Large Plastic Debris Research Articles

Micro- and Nano-Plastics Induced Release of Protein-Enriched Microbial Exopolymeric Substances (EPSs) in Marine Environments

Plastics are produced, consumed, and disposed of worldwide, with more than eight million tons of plastic litter entering the ocean each year. Plastic litter accumulates in marine and terrestrial environments through a variety of pathways. Large plastic debris can be broken down into micro- and nano-plastic particles through physical/mechanical mechanisms and biologically or chemically mediated degradation. Their toxicity to aquatic organisms includes the scavenging of pollutant compounds and the production of reactive oxygen species (ROS). Higher levels of ROS cause oxidative damages to microalgae and bacteria; this triggers the release of large amounts of exopolymeric substances (EPSs) with distinct molecular characteristics. This review will address what is known about the molecular mechanisms phytoplankton and bacteria use to regulate the fate and transport of plastic particles and identify the knowledge gaps, which should be considered in future research. In particular, the microbial communities react to plastic pollution through the production of EPSs that can reduce the plastic impacts via marine plastic snow (MPS) formation, allowing plastics to settle into sediments and facilitating their removal from the water column to lessen the plastic burden to ecosystems.

From Sea Water to Salt Crystals: An Onsite Investigation of Microplastics in a Conventional Sea Salt Farming System.

This study investigated microplastic (MP) contamination in conventional sea salt farming systems. Various crude sea salt samples (n = 22) that were traditionally produced were collected from salt farms and local vendors. Salt water (n = 15), macroalgae (n = 6), and clay of pond floors (n = 6) were collected from ponds subjected to different production (stabilization, evaporation, and concentration and crystallization concentration) processes. All samples were analyzed for MP abundance and characteristics. The potential sources of MP contamination in the salt were also investigated. The mean abundance of MPs in the salt water and clay of pond floor increased progressively throughout the production process and reached its highest level in the concentration and crystallization ponds (7400 MP particles/m3 in salt water and 19,336 MP particles/m2 in the clay of the pond floor). A maximum of 26,500 MP particles/kg of macroalgal material indicated the potential sink of MPs on the surface of the algae. Approximately 34-2377 MP particles/kg salt were found in the crude sea salt samples. However, the mean abundance (378 MP particles/kg of salt) indicated nonsignificant impacts of different harvesting processes on MP contamination. Most MP size distributions, shapes and polymer types in the salts were similar to those found in the salt water, macroalgae and clay of the pond floor. Approximately 99% of the MPs were fragments that were suspected to be decomposed from larger plastic debris and plastic machinery and tools used at the salt farm. Similar patterns of polymer distribution, in which PP > PE > PET > PS, were found for all samples studied.

New Insights into Microplastic Contamination in Different Types of Leachates: Abundances, Characteristics, and Potential Sources

Municipal solid waste (MSW) is an important destination for abandoned plastics. During the waste disposal process, large plastic debris is broken down into microplastics (MPs) and released into the leachate. However, current research only focuses on landfill leachates, and the occurrence of MPs in other leachates has not been studied. Therefore, herein, the abundance and characteristics of MPs in three types of leachates, namely, landfill leachate, residual waste leachate, and household food waste leachate, were studied, all leachates were collected from the largest waste disposal center in China. The results showed that the average MP abundances in the different types of leachates ranged from (129 ± 54) to (1288 ± 184) MP particles per liter (particles·L−1) and the household food waste leachate exhibited the highest MP abundance (p < 0.05). Polyethylene (PE) and fragments were the dominant polymer type and shape in MPs, respectively. The characteristic polymer types of MPs in individual leachates were different. Furthermore, the conditional fragmentation model indicated that the landfilling process considerably affected the size distribution of MPs in leachates, leading to a higher percentage (> 80%) of small MPs (20–100 μm) in landfill leachates compared to other leachates. To the best of our knowledge, this is the first study discussing the sources of MPs in different leachates, which is important for MP pollution control during MSW disposal.

The physiological effect of polystyrene nanoplastic particles on fish and human fibroblasts

Numerous studies have identified the detrimental effects for the biosphere of large plastic debris, the effect of microplastics (MPs) and nanoplastics (NPs) is less clear. The skin is the first point of contact with NPs, and skin fibroblasts have a vital role in maintaining skin structure and function. Here, a comparative approach is taken using three fibroblast cell lines from the zebrafish (SJD.1), human male newborn (BJ-5ta) and female adult (HDF/TERT164) and their response to polystyrene NP (PS-NPs) exposure is characterized. Cells were exposed to environmentally relevant PS-NP sizes (50, 500 and 1000 nm) and concentrations (0.001 to 10 μg/ml) and their uptake (1000 nm), and effect on cell viability, proliferation, migration, reactive oxygen species (ROS) production, apoptosis, alkaline phosphatase (ALP) and acid phosphatase (AP) determined. All fibroblasts took up PS-NPs, and a relationship between PS-NP particle size and concentration and the inhibition of proliferation and cell migration was identified. The inhibitory effect of PS-NPs on proliferation was more pronounced for human skin fibroblasts. The presence of PS-NPs negatively affected fibroblast migration in a time-, size- and concentration-dependent manner with larger PS-NPs at higher concentrations causing a more significant inhibition of cell migration, with human fibroblasts being the most affected. No major changes were detected in ROS production or apoptosis in NP challenged fibroblasts. While the ALP activity was increased in all fibroblast cell lines, only fish fibroblasts showed a significant increase in AP activity. The heterogeneous response of fibroblasts induced by PS-NPs was clearly revealed by the segregation of HDF, BJ.5ta and SJD.1 fibroblasts in principal component analysis. Our results demonstrate that PS-NP exposure adversely affected cellular processes in a cell-type and dose-specific manner in distinct fibroblast cell lines, emphasizing the need for further exploration of NP interactions with different cell types to better understand potential implications for human health.

Microplastic Pollution Prevention: The Need for Robust Policy Interventions to Close the Loopholes in Current Waste Management Practices.

Plastic materials that are less than 5 mm in size are defined as Microplastics (MPs). MPs that are intentionally produced are called primary MPs; however, the most abundant type in the environment consists of the remainder created by the fragmentation of large plastic debris through physical, chemical, and oxidative processes, which are called secondary MPs. Due to their abundance in the environment, poor degradability, toxicological properties, and negative impact on aquatic and terrestrial organisms, including humans, MP pollution has become a global environmental issue. Combatting MP pollution requires both remediation and preventive measures. Although remediation is a must, considering where the technology stands today, it may take long time to make it happen. Prevention, on the other hand, can be and should be done now. However, the effectiveness of preventive measures depends heavily on how well MP escape routes are researched and understood. In this research, we argue that such escape routes (rather, loopholes) exist not only due to mismanaged plastic waste, but also due to cracks in the current waste management systems. One known MP loophole is facilitated by wastewater treatment plants (WWTP). The inability of existing WWTP to retain finer MPs, which are finally released to water bodies together with the treated wastewater, along with the return of captured larger MPs back to landfills and their release into the environment through land applications, are a few examples. Organic waste composting and upcycling of waste incineration ash provide other MP escape pathways. In addition, it is important to understand that the plastics that are in current circulation (active use as well as idling) are responsible for producing MPs through regular wear and tear. Closing these loopholes may be best attempted through policy interventions.

Assessing the Impact of Microplastic Filaments Contaminated with PAHs on Mytilus coruscus Larvae through Surface Contact.

In recent years, microplastics have been of great concern in environmental and health research. In field surgeries and laboratory investigations, research interests were focused on the retention of microplastics inside of animals by ingestion and the series of negative effects after that. However, such large plastic debris and filaments are hardly eaten by small animals, like zooplankton, planktonic larvae, etc. In this study, the surface contact between plastic filaments contaminated with polycyclic aromatic hydrocarbons (PAHs) and mussel pediveliger larvae has been investigated to figure out the effects of "non-digestive tract route of exposure" on subject animals. In a 1600 mL artificial seawater medium, high mortalities of mussel larvae were recorded after being exposed to two PAHs-contaminated (benzo[α]pyrene (BaP) and phenanthrene (Phe)) filaments for 5 days, 68.63% for BaP and 56.45% for Phe on average. We suggest that the surface contact was the dominant pathway to transfer PAHs from contaminated filaments to larvae and that the risk of contaminated plastic ropes transferring hydrophobic organic compounds (HOCs) to larvae in mussel aquaculture should be taken seriously.

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.

Microplastic pollution in the sediments of interconnected lakebed, seabed, and seashore aquatic environments: polymer-specific total mass through the multianalytical “PISA” procedure

The total mass of individual synthetic polymers present as microplastic (MP < 2 mm) pollutants in the sediments of interconnected aquatic environments was determined adopting the Polymer Identification and Specific Analysis (PISA) procedure. The investigated area includes a coastal lakebed (Massaciuccoli), a coastal seabed (Serchio River estuarine), and a sandy beach (Lecciona), all within a natural park area in Tuscany (Italy). Polyolefins, poly(styrene) (PS), poly(vinyl chloride) (PVC), polycarbonate (PC), poly(ethylene terephthalate) (PET), and the polyamides poly(caprolactame) (Nylon 6) and poly(hexamethylene adipamide) (Nylon 6,6) were fractionated and quantified through a sequence of selective solvent extractions followed by either analytical pyrolysis or reversed-phase HPLC analysis of the products of hydrolytic depolymerizations under acidic and alkaline conditions. The highest concentrations of polyolefins (highly degraded, up to 864 µg/kg of dry sediment) and PS (up to 1138 µg/kg) MPs were found in the beach dune sector, where larger plastic debris are not removed by the cyclic swash action and are thus prone to further aging and fragmentation. Surprisingly, low concentrations of less degraded polyolefins (around 30 µg/kg) were found throughout the transect zones of the beach. Positive correlation was found between polar polymers (PVC, PC) and phthalates, most likely absorbed from polluted environments. PET and nylons above their respective LOQ values were found in the lakebed and estuarine seabed hot spots. The pollution levels suggest a significant contribution from riverine and canalized surface waters collecting urban (treated) wastewaters and waters from Serchio River and the much larger Arno River aquifers, characterized by a high anthropogenic pressure.Graphical abstract

A Path to a Reduction in Micro and Nanoplastics Pollution

Microplastics (MP) are plastic particles less than 5 mm in size. There are two categories of MP: primary and secondary. Primary or microscopic-sized MP are intentionally produced material. Fragmentation of large plastic debris through physical, chemical, and oxidative processes creates secondary MP, the most abundant type in the environment. Microplastic pollution has become a global environmental problem due to their abundance, poor biodegradability, toxicological properties, and negative impact on aquatic and terrestrial organisms including humans. Plastic debris enters the aquatic environment via direct dumping or uncontrolled land-based sources. While plastic debris slowly degrades into MP, wastewater and stormwater outlets discharge a large amount of MP directly into water bodies. Additionally, stormwater carries MP from sources such as tire wear, artificial turf, fertilizers, and land-applied biosolids. To protect the environment and human health, the entry of MP into the environment must be reduced or eliminated. Source control is one of the best methods available. The existing and growing abundance of MP in the environment requires the use of multiple strategies to combat pollution. These strategies include reducing the usage, public outreach to eliminate littering, reevaluation and use of new wastewater treatment and sludge disposal methods, regulations on macro and MP sources, and a wide implementation of appropriate stormwater management practices such as filtration, bioretention, and wetlands.

Atmospheric emission of nanoplastics from sewer pipe repairs.

Nanoplastic particles are inadequately characterized environmental pollutants that have adverse effects on aquatic and atmospheric systems, causing detrimental effects to human health through inhalation, ingestion and skin penetration1-3. At present, it is explicitly assumed that environmental nanoplastics (EnvNPs) are weathering fragments of microplastic or larger plastic debris that have been discharged into terrestrial and aquatic environments, while atmospheric EnvNPs are attributed solely to aerosolization by wind and other mechanical forces. However, the sources and emissions of unintended EnvNPs are poorly understood and are therefore largely unaccounted for in various risk assessments4. Here we show that large quantities of EnvNPs may be directly emitted into the atmosphere as steam-laden waste components discharged from a technology commonly used to repair sewer pipes in urban areas. A comprehensive chemical analysis of the discharged waste condensate has revealed the abundant presence of insoluble colloids, which after drying form solid organic particles with a composition and viscosity consistent with EnvNPs. We suggest that airborne emissions of EnvNPs from these globally used sewer repair practices may be prevalent in highly populated urban areas5, and may have important implications for air quality and toxicological levels that need to be mitigated.

Research progress on occurrence characteristic and toxicity of microplastics in marine organisms

Plastic products are light, tough, resilient, inexpensive, corrosion-resistant and easy to work with, and have been extensively used in industry, agriculture and daily lives. These plastic debris are discarded and enter the ocean as a result of many different land- and sea-based activities. Microplastics (MPs), defined as plastic fragments ranging from a few micrometers to five millimeters in any dimension, play a key role in the world’s marine litter problem. They originate from two sources, manufactured products (such as abrasive micro-beads in face scrubber cosmetic, toothpastes and antifouling of boats) that contain microplastics (primary microplastics) and fragments released from larger plastic debris through photooxidation, mechanical action and biodegradation (secondary microplastics).The presence of microplastics in the marine environment may be distributed globally by way of currents and winds. Various studies have shown that MPs are now distributed in all oceans, occurring on shorelines, sediments, surface waters even in remote locations (i.e. Arctic) and at all depths. Once entering into ocean, microplastics may pose serious hazards to marine organisms, including phytoplanktons, zooplanktons, clams, mussels, crabs and fishes. Microplastics not only can cause physical harm to marine organisms by contact, uptake and ingestion, but also can provide the marine organisms with a potential pathway for exposure to organic pollutants, metals and pathogens adsorbed from the ambient environment or to chemicals leached by themselves. Microplastics may also pose risks to human health, because they may be transferred through the food chain and can facilitate the food web transfer of incorporated/ adsorbed toxic chemicals. Therefore, the effects of microplastics on the marine environment have become major concerns, marine ecological issues caused by microplastics are now at the forefront of marine ecology and environmental research. Based on the existing research results, this paper summarized the distribution of microplastics in typical marine organisms and its influencing factors. In addition, the toxic effects of microplastics, such as physiological function, oxidative stress, immune response, neurotoxicity and even reproductive genetic toxicity, were summarized. This paper also explained the toxic mechanism of microplastics, including the particle effect of microplastics as foreign bodies into the organism, the leaching of microplastics additives, and the combined toxicity of microplastics and environmental pollutants caused by the adsorption effect of microplastics. At the end of the paper, the problems of microplastics research methods were discussed, the importance of mature and perfect microplastics research system and standards was pointed out and the suggestion that design of future toxicity exposure experiments need to be closer to the real environment was proposed, providing ideas and references for future research on microplastics.

The re-appearance of the Mytilus spp. complex in Svalbard, Arctic, during the Holocene: The case for an arrival by anthropogenic flotsam

Abstract The blue mussel Mytilus spp. complex has re-appeared in the high Arctic in Svalbard after a thousand years, with the first recent indication of its appearance in 2002 at the mouth of Isfjorden on the west coast. We examine its genetic affinity to selected North Atlantic populations and the modes of spread that may be responsible for its recent re-colonisation. We record here its distribution on Svalbard archipelago along the north-western coastline and within Isfjorden collected over a seven years period. We record for the first time the intertidal occurrence that includes a presence close to a glacier front. Genetic composition of mussels Mytilus spp. from different Svalbard locations reveal similarities mainly with populations of M. edulis, M. trossulus and their hybrid from Western Europe, Faroe Island, Scotland and Norway. The re-introduction to Svalbard most probably involved shipping and natural or anthropogenic flotsam. It seems that a new transport vector - large plastic debris - plays a significant role in this process.

Microplastic abundance in beach sediments of the Kiel Fjord, Western Baltic Sea

We assessed the abundance of microplastics (0.2–5 mm) in drift line sediments from three sites in Kiel Fjord, Western Baltic Sea. The first site is intensively used by beach visitors, the second is in close proximity to a sewage plant and the third is polluted with large-sized plastic litter. Samples were split into three grain size classes (0.2–0.5, 0.5–1, 1–5 mm), washed with calcium chloride solution, and filtered at 0.2 mm. Filters were then visually inspected, and a total of 180 fragments was classified as microplastics, of which 39% were analyzed using Raman spectroscopy. At the site that is close to a sewage plant as well as at the site with intense beach use, 1.8 and 4.5 particles (fibers plus fragments) per kg of dry sediment were found, respectively, while particle abundances reached 30.2 per kg of dry sediment at the site with high litter loads. Our data suggest that the fragmentation of large plastic debris at site seems to be a relevant source for microplastics in Western Baltic Sea beach sediments.

Seagrasses provide a novel ecosystem service by trapping marine plastics

There is strong evidence that the seafloor constitutes a final sink for plastics from land sources. There is also evidence that part of the plastics lying on the shallow seafloor are washed up back to the shoreline. However, little is known on the natural trapping processes leading to such landwards return. Here we investigate microplastics and larger plastic debris within beached seagrass remains including balls (aegagropilae) made of natural aggregates of vegetal fibers intertwined by seawater motion. We found up to 1470 plastic items per kg of plant material, which were mainly composed of negatively buoyant polymer filaments and fibers. Our findings show that seagrass meadows promote plastic debris trapping and aggregation with natural lignocellulosic fibers, which are then ejected and escape the coastal ocean. Our results show how seagrasses, one of the key ecosystems on Earth in terms of provision of goods and services, also counteract marine plastic pollution. In view of our findings, the regression of seagrass meadows in some marine regions acquires a new dimension.

Large Plastic Debris Dumps: New Biodiversity Hot Spots Emerging on the Deep-Sea Floor

Macroplastic debris recorded in the Mariana Trench and accumulated on some deep-sea canyons worldwide has aroused great public concerns. Large plastic debris dumps found in canyons of the Xisha Tro...

MICROPLÁSTICOS: OCORRÊNCIA AMBIENTAL E DESAFIOS ANALÍTICOS

MICROPLASTICS: ENVIRONMENTAL OCCURRENCE AND ANALYTICAL CHALLENGES. Plastic pollution is a major societal, economic, and environmental issue. Upon release into the environment, plastics are altered by biological and physicochemical processes that influence their fate and transport within ecosystems. Large plastic debris can fragment into smaller pieces and are called microplastics (MPs) when occurring at sizes between 1 µm and 5 mm, fragmented or produced in this range. These small pieces of plastics are ubiquitous anthropogenic contaminants found throughout the world; however, the environmental consequences and effects on biota are not clearly understood. Scientific literature on the environmental implications of MP pollution is expanding rapidly and critical review of this literature is necessary to identify areas of evolving consensus and remaining gaps in knowledge. Herein a comprehensive literature review was performed to assess (i) the sources and distribution of MPs in different environmental compartments, (ii) the analytical methods that have been applied worldwide, and the key analytical challenges that remain in assessing MPs in the environment, and, finally, (iii) to integrate the findings of Brazilian MP research, which showed that since 2004 (80 papers up to 2020) has documented the presence of MPs in aquatic matrices and sediments with focus on marine ecosystems, mainly identified by visual inspection.

Mikroplastikoen inpaktua, hedapena eta mikroorganismoen bidezko biodegradazioa ozeanoetan

Mikroplastiko sintetikoak (≤ 5 mm) gero eta kantitate handiagoan aurkitzen diren ingurumen-kutsatzaileak dira, mundu osoko estuarioetan eta itsas sistemetan metatzen direnak ezin direlako era errazean degradatu. Mikroplastikoen ugaritasunak, tamaina txikiak eta dentsitate baxuak korronte ozeanikoen bidez sakabanatzen eta garraiatzen laguntzen diete. kutsatzaile horiek erabilera handiko produktuen isurketaren bidez hel daitezke ur-sistemetara, edota ingurumen-baldintza aldakorren pean (izozte-desizoztea, erradiazio ultramorea, ur-korronteak, eta abar) deskonposatzen diren hondar plastiko handiagoetatik sor daitezke itsasoan bertan. Plastiko horien mundu-mailako urteroko fabrikazioa asko handitu da azken hamarkadan, eta konponbide bat laster ez bada eskaintzen, itsasoko mikroplastikoen metaketak eta hedapenak handiagotzen jarraituko du, horrek dakartzan ondorio ekologikoekin eta toxikologikoekin. Alde batetik, mikroplastikoak mikroorganismoen kolonizaziorako aproposak diren gainazalak dira, komunitate naturalen aktibitatean eta konposizioan aldaketak sustatzen dituztenak, eta, ondorioz, ziklo biogeokimikoetan aldaketak ere eragiten dituztenak. Beste alde batetik, mikroplastikoak eta adsorbituta daramaten kutsatzaile kimikoak zein metal astunak ingeritzeko potentzial altua dute itsas animaliek, haien ehunetan eta organoetan metatzen baitira, eta harrezkero, sare trofikoetan zehar transferitu eta biohanditu. Gainera, mikroplastikoek patogenoen, biotoxinen eta antibiotikoekiko erresistenteak diren geneen sakabanaketan parte hartzen dute, eta osasun publikoan eragin zuzena izan dezakete. Naturan badaude entzimen bidez mikroplastikoak guztiz edo partzialki degradatzeko eta energia-iturri moduan erabiltzeko gai diren mikroorganismoak. Beraz, mikroplastikoak degrada ditzaketen mikroorganismoak identifikatzea etorkizun handiko estrategia da biodegradazio naturala errazteko eta ekosistema naturalen garbiketan laguntzeko, ingurumenaren aurkako inpakturik eragin gabe.

The characteristic change of plastic film from common used packing bags under UV photodegradation

<p indent="0mm">Since its invention, plastic has brought great changes to our daily life. It is considered as one of the most basic materials for the development of modern society. Most of the plastic produced are used for packaging and disposable products. Due to the high disposable rate and mismanagement, a large amount of plastic debris enters the marine environment. Potentially lasting several hundred years in the environment, the large plastic debris can be continuously broken into microplastics which are smaller than <sc>5 mm</sc> under the action of ultraviolet light, heat, wind, tide, wave and bacteria etc. Therefore, the amount of microplastics will keep rising in the ocean. Microplastics is considered as a new emerging pollutant and has become a global concern. Understanding the degradation process of plastic in the environment is important for evaluating the contribution of plastic debris as one microplastics source. In this work, polyethylene film from 6 kinds of packaging bags commonly used in our daily life, i.e., food packing bag, garbage bag, thick film, and express packing bag, were selected to carry out photodegradation experiment under ultraviolet radiation in the laboratory. Properties of plastic films were investigated by tensile tests, infra-red spectrometry and scanning electron microscope at various time intervals. The results showed that the elongation-at-break of six kinds of polyethylene film decreased with increasing of UV exposure time. While Young’s modulus showed a trend of increase-decrease with increasing exposure time in general. The yield strength showed a general increasing-decreasing or decreasing trend with increasing exposure time. PE films from food packing bag and degradable garbage bag became brittle and tended to break into microplasics after <sc>36 h</sc> under UV irradiation of <sc>160 W/m².</sc> However, the retained elongation-at-break of PE film from express packing bag was up to 76% after <sc>180 h</sc> UV irradiation. Chain scission and structure changes occurred during photodegradation process. FT-IR spectra indicated that difference existed in photodegraded process among PE films from six kinds of plastic bags. Ether group existed in FT-IR spectra of PE film from food packing bag, while ketone, ester, carboxylic acid, and vinyl group appeared in the spectra of thick film and express packing bag. Carbonyl index, crystallinity index and vinyl index of films from food packing bag, thick film and express packing bag increased at various degrees with prolongation of exposure time. The microstructure at tensile fracture surface became smoother after photodegradation, showing appearance of small fragments. This indicated that the intermolecular force decreased significantly, which was consistent with the trend of mechanical properties. The plastic packing bags commonly used in our daily life tend to become brittle and fragment into small pieces under ultraviolet radiation and become one source of microplastics in environment. These results can provide basic data and theoretical support for study of environmental behavior processes of plastic debris and source of microplastics, assessment of environmental risk, etc.

Occurrence, Composition, and Relationships in Marine Plastic Debris on the First Long Beach Adjacent to the Land-Based Source, South China Sea

Land-based sources are the key sources of plastic debris, and mismanaged plastic debris can eventually enter the ocean via marine beaches. In this study, the spatial distribution and amount of plastic debris in the land-based source input zone of First Long Beach (FLB), China, which is a major tourist attraction, were first investigated. By using field investigation, sand samples were collected from two sections on FLB adjacent to land-based sources in December 2019, and the plastic debris in the sand samples was quantified and characterized in the laboratory. The amount of plastic debris ranged from 2 to 82 particles/m2 on this marine sand beach. There was a significant difference in plastic debris amount between the transects along the land-based source input zone (p &lt; 0.05) due to the impacts of wind, ocean currents, and waves. The most abundant size of plastics was 0.5–2.5 cm (44.4%). Moreover, the most common color was white (60.9%). The most abundant shape of plastic debris fell into the fragment category (76.2%). The plastic debris amounts were significantly correlated with multiple sizes. Our results show that land-based wastewater discharge is a large plastic debris source on FLB under coastal water tide variation. Reduction strategies should be carried out by tracing the various land-based sources of plastic debris.

Spatial variation of floatable plastic debris and microplastics in the Pearl River Estuary, South China

The estuaries of populated catchments have been documented as hotspots of plastic pollution. In this study, microplastics (0.355–5.0 mm) and large plastic debris (>5.0 mm) of surface water collected from the Inner Lingding Bay of the Pearl River Estuary (PRE) were quantified and categorized according to their size, shape, colour and composition. Both microplastics and large plastic debris were detected at all sampling sites with mean abundances of 2.376 ± 0.700 n/m3 and 0.110 ± 0.039 n/m3, respectively. Microplastics constitute 95.4% of the total abundance by number. The average microplastic concentration in the inner PRE was almost 3.5 times higher than that in the central PRE, indicating a positive correlation between plastic concentration and proximity to the river mouth. This result reveals the important role of rivers in transporting plastic debris from land to the oceans.