Prevalence of microplastics in the sediments of Odisha beaches, southeastern coast of India

Spatial and seasonal variations in abundance, distribution characteristics, and sources of microplastics in surface water of Mula river in Pune, India

Microplastics are one class of widely prevalent emerging contaminants that have a detrimental effect on ecosystems and human health. The status of microplastic pollution in rivers in Western India is not well documented, making it difficult for establishing monitoring policies and guidelines. Mula river in Pune is a lifeline for the numerous industries and residential establishments in the city and hence monitoring the health of the water of Mula river is of great societal relevance. This investigation elucidated the prevalence, abundance and characterization of microplastics in Mula River water, while it crosses Pune, one of the fastest developing cities in India. Season played a determinant role in microplastic abundance. During the pre-monsoon season, the average microplastic concentration at all the three selected locations was notably higher (1808 ± 697 particles/L) compared to the post-monsoon period (1561 ± 167 particles/L). Microplastics smaller than 100 μm were consistently dominant in both the seasons. Notably, the most common polymer found in the Mula River was Ethylene Vinyl Acetate (EVA), a copolymer of polyethylene (PE) and vinyl acetate, commonly used in plastic wraps and packaging material. Unregulated disposal of industrial waste emerged as the most potential source of microplastics in Mula river. This study addresses a critical knowledge gap about the distribution and sources of microplastics in rivers in India. This work provides baseline data that can be used to access accurate mitigation of microplastics and evaluate health and environmental impacts of microplastic pollution in Indian rivers.

Assessment of microplastic and heavy metal pollution in agricultural soils of Ernakulam District, Kerala, India

Microplastics (MPs) and heavy metal pollution pose significant environmental threat, potentially leading to agroecosystem toxicity and jeopardizing food security. Therefore, this study aims to evaluate the abundance and risk assessment of these pollutants in five different farmlands of Ernakulam district, India. Results showed that MPs content in agricultural fields near commercialized areas such as Kakkanad Nedungapuzha, Nedumbassery, and Kadamakuddy was dominant compared to Nechoor, a rural area. The average microplastic abundance was found to be 45.6 ± 26.4 items kg⁻1 dw. Polypropylene (PP) and polyethylene (PE) were the dominant polymers found in the soil samples, constituting 45% and 25% of the microplastic content, respectively. The pollution load index of MPs indicates that the sampling sites are considered to be polluted as PLI > 1 with hazard level I. The heavy metal pollution status follows the order: Cu (80.3 to 724 mg/kg) > Zn (77 to 543.5 mg/kg) > Cr (171.65 to 334.65 mg/kg) > As (10.25 to 79.5 mg/kg) > Pb (2.05 to 30.3 mg/kg) > Cd (0.3 to 14.35 mg/kg). Calculated pollution load index (PLI) geo-accumulation index (Igeo), ecological risk assessment values indicate that commercialized regions exhibit high levels of trace metals, namely Cu, Zn, As, Cd, and Cr, posing a significant concern for the agricultural ecosystem. Our results indicate heightened microplastics and heavy metals prevalence in farmlands adjacent to commercial zones, necessitating immediate preventive action to mitigate increasing concentrations.

Plastic takeaway food containers may cause human intestinal damage in routine life usage: Microplastics formation and cytotoxic effect

The microplastics and organic additives formed in routine use of plastic takeaway food containers may pose significant health risks. Thus, we collected plastic containers made of polystyrene, polypropylene, polyethylene terephthalate, polylactic acid and simulated two thermal usages, including hot water (I) and microwave treatments (M). Nile Red fluorescence staining was developed to improve accurate counting of microplastics with the aid of TEM and DLS analysis. The quantity of MPs released from thermal treatments was determined ranging from 285.7 thousand items/cm2 to 681.5 thousand items/cm2 in containers loaded with hot water with the following order: IPS>IPP>IPET>IPLA, while microwave treatment showed lower values ranging from 171.9 thousand items/cm2 to 301.6 thousand items/cm2. In vitro toxicity test using human intestinal epithelial Caco-2 cells indicated decrease of cell viability in raw leachate, resuspended MPs and supernatants, which might further lead to cell membrane rupture, ROS production, and decreased mitochondrial membrane potential. Moreover, the leachate inhibited the expression of key genes in the electron transport chain (ETC) process, disrupted energy metabolism. For the first time, we isolate the actually released microplastics and organic substances for in vitro toxicity testing, and demonstrate their potential impacts to human intestine. SYNOPSIS: Plastic take-out containers may release microplastics and organic substances during daily usage, both of which can cause individual and combined cytotoxic effects on human colon adenocarcinoma cells Caco-2.

Ecological assessment of microplastic contamination in surface water and commercially important edible fishes off Kadalundi estuary, Southwest coast of India

This study focuses on the Kadalundi estuary, Kerala's first community reserve, investigating the prevalence and impacts of microplastics on both the estuarine environment and selected fish species. This study presents the initial evidence indicating the consumption of microplastic particles by 12 commercially important edible fish species inhabiting the Kadalundi estuary. Analysis revealed significant accumulations of microplastic fibers within the surface water. In examining 12 fish species from demersal and pelagic habitats, microplastics were found in both the gastrointestinal tracts and gills. In the digestive tracts, microplastic fragments constituted the highest proportion (46%), while in the gills, microplastic fibers were dominant (52.4%). This study observed a prevalence of blue microplastics over other colors in both water and fish samples. Notably, demersal species showed a higher incidence of ingested microplastics. Polymer analysis identified Polypropylene (PP), Nylon, Low-Density Polyethylene (LDPE), Polyethylene (PE), Polypropylene isotactic (iPP), PE 1 Octene copolymer, and Rayon in water samples, while fish samples predominantly contained LDPE, PP, PE, and Nylon. Risk assessment utilizing the Polymer Hazard Index (PHI) categorized certain polymers as posing minor to moderate risks. Pollution Load Index (PLI) computations indicated moderate to high levels of microplastic contamination across various sampling sites in the estuary. Principal Component Analysis (PCA) revealed a lack of correlation between fish size and microplastic ingestion, underscoring environmental factors' influence on microplastic intake. The study emphasizes the implications of microplastic pollution on the fragile ecosystem of the Kadalundi estuary, posing potential risks to biodiversity and human health.

Microplastic from beach sediment to tissue: a case study on burrowing crab Dotilla blanfordi

Background

Microplastics (MPs) are pervasive pollutants in the marine environment, exhibiting persistence in coastal sediment over extended periods. However, the mechanism of their uptake by marine organisms and distribution in habitat is less understood. The objective of the present study was to investigate the presence of MP contamination in burrow sediment, feeding pellets, and tissue of Dotilla blanfordi in the Gulf of Kachchh, Gujarat State.

Methods

A total of 500 g of burrow sediment, 100 g of feeding pellets, and body tissue of 10 resident D. blanfordi were pooled as one replica. Such seven replicas from each site were analyzed for MP extraction from three sites, including Asharmata, Mandvi, and Serena, located in the Gulf of Kachchh. The standard protocol was used during the analysis of the collected samples in order to isolate MPs.

Results

The abundance of MP was found higher in burrow sediment, feeding pellets and tissue of D. blanfordi at study site Mandvi, followed by Serena and Asharmata. The abundance of MP was found higher in D. blanfordi tissue, followed by burrow sediment and feeding pellet. A significant variation was observed in MP abundance among burrow sediment, feeding pellets, and tissue. MPs with various shapes (fiber, film, and fragment), sizes (1-2, 2-3, 3-4, and 4-5 mm), and colors (blue, green, black, pink, purple, red transparent) were recorded from all the study sites. Polyurethane and polyvinyl chloride were recognized as the chemical profile of the extracted MPs. The current investigation revealed greater accumulation of MPs in D. blanfordi's tissues compared to sediment and pellets, suggesting a risk of MP contamination in marine benthic fauna with a greater rate of bioaccumulation. D. blanfordi plays a significant role as a structuring agent for MP distribution in the intertidal flat through burrowing activity.

Tide of change: Urgency of a national marine litter policy in India

The rise of plastics in the 20th century revolutionized modern life but inadvertently exacerbated the marine litter crisis. The proliferation of wastes such as single-use plastics has escalated pollution along the coastline, demanding coordinated, decisive, and unified action. While the absence of specific national marine litter policies is concerning, there is growing recognition of urgency to address this issue. A group of experts and stakeholders was involved through a multi-staged workshop to assess the generated information based on scientific evidence and formulate a framework for the National Marine Litter Policy (NMLP). This paper proposes policy options (4 targets & 20 strategies) to address marine litter pollution, especially plastics, and aims to elucidate the urgency and significance of implementing an NMLP as a comprehensive strategy to combat plastics pollution. Implementing dedicated policies and action plans tailored to the unique challenges faced by each country is a vital step towards sustainable oceans.

Assessment of microplastics and associated ecological risk in the Hirakud Reservoir, Odisha, India

Microplastic has emerged as a global threat owing to its chronic ubiquity and persistence. Microplastics' small size expedites their ingestion at each trophic level causing biomagnification and bioaccumulation, which has raised public concerns. The present study isolated, quantified and characterized the abundance, shape, size, color, and chemical composition of the microplastics from water and sediments of the Hirakud Reservoir through a scanning electron microscope and FTIR. The ecological risk associated with the microplastics was assessed using the species sensitivity distribution (SSD) method to derive the Predicted No-Effect Concentration (PNEC) value and risk quotient (RQ). The abundance of microplastics in the surface water and sediments of the Hirakud Reservoir was estimated at 82-89 particles/L and 159-163 particles/kg, respectively. Fiber-shaped microplastics dominated both surface water (46.21%) and sediment samples (44.86%). Small-sized microplastics (53-300 μm) prevailed in all samples. Color delineation exhibited an abundance of transparent microplastics. Chemical characterization indicated the dominance of polypropylene (38%), followed by high-density polyethylene, low-density polyethylene, and polystyrene. The calculated PNEC value was 3,954 particles/m3, and the RQ was estimated to be 0.02073-0.04122 indicating negligible ecological risk to freshwater species in all the sampling sites.

Microplastic contamination in filter-feeding oyster Saccostrea cuccullata: Novel insights in a marine ecosystem

Microplastic (MP) pollution has become a pressing global concern. Oysters are well-known filter feeders who ingest food by filtering microscopic particles suspended in the surrounding water. Along with organic matter, filter-feeding also causes accidental ingestion of MP by oysters. Hence, the aim of the current investigation is to understand the MP contamination in filter-feeding oysters. A total of 500 specimens of oyster Saccostrea cuccullata collected from the intertidal zone of five sampling locations on the Gujarat coast, India. Specimens underwent analysis following established protocols. Each specimen was found to exhibit MP contamination, showing an abundance of 2.72 ± 1.98 MPs/g. A negative relationship was found between shell length and MP abundance. Predominantly, fibers were documented across all study sites. Black, blue, and red-colored MPs with 1-2 mm sizes were most dominant. MP polymer composition was identified as polyethylene terephthalate and polypropylene. Findings provide baseline information on levels of MPs contamination, which can be used to monitor future effects of MP pollution.

Microplastics and associated polycyclic aromatic hydrocarbons in surface water and sediment of the Bay of Bengal coastal area, India: sources, pathway and ecological risk

In the aquatic environment around the world, microplastic contamination has been a common and ongoing issue. Particularly, the ability of microplastics to absorb persistent organic pollutants (POPs) and then transmit these POPs to aquatic creatures has attracted a lot of interest. A stereomicroscope was used to detect the size, shape, and color of the microplastics (MPs), and Fourier Transform Infrared (FTIR) spectroscopy was used to identify the polymer composition of the MPs. To address MP transit, destiny, and mitigation, a study of MP pollution coastal areas is required. In the current study, MP pollution in the collected sample from upper layer of water and sediment of the Digha and Puri beaches along the coast of BOB was evaluated. The average concentration with SD of MPs observed in water was 5.3 ± 1.8 items/L whereas, in sediments, it was 173.4 ± 40.1 items/kg at Digha beach. The mean MPs abundance in the Puri beach was 6.4 ± 1.7 items/L in the water and 190.4 ± 28.0 items/kg in the sediments. The investigated total 16-PAHs concentrations were 164.7 ng/g, 121.9 ng/g, 73.6 ng/g, and 101.3 ng/g on the MPs surface of foam, fragment, fibers, and film respectively in the studied MPs sample. Smaller than 1000 µm size of MPs are distributed in the largest concentration. Fibers, films, fragments, and foam were the most common shapes of MPs. The molecular structure of MPs in water and sediment samples was analysed i.e., polyesters (PEs), polypropylene (PP), polyethylene (PE), polymethyl methacrylate (PMMA), polystyrene (PS), polyamide (PA), polycarbonates (PC), and polyurethane (PU). The obtained result offers an accurate assessment of the PLI, and the investigated polymer facilitates determining the polymer hazard levels, which emphasizes the risk associated with it.

Microplastics in environment: a comprehension on sources, analytical detection, health concerns, and remediation

Contamination of ecosystems by microplastics (MPs) has been reported intensively worldwide in the recent decade. A trend of reports indicated their presence in the atmosphere; food items and soil ecosystems are rising continuously. Literature evidenced that MPs are abundant in seawater, beach sand, drinking water, agricultural soils, wastewater treatment plant (WWTP) effluent, and the atmosphere. The greater abundance of MPs in the environment has led to their invasion of seafood, human-consumed food items such as table salts, beverages, takeout food containers, and disposable cups, marine biological lives, and creating serious health hazards in humans. Moreover, the absence of guidelines and specifications for controlling MPs in the environment makes the situation alarming, and the human toxicity data of MPs is scarce. Thereby, the toxicity assessment of MPs in humans is of greater concern. This review compiles the updated information on the potential sources of MPs in different components of the environment (viz. soil, water, and air), their analysis methods, effects on human health, and remediation methods.

Microplastics in the environment: An urgent need for coordinated waste management policies and strategies

Microplastics (MPs) have become a prevalent environmental concern, exerting detrimental effects on marine and terrestrial ecosystems, as well as human health. Addressing this urgent issue necessitates the implementation of coordinated waste management policies and strategies. In this study, we present a comprehensive review focusing on key results and the underlying mechanisms associated with microplastics. We examine their sources and pathways, elucidate their ecological and human health impacts, and evaluate the current state of waste management policies. By drawing upon recent research and pertinent case studies, we propose a range of practical solutions, encompassing enhanced recycling and waste reduction measures, product redesign, and innovative technological interventions. Moreover, we emphasize the imperative for collaboration and cooperation across sectors and jurisdictions to effectively tackle this pressing environmental challenge. The findings of this study contribute to the broader understanding of microplastics and provide valuable insights for policymakers, researchers, and stakeholders alike.

Microplastic pollution in coastal areas of Colombia: Review

Microplastics are distributed in the environment and are considered emerging pollutants because they are not regulated by legislation. This article aims to know the current state of knowledge regarding microplastic pollution in coastal areas of Colombia. Therefore, a detailed search was carried out in databases such as Scopus, Google Scholar, and university repositories collecting scientific and academic information published between 2000 and March 2022. As a result of the review, the presence of microplastics in coastal areas of Colombia was identified, particularly in the water, sediments, and fish, thus evidencing the contamination in coastal ecosystems, where the Caribbean coast is the area with the highest amount of microplastics in sediments, especially Cartagena (249-1387 particles/m2) and Santa Marta (144-791 particles/m2). It was also found that of 302 species of fish, 7% contained microplastics in the Ciénaga Grande of Santa Marta. In the studies, on the other hand, it was observed that there is no standardized methodology; each researcher chooses a different approach according to the scientific literature. The studies showed that the most abundant microplastics were secondary microplastics, of which polypropylene and polyethylene are predominant due to their different applications in society. This review will serve as a baseline for future research on microplastics in coastal areas of Colombia and will identify the challenges and realities of the country in the face of these emerging pollutants.

Quantitative assessment of microplastic contamination in muddy shores of Gulf of Khambhat, India

Microplastics (MPs) have become a global concern due to their widespread distribution in marine ecosystems. The present study was aimed to assess MPs contamination in 21 muddy shores sites situated in the Gulf of Khambhat. From each site, five samples (1 kg each) were collected. In the laboratory, the replicates were homogenated, out of which a 100 g sample was used for analysis. The total number of MPs, shape, colour, size and polymer composition of MPs were assessed. The MPs abundance ranged from 0.32 ± 0.18 particles/g (Jampore) to 2.81 ± 0.50 particles/g (Uncha Kotda) among different study sites. Moreover, threads were recorded maximum followed by films, foams and fragments. In case of MPs colour, black and blue coloured MPs occurred dominantly, with sizes ranging from 1 mm to 5 mm. FTIR analysis identified seven different types of plastic polymers, out of which polypropylene was the dominant plastic polymer (32.46 %) followed by polyurethane (32.16 %), acrylonitrile butadiene styrene (14.93 %), polystyrene (9.62 %), polyethylene terephthalate (4.61 %), polyethylene (3.71 %) and polyvinyl chloride (2.51 %). Based on the results of the Contamination factor (CF) value, Alang, Mahua, Ghogha and Uncha Kotda were identified as very high contaminated sites (CF ≥ 6). Pollution Load Index (PLI) value of entire study area revealed the Gulf of Khambhat as a polluted area with MPs contamination (PLI > 1). While value of Hazardous Index (H) identified 12 study sites as class-V risk category (H value > 10,000). Moreover, Pollution Risk Index (PRI) value revealed fifteen sites as very high contaminated sites (PRI > 1200). Pollution indices can be useful in predicting the level of MPs contamination at the study site. Overall, the present study provides the information on MPs contamination in the coastal region of the Gulf of Khambhat that can be used as a baseline data for future studies on the ecotoxicity of MPs on marine biota.

Environmental impacts of microplastic and role of plastisphere microbes in the biodegradation and upcycling of microplastic

Increasing usage of plastic has led to the deposition of plastic in the environment which later become microplastic, a pollutant of global concern. These polymeric particles affect the ecosystem bestowing toxicity and impede the biogeochemical cycles. Besides, microplastic particles have been known for their role in aggravating the effect of various other environmental pollutants including organic pollutants and heavy metals. These microplastic surfaces are often colonized by the microbial communities also known as "plastisphere microbes" forming biofilms. These microbes include cyanobacteria like Nostoc, Scytonema, etc., and diatoms like Navicula, Cyclotella, etc. Which become the primary colonizer. In addition to the autotrophic microbes, Gammaproteobacteria and Alphaproteobacteria dominate the plastisphere microbial community. These biofilm-forming microbes can efficiently degrade the microplastic in the environment by secreting various catabolic enzymes such as lipase, esterase, hydroxylase, etc. Besides, these microbes have shown great potential for the bioconversion of microplastic to polyhydroxyalkanoates (PHA), an energy efficient and sustainable alternative to the petroleum based plastics. Thus, these microbes can be used for the creation of a circular economy using waste to wealth strategy. This review provides a deeper insight into the distribution, transportation, transformation, and biodegradation of microplastic in the ecosystem. The formation of plastisphere by the biofilm-forming microbes has been described in the article. In addition, the microbial metabolic pathways and genetic regulations involved in the biodegradation have been discussed in detail. The article suggests the microbial bioremediation and upcycling of microplastic along with various other strategies for effectively mitigate the microplastic pollution.

First report on microplastics contamination in a meteorite impact Crater Lake from India

Microplastic pollution is a worldwide concern affecting all environmental matrices, including pristine lakes. Lentic lakes operate as a sink for microplastics (MPs), which interfere with a biogeochemical cycle and, therefore, deserve immediate attention. We present a comprehensive assessment of MPs contamination in the sediment and surface water of a geo-heritage site, Lonar lake (India). It is the third largest natural saltwater lake and only basaltic crater in the world formed by meteoric impact around 52,000 years ago. Mean MPs abundance in lakeshore sediment and surface water was 14.44 particles/kg and 2.66 particles/L, respectively. Small-sized MPs dominate the hypersaline region of the lake. Transparent and green fragments and filaments morphotypes were abundant. Most of the MPs in Lonar lake were secondary in origin. FTIR-ATR analysis revealed 16 types of polymers in the lake, of which polypropylene, polyvinyl chloride, polyethylene, high-density polyethylene, low-density polyethylene, polystyrene, and polyester were the most common. The overall pollution load index (PLI) for Lonar lake sediment and water was 1.39 and 2.58, respectively. Although all sampling stations had significant MPs pollution (PLI > 1), there was noticeable station-specific variability, which could be linked to anthropogenic activities. Irresponsible tourist behavior and religious activities, coupled with poor waste management are the leading causes of MPs contamination in the lake. The current work fills a gap in the investigation of MP pollution in a crater lake formed by a meteorite impact by being the first to provide a precise estimate of the MPs contamination in the Lonar lake.

Contamination of microplastics, surface morphology and risk assessment in beaches along the Thoothukudi coast, Gulf of Mannar region

Microplastics accumulation on beaches raises a serious concern worldwide. Hence, the present study was conducted with the focus of investigating the abundance, characteristics, risk assessment, surface morphology and elemental composition of microplastics (MPs) in the beach sediments of the Thoothukudi region, situated on the south-east coast of India, Gulf of Mannar region. The MPs abundance ranged between 19 ± 18.62 and 78.55 ± 95.17 items/kg with a mean abundance of 33.82 ± 26.11 items/kg and the spatial distribution of MPs showed insignificant variation. Fragments (59.48%), 0.5-1 mm (43.66%) and blue-coloured MPs (45.61%) were highly predominant in the sediments. Attenuated total reflection - Fourier transform infrared (ATR-FTIR) spectroscopy showed the dominance of polyethylene polymers in sediments (52.26%) and their sources could be attributed to the direct inflow of sewage, recreational and fishing activities and accidental loss. The current study revealed that microplastics (< 5 mm) are ubiquitous along the Thoothukudi coast, posing a serious threat to the marine environment and marine organisms. The ecological risk assessment of MPs in sediments was calculated by adopting 3 models: the polymer hazard index (PHI), pollution load index (PLI) and potential ecological risk assessment (RI). The overall PHIsediments = 698.96 exhibited a hazard level of IV, which was mainly due to the varying abundance of polymer composition in sediments. The value of PLIsediments is 2.51, which mainly depends on the MPs abundance in sediments and yields the hazard level of I. The ecological risk posed by MPs in beach sediments along the Thoothukudi coast (RIsediments = 241.06) falls into the medium category, indicating that steps must be taken to reduce the flow of plastics through management measures such as proper wastewater treatment practices, recycling of plastic waste and proper waste disposal. Field emission scanning electron microscopy (FESEM) images revealed that MPs surfaces were strongly weathered and energy dispersive X-ray (EDX) spectroscopy spectra showed that the presence of inorganic elements associated with the surface MPs might be derived from the surrounding environment or additives in plastics. Hence, further research has to be conducted in view of studying the combined effects of MPs pollution and organic pollutants, which will provide further understanding of the contamination of MPs in the marine environment.

Seasonal and spatial distribution of microplastics in sediments by FTIR imaging throughout a continuum lake - lagoon- beach from the Tunisian coast

Plastics pollution in marine environment has become an issue of increasing scientific concern. This work aims to study the temporal and spatial distribution of plastics in sediments from three different Tunisian ecosystems; Rimel Beach, Bizerta lagoon and Ichkeul lake. Sediment sampling was conducted in surface (2 cm) and depth (15 cm) during spring, summer and winter. Plastics debris were separated by size fractions: macro (>5 mm), meso (1-5 mm) and microplastics (<1 mm) to optimize the time necessary for their characterisation. Macroplastics and mesoplastics were identified using an IR Attenuated total reflectance (ATR) and microplastics with Imaging Fourier transform infrared spectroscopy (FTIR) spectroscopy after an optimized extraction protocol. Results indicate that, the lowest contamination degree with macroplastics was recorded in Ichkeul lake, 2 macro debris/m² (marine protected area, national parc of Ichkeul). Mesoparticles were only detected in lagoon of Bizerte in large quantities (4900 item/kg of sediment in surface and 680 item/kg of sediment in depth) and were identified principally as paint products. For microplastics, the repartition was quite homogeneous between the three sites with an average abundance was 130.55 ± 65.61 items/kg for all seasons. The variations of microplastics abundances on the three sites could not be clearly related to the seasons. Whereas the polymer characterisation in the surface and depth sediments of the three studied areas were principally due to eight types of polymers (PVC, PET, PP, PE PS, Polyamide (PA) and polymeric methyl methacrylate (PMMA)) as reported in many other studies, surprisingly all MPs recovered in the study were smaller than 300 μm, >70 % being fragments. This study brings new results as regards to the state of plastic contamination in Tunisian coast and shows the importance of investigating different ecosystems in such studies.

Quantitative assessment of microplastic in sandy beaches of Gujarat state, India

The present study was carried out to quantify microplastic prevalence among 20 sandy beaches on the Gujarat coast. Beaches were categorised into three different classes, viz. low-impacted sites, moderately impacted sites, and highly impacted sites based on anthropogenic pressure. Microplastic (MP) (≤ 5 mm) contamination on the beaches varied with an average of 1.4 MPs/kg to 26 MPs/kg sediment. Sutrapada site-1 and Porbandar showed the highest and lowest mean abundance of microplastics, respectively, among 20 selected beaches. Out of the total assessed microplastics, threads were the maximum (89.98%), followed by the films (4.75%), fragments (3.36%) and foam (1.89%). In terms of colour and size, different microplastics were recorded in this study. The chemical composition of microplastics was identified by ATR-FTIR as polypropylene (47.5%), polyethylene (26%), and polystyrene (25%). Tourism and fishing activities are the possible sources of higher microplastic contamination at highly impacted sites.

Extraction, identification, and environmental risk assessment of microplastics in commercial toothpaste

Microplastics in personal care and food products are given much importance globally due to the adverse impact of microplastics on living beings. In the present study, microplastics from ten different commercially sold toothpaste in India were extracted by vacuum filtration and characterized with microscopic and Fourier-transform infrared spectroscopic analyses. Results revealed that colorless fragments and fibers were the microparticle types of common occurrence which ranged from 0.2 to 0.9% weight in the toothpaste with an abundance range of 32.7-83.2%. Fifty percent of the toothpaste samples showed more than 50% microplastic particle abundance indicating that the microplastic plastic particles were added by the manufacturers. The minimum size of microplastics recorded in the present study was 3.5 μm with a maximum size exceeding 400 μm. The maximum number of microplastics in the toothpaste was 167, 508 and 193 respectively, distributed in the size range of <100 μm, 100-400 μm, and >400 μm. The present study recorded four major polymer types, viz., cellophane, polypropylene, polyvinyl chloride, and polyamide in the toothpaste samples. Surprisingly, polyethylene-a common polymer reported in toothpaste was not traced in the present samples. Regarding the Indian context, the current study is a new addition to the knowledge of the occurrence of microplastics in toothpaste. The average annual addition of microplastics into the environment through toothpaste was calculated as 1.4 billion g/year for India, posing a significant threat to the environment.

Analyzing microplastics with Nile Red: Emerging trends, challenges, and prospects

The development and applications of effective analytical techniques for identification and quantification of microplastics in diverse spheres are increasing in the scientific arena. Nile Red (NR) staining has progressed as a low-cost, simple-to-use approach for analyzing the environmental impact of a wide spectrum of microplastics (e.g., ≥ 3 µm - ≤ 5 mm; polyethylene, polypropylene, and polyvinyl chloride etc.). Given the recent surge of research into this methodology, it is critical to examine the findings and present future directions. Herein, we review accomplishments to date of the current protocols describing the sample preparation, staining and fluorescence conditions, contamination measures, and data analysis based on 56 field observations focusing on microplastic pollution and NR staining technique. Additionally, we discuss the challenges in current analyses towards standardization and recommendations related to it. Finally, we conclude that, despite methodological discrepancies, the NR method has emerged as a viable standalone substitute for visual identification; yet not all that fluoresce with NR are microplastics, which necessitates extensive sample preparation or additional spectroscopy techniques for chemical analysis to validate the results. This article informs the reader about how the NR technique is advancing microplastic research and identifies current needs for future advancements.

Anthropogenic fibres in white clams, Meretrix lyrata, cultivated downstream a developing megacity, Ho Chi Minh City, Viet Nam

Anthropogenic fibres are an emerging pollutant worldwide. The Can Gio mangrove area is located downstream of the Saigon River, and is characterised by high level of anthropogenic fibres originating from domestic and industrial textile and apparel manufacturing. In this area, biota is thus subjected to a high potential risk of anthropogenic fibre contamination. This study aims to characterise the accumulation of anthropogenic fibres in different tissues, i.e. gills, digestive systems, and remaining tissues, of white clams (Meretrix lyrata) cultivated in the Can Gio beach sand, during a seven-month sampling period. The results showed an average concentration of 3.6 ± 2.1 fibres individual^-1 or 2.7 ± 2.4 fibres g^-1 ww. Higher fibre accumulation was observed in remaining tissues than in gills and digestive systems, and no temporal variation was observed in all clam tissues. The intake of fibres by humans consuming clams was estimated to be 324 fibres inhabitant^-1 yr^-1.