Prevalence of microplastics in the marine waters of Qatar

Understanding microplastic pollution of marine ecosystem: a review

Microplastics are emerging as prominent pollutants across the globe. Oceans are becoming major sinks for these pollutants, and their presence is widespread in coastal regions, oceanic surface waters, water column, and sediments. Studies have revealed that microplastics cause serious threats to the marine ecosystem as well as human beings. In the past few years, many research efforts have focused on studying different aspects relating to microplastic pollution of the oceans. This review summarizes sources, migration routes, and ill effects of marine microplastic pollution along with various conventional as well as advanced methods for microplastics analysis and control. However, various knowledge gaps in detection and analysis require attention in order to understand the sources and transport of microplastics, which is critical to deploying mitigation strategies at appropriate locations. Advanced removal methods and an integrated approach are necessary, including government policies and stringent regulations to control the release of plastics.

Marine litter along the shores of the Persian Gulf, Iran

Plastic wastes -including cigarette butts (CBs)- are dangerous for marine ecosystems not only because they contain hazardous chemicals but also because they can finally turn into micro- or even nano-particles that may be ingested by micro- and macro-fauna. Even large pieces of plastics can trap animals. In this research, the pollution status of macroplastics (abundance, size, type, and colour) and cigarette butts (CBs, number/m2) on the northern coasts of the Persian Gulf has been investigated. A total of 19 stations were explored in Bushehr province (Iran), which covers a length equivalent to 160 km of the Persian Gulf coastline. Among the collected plastic waste (2992 items), disposable mugs were the most frequent (18 %). Plastics with sizes 5-15 cm were the most abundant, and the most common type of plastic was PET (P-value <0.05). The origin of most macroplastics was domestic (2269 items). According to the Index of Clean Coasts (ICC), most surveyed beaches were extremely dirty. The average number and density of CBs in this study were 220 and 2.45 items/m2, respectively. Household litter was the most abundant type of waste in the studied beaches, and this problem can be better managed by training and improving the waste disposal culture. In general, it is suggested that an integrated and enhanced management for fishing, sewage and surface water disposal, and sandy recreational beaches be implemented in Bushehr to control plastic waste.

Generation of synthetic FTIR spectra to facilitate chemical identification of microplastics

In a context where learning databases of microplastic FTIR spectra are often incomplete, the objective of our work was to test whether a synthetic data generation method could be relevant to fill the gaps. To this end, synthetic spectra were generated to create new databases. The effectiveness of machine learning from these databases was then tested and compared with previous results. The results showed that the creation of synthetic learning databases could avoid, to a certain extent, the need for learning databases of environmental microplastics FTIR spectra. However, some limitations were encountered, for example, when two different chemical classes had very similar reference spectra or when the intensities of the bands associated with fouling became too intense. The FTIR study of the ageing and fouling of microplastics in the natural environment is one of the identified ways that could further improve this approach.

Microplastics in the Volta Lake: Occurrence, distribution, and human health implications

Pollution of plastic waste in aquatic ecosystems in Ghana is of significant concern with potential adverse effects on food safety and ecosystem function. This study examined the abundance and distribution of microplastics (MPs) in freshwater biota samples namely: the African river prawn (Macrobrachium vollenhovenii), the Volta clam (Galatea paradoxa), Nile tilapia (Oreochromis niloticus), and sediment from the Volta Lake. Both biota and sediment samples were subjected to microscopic identification and FTIR analysis. In biota samples, the highest mean microplastic abundance of 4.7 ± 2.1 items per individual was found in the prawn, while the Nile tilapia recorded the least (2.8 ± 0.6 items per individual). A total of 398 microplastic particles were observed in sediment samples from the Volta Lake. Microfibers were the major plastic shapes identified in biota and sediment samples. We examined the relationship between microplastic abundance, biota size, and sediment properties. Despite the lack of statistical significance, microplastic shape, size, and polymer composition in assessed organisms mirrored those in the benthic sediment. Polyethylene, polypropylene, polyester, and polystyrene were the four dominant polymer types identified in the organisms and sediments. Although the estimated human exposure was relatively low compared with studies from other regions of the world, the presence of microplastics raises concern for the safety of fisheries products consumed by the general populace in the country. This research is essential for developing effective mitigation measures and tackling the wider effects of microplastic contamination on Ghana's freshwater ecosystems, particularly the Volta Lake.

Microbial community structure and co-occurrence network stability in seawater and microplastic biofilms under prometryn pollution in marine ecosystems

Prometryn has been extensively detected in marine environment because of its widespread usage in agriculture and aquaculture and has been concerns since its serious effects on aquatic organisms. However, its impact on the microbial community in the marine ecosystem including seawater and biofilm is still unclear. Therefore, a short-term indoor microcosm experiment of prometryn exposure was conducted. This study found that prometryn had a more significant impact on the structure and stability of the microbial community in seawater compared to microplastic biofilms. Additionally, we observed that the assembly of the microbial community in biofilms was more affected by stochastic processes than in seawater under the exposure of prometryn. Our study provided evidence for the increasing impact of the microbial communities under the stress of prometryn and microplastics.

Potential ecological risk assessment of microplastics in coastal sediments: Their metal accumulation and interaction with sedimentary metal concentration

Metal pollution in sediments has long been recognized, while sediments are also a long-term sink for microplastics (MPs). MPs may also adsorb environmental pollutants, including metals, as well as leaching polymer components and chemicals used during production. A comprehensive survey of 21 locations around Qatari coastline investigated abundance of MPs in high-shore intertidal sediments and concentration of metals both on MPs and sediment particles. MPs abundance ranged from 3 to 156 MPs particles·kg-1 (12-624 MPs particles·m-2) with polyethylene being the most abundant (27.4 %). MPs showed physical morphologies, with 76 % displayed signs of chemical degradation as confirmed by the carbonyl absorption peak profile, possibly due to exposure to harsh environmental conditions on the Arabian Gulf shores. Most metals analyzed were found at higher concentrations in sediments than the same metals adsorbed to MPs. The average metal concentration ranged from 0.26 (Cd) to 3122.62 μg∙g-1 (Sr) in sediments while 0.22 (Mo) to 30.26 μg∙g-1 (Sr) in MPs. The calculated metal Pollution Load Index (Sed PLI, range 0.57-2.38) for sediments indicates unpolluted to moderately polluted levels, while the Potential Ecological Risk Index (Sed PERI, range 6.9-2220) indicates a relatively considerable ecological risk for metal pollution in sediments in some of the coastal areas surveyed. PLI values calculated for metals associated with MPs (MPs PLI, range 1.1-7.5), suggests relatively moderate pollution, while the PERI for metals in MPs (MPs PERI, range 25.2-1811) has similar ecological risk in terms of metal pollutants in MPs as for sediments. This may be effective in providing relative spatial indices of pollution load and risk for metals associated with MPs, which could potentially inform establishment of an appropriate assessment framework, where MPs are increasingly abundant in coastal sediments. However, this does not account for the relatively lower abundance of MPs compared to sediments.

First determination on two kinds of microplastic-air partition coefficients of seven per- and polyfluoroalkyl substances under environmentally relative conditions: Experiment measurement and model prediction

Microplastics (MPs) in the environment are the sink and vector of organic contaminants, including per- and polyfluoroalkyl substances (PFASs). Although PFASs are low- and non-volatile compounds, they have the potential to partition and diffuse from MP into the gas phase in the environmental functions. Herein, the MP-air partition coefficient (KPA) of seven PFASs was measured using a solid-fugacity meter. The PFAS KPA values in two MPs (high-density polyethylene (HDPE) and thermoplastic polyurethane (TPU)) were determined under different times, temperatures, and relative humidities (RH), and a model was developed to predict the PFAS KPA values based on the measured data. The results showed that the KPA of PFASs increased with the prolonged partition time until 90 mins, and higher temperature and RH facilitated the distribution of PFASs in MPs into the air phase, leading to smaller KPA values. Moreover, the derived equation for predicting PFAS log KPA values was robust with 0.79 of an adjusted square of correlation coefficient (R2adjusted = 0.79) and 0.35 of root mean squared error (RMSE = 0.35). These findings provided the first knowledge for understanding the partition behavior and fate of PFASs in the MP-air microenvironment.

Microplastic occurrence and phthalate ester levels in neuston samples and skin biopsies of filter-feeding megafauna from La Paz Bay (Mexico)

The impacts of microplastics on filter feeders megafauna have recently received increased attention. These organisms are potentially exposed to plastic ingestion and the release of added/sorbed contaminants during feeding activities. An assessment of microplastic abundance and the chemical impact of Phthalates esters (PAEs) were performed in neustonic samples and skin biopsies of Balaenoptera physalus and Rhincodon typus inhabiting the Gulf of California (Mexico). Sixty-eight percent of the net tows contained plastics with a maximum of 0.24 items/m³ mainly composed of polyethylene fragments. PAE levels were detected both in environmental and skin biopsy samples, with the highest values in the fin whale specimens (5291 ng/g d.w). Plasticizer fingerprint showed a similar distribution pattern between neustonic samples and filter-feeding species, with DEHP and MBP having the highest concentrations. The detection of PAE levels confirmed their potential role as plastic tracers and give preliminary information about the toxicological status of these species feeding in La Paz Bay.

An ultra-light sustainable sponge for elimination of microplastics and nanoplastics

The currently established tools and materials for elimination of the emerging contaminants from environmental and food matrices, particularly micro- and nano-scale plastics, have been largely limited by complicated preparation/operation, high cost, and poor degradability. Here we show that, crosslinking naturally occurring corn starch and gelatin produces ultralight porous sponge upon freeze-drying that can be readily enzymatically decomposed to glucose; The sponge affords capture of micro- and nano-scale plastics into its pores by simple pressing in an efficiency up to 90% while preserving excellent mechanical strength. Heterogeneous diffusion was found to play a dominant role in the adsorption of microplastics by the starch-gelatin sponge. Investigations into the performance of the sponge in complex matrices including tap water, sea water, soil surfactant, and take-out dish soup, further reveal a considerably high removal efficiency (60%∼70%) for the microplastics in the real samples. It is also suggested tiny plastics in different sizes be removable using the sponge with controlled pore size. With combined merits of sustainability, cost-effectiveness, and simple operation without the need for professional background for this approach, industrial and even household removal of tiny plastic contaminants from environmental and food samples are within reach.

Exploring the presence and distribution of microplastics in subterranean estuaries from southwest India

Rivers, surface runoff, and the wind all transport microplastics (MPs) to the ocean. There is a knowledge gap concerning the distribution of microplastics in transitional subterranean estuaries. Here, we report the presence of microplastics in the pore water, groundwater, and sea water from four locations in southwest India. Pore water, groundwater, and seawater had mean MP abundances (± standard deviations) of 0.75 (±0.66), 0.15 (±0.1), and 0.11 (±0.07) MPs/l, respectively. Fibres were the dominant category of MPs found. Fourier-transformed infrared spectroscopy revealed the presence of polymers like polyester, low-density polyethylene, and polystyrene. Possible sources of microplastic are fishing activities, tourism, and coastal residents. The microplastics-derived risk assessment scores indicate severe risk to the ecosystems. Fibrous microplastics in pore water indicate that these linear particles can migrate vertically through sandy sediments, reaching subterranean estuaries. We believe submarine groundwater discharge can act as a possible pathway for microplastics to enter the oceans.

Occurrence and risks of microplastics in the ecosystems of the Middle East and North Africa (MENA)

The ubiquitous nature of microplastics (MPs) in nature and the risks they pose on the environment and human health have led to an increased research interest in the topic. Despite being an area of high plastic production and consumption, studies on MPs in the Middle East and North Africa (MENA) region have been limited. However, the region witnessed a research surge in 2021 attributed to the COVID-19 pandemic. In this review, a total of 97 studies were analyzed based on their environmental compartments (marine, freshwater, air, and terrestrial) and matrices (sediments, water columns, biota, soil, etc.). Then, the MP concentrations and polymer types were utilized to conduct a risk assessment to provide a critical analysis of the data. The highest MP concentrations recorded in the marine water column and sediments were in the Mediterranean Sea in Tunisia with 400 items/m³ and 7960 items/kg of sediments, respectively. The number of MPs in biota ranged between 0 and 7525 per individual across all the aquatic compartments. For the air compartment, a school classroom had 56,000 items/g of dust in Iran due to the confined space. Very high risks in the sediment samples (Erⁱ > 1500) were recorded in the Caspian Sea and Arab/Persian Gulf due to their closed or semi-closed nature that promotes sedimentation. The risk factors obtained are sensitive to the reference concentration which calls for the development of more reliable risk assessment approaches. Finally, more studies are needed in understudied MENA environmental compartments such as groundwater, deserts, and estuaries.

New insights into the migration, distribution and accumulation of micro-plastic in marine environment: A critical mechanism review

Microplastics (MPs) are widely distributed in the marine environment, posing a significant threat to marine biota. The contribution of anthropogenic and terrestrial sources to the aquatic ecosystem has led to an increase in MPs findings, and their abundance in aquatic biota has been reported to be of concern. MPs are formed mainly via photo degradation of macroplastics (large plastic debris), and their release into the environment is a result of the degradation of additives. Eco-toxicological risks are increasing for marine organisms, due to the ingestion of MPs, which cause damage to gastrointestinal (GI) tracts and stomach. Plastics with a size <5 mm are considered MPs, and they are commonly identified by Raman spectroscopy, Fourier transfer infrared (FTIR) spectroscopy, and Laser direct infrared (LDIR). The size, density and additives are the main factors influencing the abundance and bioavailability of MPs. The most abundant type of MPs found in fishes are fiber, polystyrenes, and fragments. These microscale pellets cause physiological stress and growth deformities by targeting the GI tracts of fishes and other biota. Approximately 80% MPs come from terrestrial sources, either primary, generated during different products such as skin care products, tires production and the use of MPs as carrier for pharmaceutical products, or secondary plastics, disposed of near coastal areas and water bodies. The issue of MPs and their potential effects on the marine ecosystem require proper attention. Therefore, this study conducted an extensive literature review on assessing MPs levels in fishes, sediments, seawater, their sources, and effects on marine biota (especially on fishes), chemo-physical behavior and the techniques used for their identification.

Microplastics in water systems: A review of their impacts on the environment and their potential hazards

Microplastics, the microscopic plastics, are fragments of any type of plastic that are being produced today as plastic waste originating from anthropogenic activities. Such microplastics are discharged into the environment, and they enter back into the human body through different means. The microplastics spread in the environment due to environmental factors and the inherent properties of microplastics, such as density, hydrophobicity, and recalcitrance, and then eventually enter the water environment. In this study, to better understand the behavior of microplastics in the water environment, an extensive literature review was conducted on the occurrence of microplastics in aquatic environments categorized by seawater, wastewater, and freshwater. We summarized the abundance and distribution of microplastics in the water environment and studied the environmental factors affecting them in detail. In addition, focusing on the sampling and pretreatment processes that can limit the analysis results of microplastics, we discussed in depth the sampling methods, density separation, and organic matter digestion methods for each water environment. Finally, the potential hazards posed by the behavior of aging microplastics, such as adsorption of pollutants or ingestion by aquatic organisms, due to exposure to the environment were also investigated.

Acute effects of three surface-modified nanoplastics against Microcystis aeruginosa: Growth, microcystin production, and mechanisms

As plastic pollution continues to increase and plastic waste is shredded to form smaller plastic particles, there is growing concern about the potential impact of nanoplastics (NPs) on freshwater ecosystems. In this work, the effects of three surface-modified NPs, including polystyrene (PS), PS-NH₂, and PS-COOH, on the growth, photosynthetic activity, oxidative damage, and microcystins (MCs) production/release of Microcystis aeruginosa (M. aeruginosa) were investigated. Results indicated that all three NPs significantly inhibited the growth of M. aeruginosa after a 96 h exposure, and the growth inhibition followed the order of PS-NH₂ > PS > PS-COOH (p < 0.05). Meanwhile, all three NPs at the concentration of 100 mg/L significantly increased the content of intra-MCs (115 %, 147 %, and 121 % higher than the control, respectively) and extra-MCs (142 %, 175 %, and 151 % higher than the control, respectively) after a 96 h exposure (p < 0.05). Moreover, our findings also suggested that the potential mechanisms of surface-modified PS NPs on M. aeruginosa growth and MCs production/release were associated with physical constraints, photosynthetic activity obstruct, and oxidative damage. Our findings provided direct evidence for different kinds of surface modifications of PS NPs on freshwater algae and improve the understanding of the potential risk of NPs in aquatic ecosystems.

Plastic waste in sandy beaches and surface water in Thanh Hoa, Vietnam: abundance, characterization, and sources

The occurrence and characterization of marine debris on beaches bring opportunities to track back the anthropogenic activities around shorelines as well as aid in waste management and control. In this study, the three largest beaches in Thanh Hoa (Vietnam) were examined for plastic waste, including macroplastics (≥ 5 mm) on sandy beaches and microplastics (MPs) (< 5 mm) in surface water. Among 3803 items collected on the beaches, plastic waste accounted for more than 98%. The majority of the plastic wastes found on these beaches were derived from fishing boats and food preservation foam packaging. The FT-IR data indicated that the macroplastics comprised 77% polystyrene, 17% polypropylene, and 6% high-density polyethylene, while MPs discovered in surface water included other forms of plastics such as polyethylene- acrylate, styrene/butadiene rubber gasket, ethylene/propylene copolymer, and zein purified. FT-IR data demonstrated that MPs might also be originated from automobile tire wear, the air, and skincare products, besides being degraded from macroplastics. The highest abundance of MPs was 44.1 items/m³ at Hai Tien beach, while the lowest was 15.5 items/m³ at Sam Son beach. The results showed that fragment form was the most frequent MP shape, accounting for 61.4 ± 14.3% of total MPs. MPs with a diameter smaller than 500 μm accounted for 70.2 ± 7.6% of all MPs. According to our research, MPs were transformed, transported, and accumulated due to anthropogenic activities and environmental processes. This study provided a comprehensive knowledge of plastic waste, essential in devising long-term development strategies in these locations.

Overviewing the Ground Reality of Microplastic Effects on Seafoods, Including Fish, Shrimps and Crabs: Future Research Directions

While plastics are already notorious for their accumulation in the environment, which poses environmental challenges, invisible microplastics (MPS) are an even greater challenge. This review focuses on consolidating the reports available on MP accumulation in edible marine and freshwater fishes, shrimps, and crabs. The reality as to whether MPs in these edible aquatic organisms are really a cause of high concern is questioned and discussed. While the entrails of aquatic organisms are reported to contain high levels of MPs, because these products are consumed after the removal of the entrails and gut area in the majority of cases, the MP threat is questionable. The existence of MPs in these aquatic sources is validated but their potency in harming humans, aquatic organisms, and other interlinked species is unassessed. To overcome the difficulty in tracing the movement of MPs in a bigger ecosystem, this review proposes laboratory-based pilot studies mimicking real-world conditions, which will help us to understand the kinetics of MPs in the food chain. The effects of MPs on human welfare and health are yet to be assessed, and this is another gap that needs attention.

Artificial turf and crumb rubber infill: An international policy review concerning the current state of regulations

BACKGROUND

Although artificial turf fields are utilized widely around the world, sufficient research has not yet been conducted to assess the potential human and environmental health risks posed by the chemicals contained in the fields' fibers, backing, and often-used crumb rubber infill. Consequently, there is wide variation in governmental policies.

OBJECTIVE

Review the notable policies concerning artificial turf and crumb rubber infill in the European Union, United Kingdom, United States of America, Canada, China, Qatar, and the Global Stockholm Convention of the United Nations.

METHODS

Information was collected that included published papers, technical and policy reports, and grey literature. These were then analyzed by a collaborative group familiar with the environmental policies in their respective countries to extract the pertinent legislative or regulatory information. The group members were primarily identified through their involvement in publications pertinent to artificial turf and crumb rubber infill health research and included environmental health professors, active researchers, and governmental agency officials. Most information on direct policies was taken directly from reports provided to the public by various governmental agencies responsible for their countries' regulations, often available within the respective agency's online archives.

RESULTS

There are significant differences in the regulatory approaches adopted by the investigated countries with regards to artificial turf and its crumb rubber infill. Some regions, such as the European Union, have taken substantial steps to limit the fields' chemical components to which the public and environment are exposed. Other regions and countries have done far less to address the issue. Most policies relate directly to (i) the fields themselves, (ii) the microplastic components of crumb rubber infill, or (iii) the concentrations of harmful polycyclic aromatic hydrocarbons (PAHs), perfluoroalkyl and polyfluoroalkyl substances (PFAS), and heavy metals.

CONCLUSION

While nearly every country acknowledges the potential health risks posed by heavy metals, microplastics, PAHs, and PFAS chemicals, very few have actually implemented artificial turf and crumb rubber infill regulations and/or established adequate surveillance measures to protect those regularly exposed to the fields.

Seasonal change of microplastics uptake in the Pacific oysters Crassostrea gigas cultured in the Yellow Sea and Bohai Sea, China

This study investigated seasonal microplastics (MPs) pollution characteristics in oysters and surrounding surface seawater from five aquaculture farms located at the Yellow Sea and Bohai Sea. MPs abundances in oysters were 2.40 ± 0.14 (winter) to 3.28 ± 0.19 (autumn) items/individual, and 0.22 ± 0.02 (spring) to 0.45 ± 0.06 (summer) items/g (ww). In surface seawater, average seasonal MPs abundances were 3.41 ± 1.06-8.86 ± 2.48 items/L. Fibers were dominant shape, and cellophane and polyethylene terephthalate (PET) were dominant polymers in oysters and surface seawater. Positive correlation was found between oysters' MPs abundance (items/individual) and environmental factors (NO₂-N (r = 0.466), and temperature (r = 0.485)) by Spearman correlation analysis in four seasons. Main environmental factor affecting seasonal MPs abundance of oysters and surface seawater was NH₃-N and SiO₃-Si in summer and winter respectively. In conclusion, seasonal change of MPs uptake in cultured oysters was relatively small.

Assessment of trace element contamination in the historical nesting grounds of green sea turtle (Chelonia mydas) in Hainan Island, China

Trace element pollution is a potential threat to the reproduction of sea turtles. Hainan Island was previously the most important nesting ground of green sea turtles in China before they disappeared approximately 36 years ago. The Chinese government has encouraged restoration work on historical nesting grounds, and it is necessary to evaluate the status of these sites before conducting habitat restoration. This study analyzed the concentrations of seven trace elements in the surface sediments of 13 historical nesting grounds in Hainan. The average concentrations were 19.47 (Cr), 4.67 (Ni), 6.99 (Cu), 0.08 (Cd), 16.68 (Pb), 0.02 (Hg), and 5.27 (As) mg/kg, which were lower than the first-grade limit values of the GB (18668-2002) national standard in China. The concentrations were close to the background value, except for the relatively high Cd value. The potential ecological risk was ranked as Cd > Hg > As > Cu > Pb > Cr. The spatial distribution of trace element contamination in Hainan was uneven, with high potential ecological risk levels of Cd and Hg contamination in Longwan'gang, Shimeiwan, Yazhou Qu, and Fushicun. Marine mariculture, wastewater discharge, and fishing boats are the main sources of trace element contamination in Hainan. We recommend strengthening the control of Hg and Cd contamination sources, monitoring trace elements in relevant/interest areas, and the environmental protection department should curb local residents from directly discharging mariculture wastewater and domestic sewage into the sea.

Implication of microplastic toxicity on functioning of microalgae in aquatic system

Microplastics (MPs) released from both primary and secondary sources affect the functioning of aquatic system. These MPs and components leached, can interact with aquatic organisms of all trophic levels, including the primary producers, such as microalgae. Considering the ecological value of microalgae and the toxicological effects of MPs towards them, this review provides: (1) a detailed understanding of the interactions between MPs and microalgae in the complex natural environment; (2) a discussion about the toxic effects of single type and mixtures of plastic particles on the microalgae cells, and (3) a discussion about the impacts of MPs on various features of microalgae -based bioremediation technology. For this purpose, toxic effects of MPs on various microalgal species were compiled and plastic components of MPs were ranked on the basis of their toxic effects. Based on available data, ranking for various plastic components was found to be: Polystyrene (PS) (rank 1) > Polyvinyl Chloride (PVC) > Polypropylene (PP) > Polyethylene (PE) (rank 4). Furthermore, the review suggested the need to understand joint toxicity of MPs along with co-contaminants on microalgae as the presence of other pollutants along with MPs might affect microalgae differently. In-depth investigations are required to check the impact of MPs on microalgae-based wastewater treatment technology and controlling factors.

Microplastics in intertidal water of South Australia and the mussel Mytilus spp.; the contrasting effect of population on concentration

Microplastics, plastic particles <5 mm in size, are of global concern as human-caused pollutants in marine and fresh waters, and yet little is known of their distribution, behaviour and ecological impact in the intertidal environment of South Australia. This study confirms for the first time, the presence of microplastic in the South Australian intertidal ecosystem by quantifying the abundance of particles in intertidal water and in the keystone species, the blue mussel, Mytilus spp., an important fisheries species, at ten and six locations respectively, along the South Australian coastline. For a remote region known for its pristine environment, microplastic concentration in intertidal water was found to be low to moderate (mean = 8.21 particles l^-1 ± 4.91) relative to global levels and microplastic abundance in mussels (mean = 3.58 ± 8.18 particles individual^-1) was within the range also reported globally. Microplastic particles were ubiquitous across sites and bioavailable by size in water (mean = 906.36 μm) and in mussel (mean = 983.29 μm) raising concerns for the health of South Australia's unique coastal ecosystems and for the human food chain. Furthermore, a positive correlation was found between human coastal population size and microplastic concentration in intertidal water, irrespective of influences from industry - tourism, fishing and shipping ports. FTIR analysis determined plastic type to include polyamide (PA), polyethylene (PE), polypropylene (PP), acrylic resin, polyethyleneterephthalate (PET) and cellulose, suggesting synthetic and semi-synthetic particles from single-use, short-life cycle products, fabrics, ropes and cordage. Our findings shed light on the urgent need to establish the local sources of microplastic pollution in order to assist the community, industry and government to reduce the impact of microplastic on the fragile marine systems within South Australian intertidal waters and on the organisms associated with the human food chain.

First long-term evidence of microplastic pollution in the deep subtropical Northeast Atlantic

No anthropogenic pollutant is more widespread in the aquatic and terrestrial environment than microplastic; however, there are large knowledge gaps regarding its origin, fate, or temporal variations in the oceans. In this study, we analyzed sediment trap material from the deep subtropical Northeast Atlantic (2000 m) in a long-term record (2003-2015) to assess the role of the deep ocean as a potential sink of microplastics. Microplastic particles were identified in all 110 analyzed samples with flux rates of 1.13-3146.81 items d^-1 m^-2. Calculated microplastic mass fluxes ranged between 0.10 and 1977.96 μg d^-1 m^-2, representing up to 8% of the particle flux. Between years, the composition of the different polymers changed significantly, dominated by polyethylene, whose amount was correlated with the lithogenic input. The correlation between polyethylene and the lithogenic fraction was attributed to an air transport pathway from northeast Africa and surrounding regions. The second most abundant polymer detected in our study was polyvinyl chloride, which is not correlated with lithogenic or biogenic particle flux fractions. Instead, we observed seasonality for polyvinyl chloride with recurring high fluxes in winter before the plankton bloom and significantly lower amounts in summer. Other polymers identified were polypropylene, polyethylene terephthalate, and lower numbers of polystyrene and polymethyl methacrylate. The average microplastic particle size for all samples and polymers was 88.44 ± 113.46 μm, with polyethylene and polyvinyl chloride having the highest proportion of small particles (<100 μm). Our findings provide first insights into temporal variations of sinking microplastics, which are crucial for understanding the fate of plastic in the oceans.

Material flow analysis of plastic waste in the gulf co-operation countries (GCC) and the Arabian gulf: Focusing on Qatar

Global plastic waste production has increased dramatically in recent years, both globally and regionally, having a multitude of adverse effects on the environment and human health. However, little attention has been directed to this problem in the Arabian Gulf region. This study aims to delineate and map the status of the plastic waste problem in the Gulf Co-operation Countries (GCC), with a focus on Qatar. The study focuses on the plastic waste in the marine environment, depicting the different types, sizes and shapes of plastic particles found in the Arabian Gulf. To depict the flow of plastic waste, a generic material flow diagram was built using a material flow analysis software named STAN, in which transfer coefficients were assigned based on existing scientific literature and estimations built on data from local industries and recycling facilities. The recovery and recycling efforts that have been made by the different GCC countries, in efforts to reduce plastic waste and minimize the risk of plastic on the environment are analyzed, too. Our analyses indicate that approximately 11.9 Mt ± 595.395 Kt of plastic waste is produced annually in the GCC region, of which only 23 ± 15% is recycled, indicating that improvements are yet to be made in the recovery, recycling and treatment of plastics in the region. However, in Qatar, a higher percentage of plastics (40 ± 10%) is recovered-recycled with efforts to treat plastics and reuse it to generate energy.

Microplastics in Kenya's marine nearshore surface waters: Current status

Microplastics (MPs) were collected at six locations along Kenya's marine nearshore surface waters using a 300 μm mesh-size manta net. The samples were washed over a 125-μm mesh size sieve No.120 into a glass jar and preserved in 70% ethanol. MPs were sorted, counted visually under a dissecting microscope then identified using attenuated total reflection Fourier transform infrared (ATR-FTIR) spectroscopy. A total of 1473 particles with an overall mean concentration of 0.58 ± 1.29 MPs m^-3, were collected. Fragments were the most common types representing 55% of the total MPs, followed by films (40%) and fibers (2%). Polypropylene (PP) was dominant (52%), high-density polyethylene (HDPE) comprised 38% and low density polyethylene (LDPE) 10% of the total MPs. This study provided baseline information, in which Malindi was identified as a hot spot for MPs pollution. Furthermore, the outcomes will assist policy formulations and management strategies aimed at controlling marine plastics.

Are we underestimating floating microplastic pollution? A quantitative analysis of two sampling methodologies

Microplastics (MPs) are widespread in the water column of several aquatic ecosystems. Thus, the sampling methodology is considered as a basic factor influencing MPs abundance. In this baseline, a total of 67 investigations were chosen to conduct a quantitative analysis between two sampling methods: Trawl and bulk. The aim is to report a general overview of the MPs abundance and characteristic differences based on the sampling procedures and provide methodological recommendations. MPs abundance reported by bulk studies is 3500 higher than trawl studies. Furthermore, the morphological types and polymers abundances were statistically affected by the type of sampling tool. Conversely, MPs size ranges were significantly different between sampling procedures, suggesting that trawling underestimates the smaller MPs fractions. The analysis confirms that the sampling methods should be selected based on the research objectives. In this sense, it is recommended to combine both types of sampling procedures to obtain comprehensive data.

Micro- and mesoplastics in sea surface water from a Northern Adriatic coastal area

The presence of microplastics in the sea is a global issue widely studied and discussed in the last years. The whole marine ecosystem is now considered at high risk because of their presence and abundance in every studied environment all over the world because polymeric materials commonly constitute the main raw materials in contemporary industrial production. The presented study reports the results obtained from surface seawater monitoring of two sampling transects in the coastal area close to the Venice Lagoon (Italy) inlet, investigated in order to get new information about the presence and relevance of plastic pollution. Plastic particles collected by means of a manta net (0.3-mm mesh size) have been characterized in detail by utilizing a multi-technique approach in order to discriminate them by typology, dimension, colour, spatial density and chemical composition. Such information permitted the individuation of subgroups (specific groups) of plastic micro-debris in this Northern Adriatic area.

Systematical insights into distribution and characteristics of microplastics in near-surface waters from the East Asian Seas to the Arctic Central Basin

The spatial distribution and composition of microplastics in near-surface water (8 m) was investigated from the East Asian Seas to the Arctic Central Basin. Microplastics were detected in 93.9% of the sampling sites. Abundances ranged from 0.48 to 7.62 items/m³, with an average abundance of 2.91 ± 1.93 items/m³. The highest average abundance was observed in the Arctic Central Basin. Polyester (PET) was the dominant type, accounting for 71.3% of total microplastics, followed by rayon or cellophane and polytetrafluoroethylene (PTFE). Microplastics < 2 mm accounted for 81.9% of total particles. Its distribution peaked in the 1-2 mm size range. The 0.30-2 mm fibers were the most abundant. In the East Asian Seas, the abundance was significantly negatively correlated with longitude, whereas the accumulation of microplastics was not observed in the northeastern sector of Japan Sea. Abundances of microplastics at sites located in the sub-Arctic and Arctic Oceans showed a significant positive relationship with latitude, indicating that the Arctic Ocean is a potential accumulation zone of microplastics. The findings of this study will provide systematical insights into distribution of microplastics and basic information for understanding the accumulation mechanism of microplastics in near-surface waters from the East Asian Seas to the Arctic Central Basin.

Assessing the relationship between the abundance of microplastics in sediments, surface waters, and fish in the Iran southern shores

The purpose of this study was to investigate the microplastic (MP) pollution in sediments, surface waters, and four fish species in the northern coast of the Persian Gulf. Sampling was conducted in seven important regions during December 2019. The abundance of MPs was respectively 190 ± 35.5 items/kg dry weight for sediments, 9.28 ± 2.1 items/km² for surface waters, and 0.33 ± 0.05 items/individual for fish. There was no correlation between MP abundance in surface water, sediment, and fish samples. Except for Cynoglossus arel, abundance of isolated MPs did not show significant relationships with body weight, body length, and gastrointestinal tract weight (P > 0.05). MPs were ranged from 0.3 to 5 mm in size and were prevailed by fiber in shape; black, red, and blue in color; and polypropylene and polyethylene in polymer. This study may help in increasing our knowledge regarding MP pollution in marine water systems and biota.

Occurrence and spatial distribution of microplastics, and their correlation with petroleum in coastal waters of Hainan Island, China

In this study, the distribution, abundance, morphology, and composition of microplastics (MPs) in surface seawater and sediment of Hainan Island were systematically investigated. Seawater and sediment samples were collected from six functional zones, including harbor, industrial district, sparsely populated area, tourist area, residential area, and aquaculture area. The abundance of MPs in seawater was 0.46-19.32 items/L, with an average of 2.59 ± 0.43 items/L, which were similar to those detected in the South China Sea (e.g., Nansha (1.25-3.20 items/L) and Xisha (2.57 ± 1.78 items/L)). The highest level was detected in Qinglan Bay Estuary, and the lowest was in Sanya West Island. The abundance of MPs in sediment was 41.18-750.63 items/kg, with an average of 372.47 ± 62.10 items/kg; the highest concentration was detected at Tanmen Port, and the lowest was in Lingao sea area. It was detected that the MPs with smaller size exhibited a higher concentration in seawater. MPs were commonly black and white, and predominantly linear and fragmented in shape. Polyethylene terephthalate (PET) was the dominant polymer, which might be derived from laundry wastewater. The petroleum concentration was 0.02-0.21 mg/L in the investigated area, with harbors being the most severely polluted areas. Furthermore, this study also found that MPs pollution was positively correlated with petroleum in seawater, indicating similarities between MPs and petroleum-based sources of pollution. This study identifies the contamination and characteristics of MPs and their correlation with petroleum in Hainan Island, the biggest island in the South China Sea, providing important data for further research on protecting marine ecosystems.

Occurrence, potential sources and ecological risk estimation of microplastic towards coastal and estuarine zones in Malaysia

Extensive global plastic production has led to microplastic (MP) pollution of marine ecosystems. This study analysed the abundance of MPs in the surface water of tropical coastal and estuarine zones in Malaysia affected by rapid urbanisation and intense human activity. It also estimated the risk posed by MPs to the marine environment. Mean MP abundance ranged from 2.10 to 6.80 particles/L. Fourier-transform infrared spectroscopic analysis found that the MP polymers were dominated by cellophane (54%), followed by polyester (33%) and polyethylene (2%). The risk posed by MPs was estimated with the risk quotient (RQ) method which found no potential ecological risk to both coastal and estuarine areas (RQ < 1). This study will serve as a baseline for future monitoring of MP pollution of marine water to assess the impact of heavily urbanised coastal and estuarine zones.

Microplastics pollution in the ocean: Potential carrier of resistant bacteria and resistance genes

Microplastics pollution in marine environments is concerning. Microplastics persist and accumulate in various sections of the ocean where they present opportunity for micropollutant accumulation and microbial colonisation. Even though biofilm formation on plastics was first reported in the 1970's, it is only in recent years were plastic associated biofilms have gained research attention. Plastic surfaces pose a problem as they are a niche ready for colonisation by diverse biofilm assemblages, composed of specific bacterial communities and putative pathogens prone to acquiring ARGs and resistance in the biofilm. However, the nature of antibiotic resistance on aquatic plastic debris is not yet fully understood and remains a concern. Given the inevitable increase of plastic production and waste generation, microplastics released into the environment may prove to be problematic. This review explores microplastic waste in the ocean and possible concerns that may arise from the presence of microplastics in conjunction with favourable conditions for the development and dispersal of antibiotic resistance in the ocean and food web.

Impact of Microplastics on Oil Dispersion Efficiency in the Marine Environment

Oil spill and microplastics (MPs) pollution has raised global concerns, due to the negative impacts on ocean sustainability. Chemical dispersants were widely adopted as oil-spill-treating agents. When MPs exist during oil dispersion, MP/oil-dispersant agglomerates (MODAs) are observed. This study explored how MPs affect oil-dispersion efficiency in oceans. Results showed that, under dispersant-to-oil volumetric ratio (DOR) 1:10 and mixing energy of 200 rpm, the addition of MPs increased the oil droplet size, total oil volume concentration, and oil-dispersion efficiency. Under DOR 1:25 and mixing energy of 120 rpm, the addition of MPs increased the oil droplet size but resulted in a decrease of total oil volume concentration and dispersion efficiency. Compared with the oil volume concentration, the oil droplet size may no longer be an efficient parameter for evaluating oil-dispersion efficiency with the existence of MODAs. A machine learning (ML)-based XGBRegressor model was further constructed to predict how MPs affected oil volume concentration and oil-dispersion efficiency in oceans. The research outputs would facilitate decision-making during oil-spill responses and build a foundation for the risk assessment of oil and MP co-contaminants that is essential for maintaining ocean sustainability.

An annual study on plastic accumulation in surface water and sediment cores from the coastline of Tenerife (Canary Island, Spain)

Sediment core samples from high tide lines and in submerged zones as well as surface water samples from eight beaches of Tenerife were analysed. Sampling was conducted over a period of one year in intervals of 5 weeks. The majority of particles were found in the high tide sediment (66%), followed by water samples (23%) and finally in sediment from submerged zones (11%). Regarding the particle amount per volume (items/L), accumulation in sediment samples was statistically higher compared to water samples. Mean values of items/L were higher in high tide sediments. In high tide and water samples, mostly white and transparent particles >1 mm were found. More than 70% were represented by fragments. In sediments from submerged zones, yellow and blue microparticles (<1 mm) were predominant and 61.9% consisted of fibres. Larger particles were mainly identified as PP, PE, PS, PTFE and PVC, while polymer types of smaller particles were more variable.

Characteristics and Seasonal Distribution of Microplastics in the Surface Waters of Southwest Coast of the Caspian Sea (Guilan Province, Iran)

The aim of this study was to investigate the occurrence, abundance and distribution of microplastics (MPs) in the southwest coast of the Caspian Sea in four seasons. Three stations were chosen and their surface waters were sampled between April 2019 and February 2020. The average number of MPs was 1.37 ± 0.47 items/m³ and the predominant frequency in different seasons were as follows: summer > autumn > spring > winter. MPs were dominated by fiber in shape. Black and blue were the most common colors respectively. The size was in the range of 0.3-5 mm with a mean of 1.44 ± 1.08 mm. Due to Fourier-transform infrared spectroscopy equipped with attenuated total reflection (ATR-FTIR), four different polymers were identified dominating by polypropylene. The low MP concentrations detected in the present study can be related to lower sewage inlet and more MPs sedimentation in the investigated stations.

Microplastic pollution in inshore and offshore surface waters of the southern Caspian Sea

In this study, as the first comprehensive monitoring, the occurrence of microplastics (MPs) in inshore and offshore surface waters of the southern Caspian Sea was investigated. Our data indicated that MPs, which were detected in all the samples, were widely distributed in the thirteen studied stations. Non-normally distribution of the MPs was observed among the studied stations (p<0.05). The average concentration of microplastics in the selected stations was 0.246 ± 0.020 MP/m³. In most of the transects, negative gradients of MPs from coastal waters to deeper waters were observed. The dominant size and color of MPs in the inshore and offshore water samples was 1000-5000 μm and white-transparent, respectively. Films and fibers constituted about 50% and 40% of the total number of MPs of the water samples, respectively. Also, polyethylene (PE), polypropylene (PP) and polyethylene terephthalate (PET) were the three main polymer types of microplastics in the inshore and offshore surface waters. Our data provide valuable evidence for the comparative assessing of future data regarding decreases or increases of MPs in the southern Caspian Sea.

Typhoon-induced turbulence redistributed microplastics in coastal areas and reformed plastisphere community

The increasing microplastic pollution together with the plastisphere-associated ecological threats in coastal areas have aroused global concern. Tropical cyclones have been increased in both frequency and intensity under global warming, causing intense impact on the microplastics distribution and the structure of coastal ecosystems. However, until most currently, the extent to which typhoon impacts the microplastics and plastisphere community remains poorly known. This study analyzed the effects of Typhoon Wipha (Code: 1907) on microplastics abundance and composition in surface water and sediment crossed coastal areas of Shenzhen. Here we found a significant typhoon-induced increase in microplastics abundance in surface water, whereas an opposite trend was observed in sediment. Despite the evident transportation of microplastics from sediment to surface water by agitation, a possible microplastics influx was introduced by typhoon as evidenced by the large attribution of unknown force in source tracking analysis. Furthermore, typhoon had adeptly uniformed the plastisphere community in the sediment along the 190 km costal line overnight. A significant increase of nitrogen fixer, Bradyrhizobiaceae, was observed ubiquitously after typhoon, which might alter the nitrogen cycling and increase eutrophic condition of the coastal ecological system. Together, this study expanded the knowledge about the impact of typhoon-induced influx of the microplastics on coastal biogeochemical cycling. Moreover, the microplastics and the plastisphere compositional pattern revealed here will underpin future studies on adsorption behavior, interfacial processes and ecotoxicity of the coastal microplastic pollution.

Separation of microplastics from mass-limited samples by an effective adsorption technique

Microplastic in the environment hides visible and invisible dangers for the ecosystems and domiciled organisms. Due to the large quantities of microplastics already distributed worldwide, comparative studies to investigate the associated hazards, distribution patterns, and abundances are becoming increasingly important. Due to varying efforts and budgets, there is still no homogenized detection method for microplastics in the environment, which severely compromises the comparability and reliability of results between previous studies. In this study, we compare the efficacy, degradative effect on microplastics, and microplastic recovery rates of different digestion and separation methods for isolating microplastics from mass-limited environmental samples with high biogenic content. Our results show that the most gentle and effective isolation method is an adsorption-based technique that exploits the lipophilic properties of plastic for separation. This technique achieves an average microplastic recovery rate of 98.0 ± 3.8% and a matrix removal of 96.3 ± 0.3% at low cost and minimum effort. To examine the applicability of this technique to natural environmental samples, eight sediments and two plankton net samples from the South China Sea were selected to determine microplastic abundances. In the analyzed sediment samples, 0-9 microplastic items per 10 g sediment d. w. were found, while 17-25 items per m³ were detected in net samples. Considering the respective mean plastic density, this corresponds to a calculated microplastic mass of 0-39 μg (10 g d.w.)^-1 and 3.7-7.1 μg m^-3 in sediment and water samples, respectively. This study represents a new way of microplastic extraction from matrix-rich mass-limited samples with high accuracy and easy feasibility at low costs, which would be useful as a worldwide homogenized method in future microplastic research projects and related data comparability.

Microplastics and plankton: Knowledge from laboratory and field studies to distinguish contamination from pollution

Due to their ubiquitous presence, size and characteristics as ability to adsorb pollutants, microplastics are hypothesized as causing a major impact on smaller organisms, such as plankton. Despite this, there is a need to determine whether these impacts just relate to the environmental presence of the materials or their effects on biological processes. Therefore, we aimed to 1) review current research on plankton and microplastics; 2) compare field and laboratory experimental findings, and 3) identify knowledge gaps. The systematic review showed that 70% of the 147 relevant scientific publications were from laboratory studies and microplastics interactions with plankton were recorded in 88 taxa. Field study publications were relatively scarce and the characteristics of microplastics collected in the field were very different from those used in laboratory experiments thereby limiting the comparison between studies. Our systematic review highlighted knowledge gaps in: 1) the number of field studies; 2) the non-comparability between laboratory and field conditions, and 3) the low diversity of plankton species studied. Furthermore, this review indicated that while there are many studies on contamination by microplastics, the effects of this contamination (i.e., pollution per se) have been less well-studied, especially in the field at population, community, and ecosystem levels.

Ingestion of microplastics by the estuarine polychaete, Namalycastis sp. in the Setiu Wetlands, Malaysia

In this study, the ingestion of microplastics by the deposit-feeding polychaete Namalycastis sp. in the estuarine area of the Setiu Wetlands, Malaysia was confirmed. Samples were collected from six stations, covering the wetland from the south to the north, bimonthly between November 2016 and November 2017. Microplastics were extracted from polychaete samples following digestion in an alkaline solution (10 M NaOH). They were identified by physical characteristics (i.e., shape and color under dissecting microscope and scanning electron microscope), and chemical analysis using a LUMOS Fourier Transform Infrared Microscope (μ-FTIR). A total of 3277 pieces were identified, which were dominated by filaments (99.79%) and with the majority transparent in color (84.71%). Most of the microplastics identified were polypropylene (PP) followed by polyamide (PA) based on their main peak in the of μ-FTIR spectrum. Principal component analysis demonstrated the dominance of microplastics at stations 3 and 4 of the sampling area, probably because of the influx from the open sea and from aquaculture. The findings of this research provide baseline information on microplastics ingested by benthic organisms and their fate in the estuarine food web.

Microplastic pollution in Southern Atlantic marine waters: Review of current trends, sources, and perspectives

Microplastics (MPs) are emerging and ubiquitous contaminants which have been gaining prominence since the last decade to nowadays. This is due to their possible adverse effects in aquatic ecosystems as well as the huge amount of plastic waste exponentially generated around the globe. Plastics may be introduced either directly to water bodies or indirectly to the aquatic systems by being carried by the wind, from emissions of contaminated effluents, and soil leaching, among other processes. In turn, these debris may interact with organic and inorganic contaminants, such as polycyclic aromatic hydrocarbons (PAHs), polybrominated diphenyl ethers (PBDEs) and trace constituents, and with microorganisms. Although the abundance of microplastics from South Atlantic waters is among the highest found worldwide, the number of studies in these marine waters regarding MP contamination is still scarce. Additionally, there still are no consensus on the best sampling conditions, which may be underestimating MPs. In this way, adequate MPs studies regarding their distribution, exposure levels, chemical and biological interactions are highly suggested in order to better understand both environmental and human health potential risks. This review assessed advances in sampling, analytical methodologies, characterization and understanding of MP sources in these marine waters in comparison to data from other regions around the globe.

Characterization of plastic debris from surface waters of the eastern Arabian Sea-Indian Ocean

The quantity of floating plastic debris (FPD) is continuously being increased in the oceans. To assess their size, structure, and composition along the eastern Arabian Sea (EAS), FPD samples were collected by using a surface plankton net. The microplastic size fraction (0.5-5 mm) was the most prevalent accounting for >50% of the total, followed by mesoplastics (5-25 mm; ~40%) and macroplastics (>25 mm; ~10%). The collected FPDs were categorized into five different types and eight colours. Attenuated Total Reflectance-Fourier Transform Infrared Spectrometry (ATR-FTIR) analysis of the plastics revealed that polypropylene, polyethylene, and nylon were the most dominant polymers, and these comprised mostly of fibre/fishing line. The abundance of FPD in the EAS (0.013 ± 0.012 no.s/m³) was found to be very low compared to elsewhere. The prevalent microplastics presence in the oceans might have occurred mainly by the degradation of larger items. It increases bioavailability, and hence, is a risk to marine ecosystems.

Microplastic fibers - Underestimated threat to aquatic organisms?

Awareness of microplastic pollution in aquatic environments increased strongly during the last decade. Environmental monitoring studies detected microplastic items in every tested water body and found them in various aquatic organisms. Yet, many studies conducted so far, refer to microplastic particles and spheres but not fibers. Microplastic fibers are often not considered due to methodological issues and high contamination risk during sampling and analysis. Only a few of the microplastic exposure studies with aquatic organisms were conducted with microplastic fibers. Recent effect studies demonstrated several negative impacts of microplastic fibers on aquatic organisms, which include tissue damage, reduced growth, and body condition and even mortality. Such negative effects were predominantly observed in taxa at the basis of the food chain. Higher taxa were less heavily affected in direct exposure experiments, but they presumably suffer from negative effects on organisms at lower food chain levels in the wild. Consequently, ongoing and future pollution with microplastic fibers may disturb the functioning of aquatic ecosystems. The present review outlines the current state of knowledge on microplastic fiber abundance in nature, bioavailability, and impacts on aquatic animals. Based on these findings, we recommend inclusion of microplastic fibers in prospective monitoring studies, discuss appropriate methods, and propose to conduct exposure studies with - as well as risk assessments of - these underestimated pollutants.

Hitchhiking of encrusting organisms on floating marine debris along the west coast of Qatar, Arabian/Persian Gulf

The floating marine debris (FMD) and the associated rafting communities are one of the major stressors to ecosystem services, global biodiversity and economy and human health. In this study, assemblages of encrusting organisms on different types of stranded FMD along the west coast of Qatar, Arabian/Persian Gulf (hereafter referred to as 'Gulf') were examined. The analysis showed 18 fouling species belonging to 5 phyla (Annelida, Anthropoda, Bryozoa, Mollusca and Porifera) on the FMD. The most abundant fouling species were the encrusting Amphibalanus amphitrite, polychaete Spirobranchus kraussii, Bryozoan species and Megabalanus coccopoma. More number of taxa were found on larger size FMD than on smaller FMD. Some of the barnacle rafting types were found to be non-indigenous species. The central and northwest parts of the Qatar had more FMD and fouled species than in other locations. Winds and the prevailing hydrodynamic conditions (waves and currents) played an important role in the transportation and distribution of FMD and associated organisms along the west coast of Qatar. The present study confirmed that huge amount of bio-fouled FMD items, causing great damage to biodiversity, drift in the surface layer of ocean and eventually strand onto the beaches. We propose a simple, but an effective management plan for FMD and associated organisms at regional scale to restore the biodiversity, sustainability and health of the marine ecosystem in the Gulf.

Factors influencing the vertical distribution of microplastics in the beach sediments around the Ras Rakan Island, Qatar

Microplastic (MP) pollution is an emerging environmental problem, particularly in the marine environment, and nations are concerned about this issue. In this study, an attempt has been made to investigate the vertical distribution of MPs present in the beach sediments around the Ras Rakan Island of Qatar. Sampling was conducted at 9 locations, vertically to a depth of 30 cm with an interval of 5 cm. Attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopy was used to chemically identify the subsets of MPs as polyethylene (PE), polypropylene (PP), polyamide (PA), polyethylene terephthalate (PET), polyvinyl chloride (PVC), and polystyrene (EPS). The counts of MPs were found to be higher in the western and northern parts of the island. The vertical distribution of MPs ranged from 0 to 665 particles/kilogram with maximum abundance at the surface layer (0-5 cm). Pellets were the dominant type of MPs in the surface sediments, whereas fibers were dominant in the bottom sediments. The prevailing winds, waves, tides, and currents are the forces responsible for the distribution and transport of MPs from offshore to the island and further to vertical re-distribution as time progresses. The level of MP pollution along the coast of Ras Rakan Island was higher than that found on the coast of mainland Qatar. Thus, informing that remote islands should also be considered for MP pollution monitoring programs to assess the risk associated with MP on the biota.

Microplastics alone or co-exposed with copper induce neurotoxicity and behavioral alterations on zebrafish larvae after a subchronic exposure

Microplastics (MPs, <5 mm) have been frequently detected in aquatic ecosystems, representing both health and ecological concerns. However data about the combined effects of MPs and other contaminants is still limited. This study aimed to evaluate the impact of MPs and the heavy metal copper (Cu) on zebrafish (Danio rerio) larvae development and behavior. Zebrafish embryos were subchronically exposed to MPs (2 mg/L), two sub-lethal concentrations of Cu (60 and 125 µg/L) and binary mixtures of MPs and Cu using the same concentrations, from 2-h post fertilization until 14 days post fertilization. Lethal and sub-lethal responses (mortality, hatching, body length) were evaluated during the embryogenesis period, and locomotor, avoidance, anxiety and shoaling behaviors, and acetylcholinesterase (AChE) activity were measured at 14 dpf. The results showed that survival of larvae was reduced in groups exposed to MPs, Cu and Cu+MPs. Regarding the behavioral patterns, the higher Cu concentration and mixtures decreased significantly the mean speed, the total distance traveled and the absolute turn angle, demonstrating an adverse effect on swimming competence of zebrafish larvae. Exposure to MPs and Cu, alone or combined, also affected avoidance behavior of zebrafish, with larvae not reacting to the aversive stimulus. There was a significant inhibition of AChE activity in larvae exposed to all experimental groups, compared to the control group. Moreover, a higher inhibition of AChE was noticed in larvae exposed to MPs and both Cu+MPs groups, comparatively to the Cu alone groups. Our findings demonstrate the adverse effects of MPs, alone or co-exposed with Cu, on fish early life stages behavior. This study highlights that MPs and heavy metals may have significant impacts on fish population fitness by disrupting locomotor and avoidance behaviors.

The nexus of macroplastic and microplastic research and plastic regulation policies in the Philippines marine coastal environments

The Philippines was reported as one of the top plastic polluters (macroplastics and microplastics (MPs)) to the marine coastal environment, which necessitated the development and enforcement of plastic regulation policies. However, the nexus between the growing research on macroplastic/MP and the plastic regulation policies in the country is unexplored. Current review suggests that macroplastic/MP research in the Philippines is still in its infancy owing to methodological and technological constraints to apportion the sources and fluxes, characterize macroplastics/MPs, and identify influencing socio-environmental factors. While government efforts are underway, it is also unclear if local researches on macroplastics/MPs were the basis in institutionalizing the existing plastic regulation policies. Therefore the nexus between the researches carried out on this problem and the policies enforced cannot be concluded. Overall, this review presents gaps on the macroplastic/MP research needing more work on the problem to establish a sound science plastic regulation policy.