summer and monsoon, organic matter remineralization, sewage effluents, and so on [64]. Therefore, high inorganic N levels favours denitrification and, as a result, more N 2 O generation. ...
Article
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The increase in greenhouse gases, especially carbon dioxide, in the atmosphere contributes to climate change. People and policy makers are becoming more interested in the role of urban trees in regulating the global carbon cycle. Carbon dioxide emissions from anthropogenic sources are mainly caused by the burning of fossil fuels, which are major contributors to the increase in greenhouse gases in the atmosphere. Therefore, a better understanding of the carbon sequestration process by urban forests and its exchange between air and soil is the first step to offsetting the impacts of climate change in urban areas. Here, a dynamic model was constructed including the carbon stock of forest, litter carbon and soil organic carbon pool. The study emphasized the relationship between the three carbon pools. The monthly dynamics of the pools were studied. A sensitivity analysis was performed followed by calibration and validation. The results showed that the mean growth rate of forest biomass was the most sensitive factor, followed by the decomposition rate and the uptake rate of organic carbon by detritivores. If the biomass of the existing forest is maintained sustainably, more carbon dioxide could be sequestered. In addition, the model showed that afforestation in the Asansol-Durgapur Planning Area would increase the carbon stocks of the forest and to some extent offset the problem of carbon dioxide release from the nearby coal mines and other factories. In the near future, the model will benefit forest managers in carrying out urban management in the Earth’s tropical belt.
... For the same estuary, the variation between periods from 133 (dry season) to 1400 items.m −3 (rainy season) was attributed to increased freshwater discharge, which provided more MPs from continental sources (Barletta et al., 2019). The higher abundances during the rainy season for the Brazilian coast are thus linked to a possible higher flux of continental and riverine MPs to the oceans (Meijer et al., 2021). ...
Article
The composition and distribution of microplastics (MPs) in the Brazilian Amazon Continental Shelf surface waters are described for the first time. The study was conducted during the 2018 rainy and dry seasons, using 57 water samples collected with aluminum buckets and filtered through a 64-μm mesh. The samples were vacuum filtered in a still-air box, and the content of each filter was measured, counted, and classified. A total of 12,288 floating MPs were retrieved; particles were present at all 57 sampling points. The mean MP abundance was 3593 ± 2264 items·m−3, with significantly higher values during the rainy season (1500 to 12,967; 4772 ± 2761 items·m−3) than in the dry season (323 to 5733; 2672 ± 1167 items·m−3). Polyamides (PA), polyurethane (PU), and acrylonitrile butadiene styrene (ABS) were the most common polymers identified through Fourier Transform Infrared Spectroscopy (FTIR) analysis. Cellulose-based textile fibers were also abundant (~40%). Our results indicate that the Amazon Continental Shelf is contaminated with moderate to high levels of MPs; the highest abundances were recorded at stations near land-based sources such as river mouths and large coastal cities.
... Release of microplastics from larger plastic fragments, particularly those which accumulate on the sea surface microlayer are typically non-biodegradable and sorb toxic organic and inorganic compounds (Bakir et al., 2014;Song et al., 2014;Hermabessiere et al., 2017;Carbery et al., 2018;Hahladakis et al., 2018;Huffer et al., 2018;Wang et al., 2018;Barletta et al., 2019;Naik et al., 2020). Finally, the action of fouling alters the overall buoyancy of these particles and leads to their aggregation as marine snow that settles from surface water to seabed, potentially threatening benthic life (Sfriso et al., 2020). ...
Article
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Marine plastic debris is an environmental problem, and its degradation into microplastics (1-5000 μm) introduces them into the food chain. In this study, small polyoxymethylene (global production ~3000 Tg per year) pellets were exposed in terrestrial and simulated marine environments to heat and light, resulting in cracking during decay with increasing IR absorption (OH-bonds). Furthermore, sunlight over three years reduced pellet mass and diameter (~10% and ~40%), initially yielding 100-300 μm fragments. Changes under UV irradiation were smaller as it could not penetrate into particle interiors. Characteristic spacing of surface striations (100-300 µm) initiated radial cracks to pellet interiors, and breakdown ultimately meant 95% of particles were <300 µm, which are potentially incorporated in marine turbidites.
... Teniendo en cuenta su forma, los MPs se pueden clasificar en dos grandes categorías: fibras (cuando una de las dimensiones predomina sobre las demás) y fragmentos (cuando dos dimensiones predominaron sobre la tercera) (Hidalgo-Ruz et al., 2012;Dris et al., 2015) También se suele documentar información sobre el color de los MPs. Las fibras constituyen uno de los grupos de MPs más abundantes hasta la fecha (50-90 %), tanto en muestras de agua como de biota (Dris et al., 2015;Barletta et al., 2019;Hartmann et al., 2019). ...
Thesis
The widespread use of plastic goods in our modern life represents a threat to the environment, animals and humans exposed to plastic waste generated by these products. Although the presence of microplastics (MPs) has been reported in the biota of several freshwater systems around the world, mountainous environments have been little studied so far. Here, we postulate that top predatory fish, such as the trout species analyzed, represent a more useful tool for MPs assessment than species of lower trophic levels. To address this, we evaluated whether MPs can biomagnify from the native torrent catfish Hatcheria macraei (benthic-omnivorous fish and main prey of trout), to predatory fish (rainbow trout Oncorhynchus mykiss and brown trout Salmo trutta, both exotic and invasive species). The MPs burden (i.e., the abundance of MPs per fish) in the gastrointestinal tract (GIT) was correlated, at intra-specific level, with morphometric fish traits (weight, length and K index) to explore a potential link with fish heath and body condition. The results showed that blue fibers were the main type of MPs in the GITs of fish from the Mendoza River and this finding is consistent with the pattern reported on a global scale. In addition, through the field-based biomagnification factor, we obtained evidence that blue fibers biomagnify from torrent catfish to both trout species in a similar way in the Mendoza River. The correlational approach did not detect any association between MPs burden and fish morphometry. This study represents a baseline on the presence of MPs in native and exotic riverine fish that inhabit the central Andes Mountain range.
... The same is equivalent to a garbage truck full of plastic dumped into the ocean/minute Of the total amount of plastics sent to landfills, 79% is transported to the oceans, <10% is recycled and 12% is incinerated ratios causing the adsorption of other micropollutants present in the water and act either as source or sink of the contaminants in the organisms (Cole et al. 2011). The variety of chemicals used in the manufacturing of the plastic particles to improve their characteristic properties are found to leach into the ecological systems resulting in the bioaccumulation of toxic substances in the organisms incorporating a new route of exposure to plastic contamination (Barletta et al. 2019). A variety of rules and legislative tools exists in different countries worldwide aimed at handling or reducing the increasing use of plastic products especially single-use plastics (SUPs). ...
... However, this is not the only implication caused by the spread of MPs in nature, since they contain or can interact with other pollutants (i.e., metals, metalloids), resulting in a chemical impact beyond the physical damage ( Roman et al., 2020 ). The transfer of contaminants from MPs to the tissues of organisms has been already reported, potentially causing increased concentrations and toxicological effects on aquatic biota ( GESAMP, 2015 ;Luís et al., 2015 ;Barletta et al., 2019 ;Rivera-Hernández et al., 2019 ). Plastics are produced with the addition of organic and inorganic components, acting as plasticizers, stabilizers, surface modifiers, flame retardants, or pigments. ...
Article
Microplastics (MPs) are being recognized as an emergent route of contaminants to aquatic environments, which initially attracted the research interest on their interactions with organic pollutants. Lately, a turning point of attention is evident, with more published studies reporting the presence of metal(oid)s in plastics. This review assembles the mechanisms occurring on microplastics surfaces that enhance sorption of hazardous elements (i.e., metals and metalloids) over environmental exposure. Reported findings of experimental studies are of major importance to understand the factors controlling the sorption/desorption of metal(oid)s to/from microplastics as much as determination of metal(oid)s in environmental plastics. Existence or formation of oxygen-containing functional groups and complexes from surface coatings strongly allow bond of metal(oid)s on reactive surfaces while sorption dynamics are strongly controlled by water chemistry parameters. Moreover, the present work evidences the potential impacts caused by metal(oid)s-MPs interactions to aquatic organisms, prioritizing the need of environmental realistic parameters to test. Bioaccumulation of metal(oid)s desorbed from ingested MPs prove the significant influence of these plastic particles in the bioavailability of pollutants to aquatic biota. In this way, this is a comprehensive manuscript committed to the estimation of the potential ecological risk of MPs to aquatic environments due to their association with metal(oid)s.
... Nutrient pollution is responsible for an array of problems in many aquatic bodies causing a range of debilitating effects in humans and with substantial health, economic, with ecological implications (Camargo & Alonso, 2006;Cloern et al., 2020). Some of the identified effects include eutrophication, harmful algal blooms, dead zones, fish kills, shellfish poisoning, loss of seagrasses and kelp beds, coral reef destruction and diseases, destruction of spawning grounds for aquatic life, and deaths of some marine mammals and seabirds (Barletta et al., 2019;Dougan et al., 2020;Ferreira et al., 2011;Johnson et al., 2010;Silbiger et al., 2018). ...
... Phosphorus retention is further affected by physicochemical means, such as sediment sorption/ desorption reactions (Bai et al., 2017;Canga, Heckrath, and Kjaergaard, 2016). Chemical adsorption to sediment after the flood and the dry season enhances phosphorus retention (Barletta, Lima, and Costa, 2019;Li et al., 2017). Net sedimentation occurs in shallow waters with little flow (Horvatinčić et al., 2018). ...
Article
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The Boğaçay is a river situated in the Konyaaltı district of Antalya. In 2017, Antalya Metropolitan Municipality implemented a large project in which the river bed was excavated to 1.5 m below sea level. The aquifer is vital for meeting the drinking water needs of the city of Antalya. The goal of this research is to discover the applications that may be made to combat seawater intrusion and nutrient contamination, both of which were brought to the forefront by the Bogaçay Project. In this work, modeling was used to estimate the extent to which agricultural best management practices (BMPs) will be efficient in reducing pollutant load. In BMP modeling with the soil and water assessment tool (SWAT), a decrease of 39%, 38%, and 38% is anticipated in the 5-day biochemical oxygen demand (BOD 5), total phosphorus, and total Kjeldahl nitrogen loads, respectively. Sediment accumulated in the channel, and sediment transport occurred on the beach due to coastal erosion. Coastal erosion of up to 25 m was observed from the project's beginning to the present. Substantial land base pollution because of the diffused sources was found. Saltwater intrusion in the Bogaçay River estuary functions as a catalyst in the production of poor odor and appearance, as well as the rapid expansion of algae. The municipality is attempting to remedy this problem by periodic harvesting, which is an overly expensive and ineffective option. Instead, the elevation of the riverbed should be restored to preproject levels to prevent additional environmental and geographic damages.
... Cabral Pinto et al. , 2020aMezzaroba et al., 2019;Ajsuvakova et al. 2020;Macdonald et al. 2021;Xu et al. 2021;Capriello et al. 2021;Ravanfar et al. 2021;Kabir et al. 2021). Metal(oid)s pollution can be hidden, permanent and irreversible due to their basic behaviour, such as accumulation, persistence and low mobility in soils (McBride 2003;Mohammed et al. 2011;Barletta et al. 2019). As such, knowledge of the geochemistry of the near-surface environment is essential to understand the potential for ecological and human health risks, including endemic diseases. ...
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Volcanic regions are associated with increased environmental and human health risks due to elevated concentrations of potentially toxic elements (PTEs). Fogo Island, Cape Verde, experienced recent volcanic eruptions, which raised the questions around the potential for local soils to pose such risks. In order to better understand the relationships between local mineralogy and geochemistry, and environmental and probabilistic human health risks, we (i) present the distribution of selected PTEs based on 136 soil samples, (ii) determine major associations between minerals and geological units based on a principal component analysis, (iii) calculate the potential ecological risk index and potential ecological risk and (iv) model human health risks based Monte Carlo simulations. The soils overlaying the older units yield higher contents of secondary minerals, with relative enrichment is some PTEs. The soils covering more recent units are enriched with primary minerals and show elevated concentrations of Pb. The results show that (i) As, Pb, Cd and Hg pose considerable to very high ecological risks, (ii) metal(oid)s are unlikely to cause a non-carcinogenic health risk, although As may pose a cancer risk for children. This research also provides health and environmental authorities with a toll to manage such risks.
... The lack of consistency and standardization of sampling and analytical methods for detection of MNP pollution inhibits a global comparison of MNP deposition (Van Cauwenberghe et al. 2015). Geographical variations in MNP pollution are not only influenced by anthropogenic factors, but also by environmental causes such as oceanic currents, wind direction, and atmospheric deposition, driving the distribution of MNP particles on the planet (Barletta et al. 2019). To get an idea of regional differences in MNP exposure for humans, a comparison of the MNP load in filter feeders like mussels can be used as a surrogate. ...
Article
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Micro- and nanoplastics (MNPs) are recognized as emerging contaminants, especially in food, with unknown health significance. MNPs passing through the gastrointestinal tract have been brought in context with disruption of the gut microbiome. Several molecular mechanisms have been described to facilitate tissue uptake of MNPs, which then are involved in local inflammatory and immune responses. Furthermore, MNPs can act as potential transporters (“vectors”) of contaminants and as chemosensitizers for toxic substances (“Trojan Horse effect”). In this review, we summarize current multidisciplinary knowledge of ingested MNPs and their potential adverse health effects. We discuss new insights into analytical and molecular modeling tools to help us better understand the local deposition and uptake of MNPs that might drive carcinogenic signaling. We present bioethical insights to basically re-consider the “culture of consumerism.” Finally, we map out prominent research questions in accordance with the Sustainable Development Goals of the United Nations.
... Devido à intrusão de água salina nos rios e sua respectiva diluição pela água doce, as regiões estuarinas contribuem para o estabelecimento de gradientes ambientais, que por sua vez, auxiliam uma crescente diversificação de habitats e maior disponibilidade de nutrientes na água (BARLETTA et al., 2019;NUNES;CAMARGO, 2018). Um dos fatores que interferem diretamente no funcionamento do estuário e seu respectivo equilíbrio é a presença da urbanização em seu entorno (CHAPMAN; UNDERWOOD; BROWNE, 2018), que no que lhe concerne, modifica relação entre o solo e o rio, e consequentemente, provoca alterações na hidrodinâmica do estuário e nos serviços ecossistêmicos (WEINSTEIN, 2008;VAN NIERK et al., 2019). ...
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Estuaries are environments connecting land and oceans. Due to the mixture of water and other hydrodynamic factors, these regions have great potential for ecosystem services. However, due to the accentuated urban contribution, many of these regions suffer external pressures that interfere with their environmental quality. Thus, constant investigations and monitoring of these regions are essential for thinking about integrated management. Thus, the research aimed to list the main impacts and interferences that affect the quality of estuarine water of the Capibaribe River, located in Recife – Pernambuco, identifying the degree of its environmental effects, to support better development of the integrated management of this region. To this end, 12 visits were carried out to the estuary, from 2018 to 2020, with the aid of a motorized vessel to apply the Environmental Impact Assessment methodology, with the aid of 9 indicators for visualization and classification of environmental impacts present in the region. With the visits, it could be seen that the situation of the estuary is compromised mainly due to the large urban contribution, with the main problems being the construction of regular or non-regular projects on its banks, which has caused the native vegetation suppression, and also the release of effluents into the water, greatly interfering in the region’s ecosystem services. The identification of these problems is fundamental for the process of integrated coastal management and the elaboration of environmental monitoring networks, corroborating decision-making for the planning of hydrographic basins.
... Several studies reported that MPs and NPs are vectors for toxic chemicals transport, like, antibiotics, nutrients, heavy metals (i.e., cadmium, lead, zinc, copper, chromium, etc.), polychlorinated biphenyls (PCBs), polycyclic aromatic hydrocarbons (PAHs), persistent organic pollutants (POPs), dichlorodiphenyltrichloroethane (DDT), etc., in natural ecosystems (Ashton et al., 2010;Barletta et al., 2019;Yu et al., 2019Mao et al., 2020;Naqash et al., 2020). Chemical additives associated with plastics are equally toxic, as MPs and NPs can accumulate toxic chemicals due to high affinity of toxic chemicals for plastics compared with water and transfer to aquatic animals and humans. ...
Article
Microplastics (MPs) and nanoplastics (NPs) are key indicators of the plasticine era, widely spread across different ecosystems. MPs and NPs become global stressors due to their inherent physicochemical characteristics and potential impact on ecosystems and humans. MPs and NPs have been exposed to humans via various pathways, such as tap water, bottled water, seafood, beverages, milk, fish, salts, fruits, and vegetables. This paper highlights MPs and NPs pathways to the food chains and how these plastic particles can cause risks to human health. MPs have been evident in vivo and vitro and have been at health risks, such as respiratory, immune, reproductive, and digestive systems. The present work emphasizes how various MPs and NPs, and associated toxic chemicals, such as polycyclic aromatic hydrocarbons (PAHs) and polychlorinated biphenyls (PCBs), impact human health. Polystyrene (PS) and polyvinyl chloride (PVC) are common MPs and NPs, reported in human implants via ingestion, inhalation, and dermal exposure, which can cause carcinogenesis, according to Agency for Toxic Substances and Disease Registry (ATSDR) reports. Inhalation, ingestion, and dermal exposure-response cause genotoxicity, cell division and viability, cytotoxicity, oxidative stress induction, metabolism disruption, DNA damage, inflammation, and immunological responses in humans. Lastly, this review work concluded with current knowledge on potential risks to human health and knowledge gaps with recommendations for further investigation in this field.
... MP are defined as any synthetic solid particle or polymeric matrix, insoluble in water, with size ranging from 1 μm to 5 mm, with regular or irregular shape (Betts, 2008;Frias and Nash, 2019). MP have been found globally across a range of habitats, including in South America (Alfonso et al., 2020;Barletta et al., 2019;Pazos et al., 2018). They may be released to the environment either as primary particles in consumer products (Fendall and Sewell, 2009) or secondary particles resulting from the fragmentation of macroplastic debris (Stefani et al., 2014). ...
Article
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Microplastics (MP) are emerging contaminants with the capacity to bind and transport hydrophobic organic compounds of environmental concern, such as polybrominated diphenyl ethers (PBDEs). The aim of this study was to investigate the ingestion of nylon (polyamide) MP alone and when associated with PBDEs and their effects on Chironomus sancticaroli larvae survival and microbiome structure. Survival, PBDE uptake and microbial community composition were measured in fourth instar larvae exposed for 96 h to BDEs- 47, 99, 100 and 153 in the presence and absence of 1% w/w MP in sediment. Microbiome community structures were determined through high throughput sequencing of 16S small subunit ribosomal RNA gene (16S rRNA). Initial experiments showed that larvae ingested MP faster at 0.5% w/w MP, while depuration was more efficient at 1% w/w MP, although retention of MP was seen even after 168 h depuration. No mortality was observed as a result of PBDEs and MP exposure. MP had a negative effect on PBDE concentration within larvae (η² = 0.94) and a negative effect on sediment concentrations (η² = 0.48). In all samples, microbial communities were dominated by Alphaproteobacteria, Betaproteobacteria, Actinobacteria and Gammaproteobacteria. Bacterial alpha diversity was not significantly affected by PBDEs or MP exposure. However, the abundance of discrete bacterial taxa was more sensitive to MP (X² = 45.81, p = 0.02), and PBDE exposure. Our results highlight that C. sancticaroli showed no acute response to MPs and PBDEs, but that MPs influenced bacterial microbiome structure even after only short-term acute exposure.
... Water quality has an impact on aquatic organisms, industrial production, and domestic use. Water quality deterioration has significant ecological ramifications (Barletta et al. 2019;Brewer et al. 2018;Dauer and Weisberg 2000;Douglas Shields et al. 2013). To develop effective and long-term management strategies for estuarine water quality, in particular, we would like to reveal the underlying natural and anthropogenic controls on this variation occurred in the Yangtze Estuary, which is rarely studied but believed to be of significance. ...
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Water quality plays an important role in estuarine habitats and affects aquatic organisms. The focus of this study was to understand the temporal-spatial variation of water quality and reveal the natural and anthropogenic drivers by using multiple analysis approaches. Herein, during 2012–2018, six water quality constituents (pH, electrical conductivity (EC), dissolved oxygen (DO), ammonia nitrogen (NH3N), total nitrogen (TN), and total phosphorus (TP) were examined for eight sites in the Yangtze Estuary, and the hydro-sediment data, i.e., discharge (Q) and sediment transport rate (STR), was collected from the upstream hydrological station Datong. The cluster analysis (CA), principal component analysis (PCA)/factor analysis (FA), Canadian Council of Ministers of the Environment Water Quality Index (CCME-WQI), and the Mann–Kendall (MK) test were applied. The eight sampling sites were geographically grouped into cluster I, cluster II, and cluster III based on the characteristics of water quality changes, which are under the influence of the upstream runoff, the anthropogenic activities, and seawater. The results are as follows: (1) NH3N, TN, and DO were key constituents representing the water quality of cluster I and cluster III, and those were EC, TN, and DO for cluster II; (2) The monthly-average Q and STR of Datong were negatively correlated to water quality constituents with seasonal variation except for pH; (3) The impact of anthropogenic activities on water quality was especially reflected in cluster III which is close to the Huangpu River Estuary; upstream runoff was the natural driver of water quality changes for cluster I while that was seawater for cluster II. Seawater acts a key role in affecting the water quality of cluster II situated at the North Branch. Revealing the key drivers of water quality change in the Yangtze Estuary provides a reference for water quality management.
... There have been correlations drawn between seasons and/or weather, and microplastic abundance, and picking apart the two terms may be difficult. Research into seasonal differences in the tropical regions of South America is well-summarised by Barletta et al. (2019), with studies located mostly in estuarine regions of Brazil and Colombia. Less research has occurred at locations with temperate climates, where seasonal differences in weather may be less distinct. ...
Thesis
Microplastics are an emerging and environmentally problematic suite of contaminants. Their fate, transport and impacts are poorly understood. The so-called “missing plastic problem”, in which global surface ocean plastic aligns with only a single year’s estimate of inputs, may be partially solved by considering if microplastics are retained within estuaries, by way of an “estuarine filter”, similar to that which exists for suspended sediment and other contaminants. To investigate the fate of microplastics in estuaries, a series of field and laboratory studies were conducted, using Southampton Water, U.K., as a study site. These investigated environmental controls on microplastic abundance in estuarine waters; the intertidal trapping of microplastics in a salt marsh system; and the settling and resuspension of microplastics. The sea surface microlayer (SML) was sampled, to better understand this key interface between atmosphere and oceans, and the role it plays in the estuarine filter. Environmental controls were considered during a four-month water sampling campaign, which determined that within Southampton Water, the partially-mixed nature of the estuary meant that there were limited controls exerted by environmental variables such as weather conditions and river flow. The strong tidal currents in Southampton Water meant that abundances were highly variable with time and space. Intertidal trapping was investigated using high-resolution salt marsh creek sampling, which found a significant decrease in microplastic abundance when comparing abundances in flood tide samples to ebb tide samples, during both neaps and springs. Laboratory settling column and flume studies were utilised to investigate settling and resuspension. Limited settling was seen after an extended period, but flocculation of microfibres was not observed. During resuspension experiments, microplastic fibres were suspended at velocities similar to those that moved fine unconsolidated cohesive sediments. Nurdles were suspended at velocities that eroded sand of a smaller grain size than the nurdles themselves, but were also were observed to be buried by moving sediment. The findings within this thesis support the hypothesis of an estuarine filter for microplastics, indicating that salt marshes and other low-energy intertidal areas are significant sinks. Both burial and resuspension might occur depending on the tidal cycle, so that whether an estuary acts as a filter depends on the balance of these processes, driven by tidal asymmetry. However, results also suggest that the hydrodynamic regime of estuaries is a key control of microplastic abundance and distribution. Southampton Water’s partially-mixed, ebb-dominant system likely transports microplastics out of the estuary. There are significant global implications from this research, including to microplastic budgets and estimates of global ocean inputs, and to the potential risks posed to estuaries and intertidal wetlands.
... A series of experimental studies in recent years have investigated the leaching and adsorption capacity of MPs in terms of organic and inorganic contaminants such as pesticides (PAHs, PCBs, DDTs) and metals and their ecotoxicological implications to aquatic organisms (Bour et al., 2021;Mato et al., 2001;Rai et al., 2021). To date, several reviews have focused on the spatial-temporal distributions of MPs (Barletta et al., 2019;Yuan et al., 2019), the mechanisms in relation to the interactions between MPs and toxic contaminants such as heavy metals (HMs) (Binda et al., 2021) and microbial contaminants (Mammo et al., 2020;Wang et al., 2021b), as well as the implications of MPs toxicity on aquatic organisms (Ateia et al., 2022;Rai et al., 2022;Verla et al., 2019). However, little knowledge is currently available on the risk associated with the occurrence and movement of various MPs in freshwater systems. ...
Article
The presence of microplastics (MPs) has been recognized as a significant environmental threat due to adverse effects spanning from molecular level, organism health, ecosystem services to human health and well-being. MPs are complex environmental contaminants as they bind to a wide range of other contaminants. MPs associated contaminants include toxic chemical substances that are used as additives during the plastic manufacturing process and adsorbed contaminants that co-exist with MPs in aquatic environments. With the transfer between the water column and sediments, and the migration within aquatic systems, such contaminants associated MPs potentially pose high risk to aquatic systems. However, only limited research has been undertaken currently to link the environmental risk associated with MPs occurrence and movement behaviour in aquatic systems. Given the significant environmental risk and current knowledge gaps, this review focuses on the role played by the abundance of different MP species in water and sediment compartments as well as provides the context for assessing and quantifying the multiple risks associated with the occurrence and movement behaviour of different MP types. Based on the review of past literature, it is found that the physicochemical properties of MPs influence the release/sorption of other contaminants and current MPs transport modelling studies have primarily focused on virgin plastics rather than aged plastics. Additionally, risk assessment of contaminants-associated MPs needs significantly more research. This paper consolidates the current state-of-the art knowledge on the source to sink movement behaviour of MPs and methodologies for assessing the risk of different MP species. Moreover, knowledge gaps and emerging trends in the field are also identified for future research endeavours.
... Heavy metals, such as cobalt (Co), copper (Cu), and lead (Pb), are toxic and can accumulate in the human body and impact human health [1]. Therefore, heavy metals have been listed as priority control contaminants by the Chinese government. ...
Article
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Lanzhou is located in the northwest of China and is famous for its petrochemical and heavy industries of China. The city has suffered long-term pollution of heavy metals in recent years. Significant efforts, such as tax subsidies for new energy vehicles and treating solid waste, have been launched by the Lanzhou municipal government to address the pollution of heavy metals since 2010. What is the current status of heavy metal pollution in Lanzhou? In this study, the concentrations of 12 heavy metals (V, Cr, Mn, Co, Ni, Cu, Zn, As, Mo, Cd, Sb, and Pb) were tested from 20 sediment samples. Mn, Zn, V, and Cr are the predominant heavy metals, with mean concentrations of 534.65, 65.85, 56.29, and 36.05 mg/kg; Ni, Cu, Pb, Co, and As are in moderate amounts, with mean concentrations of 25.2, 21.5, 16.7, 9.87, and 4.86 mg/kg; Mo and Cd have the lowest mean concentrations of 0.54 and 0.15 mg/kg. A low ecological risk is confirmed by two indices, the Hakanson potential ecological risk index (RI) and the geoaccumulation index (Igeo). The RI index has lower Eir values (
... Such low DO can prolong hypoxia and affect major estuarine ecosystem-level processes, including fluxes and rates linked to carbon and nitrogen biogeochemical cycling. Therefore, maintaining the best possible conditions across the river basins, including coastal and offshore waters, is essential (Karydis and Kitsiou, 2013;Barletta et al., 2019) and crucial for ecosystem functioning and maintaining estuarine biodiversity (Ghosh et al., 2022). ...
Article
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The Mahanadi Estuarine System (MES), with a complex network of freshwater channels, rivers, and mangroves, is a leading seaport in State Odisha on the east coast of India, but subjected to intense human activity in recent years. Such anthropic impingements are known to impact sediment-dwelling biota adversely. However, information on the macrobenthic community of the MES is not well documented yet. Therefore, the primary objectives of this study (February 2013-March 2017) were to address knowledge gaps on the macrobenthic community structure vis-à-vis local environmental conditions and to evaluate the extent of anthropogenic disturbances on macrobenthos. The results from 264 benthic grab samples (van Veen, 0.04 m2; 2 replicates × 12 GPS fixed locations × 3 seasons) revealed 73 taxa representing 64 genera and 48 families of macrobenthic fauna. The polychaetes (81.41%) and crustaceans (15.42%) were significant faunal groups that contributed mainly to the benthic population and diversity. Multivariate approaches using benthic community attributes and biotic indices (AMBI and M-AMBI) as proxy measures of environmental disturbances proved effective for appraisal. The correlations between the environmental parameters (temperature, pH, salinity) and community estimates were statistically significant. Hierarchical clustering analysis disclosed three major groups (Global R 0.70; p < 0.002) influenced by tolerant/opportunist species. The lower abundance, richness, diversity, and dominance of opportunistic species mark the signs of environmental stress. The community health status remained unbalanced, as indicated by AMBI scoring. M-AMBI analysis contributed best in differentiating areas exposed to diverse impacts and indicated polluted community health status with moderate ecological quality. Our results reiterate the effective use of macrobenthos as bioindicators for ecological status and monitoring. The findings could be utilized for future monitoring assessments, translated into valuable information, and designed into well-defined sustainable management strategies for the MES.
... Researches have reported that heavy metals are carcinogenic, teratogenic, sensitizing, and could induce behavioral and neurological changes (Yang et al., 2015;Rodrigues et al., 2022). Waste and wastewater from agriculture, metallurgy and mining are the main sources of heavy metals in the environment, and thus MPs have many opportunities to combine with heavy metals in the water (Barletta et al., 2019). The analysis of polyethylene (PE) plastic pellet samples collected from different beaches in southwest England by Ashton et al. revealed that a variety of trace metal elements (Cr, Co, Ni, Cu, Zn, Cd and Pb) were adsorbed on the pellets (Ashton et al., 2010). ...
Article
With the reported ability of microplastics (MPs) to act as “Trojan horses” carrying other environmental contaminants, the focus of researches has shifted from their ubiquitous occurrence to interactive toxicity. In this review, we provided the latest knowledge on the processes and mechanisms of interaction between MPs and co-contaminants (heavy metals, persistent organic pollutants, pathogens, nanomaterials and other contaminants) and discussed the influencing factors (environmental conditions and characteristics of polymer and contaminants) that affect the adsorption/desorption process. In addition, the bio-toxicological outcomes of mixtures are elaborated based on the damaging effects on the intestinal barrier. Our review showed that the interaction processes and toxicological outcomes of mixture are complex and variable, and the intestinal barrier should receive more attention as the first line of defensing against MPs and environmental contaminants invasion. Moreover, we pointed out several knowledge gaps in this new research area and suggested directions for future studies in order to understand the multiple factors involved, such as epidemiological assessment, nanoplastics, mechanism for toxic alteration and the fate of mixtures after desorption.
... Estuaries are highly diverse and productive environments, providing key ecosystem services such as nutrient cycling, water filtration and acting as nursery grounds for fish (Morrisey et al., 1997), yet they are often threatened by anthropogenic activity, resulting in high levels of disturbance from multiple stressors (Dafforn et al., 2012). As the interface between terrestrial and marine ecosystems, urbanised estuarine sediments are often sinks for a wide range of contaminants (Barletta et al., 2019), most commonly metal(loid)s, organic chemical contaminants and nutrients (Jiang et al., 2001). Metal contamination is a global problem in estuaries, often due to the legacy impacts of historical industrialisation (Förster & Wittmann, 1979). ...
Article
Estuaries are critical habitats subject to a range of stressors requiring effective management. Microbes are gaining recognition as effective environmental indicators, however, the response of host associated communities to stressors remains poorly understood. We examined microbial communities from seawater, sediments and the estuarine fish Pelates sexlineatus, in Australia's largest urbanised estuary, and hypothesised that anthropogenic contamination would be reflected in the microbiology of these sample types. The human faecal markers Lachno3 and HF183 were not detected, indicating negligible influence of sewage, but a gradient in copy numbers of the class 1 integron (intI-1), which is often used as a marker for anthropogenic contamination, was observed in sediments and positively correlated with metal concentrations. While seawater communities were not strongly driven by metal contamination, shifts in the diversity and composition of the fish gut microbiome were observed, with statistical links to levels of metal contamination (F2, 21 = 1.536, p < 0.01). Within the fish gut microbiome, we further report increased relative abundance of amplicon sequence variants (ASVs; single inferred DNA sequences obtained in sequencing) identified as metal resistant and potentially pathogenic genera, as well as those that may have roles in inflammation. These results demonstrate that microbial communities from distinct habitats within estuarine systems have unique response to stressors, and alterations of the fish gut microbiome may have implications for the adaptation of estuarine fish to legacy metal contamination.
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Poluentes orgânicos foram identificados em diferentes matrizes ambientais: água, sedimento e organismos de nível trófico secundário. A identificação ocorreu em nove sites ao longo de três zonas, durante os meses de dezembro de 2017 e junho de 2018 em dois períodos amostrais, respectivamente estiagem e chuvoso. A área de estudo foi o Estuário do Rio Mamanguape, localizado no bioma Floresta Atlântica no estado da Paraíba-Brasil, a qual faz parte de uma Área de Preservação Permanente. Foram identificados 62 poluentes nas matrizes ambientais durante os dois períodos amostrais. As substâncias identificadas são utilizadas para diversos fins, como: Agentes de produtos industriais 53%, Fármacos 24%, Agrotóxicos 16% e Produtos de cuidado pessoal 6%. Durante os dois períodos houve diferença significativa da ocorrência dos poluentes orgânicos, com α< 0,05 para a água e o sedimento, sendo o período de estiagem o com maior diversidade de poluentes. No entanto, o mesmo comportamento não foi encontrado para os organismos de nível trófico secundário. Palavras-chave: Nível trófico. Poluentes emergentes. Cromatografia gasosa. Sedimento. Água.
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Indoor dust is an important medium to evaluate human exposure to emerging organic contaminants. The principal aim of this study was to determine overall status of organic micropollutants (OMPs) of indoor dust in Kuala Lumpur, Malaysia and assess their corresponding health risks. One hundred thirty-three OMPs, ascribed to 13 chemical groups, were screened by Automated Identification and Quantification System with a GC-MS database. The concentrations of OMPs ranged between 460 and 4000 μg/g, with the median concentration of 719 μg/g. The dominant chemical groups were ascribed to n-alkanes (median: 274 μg/g), plasticizers (151 μg/g), sterols (120 μg/g), and pesticides (42.6 μg/g). Cholestrol was the most abundant compound (median: 115 μg/g). Different sources and usage patterns of OMPs in various houses were expected. Toxicity values of OMPs were obtained from existing databases or predicted by quantitative structure-activity relationship models. Cumulative hazard quotients for OMPs through ingestion route were lower than one for all the dust samples, demonstrating that there was no remarkable non-cancer risk. The cancer risks of these OMPs were greater than 10⁻⁴, with cholestrol dominating 99.1% of the carcinogenic risks, which suggested that there was a significant cancer risk. This study might offer a benchmark to ensure the safety of chemical usages in future in Malaysia.
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Sewage treatment plants (STPs) as a carrier of microplastics (MPs) have received considerable attention worldwide recently. In India, the majority of studies on MPs have been conducted in sediments, riverine, and marine systems, while knowledge on MPs occurrence in STPs is scarce. Henceforth, this work evaluated the presence of MPs in sewage and sludge in a hybrid growth, secondary treatment-based STP system. Optical microscopy, scanning electron microscopy (SEM), and Fourier-transform infrared (FTIR) spectroscopy methods were used to examine the abundance of MPs in raw sewage, effluent from different treatment units of the STP, and sludge samples. A total number of MPs of 201 ± 19 (2021) and 197 ± 22 (2022) were detected in the studied STP system. Results showed that MPs ranged between 64.3 ± 4.89–47.66 ± 4.71 n/L (sewage) and 1.14 ± 0.30–1.38 ± 0.65 n/g (sludge) with the overall removal efficacy of the studied STP estimated to be around 80%. Fragments and fibers were predominant among all shapes and particles mostly belonged to sizes <50 μm and <50 μm–250 μm in sewage and sludge, respectively. In total, seven polymers were identified of which low-density polyethylene (LDPE) constituted the highest proportion in sewage (26%–31%) and polyvinyl chloride (PVC) contributed the highest in the sludge (22%–27%). Moreover, MPs control measures have been discussed based on the findings of this study to restrict MPs re-entry into the environment via treated effluent and sludge.
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Cu2O is an attractive material for the architectural design of integrated nanomaterials in photocatalysis. Herein, a contrastive study was carried out to explore the influence of morphology/exposed Cu2O facets on the template growth process and the difference of fabricated composites in photocatalysis performance. A series of Cu2[email protected] with core-shell structure was developed via a self-confinement strategy, in which Cu2O nanocrystals with various shapes (cube, truncated octahedron and octahedron) act as self-confinement template to grow Cu-based metal-organic frameworks (HKUST-1) shell. It was revealed that the growth of HKUST-1 on Cu2O crystal depended on the original Cu2O crystal. The exposure of (111) facet in Cu2O was more favorable to the growth of HKUST-1 than (100) crystal plane. Optical and photoelectrochemical characterizations revealed that the cubic Cu2[email protected] exhibited the outstanding light response and most efficient interfacial charge transfer and separation among three types of composites. As a result, the degradation rates of tetracycline hydrochloride (TC-HCl) by cubic Cu2[email protected] under the visible light irradiation was 95.35% within 60 minutes, which was much higher than truncated octahedral Cu2[email protected] (78.81%) and octahedral Cu2[email protected] (66.58%). Mechanism explorations including radical capture experiments, electron paramagnetic resonance and band structure analysis showed that type II heterojunction was formed in cubic Cu2[email protected] and truncated octahedral Cu2[email protected], which was conducive to the separation and transfer of photo-generated carriers. However, type I heterojunction existed in octahedral Cu2[email protected] lead to the recombination of photocarriers. These findings revealed the interface-dependent photocatalytic performance in Cu2[email protected] and provided useful guidance for controllable construction of photocatalysts with heterojunction structure.
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Serious environmental pollution of heavy metals has attracted people's attention in recent years and halophiles seem to be potential bioremediation in the controlling of heavy metals contamination. In this study, the adaptive mechanism of halophilic Brachybacterium muris (B. muris) in response to salt stress and its mitigation of copper (Cu) toxicity in hydroponic plants were investigated. The cell morphology was observed using transmission electron microscopy. The cell membrane composition and fluidity were examined by the combination of gas chromatography, gas chromatography-mass spectrometry, ultra-high performance liquid chromatography-mass spectrometry, and fluorescence spectrophotometry. Moreover, the metabolic pathways of B. muris in response to salt stress were analyzed using the prokaryotic transcriptomics approach. A hydroponic co-culture model was further conducted to explore the effects of B. muris on wheat seedlings subjected to Cu toxicity. It was found that B. muris can respond to high osmotic pressure by improving the cell membrane fluidity, altering the cell morphology and cell membrane compositions. The proportion of unsaturated fatty acids, phosphatidylethanolamine, and phosphatidylinositol in B. muris cell membranes increased significantly, while zymosterol, fecosterol, and ergosterol contents decreased under a high salinity situation. Further transcriptomic analysis showed that genes encoding L-glutamate synthase, glutamate ABC transporter ATP-binding protein, and sodium cotransporter were up-regulated, indicating that both the synthesis and transport of glutamate were significantly enhanced under high osmotic pressure. Additionally, B. muris alleviated the inhibitory effect of Cu²⁺ on wheat seedlings' growth, causing a 30.14% decrease in H2O2 content and a significant increase of 83.86% and 45.96% in POD activity and GSH content in wheat roots, respectively. The findings of this study suggested that the salt-tolerant B. muris may serve as a promising strategy for improving the bioremediation of metal-contaminated saline water and soils.
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One of the environmental challenges that is currently negatively affecting the ecosystem is the continuous discharge of untreated industrial waste into both water sources and soils. For this reason, one of the objectives of this qualitative study of exploratory-descriptive scope was the review of scientific articles in different databases—Scopus, Web of Science, and Science Direct—published from 2010 to 2021 on the use of fruit peels as a sustainable waste in the removal of heavy metals present in industrial wastewater. For the selection of articles, the authors used the PRISMA guide as a basis, with which 210 publications were found and 93 were compiled. Considering the reported work, a content analysis was carried out using NVivo 12 Plus and VOSviewer 1.6.17 software. The results show that the fruits mentioned in these publications are lemon, banana, mango, tree tomato, pineapple, passion fruit, orange, coconut, avocado, apple, lulo, and tangerine. However, no studies were found with lulo and tree tomato peels. On the other hand, the heavy metals removed with the selected fruit peels were Pb+2, Cr+3, Cr+6, Ni+2, Cd+2, As+5, Cu+2, and Zn+2.
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Tropical estuaries are productive dynamic ecosystems where water quality is mediated by physicochemical and biological processes and by fluvial and anthropogenic discharges. The objective of the study was to determine the influence of environmental variables on the spatiotemporal dynamics of water quality in Buenaventura Bay, which is a highly impacted estuary. Sampling was carried out during the dry and rainy season, at three depths, in four stations that represent the environmental gradient of the bay. Temperature, total dissolved solids, salinity, dissolved oxygen, and pH were determined for each sample. In addition, alkalinity, phosphates, nitrites, and nitrates as indicators of water quality were also measured. The estuary was classified as meso- and polyhaline, with appropriate oxygen and pH conditions and spatiotemporal gradients of temperature and solids mediated by river discharges. Significant variations were found in the physicochemical variables by season, with maximum salinity, pH, and solids in the dry season and oxygen and temperature in the rainy season. Likewise, most of these environmental variables were higher in the outer zone of the estuary and lower in the inner stations. Alkalinity and nitrite values were within the permitted ranges, while phosphates and nitrates indicated low water quality. There was a significant direct influence of temperature and oxygen on alkalinity and nitrites. However, for phosphates, no significant influence of environmental variables was found, suggesting a greater influence by fluvial and anthropogenic discharges, which produce a decrease in the environmental quality of the estuary.
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Marine suspended particulate matter (SPM) plays a pivotal role in the marine biogeochemical cycling of trace elements. This study investigates metal distributions and copper (Cu) and zinc (Zn) stable isotope ratios in different size fractions of SPM from two sampling stations on the inner continental shelf of northern Bay of Biscay (NE Atlantic), a zone highly influenced by the macrotidal Loire estuary, the outlet of a major European river. The objective of this study is to test stable isotopes as tools to infer the origins of particles and their formation processes, and to infer relevant Cu and Zn biogenic pools involved in marine trophic transfers of these metals. SPM samples were nearly quantitatively mineralized (i.e., without HF) to determine metals and Cu and Zn isotopes in their more labile and reactive phases. Their δ⁶⁵CuSRM-976 values ranged from −0.45 to +0.51‰, with higher Cu concentrations accompanying particle size decreasing. The δ⁶⁶ZnJMC-Lyon values in SPM sub-fractions varied from +0.14 to +0.76‰, and were uncorrelated to both Zn concentrations and particle size. Compared to larger size fractions, increased Al and Fe levels (proxies for terrigenous materials) and enrichments in lighter Cu and Zn isotopes observed in the smaller size SPM sub-fractions suggest that a major proportion of SPM Cu and Zn is associated with geogenic particles. Conversely, the relative enrichment of heavy isotopes in coarser particles is attributable to an increase of Cu and Zn metabolically incorporated into biogenic organic particles (e.g., plankton), and by surface adsorption onto organic detrital particles. The higher δ-values attributed to biogenic particles likely represents the isotope composition of the local marine organic matter available to primary consumers like filter-feeders (oysters). Thus, this study shows that targeting particles of specific size classes allows to identify relative dominances of biogenic and geogenic carrier phases. Identifying these pools and their isotopic composition may help track Cu and Zn transfers through marine food-web metal in future studies.
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Rivers and estuaries are a key transport pathway for microplastics to enter the world's oceans. Despite this, knowledge of the fate of plastic debris in estuaries is limited. Our study assesses the current state of knowledge on the distribution of microplastic debris in estuaries and their intertidal habitats. The literature is reviewed, and an estuarine plastics conceptual model is presented. The conceptual model is populated with data to show the globally averaged standing stocks of microplastic (<5 mm) debris in estuarine waters and sediments. Estuarine plastic debris studies have previously focused on subtidal sediment and surface waters more than intertidal habitats. Estimated mean microplastic abundance is found to be greater (H = 53.136, P = 0.000175) per volume of sediment than per volume of water, although there are large standard deviations within habitats and some caveats regarding variation in methods and limited data in published studies. We found that the most commonly recovered microplastics align with the most commonly used polymers, and that the rates of microplastic transfer between estuarine compartments remain poorly understood. This study informs global plastic transport models by demonstrating the ability of estuaries to trap large quantities of microplastic debris, but substantial differences in the methodologies between estuarine microplastic studies limit the value of global assessments of estuarine microplastics. The main recommendations from this study focus on improving data availability and standardisation to better enable study comparisons and to improve our ability to examine global trends.
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Estuarine saltmarshes from South America are exposed to several anthropogenic impacts due to diverse human activities that occur in both Atlantic/Pacific coastal environments. Primarily, chemical and petrochemical industries negatively impact saltmarshes generating inputs/deposition of non-essential trace elements (NTEs) and polycyclic aromatic hydrocarbons (PAHs) in sediments. The native cordgrass Spartina densiflora inhabits a wide range of environments, from non-impacted to highly impacted areas. It is important to know its performance towards pollution in different environmental settings in South America. The content of Cd, Hg, Pb, and PAHs was determined in the roots and leaves of S. densiflora, bulk sediments (Bs), and rhizosediments (Rs) of estuaries from Argentina, Brazil, and Chile. Differences in NTEs and PAHs levels were observed between Bs, Rs, and Spartina tissues from different saltmarsh areas. Differences in Rs/Bs (RHICF; rhizosediments concentration factors), roots/Bs (RCF; roots concentration factors) and leaves/roots (TF; translocation factors) factors were also found. In terms of NTEs, S. densiflora showed a high capability to increase levels in their Rs (RHICF>1) and bioconcentrate Cd in roots (RCF > 1), while no general translocation (TF < 1) was observed. Conversely, in cordgrass tissues, Bs and Rs, PAHs contents showed RCF and TF > 1, which was in line with lower levels in Rs related to Bs (RHICF<1) in most sites. These findings showed the S. densiflora capacity to retain, remove and/or translocate priority contaminants depending on intrinsic chemical characteristics and the level of contamination. The present study enables future considerations regarding the biomonitoring and phytoremediation/stabilization capabilities of Spartina in coastal environments.
Chapter
Globally, the problem of microplastics (MPs) pose to water resources is current concern to scientists. Sources of MPs to water resources include wastewater, atmospheric deposition, surface runoff and leaching. Many marine animals suffer from ingesting high amounts of MPs accumulating in the gut and cause obstruction and inflammation in their organs. Humans are equally exposed from the use of surface water and drinking water or ground water. In view of these problems and in a bid to mitigate potential risks from the release of MPs to receiving waters, stringent water quality requirements for effluents are required and scientists are now developing methods or techniques to remove MPs from water resources. We reviewed techniques developed or modified for MPs removal in water and wastewater such as Dynamic Membranes Technology (DM), membrane bioreactors (MBR), reverse osmosis (RO), dissolved air flotation (DAF), rapid sand filtration (RSF), disc filter (DF), inorganic–organic hybrid silica gels, metal based-coagulation and electrocoagulation. The principles of these techniques were discussed as well as the advantages and disadvantages. Conclusions were drawn and future areas of research were recommended.
Chapter
Aquatic ecosystems are hotspots for water contamination, which results from various anthropogenic activities such as industrialization, agricultural activities and urbanization. The diverse use of various chemicals in pesticides, detergents and inorganic salts in various industries drain as effluents and find their way to various water bodies. The aquatic ecosystem has an emerging threat caused by microplastic as a result of dumping plastic into water bodies. Thus, resulting in degradation of the quality of aquatic sediments, which is assessed by the enrichment factor. The effect of pollution on sediments can be evaluated by “degree of pollution.” Aquatic sediments are the primary source of essential nutrition for the ecosystem. Potential contamination of sediments with high concentrations of heavy metals and microplastics affects all forms of aquatic organisms, most particularly Phyto and Zooplanktons. Eutrophication, oil spills and aquaculture activities are other factors that affect the aquatic ecosystem.
Article
Globally, the ability of estuaries to sustain functionality and productivity is deteriorating rapidly under ever-increasing anthropogenic pressures. We present a systematic approach to identify, characterise and rank global change pressures affecting estuaries. Six main pressure categories are reviewed: freshwater flow modification; pollution; exploitation of fish and invertebrates; land-use and development; manipulation of inlets; and biological invasions (plants and fish). Patterns in pressure effects are evaluated across biogeographic regions and estuary types. Activities contributing to these pressures are identified to prioritise management interventions and assessments of the trajectories of change and data availability are estimated, with associated confidence ratings on these. Approximately 15% of national estuarine area is under severe flow modification pressure. Land-use and development result in severe pressures on 40% of the area. Approximately 15% of inlets are artificially manipulated, which affects 60% of estuarine area. Pollution places 34% of the area under severe pressure and 78% of the area is severely impacted by overfishing. Invasive terrestrial vegetation has infested a third of South African estuaries, and aquatic invasive plant species occur in at least 8% of estuaries. Alien or extralimital (translocated) fish cause severe pressure in 35% of the estuaries. Management responses to mitigate these impacts are recommended for systems under severe pressure and future research directions are identified.
Article
Objectives : Recently, microplastics (MPs) is observed at surface water in worldwide because of massive use of plastics. Since MPs have a large specific surface area, they could provide adsorption sites to water contaminants such as Levofloxacin (LVF). LVF is one of widely used antibiotics and is detected in surface water. Therefore, the aim of this study is to evaluate adsorption trend of LVF on polypropylene (PP) and polyethylene(PE) microplastics in aqueous solution.Methods : For kinetic adsorption experiment, 0.02 g of PP and PE MPs were placed in glass vials and mixed with LVF solution (10 mg/L) for 1-48 hours. And the experimental data was fitted to pseudo-first order and pseudo-second order. For isotherm adsorption experiment, initial LVF concentrations were varied from 1 to 25 mg/L for 24 hours and the results were applied to Langmuir and Freundlich models. The Thermodynamic adsorption experiment was conducted in the temperature range of 298-318 K. Each cations (Na+, Ca2+, Cu2+, Cr3+, Pb3+) and LVF solution were both reacted with the MPs to determine effect of LVF adsorption when cations were coexistence.Results and Discussion : Based on the FT-IR analysis, it was confirmed that the prepared PP and PE MPs were consisted of the respective single polymer. The kinetic experiment results showed that LVF adsorption on PP and PE MPs reached equilibrium at 24 hours with adsorption capacities of PP (0.748 mg/g) and PE (0.801 mg/g) MPs, respectively. Kinetic data of PP MPs was well fitted to the pseudo-first order (R2=0.986) model, while the data of PE MPs was described well by the pseudo-second order (R2=0.992) model. The results of the isotherm experiments were explained well by the Freundlich model (R2>0.97), indicating that multilayer adsorption occurred in both MPs. The thermodynamic experiments showed that LVF adsorptions on each MPs were exothermic reaction and physical adsorption process. Cations can inhibit the adsorption of LVF to the MPs.Conclusion : This study shows that LVF could be adsorbed to PP and PE MPs in aqueous solution and its adsorption capacity can be changed according to the various factors: characteristics of polymer, reaction time, initial concentration of LVF, temperature, and coexistence of cations.
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Although nanoplastic (NP) pollution across aquatic environments has elicited widespread attention in recent years, its associated risks remain unclear. Using intertidal Monodonta labio as the test organism, RNA-Seq was performed to analyze the expression levels of genes under acute exposure to different concentrations of NPs in this study. A large quantity of differentially expressed genes (DEGs) were detected in response to three concentrations (0.1, 1, and 10 mg/L) of NPs. The expression levels of genes related to immunity, oxidative stress, and apoptosis were altered after NP exposure, and most of them were suppressed. These findings establish the foundation for future research on the biological effects of NP ingestion among aquatic organisms and their potential effects on humans via the consumption of these marine resources. However, further research on DEGs is needed to gain a better understanding of the molecular mechanisms behind their responses to NP toxicity in aquatic organisms.
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Phytoplankton are key marine components in global primary productivity and ocean biogeochemistry. However, anthropogenic activities impact phytoplankton through toxic metal dispersion—threatening the food web with increased metal bioaccumulation. This study assessed the phytoplankton trace metal concentrations, distribution, and relationship with community structure. Environmental parameters (temperature, salinity, pH, dissolved oxygen, biological oxygen demand, suspended solids, chlorophyll-a, ammonium, nitrate, nitrite, phosphate, silicate, total phosphorus) and phytoplankton were collected in southern Taiwan; from five transects (estuaries; T1–T5), composed of estuarine (Es) and offshore (Os) sites. This study respectively used size and density fractionation to accurately measure phytoplankton trace metals. Results showed that anthropogenically-impacted rivers and marine outfall discharges drive community structure and phytoplankton trace metal distribution. Among sites, T3–T5Es differed in its environmental characteristics. Significant differences on environmental characteristics and trace metals in phytoplankton were found between transects—indicating higher anthropogenic impacts in T3 (Dianbao-Houjin estuary) and T4 (Kaohsiung Harbor estuary). Phytoplankton trace metals follows an order of Fe >> Mn > Cr > Cu > Ni > Co > As > Pb > Hg. Metals in estuarine phytoplankton were higher compared offshore, but not significantly different (p > 0.05), highlighting the role of marine outfalls in offshore pollutant diffusion. Phytoplankton metal distribution showed a distinct spatial gradient between agriculture- and industry-associated areas. Significantly high Cr bioaccumulation factor (BCF > 100) were also found in transects T2 and T4. Overall, this study presents an accurate trace metal data and BCF in phytoplankton of southern Taiwan. Further, insights on the potential relationship between phytoplankton community structure and trace metal concentrations are presented—with nutrients mainly impacting phytoplankton community, initiating a ripple effect which likely favored blooming of metal-tolerant species (high dominance)—increasing the trace metal bioaccumulation.
Chapter
Waste generated from plastics is widely distributed across the world, impacting both land and aquatic ecosystems, and is thus becoming a serious environmental concern. Over the past few decades, there has been tremendous concern related to the abundance and effects of plastic wastes in freshwater ecosystems, globally. The abundance of microplastics in fresh water also poses direct threat to urban water quality. Since the 1950s, approximately 1 billion tons of plastic have been disposed of and currently about 280 million tons of plastic are generated every year, of which more than 10% eventually enters the aquatic ecosystems. The plastic has become a topic of focus for the scientific community because of its ability to persist in the environment for a longer period, which helps it to distribute widely from their source and accumulate in the aquatic ecosystems. Synthetic polymers such as fragments, fiber, pellet, film, bead, or foam ranging from 100 μm to 5 mm in size are called microplastics (MPs). The microplastics are formed via mechanical/biological fragmentation of larger plastic debris. The main cause of MPs in the global waters can be attributed to the mismanagement of wastes generated by solid and liquid products. Consequently, microplastics become ubiquitously available in aquatic ecosystems, and inflict physical damage and compromise feeding behavior of aquatic biota. Thus, it has become highly desirable to comprehend the techniques that are largely used for the quantitative and qualitative assessment of these polymeric contaminants in aquatic environments. This chapter aims to provide a thorough and systematic compilation of various sampling and related analytical techniques for the assessment of microplastics in various water systems.
Chapter
Microplastics (MPs) have been detected in diverse aquatic environments, including oceans, seas, lakes, rivers, beaches, coastlines, and even in mangroves. A recent study has brought to light that almost 22% of the countries have carried out studies on MPs. From these it is evident that MPs have been observed in almost 44 countries globally. However it cannot be taken for granted that the remaining countries are pristine to MPs. More studies on MPs need to be carried out across all countries by employing uniform protocols right from collection to analyses and units of expression. The microplastics may be accumulated in all environments across different countries of the world. However, the quantum of MPs present globally remains under estimated since there is lacuna of information in many parts of the world. All countries in unison should minimize plastic discharges and find alternatives to reduce MP accumulation.
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Anthropic processes degrade quality of estuarine environments, resulting in a worrying form of water pollution. The objective of the study was to describe and discuss interannual and seasonal changes of water quality based on indicators monitored in Goiana River estuary, as well as identifying the main drivers of such changes. We considered three estuarine areas or habitats (upper estuary, middle estuary and lower estuary), and two seasons (dry and rainy) for anchoring sample design. The information collected for surface and bottom water include water temperature (°C), salinity, dissolved oxygen (mg L−1), saturation (%) and Secchi depth (cm) (n = 864). The monthly total rainfall (mm) was compiled from public database. Multivariate analyses highlight inter dependency among these parameters. Water quality was reduced in dry periods (including episodes of hypoxia), but generally increased toward the mouth of estuary. Rainfall is the most important factor in the renewal and maintenance waters of small tropical estuaries. Regions most sensitive to climate change where water resources are depleted and/or compromised should pay even more attention to upcoming changes in rainfall (seasonal) and climatic patterns in addition to better water management practices.
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Mercury (Hg) concentrations and stable isotopes along with other trace metals were examined in environmental samples from Ecuador and Peru's shared Puyango-Tumbes River in order to determine the extent to which artisanal- and small-scale gold mining (ASGM) in Portovelo-Zaruma, Ecuador contributes to Hg pollution in the downstream aquatic ecosystem. Prior studies investigated the relationship between ASGM activities and downstream Hg pollution relying primarily on Hg concentration data. In this study, Hg isotopes revealed an isotopically heavy Hg signature with negligible mass independent fractionation (MIF) in downstream sediments, which was consistent with the signature observed in the ASGM source endmember. This signature was traced as far as ∼120 km downstream of Portovelo-Zaruma, demonstrating that Hg stable isotopes can be used as a tool to fingerprint and trace sources of Hg over vast distances in freshwater environments. The success of Hg isotopes as a source tracer in fresh waters is largely due to the particle-reactive nature of Hg. Furthermore, the magnitude and extent of downstream Hg, lead, copper and zinc contamination coupled with the Hg isotopes suggest that it is unlikely that the smaller artisanal-scale activities, which do not use cyanidation, are responsible for the pollution. More likely it is the scale of ores processed and the cyanide leaching, which can release other metals and enhance Hg transport, used during small-scale gold mining that is responsible. Thus, although artisanal- and small-scale gold mining occur in tandem in Portovelo-Zaruma, a distinction should be made between these two activities.
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A presença de elementos não essenciais nas águas superficiais do rio Amazonas é uma preocupação global, o objetivo da pesquisa foi estudar a distribuição dos elementos As, Al, Mn, e Pb na água do estuário do rio Amazonas. As amostras foram coletadas em três regiões distintas: Canal Norte (AP), Canal Sul (PA) e rio Pará (PA) em três profundidades, com um total de 84 amostras. A espectrometria de emissão atômica com plasma indutivamente acoplado (ICPAES) foi utilizada para avaliar os teores de Al, Mn e Pb e a espectrofotometria de absorção atômica com geração de hidretos (HGAAS) foi usada para a análise do As. O As variou de <0,35 a 50,60 μg/L, o Al de <1,88 a 3347,70 μg/L, o Mn de 0,13 a 403,39 μg/L e Pb de <0,18 a 57,78 μg/L. Em média As (canal Sul), Al (todas as regiões), Mn (canal Norte e Sul) e Pb (canal Norte e Sul) se encontraram em valores acima do permitido pela legislação brasileira. Os elementos podem ter origem antrópica originária de atividade de mineração e industrial e origem natural proveniente de decomposição de rochas ígneas da bacia de drenagem do rio Amazonas que disponibilizam o elemento na forma ligada ao material particulado em suspensão.
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Waters entering the small estuaries of the Brazilian north-east originate from drainage basins that cross semi-arid and tropical rainforest areas at various levels of use and conservation. Such rivers are often under heavy demand for water supply and other services, such as effluent dilution. The present study examines four consecutive years (2006–2009) of water quality-monitoring data divided by season (rainy and dry) just before the Goiana River enters its estuary. The environmental variables are largely controlled by rainfall patterns. The water temperatures are consistently above 25 °C, which impairs dissolved oxygen levels (3.1 to 6.7 mg L⁻¹) and may suggest eutrophication. By contrast, biochemical oxygen demand, percentage O2 saturation and total phosphorous (which are eutrophication indicators) do not show non-compliant levels, according to local legislation. Although the monitoring stations surround a municipal centre, the estuary is downstream from this area, the main uses of which are artisanal fisheries, nature conservation, leisure and aquaculture. Therefore, continuous monitoring and long-term analysis of the resulting water quality are important.
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Plastic production has increased exponentially since the early 1950s and reached 322 million tonnes in 2015, this figure does not include synthetic fibres which accounted for an additional 61 million tonnes in 2015. It is expected that production of plastics will continue to increase in the foreseeable future and production levels are likely to double by 2025. Inadequate management of plastic waste has led to increased contamination of freshwater, estuarine and marine environments. It has been estimated that in 2010 between 4.8 million to 12.7 million tonnes of plastic waste entered the oceans. Abandoned, lost or otherwise discarded fishing gears (ALDFG) are considered the main source of plastic waste by the fisheries and aquaculture sectors, but their relative contribution is not well known at regional and global levels. Microplastics are usually defined as plastic items which measure less than 5 mm in their longest dimension, this definition includes also nanoplastics which are particles less than 100 nanometres (nm) in their longest dimension. Plastic items may be manufactured within this size range (primary micro- and nanoplastics) or result from the degradation and fragmentation of larger plastic items (secondary micro- and nanoplastics). Microplastics may enter aquatic environments through different pathways and they have been reported in all environmental matrices (beaches, sediments, surface waters and water column). Ingestion of microplastics by aquatic organisms, including species of commercial importance for fisheries and aquaculture, has been documented in laboratory and field studies. In certain field studies it has been possible to source ingested microplastics to fisheries and aquaculture activities. Microplastics contain a mixture of chemicals added during manufacture, the so-called additives, and efficiently sorb (adsorb or absorb) persistent, bioaccumulative and toxic contaminants (PBTs) from the environment. The ingestion of microplastics by aquatic organisms and the accumulation of PBTs have been central to the perceived hazard and risk of microplastics in the marine environment. Adverse effects of microplastics ingestion have only been observed in aquatic organisms under laboratory conditions, usually at very high exposure concentrations that exceed present environmental concentrations by several orders of magnitude. In wild aquatic organisms microplastics have only been observed within the gastrointestinal tract, usually in small numbers, and at present there is no evidence that microplastics ingestion has negative effects on populations of wild and farmed aquatic organisms. In humans the risk of microplastic ingestion is reduced by the removal of the gastrointestinal tract in most species of seafood consumed. However, most species of bivalves and several species of small fish are consumed whole, which may lead to microplastic exposure. A worst case estimate of exposure to microplastics after consumption of a portion of mussels (225 g) would lead to ingestion of 7 micrograms (µg) of plastic, which would have a negligible effect (less than 0.1 percent of total dietary intake) on chemical exposure to certain PBTs and plastic additives.
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The impacts of the SAMARCO iron tailing spill along more than 650 km, between the dam and the plume of the Doce River in the Atlantic, were assessed by the determination of toxic metals. The tailing spill caused a substantial increase in suspended sediment loads (up to 33,000 mg L⁻¹), in addition to large depositions of waste along the Doce basin. The highest estimated transport of dissolved metals was observed for Fe (58.8 μg s⁻¹), Ba (37.9 μg s⁻¹) and Al (25.0 μg s⁻¹). Sediments reached the highest enrichment factors (EFs) for Hg (4,234), Co (133), Fe (43), and Ni (16), whereas As (55), Ba (64), Cr (16), Cu (17), Mn (41), Pb (38) and Zn (82) highest EFs were observed for suspended particulate matter (SPM). Iron, As, Hg, Mn exceeded sediment quality guidelines. Therefore, the risk of occurrence of adverse effects is highly possible, not only due to the dam failure, but also due to the Fe mining and the artisan Au mining. Heavy rain episodes will likely cause enhanced erosion, remobilization, and transport of contaminated particles, sustaining high inputs of SPM and metals for the years to come and threatening the ecosystem services.
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Fisheries in Brazil, the country with most territory in South America, is not comprehensive at all. The lack of precise historical data is the main concern faced by perspectives of fishery management. The majority of data are simplistic records of extrapolated biomass published by federal entities regardless the habitat from where fish resources were harvested, how they were captured and lengths of capture. Little attention was given to the social, economic and cultural aspects of traditional communities and their livelihood. Worst is the case of estuarine systems of the Western Atlantic, where artisanal fishery rules the landings and the absence of proper monitoring, control and surveillance leads to poor managerial actions. As a result, fishery studies conclude that most fish stocks of Western Atlantic estuaries show signs of over-exploitation. Palliative measures such as closed periods for capture of common resources has emerged as urgent option aiming to reduce the impacts of overfishing. Bycatch reduction devices are examples of emerging options. Fishery management of Brazilian estuaries urges accelerated actions: introduce rights and duties-based fishery management to guarantee the declaration of every fisherman activities; enable fishers to organize themselves through the idea of ecological sustainability and economic efficiency; and acquiring daily reports of fish landings through stakeholder approach and co-management. Fishery pressure is not the unique responsible for reduced estuarine production. Bycatch due to small-mesh nets, oxygen-consuming effluents, emerging pollutants, solid wastes, deforestation of mangrove forest for human purposes and human-driven changes in river flow and estuarine morphology are rapidly changing the nature of a nursery environment. Co-management, long-term data and daily reports on production can help to design stock assessment models, understand variations in biomass over time, detect problems of uncontrolled fishing effort, point periods of seasonal habits for each fishery resource, and, most importantly, guarantee that enough juveniles of each living resource can be recruited to adult stocks. The compliance of ecological data and biological research, robust data for landing stats and the social profile of the fishery community seems to be the ideal approach to build proper rules of co-management in Western Atlantic estuaries.
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Ecocline is defined as a “gradation from one ecosystem to another when there is no sharp boundary between the two” containing relatively heterogeneous communities influenced by gradual changes between river-dominated to marine-like waters. It creates heterogeneous habitats, differing in abiotic characteristics, mainly water salinity. Estuarine fish fauna is highly influenced by the major annual water quality shifts resulted from seaward river flow during the rainy season and upstream coastal water inflow during drier seasons. Thus, faunal communities change seasonally in terms of quali-quantitative variables or living strategies. Estuarine ecocline can also set the seasonal retention, bioavailability or sinking of dissolved oxygen, pollutants and microbiological contaminants whose effects are crucial to determine the pattern of use, fish entering, tissue contamination and survival of early stages. Abrupt changes in climatic patterns or in the river flow induce changes in the ecocline and fishes will respond by modifying assemblage structures. The use of robust and consistent scientific information regarding fish fauna and their ecocline can provide reliable ecological information. This generates descriptors of reference conditions taking into account how human impacts affect coastal systems, providing steps to guarantee the sustainable use of estuarine resources.
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Plastics in the marine environment have become a major concern because of their persistence at sea, and adverse consequences to marine life and potentially human health. Implementing mitigation strategies requires an understanding and quantification of marine plastic sources, taking spatial and temporal variability into account. Here we present a global model of plastic inputs from rivers into oceans based on waste management, population density and hydrological information. Our model is calibrated against measurements available in the literature. We estimate that between 1.15 and 2.41 million tonnes of plastic waste currently enters the ocean every year from rivers, with over 74% of emissions occurring between May and October. The top 20 polluting rivers, mostly located in Asia, account for 67% of the global total. The findings of this study provide baseline data for ocean plastic mass balance exercises, and assist in prioritizing future plastic debris monitoring and mitigation strategies.
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As concentrações de selênio foram determinadas em tecidos de diferentes organismos marinhos coletados na Baía de Guanabara, entre 2000 e 2003. Foram analisados o tecido muscular e o fígado de 79 indivíduos de peixe com diferentes hábitos alimentares, Micropogonias furnieri, Bagre spp., Mugil liza, (carnívoro, onívoro e iliófago) e os tecidos moles de 40 indivíduos de mexilhão, Perna perna, (filtrador). As amostras sofreram uma digestão ácida e foram analisadas por Absorção Atômica com forno de grafite (GF-AAS) equipado com corretor Zeeman. O fígado foi o órgão que apresentou as maiores concentrações de selênio para todas as espécies de peixe. As concentrações de selênio no tecido muscular foram mais elevadas no peixe carnívoro (0,12-1,25 µg.g-1 p.u.). As espécies de peixe onívoro e iliófago apresentaram concentrações de selênio no tecido muscular similares, na faixa de < 0,05-0,18 µg.g-1 p.u., e estas foram similares às encontradas nos tecidos moles do mexilhão (0,16-0,21 µg.g-1 p.u.). O tecido muscular mostrou ser o único tecido a sofrer influência direta do hábito alimentar. Os peixes carnívoro e iliófago apresentaram uma correlação significante (Spearman) e positiva entre a concentração de selênio no tecido muscular e o comprimento total dos indivíduos. O peixe carnívoro foi a única espécie que apresentou uma correlação significativa entre as concentrações de selênio nos dois tecidos analisados (músculo e fígado). O mexilhão apresentou uma correlação significativa entre a concentração de selênio nos tecidos moles e o índice de condição (IC). Não foram observadas diferenças significativas (p<0,05) entre as concentrações de selênio nos tecidos moles dos mexilhões entre os diferentes locais de coleta dentro da baía. As espécies estudadas apresentaram concentrações de selênio em seus tecidos semelhantes às encontradas em ecossistemas considerados não impactados. Palavras-chave: selênio, peixes, mexilhão, Baía de Guanabara, hábito alimentar.
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Temporal changes in larval fish species composition and abundance compared with other components of the seston are described in four estuarine habitats in the Atrato Delta, Colombia. In comparison with zooplankton, fish larvae and egg density and anthropogenic debris abundance were low in the South Atrato Delta. Transparency, water temperature and chlorophyll a were the major factors influencing the spatiotemporal distribution of ichthyoplankton in the delta. The most abundant fish larvae were Astyanax sp. 1, Anchovia clupeoides, Cetengraulis edentulus, Anchoa sp., Bathygbius curacao, Dormitator maculatus, Hyporhamphus sp., Atherinella blackburni, Gobiosoma sp. 1 and Menticirrhus americanus (92·8% of total abundance). Spatial temporal analysis shows that in this delta, shrub (arracachal) and grass (eneal) habitats are important for freshwater and estuarine species, whilst mudflat and mangrove are important for estuarine species and estuarine–marine species, since most flexion and post-flexion stages of these species were found there. Anthropogenic debris density never surpassed the total ichthyoplankton density, but was ubiquitous. Shrub and mangrove habitats had higher densities of anthropogenic debris, since these are flood-stem habitats that trap solids.
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The total content of Hg was evaluated in surface sediments at three localities in the coastal area of the province of El Oro, Ecuador. In each locality nine area of sampling were established, in which the total solids (ST), humidity (H), organic matter (MO) and Hg was analyzed. The Hg concentration was determined by atomic absorption spectrophotometry, by hydride generation with atomization in a quartz cell. The concentrations of Hg showed significant differences between localities, with the largest concentration in the Huayla estuary (range: 6,57-7,61 mg kg(-1)) and the lowest in Bajo Alto (range: 3,46-4,83 mg kg(-1)). The levels of Hg in sediments suggest a clear anthropic incorporation in the three localities of the coastal profile of the province of El Oro, which represent a risk to the biota and human health.
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Purpose A medium-term study of sedimentary aliphatic hydrocarbons in the Gulf of Trieste was performed. The content of the aliphatic hydrocarbons, including their spatial and temporal distributions and origins, was determined. The collected data on the content of these compounds for the period of 2004–2013 were then processed using different evaluation indices and statistical analyses. Materials and methods Sediment samples were collected using a gravity core sampler. Hydrocarbons were extracted with hexane and dichloromethane (1:1), and their concentrations were determined by gas chromatography (using an FID detector). Principal component analysis (PCA) was performed to establish the differences between the different sampling sites. Results and discussion The study’s results reveal spatial and temporal variabilities in the aliphatic hydrocarbons within the investigated area. The mean concentrations of total aliphatic hydrocarbons were in the range of 17.9–84.6 μg g⁻¹ d.w., while the concentrations of n-alkanes from C12 to C34 were 934–5232 ng g⁻¹ d.w. The results of the analyses show higher concentrations of hydrocarbons in the coastal areas, with a decrease toward the central part of the Gulf of Trieste. The interannual differences in hydrocarbon concentrations were generally larger close to river estuaries and pollution sources, where degradation processes are more intensive. Different evaluation indices revealed the hydrocarbons to have different origins. The temporal distribution of aliphatic hydrocarbons shows a decrease in concentrations over the past few years at certain sites. Important changes in the concentration and composition of the aliphatic fraction were observed in and after 2010, characterised by intensive fluvial input and long-lasting decreased salinity. Conclusions The content and distribution of aliphatic hydrocarbons are largely dependent on coastal sources of these compounds. Although the investigated area could be considered only slightly to moderately contaminated by hydrocarbons, the recently applied measures for pollution reduction should be continued and intensified.
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Plastic as waste-material is increasingly littering the world's environments. Small particles of plastic-microplastics-are an increasing cause of concern because they can potentially cause a range of environmental problems for organisms and for the assemblages in which they live. Particles are a potential source of impacts in their own right, or as carriers of toxins that can then become absorbed into animals or plants. As a result, there has been increasing publication of programmes of sampling to quantify microplastics, to identify what types are where and to consider the extent to which they are causing impacts. Some of the sampling is to consider large-scale patterns. Some is to gather information about temporal trends. Regardless of the objectives, much of the sampling is not adequate to provide robust data to allow comparative assessments, examine trends or, in some cases, even to be sure about the quantities of plastic being encountered. The problems in such sampling programmes have been widely discussed in the ecological literature. Here, we attempt to identify some of the major problems and their causes and to promote thinking about the available solutions, in terms of improved sampling designs. This is done in the hope that more thought about the pitfalls will lead to more seeking of advice from statisticians and those who are expert in sampling, so that better information will become available in the future.
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Temporal length-weight relationships are presented for the juveniles of the sciaenid Micropogonias furnieri, in a temperate sub-estuary from Uruguay. Parameter b varied from 2.75 to 3.23 and mean condition factor between 0.73 and 0.94. Smallest juveniles presented lower b values for every period.
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