Microplastics In Coastal Sediments Research Articles

Vertical distribution of microplastics in coastal sediments of Xuwen Coral Reef National Nature Reserve, China

Vertical distribution of microplastics in coastal sediments of Xuwen Coral Reef National Nature Reserve, China

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.

WITHDRAWN: Sediment pollution in coastal and marine environments

Sediment pollution in coastal and marine environments has emerged as a pressing concern due to its far-reaching ecological, environmental, and human health impacts. This Special Issue of the Marine Pollution Bulletin assembles a diverse range of studies investigating sediment pollution, its causes, and potential mitigation strategies, covering topics such as geophysical assessment of anthropogenic activities, biological responses to pollution, contamination, and ecological risk assessments, and microplastics in coastal sediments. The findings emphasize the need for effective monitoring, management, and interdisciplinary research to address the multifaceted challenges posed by sediment pollution. As the global population grows and human activities expand, it is essential to prioritize sustainable practices and policies to minimize anthropogenic impacts on coastal and marine ecosystems. By advancing collective knowledge and sharing best practices, we can work towards ensuring a healthier and more resilient future for these crucial ecosystems and the lives they support.

Identification of microplastics in coastal sediments of three ports of Dayer, Kangan, and Siraf in Bushehr province, Iran

The microplastic particles in surface and deep sediments of the Persian Gulf coast located in three ports of Dayer, Kangan, and Siraf in Bushehr province, Iran were investigated. Sediment samples were collected from 18 stations in the low tide range of the Persian Gulf coast at two depths of 0–5 cm and 5–20 cm. After the separation of microplastics through the floating method, their characteristics were identified using a stereomicroscope. The average abundance of microplastics identified in surface and deep sediment were 587.77 ± 145.54 and 569.44 ± 131.16 items per kg dry sediment respectively. Identified microplastic shapes included fiber, fragment, film, and foam, that fiber particles having the highest abundance at both depths compared to the other shapes. Most of microplastic particles were in the range of 500–1000 μm, and they were blue, black, and green. The highest abundance of microplastics in ports was found at stations near residential and populated areas, and industrial areas. The results of this study provide useful information for further research to understand the sources of pollutants entering the environment and regular management to protect coastal areas.

Effect of lithological properties of beach sediments on plastic pollution in Bodrum Peninsula (SW Türkiye)

The effects grain size on transport and retention of plastics in sediments are controversial issue. Four beaches were selected on the Bodrum Peninsula (SW Türkiye) for this study. Twenty-four samples with poorly to well sorted, sandy gravel, gravel, or gravelly sand were collected from the top five cm of the sampling quadrant's four corners and center of 1 m2 area, from shoreline and backshore. The highest plastic content (38 mesoplastics/600 g – 455 microplastics (MPs)/1200 g) was determined on the Bodrum Coast having the highest population. Polyethylene (PE), polypropylene (PP), polyvinyl chloride (PVC), polystyrene (PS), polyethylene terephthalate (PET) and polyurethane (PU) were predominantly detected with Fourier Transform Infrared Spectroscopy (FTIR) analysis as MPs as a fragment and fiber. This study indicates the negative correlation between grain size and the number of MPs in coastal sediments. Anthropogenic activities are evaluated as a possible primary source of plastic pollution in the study area.

Are seafloor habitats influencing the distribution of microplastics in coastal sediments of a Marine Protected Area?

The marine environment is affected by the increasing presence of microplastics (MPs; < 5 mm), and the seafloor acts as a sink for these particles. Locations with different predominant seafloor habitat and protection level applied were selected from Cabrera Marine-Terrestrial National Park (henceforth, Cabrera MPA) (western Mediterranean Sea) with the aim to assess the distribution of MPs along the sediments of this Mediterranean MPA. A total of 37 samples were collected. A high diversity of sediment between locations was detected according to the Udden-Wentworth classification and locations were clustered into two main groups according to the predominance of different particle size fractions. The identification of MPs was carried out according to the sediment particle size classification. A total of 1431 MPs and a mean value (± SD) of 314.53 ± 409.94 items kg−1 D.W. were identified, and 70% of the particles were fibers. Statistically higher abundances of MPs were found in sediments collected from sandy habitats, with a mean value of 630.80 ± 636.87 items kg−1 D.W., compared to the abundances of MPs found in locations with different predominant seafloor habitats, that ranged from 136.79 ± 156.33 items kg−1 D.W. in habitats with similar predominance of seagrass and sand to 223.02 ± 113.35 items kg−1 D.W. in habitats with similar predominance of rocks and sand. The abundance of MPs regarding each sediment particle size fraction differed between years and locations, and the abundance of MPs according to each identified shape differed between sampling years, particle size fraction, and predominant seafloor habitat. The present study highlights the ubiquitous presence of MPs in seafloor sediments from a MPA. Furthermore, the results suggest that the predominant seafloor habitat can modulate the presence of MPs in marine environments in both general abundances and shape of items.

Understanding the underestimated: Occurrence, distribution, and interactions of microplastics in the sediment and soil of China, India, and Japan

Microplastics (MPs) are non-biodegradable substances that can sustain our environment for up to a century. What is more worrying is the incapability of modern technologies to annihilate MPs from om environment. One ramification of MPs is their impact on every kind of life form on this planet, which has been discussed ahead; that is why these substances are surfacing in everyday discussions of scholars and researchers. This paper discusses the overview of the global occurrence, abundance, analysis, and remediation techniques of MPs in the environment. This paper primarily reviews the event and abundance of MPs in coastal sediments and agricultural soil of three major Asian countries, India, China, and Japan. A significant concentration of MPs has been recorded from these countries, which affirms its strong presence and subsequent environmental impacts. Concentrations such as 73,100 MPs/kg in Indian coastal sediments and 42,960 particles/kg in the agricultural soil of China is a solid testimony to prove their massive outbreak in our environment and require urgent attention towards this issue. Conclusions show that human activities, rivers, and plastic mulching on agricultural fields have majorly acted as carriers of MPs towards coastal and terrestrial soil and sediments. Later, based on recorded concentrations and gaps, future research studies are recommended in the concerned domain; a dearth of studies on MPs influencing Indian agricultural soil make a whole sector and its consumer vulnerable to the adverse effects of this emerging contaminant.

Effects of waves, burial depth and material density on microplastic retention in coastal sediments

Coastal sediments, recognized as a major sink for microplastics (MPs), are subject to frequent physical disturbances, such as wave disturbance and associated sediment dynamics. Yet it remains poorly understood how wave disturbance regulates MPs accumulation in such a dynamic environment. Here, we examined the effects of waves and their interactions with material density and burial depth on the retention of MPs in coastal sediments, through manipulative experiments in a mangrove habitat along the coast of South China. The results clearly revealed that stronger waves removed more buried MPs from the sediments. Moreover, storms can have disproportional effects on MPs retention by inducing large waves and strong sediment erosion. We also demonstrated that MPs retention generally increased linearly with growing material density and non-linearly with raised burial depth in the sediment. Overall, our findings highlight the importance of both external and internal factors in shaping MPs retention in coastal ecosystems like mangroves, which is essential to assess and predict MPs accumulation patterns as well as its impacts on ecosystem functioning of such blue carbon habitats.

Textural characteristics and abundance of microplastics in Tecolutla beach sediments, Gulf of Mexico.

Abundance of microplastics in coastal sediments is considered an emerging pollution problem worldwide. In Mexico, studies focused on microplastics in coastal sediments are little. In this study, we analyzed the textural characteristics and investigated the abundance of microplastics in the Tecolutla beach sediments, SW Gulf of Mexico. The extraction of microplastics in sediments was done by density separation. Microplastics were identified by stereomicroscope and scanning electron microscopy, and were classified based on their morphology, color, length, texture, and abundance. Among 181 microplastics, fiber type is predominant (number of microplastics n = 166; 92%) and followed by film (n = 12; 6%) and fragment (n = 3; 2%) types. The most abundant color of microplastics is black (n = 81; 45%) and second dominant color is blue (n = 65; 36%); most of them are fiber type. Based on the textural characteristics of sediments, it was observed that microplastics were derived from the fluvial contribution of the Tecolutla River and were deposited in the coastal environment by ocean currents. This study revealed that the abundance of microplastics was high in fine-grained sediments and was directly proportional to skewness. The results of this study can act as a reference for understanding the abundance of microplastics in the Gulf of Mexico coastal sediments.

Prevalence of small-sized microplastics in coastal sediments detected by multipoint confocal micro-Raman spectrum scanning

Microplastics have become global emerging issue and received widespread attention in recent years. Due to their chemical persistence, plastic particles can be broken into smaller items but accumulated for long time in the environment like sediment. However, limited by current detection technologies, the distribution and characteristics of small-sized microplastics in coastal sediment remain uncertain. In this study, we established a new method based on micro-Raman spectroscopy for detecting small-sized microplastics, namely multipoint confocal micro-Raman spectrum scanning (MCmRSS). The MCmRSS was first applied in detecting microplastics in the sediment samples collected from three bays of the East China Sea. The minimum size of microplastics was 4 μm and average microplastics concentration was 91 ± 55 items /g dry weight sediment, with fragment and polyethylene as the most common shape and polymer type, respectively. The spatial variation of microplastics was in accordance with the strength of coastal human activities and marine dynamics. In all the microplastic items, the small-sized ones (<10 μm) accounted for 67%; and the relationship between microplastic concentration and its size followed a power-exponential equation. Compared with previous studies, the number of microplastics in coastal sediments detected by the MCmRSS increased by 2 orders of magnitude, which was benefited from the advantages of multipoint scanning in the fixed identification areas and high resolution of micro-Raman spectrum. Our findings would summon the re-evaluation of the potential risks of small-sized microplastics in the coastal environment.

Accumulation and distribution of microplastics in coastal sediments from the inner Oslofjord, Norway

Microplastic presence in benthic marine systems is a widely discussed topic. The influence of the natural matrix on microplastic distribution within the sedimentary matrix is often overlooked. Marine sediments from the western inner Oslofjord, Norway, were investigated for temporal trends, with a particular focus on the relationship between sediment grain-sizes and microplastic distribution. Density separation, optical microscopy and chemical validation were used to categorize microplastics. Microplastic concentrations ranged from 0.02 to 1.71 MPs g −1 dry weight (dw). Fibres were the most common (76%), followed by fragments and films (18%, 6%). Common polymers were polyesters (50%), polypropylene (18%), polymethylmethacrylate (9%), rayon and viscose (5%) and elastane (4%). Microplastics appear to accumulate preferentially according to their morphology and polymer type in certain sediment grain-sizes. Microplastics inputs to the Oslofjord appear to derive from a wastewater treatment plant in the vicinity. Although, the redistribution of microplastics within the fjord needs further investigation.

Distribution and abundance of microplastics in coastal sediments depends on grain size and distance from sources

Microplastic deposition in marine sediments is a geographically widespread problem. This study examines microplastics in intertidal and subtidal sediments at 87 locations in habitats designated as Special Areas of Conservation (SACs) and Special Protection Areas (SPAs) on the coastline of Ireland. Established methodological approaches including, organic matter digestion, density separation, particle extraction and polymer identification were applied. Microplastic abundance was closely related with distance from known sources and concentrations were greater in intertidal as opposed to subtidal sediments. Colourless, polyethylene fibres and polypropylene fragments were the most abundant MP recorded and finer grained sediments were shown to entrap more MPs than coarser sediments. The results demonstrate that an understanding of potential sources of pollution, sediment type and hydrodynamic conditions are very important in terms of MP abundance and distribution in marine sediments and also in terms of effective waste management strategies and policy aimed at reducing the global plastics problem.

Personal Care and Cosmetic Products as a Potential Source of Environmental Contamination by Microplastics in a Densely Populated Asian City

The prevalence of microplastics in the environment has become a major global conservation issue. One primary source of environmental microplastics is personal care and cosmetic products (PCCPs) containing microbeads. The market availability of PCCPs containing microbeads and the level of contamination of coastal sediments by microplastics was studied in one of the most densely populated cities in the world, Macao in China. We found that PCCPs containing microbeads are still widely available for sale in the region, with over 70% of surveyed PCCPs containing at least one type of microbeads as an ingredient, with polyethylene (PE) being the most common one. In an estimate, the use of PCCPs in the territory may release over 37 billion microbeads per year into the environment via wastewater treatment plants. The density of microplastics in coastal sediments varied between 259 and 1,743 items/L of sediment, amongst the highest reported in the world. The fraction of &amp;lt; 1 mm was the most abundant, representing an average of 98.6% of the total, and correlated positively with the abundance of larger sized fragments. The results show that although environmental pollution with microplastics released from PCCPs usage is significant, other sources, namely fragmentation of larger plastic debris, likely contribute more to the issue. The study highlights the magnitude of the problem at a local level and suggests possible mitigating strategies.

Source and risk assessment of heavy metals and microplastics in bivalves and coastal sediments of the Northern Persian Gulf, Hormogzan Province

The objectives of the current study are to investigate the concentration, biological risks, chemical speciation, and mobility of of heavy metals and also the determination of their distribution, physicochemical characteristics, and abundance of microplastics in coastal sediments and edible bivalves in the Persian Gulf, the coastal area of Hormozgan Province. Sampling points were selected considering the location of industrial, urban and Hara forest protected areas. In November 2017, a total of 18 sediment samples from coastal sediments (top 0–10 cm) and the most consumed bivalve species in the region were collected from two stations, Lengeh and Bandar Abbas Ports. The average concentration of heavy metals (except for Ni and Cd) in the sediments were lower than their average shale and the upper continental crust. Enrichment factors revealed significant enrichment of Ni, Mn, Cr, Cd and As. The fractionation of heavy metals using the Community Bureau of Reference (BCR) sequential extraction scheme indicated the high bioavailability of Zn, As, Mn, and Co. In general, the highest concentration of Mo, Cd, Pb, Zn, Cr, Cu, Mn, Hg, and Sb was detected in areas with frequent human activities including Shahid Rajaee Port, Shahid Bahonar Port, and Tavanir station. Shahid Rajaee and Shahid Bahonar Ports are the most important ports on the coast of Hormozgan province. The Risk Assessment Code calculated for the study elements indicates that As, Co, Zn, and Cu pose a moderate environmental risk a threat to the aquatic biota. Health risks of most heavy metals arising from bivalves consumption were safe, except for As which is associated with the high target cancer risk values. With reference to the type of microplastics found, they were mainly fibeours with lengths ranging between 100 and 250 μm in sediments and bivalves. Most of the microfibers found in the sediments were made of polyethylene terephthalate (PET) and polypropylene (PP), and the fibers found in the bivalves were made of PP.

Microplastics in coastal sediments of Ełckie Lake (Poland)

Plastics are materials with many properties that make them extremely popular in everyday life and various industries. Studies show that plastic debris is global pollution and widespread in virtually all ecosystems. This study aimed to assess the coastal sediments of Ełckie Lake in terms of the presence of microplastics. Samples of sediments (n = 37) from the coastal zone of Ełckie Lake were drawn from different areas, including urban, rural, and tourist locations, and beaches. After the coastal sediment samples taking, they were subjected to density separation, filtration, and visual evaluation using the Olympus BX63 fluorescent microscope. Particles were classified according to the category of visible characteristics of microplastics including size, shape and colour. The results of the study showed the presence of microplastics in 84% of the examined coastal sediment samples of Ełckie Lake. Fibres, flakes, granules, and foils (films) had found in 58%, 45%, 32%, and 13% of the samples that contained microplastic, respectively. The majority of the detected microplastic was 0.5–1 mm in size and black was the dominant colour. Spatial variability was perceived in microplastic concentrations, giving premises to the assumption of dependence between local human activity and the content of particles.

Factors influencing the occurrence and distribution of microplastics in coastal sediments: From source to sink

Microplastic (MP) pollution is attracting growing global attention, but little is known about the factors influencing MP occurrence and distributions in marine sediments. Here, MPs were sampled from the sediments of two semi-enclosed bays (Jinghai Bay and Laizhou Bay) and two coastal open zones (Lancelet Reserve and Solen grandis Reserve) in China. The order of MP abundance was Jinghai Bay > Laizhou Bay > Lancelet Reserve > Solen grandis Reserve. Average MP diversity indices for Laizhou Bay (1.84 ± 0.18), Lancelet Reserve (1.59 ± 0.43), S. grandis Reserve (1.58 ± 0.89), and Jinghai Bay (1.43 ± 0.14) revealed Laizhou Bay had the most complicated MP sources. A significant negative correlation between MP abundance and sediment grain size occurred in the semi-enclosed coastal zones (p = 0.004, r = −0.618) rather than in the open coastal zones (p = 0.051, r = −0.480), indicating small sediment particles can strongly enhance MP accumulation in semi-enclosed costal sediments. Although anthropogenic activities influence the MP distribution at source, the composition of regional and local sediments might impact MP occurrence in semi-enclosed coastal zones from the sink. These results help to improve our understanding of the fate and inventory of MPs in coastal sediments.

Geochemistry and environmental effects of potentially toxic elements, polycyclic aromatic hydrocarbons and microplastics in coastal sediments of the Persian Gulf

Coastal areas are critical parts of the Persian Gulf with regard to high populations and economically driven activity. They pose major concerns because of the presence of toxic chemicals, and hence harmful effects on marine ecosystems. In this study, 14, 15 and 12 coastal sediment samples were collected in Bushehr province and analyzed, respectively, for potentially toxic elements (PTEs), polycyclic aromatic hydrocarbons (PAHs) and microplastics (MPs). The results showed that almost all PTEs were not significantly enriched. Most elements exhibited their highest levels at stations close to urban areas and along the pathway of ships and boats. Based on enrichment factor and statistical evaluations, two main sources of trace elements were identified: anthropogenic (Mo, Cu, Pb, As and Sb) and geogenic (Zn, Ni, Co, Mn, Fe, Cd, Cr and Al). Regarding MPs, a total of 577 pieces were observed with sizes ranging between 500 and 1000 µm. The dominant shape of the MPs was fibrous with the dominant colors being white and black. The concentration of total PAHs were fairly low in the sediments, with their source determined to be pyrogenic in origin.

Microplastic distribution in surface sediments along the Spanish Mediterranean continental shelf

Microplastics (MPs) are widely recognised as a contaminant of emerging concern in the marine environment. This work provides original data of the presence of MPs in coastal sediments along the Spanish Mediterranean continental shelf. Ten surface sediment samples were collected in order to document baseline microplastic distribution from Algeciras to Barcelona. Microplastics were extracted from bulk sediments by density separation. The number of microplastics per kilogramme of dry weight ranged from 45.9 ± 23.9 MPs/kg d.w. observed at Palma de Mallorca to 280.3 ± 164.9 MPs/kg d.w. noted at Málaga, with an average value of 113.2 ± 88.9 MPs/kg d.w. The lower limit is defined by the pore filter size used (1.2μm). For all analysed locations, the dominant microplastic type was fibres (82.9%), followed by fragments, and the main colours were transparent and blue. Microplastic size distribution was presented; in the case of fragments, 85% was lower than 0.5mm, and in the case of fibres, the three studied intervals (0.5-1, 1-2, 2-5mm) had similar distribution (35, 34 and 31%, respectively). Attending to all available data, no statistically significant relationship (Spearman's correlation) was found between microplastic average size and distance to the coast, the depth, density population and sediment grain size. Neither relationship was observed between these variables and microplastic concentration using the non-parametric Kruskal-Wallis H test. This study has confirmed the widespread distribution of MPs in surface sediments from the Spanish Mediterranean continental shelf, and these data are useful to define baselines for MPs in the Western Mediterranean region.

First record of characterization, concentration and distribution of microplastics in coastal sediments of an urban fjord in south west Norway using a thermal degradation method

Plastic waste is of increasing concern in the aquatic environment. A large proportion of plastic waste is generated onshore from where it eventually reaches the marine environment, which is considered the main sink of plastic debris To date there is a substantial lack of knowledge on the composition of these accumulated polymers, their environmental levels and distribution in marine and coastal areas. Current efforts are underway to develop standardized methods to characterize and quantify the occurrence of microplastic in different environmental matrices using microscopy-oriented methods using Fourier Transformed Infra-Red (FTIR) or Raman techniques. However, time-consuming sample preparation, processing and interpretation of complex data limits their use within monitoring programs. As an alternative, a thermal degradation method based on a gas chromatographic mass spectrometer coupled with pyrolysis represents a validated method for qualitative and quantitative polymer analyses. A technique has been developed that combines sample preparation and thermo-analysis for identifying microplastics in samples of marine sediment. Quantification and polymeric composition of plastic particles found in sediment samples taken from ten sites located in Boknafjorden subjected to diverse sources of pollution and anthropogenic pressure were investigated. Plastic microparticles were extracted from 8 kg of wet sediments per site, purified, size-fractionated thorough a set of stainless-steel certified sieves covering the range of 10–250 μm mesh size, pre-concentrated on fiberglass filters and whole filters analyzed by thermal desorption pyrolysis gas chromatography/mass spectrometry. Most of the detected polymers were identified as polypropylene, polyethylene, polyethylene terephthalate, polyvinylchloride, polystyrene or polyamide. In most of the sites, the largest fraction of the extracted micro debris fell in the size range 10–40 μm. Some shifts in size distribution were also observed in some sites and were likely related to the marine sea bottom currents and the influence of specific anthropogenic activities. The adopted thermal degradation method showed good sensitivity, reliability and rapidity and therefore represents a promising technique for microplastic analysis within monitoring activities.

Microplastics are ubiquitous on California beaches and enter the coastal food web through consumption by Pacific mole crabs

Microplastics are commonly found in marine ecosystems, but their distribution, prevalence, and impacts on resident fauna are still not well understood. Microplastics in coastal sediments expose invertebrate infauna to the risk of ingestion of plastic debris and associated toxicants. We assessed the prevalence of microplastics in beach sediments and ingested by Pacific mole crabs (Emerita analoga) at sandy beaches spanning >900 km of the California coast. Microplastics were present in sediments of every one of 51 beaches sampled. At a subset of 38 beaches Pacific mole crabs were collected and crabs at every beach had ingested microplastics. Across all beaches sampled, an average of 35% of Pacific mole crabs examined had microplastics in their guts. Our study demonstrates that microplastics are ubiquitous in sediments on California beaches and they are frequently consumed by a filter-feeding crustacean that is a common prey item in the diet of a wide variety of taxa, including fishes and birds.