Polyethylene Fragments Research Articles

Oxidative Stress in Mussel Mytilus trossulus Induced by Different-Sized Plastics.

Polyethylene and polystyrene are massively used around the world in various applications and are the most abundant plastic waste. Once in the marine environment, under the influence of physical and chemical factors, plastic products degrade, changing from the size category of macroplastics to microplastics. In order to study the effect of plastic on marine organisms, we modeled the conditions of environmental pollution with different-sized plastic-polystyrene microparticles of 0.9 µm and macro-sized polyethylene fragments of 10 cm-and compared their effect on biochemical parameters in the tissues of the bivalve mollusk Mytilus trossulus. Using biomarkers, it was found that regardless of the size and type of polymer, polystyrene microparticles and polyethylene macrofragments induced the development of oxidative stress in mussels. A significant decrease in the level of lysosomal stability in mussel hemocytes was observed. Increases in the level of DNA damage and the concentration of malonic dialdehyde in the cells of gills and the digestive gland were also shown. The level of total antiradical activity in cells varied and had a tissue-specific character. It was shown that both ingested polystyrene particles and leachable chemical compounds from polyethylene are toxic for mussels.

Microplastics in sea surface waters in the Southern Bight of the North Sea

Microplastic pollution in the marine environment is of concern, with evidence of harmful effects on marine biota and ecosystems. There is still a knowledge gap of the mass of plastics supplied to the ocean and plastics observed in the ocean, indicating a missing sink. Therefore, baseline and monitoring data are needed to inform policy and regulatory measures. The goal of this study was to collect harmonised data of microplastics from the surface of the ocean using the Neuston Microplastic Catamaran. This study shows that the surface water of the coastal ocean in the North Sea holds/sustains high concentrations of microplastic, which exceed previously recorded measurements from the North-East Atlantic and Scottish Waters, indicating that the total stock of plastics might be much higher than previously determined. Microplastics were detected in all samples with concentrations ranging from 857 to 25,462 items km−2. The majority of microplastics analysed were fragments of polyethylene, polypropylene, and polystyrene in the size range of 1,000–5,000 µm. Mesoplastics (>5,000 µm) mainly in the form of filaments were found with concentrations ranging from 0 to 2,139 items km−2, and macroplastics (>5,000 µm) in the form of fragments and filaments were also found with concentrations ranging from 0 to 1,078 items km−2. These fragments and filaments likely originate from the break-up of common macrolitter items in the environment, such as plastic bags, bottles, and fishing gears, which are commonly comprised of similar polymers to those found in the present study. Our findings demonstrate that litters of all size classes are abundant in surface water, highlighting that it is a key compartment for the transport of marine litter and should be monitored to better our understanding of the fate and danger of plastic contamination in our ocean.

Modification of Petroleum Bitumen with Secondary Polyethylene in the Presence of Vermiculite

This article presents studies on the modification of petroleum bitumen with polymer waste in the presence of vermiculite. An increase in temperature leads to an increase in the interaction of components, partial breakage of polyethylene and bitumen macromolecules, and the formation of radical-free valences. As a result, fragments of polyethylene and bitumen molecules react with each other, and the formation of qualitatively new structural formations occurs via the strong connection of polar and amorphous bitumen with nonpolar structurally viscous polyethylene. Domestically produced Kulantau vermiculite was used to ensure stable adhesion over a wide temperature range and increase the specific surface area, which acquired additional energy, resulting in an increase in the degree of adhesion to bitumen and increased durability of the binder with improved rheological characteristics. Because of the increased service life of road asphalt pavements, the use of the latter results in a considerable decrease in the cost of polymer-bitumen binders. Based on improved binder formulations, asphalt concrete exhibits excellent water resistance and strength at 50 °C (4.7 to 5.0 MPa). In summary, the modification of bitumen with polymer waste and vermiculite offers a promising avenue for improving the performance and longevity of asphalt pavements.

Biodegradation of polyethylene in digestive gland homogenates of marine invertebrates.

Вiotic factors may be the driving force of plastic fragmentation along with abiotic factors. Since understanding the processes of biodegradation and biological depolymerization of plastic is important, a new methodological approach was proposed in this study to investigate the role of marine invertebrate digestive enzymes in plastic biodegradation. The aim of this study is to evaluate the possibility of enzymatic biodegradation of polyethylene fragments in the digestive gland homogenate of marine invertebrates differing in their feeding type (Strongylocentrotus nudus, Patiria pectinifera, Mizuhopecten yessoensis). Significant changes are found in the functional groups of the polymer after 3 days of incubation in the digestive gland homogenates of the studied marine invertebrates. A significant increase in the calculated CI (carbonyl index) and COI (сarbon-oxygen index) indices compared to the control sample was observed. The results suggest that digestive enzymes of studied organisms may play an important role in the biogeochemical cycling of plastic.

Cellular effects of microplastics are influenced by their dimension: Mechanistic relationships and integrated criteria for particles definition.

The definition of microplastics (MPs) is nowadays too generic from a biological perspective, since different characteristics of these particles might influence their effects. To provide experimental evidence that size is an important factor to be considered, Mediterranean mussels Mytilus galloprovincialis were exposed to five size classes of polyethylene fragments (PE-MPs, 20–50 μm, 50–100 μm, 100–250 μm, 250–500 μm, 500–1000 μm). After 10 days of exposure, MPs ingestion and mechanistic relationships between particles size and cellular effects were analysed through a wide panel of biological alterations, including immune system responses, cholinergic function, antioxidant system, lipid metabolism and peroxidation. Results were further elaborated through a Weight of Evidence approach, summarizing the overall biological significance of obtained results in a hazard index based on the number and magnitude of variations and their toxicological relevance. PE-MPs 500–1000 μm were identified as the less biologically reactive size class due to the limited ingestion of particles coupled with the lack of biological effects, followed by PE-MPs 250–500 μm, which slightly altered the cholinergic function and lysosomal membranes. Conversely, PE-MPs smaller than 250 μm provoked a more consistent onset of biological alterations in terms of immune system composition and functioning, redox homeostasis, and lipid metabolism. The overall findings of this study highlight the importance of considering the size of particles for monitoring and risk assessment of MPs, introducing a more integrated evaluation of plastic pollution that, beside particles concentration, should adequately weigh those characteristics triggering the onset of biological effects.

Enzymatic Stress Responses of Coreius guichenoti to Microplastics with Different Particle Sizes.

The wild population resources of Coreius guichenoti have sharply declined in recent decades, and any negative factors may have a significant impact on their survival. In this study, the enzymatic stress responses of C. guichenoti to 25 and 48 μm polyethylene fragments were explored for the first time. This was achieved by evaluating the changes in physiological and biochemical indicators of the species in response to the environmental stimuli of microplastics. In this study, we observed an early stress response in the external tissues of C. guichenoti following exposure to microplastics. The TP content in skin and muscle and the MDA content in skin, gill and muscle initially showed a significant increase. The skin, gill, and muscle exhibited greater stress responses to M5 particles, whereas M3 particles caused a greater response in the intestine and especially the liver. After the removal of microplastic exposure, the stress state of the C. guichenoti would be alleviated in a short period, but it could not fully recover to the pre-exposure level. In summary, microplastics pose a significant threat to C. guichenoti. While their negative effects can be alleviated by the removal of microplastics exposure, full recovery does not occur in a short period. Continuous monitoring of microplastics in natural waters and targeted aquatic ecological restoration are essential to ensure the normal growth and reproduction of the wild population of C. guichenoti.

Investigating the correlation between morphological features of microplastics (5–500 µm) and their analytical recovery

As a direct result of laboratory sample manipulation required to identify microplastics (MPs) within a given matrix, some MPs are inevitably lost. The extent of this loss can be quite significant and varies greatly depending on the sample matrix, choice of protocol and target MPs in question. Defining analytical MP recovery is therefore a critical component in ensuring the quality of MP protocols. The potential relationship between particle size and recovery rate has been widely discussed but remains uncertain. To determine whether MP loss correlated with particle size, three aliquots of polyethylene fragments in the 5–50 µm size range and three aliquots of polypropylene fragments in the 50–500 µm size range, were consecutively transferred back and forth from filter to liquid. After each individual transfer the analytical recovery within specified size groups, was evaluated by applying high-resolution darkfield microscopy. Average recovery across the entire size range was estimated at 80% with a standard deviation (std. dev.) of 26%. Notably, particle coverage on filters (A%) showed a more significant impact on recovery than particle size. Maintaining A% below 5% on filters for microscopic analysis is advised to prevent excessive loss due to particle agglomeration. To determine whether the use of red polyethylene fragments in the 5–50 µm size range in combination with darkfield microscopy could potentially improve MP recovery evaluation in environmental samples, three aliquots of 0.5 g of dry brown trout muscle tissue were spiked and treated according to a relevant protocol. This size-discriminating approach accurately determined average recovery at 52% with a std. dev. of 4% and demonstrated the potential for correction of the concentration enhancement of smaller MPs resulting from particle breakup during sample pre-treatment, which would otherwise lead to overestimation of smaller size fractions.

P14-02: Pulmonary toxicity assessment of polypropylene, polystyrene, and polyethylene fragments in mice

P14-02: Pulmonary toxicity assessment of polypropylene, polystyrene, and polyethylene fragments in mice

Occurrence and distribution of microplastics in long-term biosolid-applied rehabilitation land: An overlooked pathway for microplastic entry into terrestrial ecosystems in Australia

Wastewater treatment plants (WWTPs) efficiently eliminate over 98% of microplastics (MPs) from wastewater discharge, subsequently accumulating them in sludge. This sludge is frequently employed as fertilizer in agricultural practices or land rehabilitation. While there is significant research on biosolid application in agriculture, the discussion regarding its application in rehabilitating industrial zones and MPs contamination is limited. The current study investigates the abundance, distribution, and composition of MPs in rehabilitation land with long-term biosolid-application in Australia. Three minesite fields (designated 1–3), each with distinct biosolid application histories since 2011, 2012, and 2017, and a control field without any biosolid application history, were chosen for this study. The abundances of MPs in biosolid-applied fields 1–3 (6.04 ± 1.92 x 102 MP kg−1; 4.94 ± 0.73 x 102 MP kg−1; 2.48 ± 0.70 x 102 MP kg−1) were considerably higher compared to non-biosolid-applied field (0.70 ± 0.63 x 102 MP kg −1). This indicates that the application of biosolids significantly contributes to the presence of MPs in the soil. Moreover, the results suggest that with each successive application, the abundance of MPs increases. The abundance and size of MPs in both biosolid and non-biosolid soils decreased as the soil depth increased. Microbeads were dominant in soils where biosolids were applied (up to 61.9%), while fibres were dominant in non-biosolid soils (accounting for 85.7%). The distribution of plastic polymer types varied among fields and soil depths. Most MPs were microbeads of polyamide (PA), fragments of polyethylene (PE), foam of polystyrene (PS), and fibres of rayon. This research presents evidence that the extended utilization of biosolids results in elevated MP pollution in minesite rehabilitation land, highlighting a frequently overlooked origin of MP contamination in terrestrial settings. Additional evaluations needed to understand ecological risks of MPs in soil ecosystems affected by biosolid application.

Microplastic pollution and the related ecological risks of organic composts from different raw materials

Organic composts are considered emerging contributors to microplastics (MPs) accumulation in agricultural soils. However, MPs pollution in organic compost from different raw materials is unknown. This study investigated MPs occurrence and characteristics in 124 organic compost samples, including single feedstock (livestock manure, poultry manure, crop straw, and solid waste) and compound organic composts, and quantitatively assessed related ecological risks of MPs pollution. The highest and lowest MPs abundances were observed in solid waste (6615 items kg−1) and crop straw (1500 items kg−1) composts, respectively. Compost MPs were mainly 0.5–1 mm (39.5%), colorful polypropylene and polyethylene fragments and films, and polyethylene terephthalate fibers, and the input to farmland soils was 6.96 × 107 to 1.88 × 108 items ha−1 yr−1. Regardless of feedstock, compost-based MPs of different shapes exhibited complicated weathering morphologies and adhered to some mineral colloids. The highest and lowest MPs-induced risk indices in solid waste (H = 134.3) and crop straw (H = 8.9) composts yielded hazard levels IV (high risk) and II (low risk), respectively, due to the different abundance of polymers with diverse hazard scores. These findings provide insights into MPs pollution in organic composts and a theoretical basis for the safe production and application of compost.

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.

Long-term application of organic compost is the primary contributor to microplastic pollution of soils in a wheat–maize rotation

Microplastics (MPs) are posing new threats to soil ecosystems. Organic fertilizers are considered as an emerging contributor to MPs accumulation in agricultural soils. However, few studies have focused on the MPs fate in soils under long-term organic fertilizer application. Based on an 11-year field test with wheat-maize cropping rotation, this study investigated the characteristics of MPs in pig manure and cow manure composts, and examined the impact of long-term compost application on soil MPs accumulation, surface morphology, and distribution. The MPs contents in pig manure and cow manure composts were 3547 and 4520 items kg−1, respectively. Microplastics abundances in soils under long-term use of these two composts were 144 to 287 and 140 to 316 items kg−1, respectively, which increased significantly with increasing compost application amount and was substantially higher than that in soils without compost. Accumulated soil MPs sourced from long-term compost application were 1.73 × 108 to 7.22 × 108 items ha−1, accounting for 43.0 %–75.9 % of the total, and the contribution value doubled as the compost application rate doubled. The proportion of MPs <1 mm in composts (31.0 %) was lower when compared with that in compost-amended soils (43.8 %), and size and abundance reduced with increasing soil depth. Microplastics shapes and polymer types in composts and compost-amended soils were similar and mostly included fragments of polyethylene and polypropylene and fibers of polyethylene terephthalate. Microplastics in compost-amended soils showed complicated weathered surface morphologies, and soil mineral colloids were attached. These results demonstrate that compost-derived MPs in soils can be gradually weathered and degraded into smaller particles under long-term compost application. These findings provide key insights into the pollution level of soil MPs with organic fertilizer application and serve as a scientific basis for developing MPs mitigation measures in agricultural soils.

Breaking the paradigm: Marine sediments hold two-fold microplastics than sea surface waters and are dominated by fibers

We conducted one of the first studies to integrate the quantification and characterization of microplastics (MPs), including fibers, in different habitats (sea surface, seafloor and beach sediments) of a coastal Mediterranean marine protected area, analyzing their ingestion in several marine species. The objectives of the study were to evaluate the distribution of MPs according to shape and polymer, to assess the contribution of fibers to local plastic pollution and to evaluate their ingestion in fish and invertebrates species that inhabit the study area (Pagrus pagrus, Serranus scriba, Spondyliosoma cantharus, Diplodus vulgaris, Oblada melanura, Holothuria forskalii, Holothuria tubularis, Holothuria polis, Arbacia lixula, Paracentrotus lividus, Modiolus barbatus, Mytilus galloprovincialis and Arca noae). A total of 111 environmental samples were analyzed. The mean abundance of MPs (excluding fibers) quantified in beach sediments (13,418.86 ± 28,787.99 MPs/m2) was two orders of magnitude higher than that found in seafloor sediments (76.92 ± 108.84 MPs/m2), which in turn was two orders of magnitude higher than sea surface samples (0.17 ± 0.39 MPs/m2). The fibers were the most abundant shape of MPs identified in all habitats. Variability in MPs ingestion was detected between species, with ingestion rates ranging from 43 % to 100 % for general MPs and ranging from 7 % to 100 % for fibers. The highest ingestion was observed in Holoturians, representing suitable bioindicators for plastic pollution. The composition of the polymer varies weakly depending on habitats and biota, but the result is strongly correlated with the morphology of the plastic. Fibers were mainly composed of cellulose acetate (29 %), styrofoam of polystyrene (18 %), and filaments, films and fragments of polyethylene and polypropylene. The results highlighted the need to expand integrated approaches to effectively study marine plastic pollution and to undertake efficient actions to limit the input of plastics, particularly fibers, into the marine environment.

A Ziegler-type spherical cap model reveals early stage ethylene polymerization growth versus catalyst fragmentation relationships

Polyolefin catalysts are characterized by their hierarchically complex nature, which complicates studies on the interplay between the catalyst and formed polymer phases. Here, the missing link in the morphology gap between planar model systems and industrially relevant spherical catalyst particles is introduced through the use of a spherical cap Ziegler-type catalyst model system for the polymerization of ethylene. More specifically, a moisture-stable LaOCl framework with enhanced imaging contrast has been designed to support the TiCl4 pre-active site, which could mimic the behaviour of the highly hygroscopic and industrially used MgCl2 framework. As a function of polymerization time, the fragmentation behaviour of the LaOCl framework changed from a mixture of the shrinking core (i.e., peeling off small polyethylene fragments at the surface) and continuous bisection (i.e., internal cleavage of the framework) into dominantly a continuous bisection model, which is linked to the evolution of the estimated polyethylene volume and the fraction of crystalline polyethylene formed. The combination of the spherical cap model system and the used advanced micro-spectroscopy toolbox, opens the route for high-throughput screening of catalyst functions with industrially relevant morphologies on the nano-scale.

Spatial Patterns of Microplastics in Surface Seawater, Sediment, and Sand Along Qingdao Coastal Environment

Coastal environments, ecologically fragile zones, are subjected to great human pressures, particularly, xenobiotic pollutants such as microplastics (MPs) and trace metals. Yet, the impact of anthropogenic intervention on the spatial patterns of MPs in different coastal environmental compartments of Qingdao, a city located in the west Yellow Sea, is still unclear. Therefore, the spatial distribution, characteristics, and diversity of MPs (≥ 50 µm) in seawater, sediment, and sand samples collected from 10 zones intervened by different anthropogenic activities in Qingdao coastal environment were investigated. The abundance of MPs was 93.1 ± 63.5 items/m3 in seawater, which was 4577 ± 2902 items/kg in sediments and 3602 ± 1708 items/kg in the beach sands. A spatial analysis indicated that the distribution characteristics of MPs, including abundance, color, and type, greatly varied among the zones with different extent of human activities. The highest abundance of MPs in the seawater was detected in the abandoned aquafarm, followed by harbors, beaches, estuary, sewage discharge areas, operational aquafarm, and rural areas, whereas the highest MP abundance in the sediments followed the order of harbor, sewage discharge, estuary, abandoned aquafarm, beaches, rural area, and operational aquafarm. The highest MP abundance in the scenic and recreational beach sands was, respectively, in the intertidal and supratidal zone. The transparent chlorinated polyethylene fragments with the relatively small size of 50–100 μm were the dominant MPs in the coastal environment. The higher physicochemical characteristic diversity in terms of size, color, shape, and type of MPs in the aquafarms, harbors, and recreational beach than those of the other zones, illustrated the higher complexity and diversity of MP pollution sources in these zones. These results jointly indicated that aquaculture, navigation, and tourism mainly determined MP spatial distribution patterns in the coastal environment of Qingdao. These results also extend the understanding of the inventory and fate of MPs in coastal environment, thus providing important data to establish effective strategies for abating MP pollution in marine ecosystems.

Microplastic pollution in fragile coastal ecosystems with special reference to the X-Press Pearl maritime disaster, southeast coast of India

Microplastics (MPs) are a global environmental concern and pose a serious threat to marine ecosystems. This study aimed to determine the abundance and distribution of MPs in beach sediments (12 beaches), marine biota (6 beaches) and the influence of microbes on MPs degradation in eco-sensitive Palk Bay and Gulf of Mannar coast. The mean MP abundance 65.4 ± 39.8 particles/m2 in beach sediments; 0.19 ± 1.3 particles/individual fish and 0.22 ± 0.11 particles g−1 wet weight in barnacles. Polyethylene fragments (33.4%) and fibres (48%) were the most abundant MPs identified in sediments and finfish, respectively. Histopathological examination of fish has revealed health consequences such as respiratory system damage, epithelial degradation and enterocyte vacuolization. In addition, eight bacterial and seventeen fungal strains were isolated from the beached MPs. The results also indicated weathering of MPs due to microbial interactions. Model simulations helped in tracking the fate and transboundary landfall of spilled MPs across the Indian Ocean coastline after the X-Press Pearl disaster. Due to regional circulations induced by the monsoonal wind fields, a potential dispersal of pellets has occurred along the coast of Sri Lanka, but no landfall and ecological damage are predicted along the coast of India.

Solid electrolyte interface formation between lithium and PEO-based electrolyte

One of the approaches to improve the performance and ensure safe operation of lithium-metal batteries is the use of solid polymer electrolytes (SPE) that demonstrate relatively low reactivity towards metallic lithium. However, when lithium comes into contact with SPE, a solid electrolyte interphase (SEI) film is formed at the interface, although its composition, properties, and formation mechanism have not yet been sufficiently investigated. The present paper focuses on the issue of the lithium metal - polymer electrolyte interface stability. We used cyclic voltammetry and impedance spectroscopy to show that a passivating SEI layer forms at the working electrode in contact with SPE (PEO20LiTFSI) both during the cell cycling and at an open circuit potential, with the SEI thickness increasing to a certain point depending on the temperature. The chemical reaction that corresponds to the SEI formation was studied by XPS and NEXAFS spectroscopy for model experiments, including lithium deposition on polyethylene oxide (PEO) under ultrahigh vacuum. Based on the spectroscopy data, we propose a reaction mechanism that features reductive cleavage of a PEO molecule by lithium atoms, which yields not only lithium alkoxides (ROLi) but also polyethylene fragments. Although such kind of SEI should generally reduce the ionic conductivity of SPE, it adds stability to the system at the same time.

Comparison of Microplastic Pollution in Beach Sediment and Seawater at UNESCO Can Gio Mangrove Biosphere Reserve.

Microplastics have become a global concern due to their persistent properties and impacts on the marine environment. This research investigates pollution sources and behaviors of microplastics at UNESCO Can Gio Mangrove Biosphere Reserve. Density flotation with sodium chloride is employed to extract microplastics from sand at Can Gio Beach, and a double‐filtration procedure is developed to recover microplastics from seawater at the beach and Dong Tranh Cape. The microplastics’ morphology and type are analyzed by micro‐Raman spectroscopy. The results show that microplastics are accumulated at concentrations from 31.99 to 92.56 MPs g−1 at various sand layers. The seawater at Can Gio Beach and Dong Tranh Cape contains 6.44 and 3.75 MPs L−1 of microplastics, respectively. White polyethylene fragments predominate, and all the microplastics comprise small secondary microplastics with a minimum size of 25 µm and a maximum size of 260 µm for fragments and a length of 640 µm for fibers. The proportions of polyethylene, polypropylene, polystyrene, and polymethylmethacrylate are similar. The differing percentages of other compositions in sand and seawater are attributed to the morphology and density of the microplastics. The results indicate the extent of microplastic pollution and suggest appropriate strategies for tourism development at the Biosphere Reserve.

Spatiotemporal variations of surface water microplastics near Kyushu, Japan: A quali-quantitative analysis

Microplastics in the ocean are threatening marine ecosystems. Although plastic contaminants are ubiquitous, their distribution is thought to be heterogeneous. Here, we elucidate the spatial and temporal variations in the quanti-qualitative characteristics of microplastics near Kyushu, Japan in the East China Sea. Six surveys across nine stations were conducted over a 14-month period, and a total of 6131 plastic items were identified. The average microplastic abundance and size were 0.49 ± 0.92 (items·m−3 ± S.D.), and 1.71 ± 0.93 (mm ± S.D.), respectively. Differences between the highest and lowest abundances were 50-fold among monthly means, and 550-fold across all net tows. With respect to colour, polymer type, and shape, white and transparent polyethylene fragments were the dominant composition. There were significant differences for each of the analytical microplastic parameters among the survey months. Our results provide baseline data and lead to a more comprehensive understanding of the spatiotemporal characteristics of microplastic pollution.

Water Temperature and Microplastic Concentration Influenced Microplastic Ingestion and Retention Rates in Sea Cucumber (Holothuria cinerascens Brandt, 1835)

The continuous increases in temperature and microplastic concentration have raised grave concerns worldwide. The influence of water temperature and microplastic concentration on microplastic ingestion and retention rates in Holothuria cinerascens (Brandt, 1835) was investigated. H. cinerascens were sampled by handpicking during low tide from Park Rynie beach on the south coast of KwaZulu-Natal, South Africa. They were then cleaned and transported to the control temperature room. Animals were placed in pairs in aerating tanks and acclimated for 48 h. For the exposure experiment, 50, 100, and 150 polyethylene fragments per litre of sizes (0.5–1 mm and 1–2 mm) were added to each tank at varied temperatures (19, 24, 28, and 32 °C) and were left for 48 h and 72 h. Thereafter, animals were transferred to tanks void of microplastics and left to depurate for 48 h for the retention experiment. Microplastic collected from the gut and faecal samples were used to calculate the ingestion and retention rates. Water temperature significantly influenced ingestion and retention rates, while microplastic concentration influenced the ingestion rate only. The highest microplastic particle number/g.h was recorded in high microplastic concentration for both ingestion and retention experiments. Also, the highest microplastic particle number/g.h was obtained at 28 °C in the ingestion experiment. More microplastic particle number/g.h was retained at 19 °C in the ingestion experiment. Ingestion rate increased with increased microplastic concentration, and temperature up to 28 °C and then decreased at 32 °C. More microplastics were retained at high temperature (28 °C) and low temperature (19 °C) at 48 h and 72 h exposure, respectively. Increase in water temperature and microplastic concentration will increase the susceptibility of H. cinerascens to ingest more microplastics from their natural habitat.