Microplastics in Salt of Tuticorin, Southeast Coast of India

Assessment of microplastics in highland rock salts of Northern Borneo

Mountain salts produced from the highland region in NE Sarawak have a market value and also provide basic income to the communities. During the salt-making process, microplastics (MPs) may enter into commercial table salts from various sources, which has not been explored yet. Hence, the current research investigates the presence of MPs in the rock salts produced from the highland saline water in two different locations (L1 and L2) in NE Sarawak. Among the brine water and rock salt samples analysed, the highest concentrations of MPs were detected from the salt samples. It has been revealed that both the water and salt samples have the highest concentration of MPs occurring within the size range of 1-1000 μm. Transparent MPs are the most common colour observed in both salt and water samples, followed by white, blue, red, and black. The most prevalent shapes of MPs are fibers, which account for almost 47% in water samples and 87% in salt samples. Based on the ATR-FTIR study, polyethylene (PE) is the most prevalent polymer observed in salt samples, followed by polypropylene (PP), polystyrene (PS), and polyethylene terephthalate (PET). In water samples, PP is the most dominating polymer, followed by PE and PS. Through SEM microphotographs, fiber-type MPs have smooth surfaces, fragment-type MPs have rough edges, and sheet-type MPs have layered surfaces. EDX analysis revealed that carbon (C) and oxygen (O) are the most abundant elements, followed by aluminium (Al) and sodium (Na) in MPs. Based on the results, it is inferred that the MPs in the rock salts are mainly sourced from the different stages of salt-making production. This preliminary study shed light on the presence and characteristics of MPs in rock salts in this region. The research outcomes could support sustainable management plans to improve the salt quality and enhance the market value.

First-ever study uncovers microplastic contamination in Nepalese table salt

Despite numerous studies on microplastic contamination in table salt worldwide, research focusing on Nepalese table salts is remarkably lacking. This study aims to address this gap by investigating microplastic contamination in salt samples collected from all seven provincial zones of Nepal. Our objective is to comprehensively assess the presence and characteristics of microplastics in salt sold within local markets across the country. Five salt packaging companies utilized by Nepalese consumers were identified. The collected salt samples were digested with Fenton's reagent to extract microplastics, which were then observed under a digital microscope. Using an OMAX stereomicroscope at 30× magnification and an OMAX A3503S digital camera, each microplastic was carefully identified and quantified. FTIR analysis was conducted to identify the polymer types. All tested salt samples (100 %) from both Nepalese and Indian packaging companies contained microplastics. Microplastic abundance exhibits variability among the samples, ranging from 80 to 1040 microplastics per kilogram of salt. The average value stands at 381 ± 219 microplastics per kilogram of salt sample. The distribution of microplastic concentrations within the salt samples reveals that the majority fall within the 301-400 microplastics per kilogram salt range, constituting 33 % of the total samples. Color analysis showed diverse contamination sources, while microplastic shapes included fibers (56 %), films (17 %), fragments (16 %) and pellets (11 %). Polymer type analysis confirmed the presence of polyethylene and polypropylene in tested microplastics. The study estimated that Nepalese individuals ingest an average of 1853 microplastics annually, indicating significant exposure from salt consumption. Surprisingly, factors such as storage conditions, date of salt packaging and thickness of packaging material did not significantly affect microplastic presence in the samples, suspecting manufacturing processes as the primary contributors to contamination. Therefore, the raw materials and purification practices for salt need improvement, as existing methods are insufficient to eliminate microplastics. These findings emphasize the need for further research and mitigation efforts to address microplastic contamination in Nepalese salt and its potential health impacts.

Microplastics and Anthropogenic Particles in Recreationally Caught Freshwater Fish from an Urbanized Region of the North American Great Lakes

BACKGROUND

Microplastics are a pervasive contaminant cycling through food webs-leading to concerns regarding exposure and risk to humans.

OBJECTIVES

We aimed to quantify and characterize anthropogenic particle contamination (including microplastics) in fish caught for human consumption from the Humber Bay region of Lake Ontario. We related quantities of anthropogenic particles to other factors (e.g., fish size) that may help in understanding accumulation of microplastics in fish.

METHODS

A total of 45 samples of six fish species collected from Humber Bay in Lake Ontario near Toronto, Ontario, Canada, were examined for anthropogenic particles in their gastrointestinal (GI) tracts and fillets. Using microscopy and spectroscopy, suspected anthropogenic particles were identified and characterized.

RESULTS

We observed anthropogenic particles in the GI tracts and fillets of all species. Individual fish had a mean ± standard deviation of 138 ± 231 anthropogenic particles, with a single fish containing up to 1,508 particles. GI tracts had 93 ± 226 particles/fish (9.8 ± 32.6 particles/gram), and fillets had 56 ± 61 particles/fish (0.5 ± 0.8 particles/gram). Based on a consumption rate of 2 servings/week, the average yearly human exposure through the consumption of these fish fillets would be 12,800 ± 18,300 particles.

DISCUSSION

Our findings suggest that consumption of recreationally caught freshwater fish can be a pathway for human exposure to microplastics. The elevated number of particles observed in fish from Humber Bay highlights the need for large-scale geographic monitoring, especially near sources of microplastics. Currently, it is unclear what the effects of ingesting microplastics are for humans, but given that recreationally caught freshwater fish are one pathway for human exposure, these data can be incorporated into future human health risk assessment frameworks for microplastics. https://doi.org/10.1289/EHP13540.

An exploratory study of fibre microplastics pollution in different process stages of salt production by solar evaporation in Spain

Microplastics are a pollutant of growing concern. Several studies have found microplastics in table salt worldwide in the last decade, although most have focused on already prepackaged salt. To the best of our knowledge, there is no previous research analysing the entire salt production process. In this study focused on solar evaporation salinas, brine and salt samples were obtained from each stage of production, starting with the entrance of seawater/brine until the final stage of ready-to-sell salt, in six sites in Spain. We extracted microplastics from each sample after 30 % H2O2 digestion and filtration through cellulose nitrate 5 μm pore filters. Microplastic fibres were optically analysed with an Olympus DSX1000. Results indicate that microplastics are present both in seawater and air, with atmospheric fallout identified as the primary source. Microplastic concentrations from the entrance to the salina till the inlet to the crystallizers ranges from 256 to 1500 items per liter and from 79 to 193 microplastics per kg for packaged salt were estimated. Artisanal salina F shows the highest content in microplastics. This study hopes to give insight into the origin and causes of microplastic pollution in solar evaporation salinas and contribute to preventing this form of pollution in food-grade salt.

Microplastics and environmental effects: investigating the effects of microplastics on aquatic habitats and their impact on human health

Microplastics (MPs) are particles with a diameter of <5 mm. The disposal of plastic waste into the environment poses a significant and pressing issue concern globally. Growing worry has been expressed in recent years over the impact of MPs on both human health and the entire natural ecosystem. MPs impact the feeding and digestive capabilities of marine organisms, as well as hinder the development of plant roots and leaves. Numerous studies have shown that the majority of individuals consume substantial quantities of MPs either through their dietary intake or by inhaling them. MPs have been identified in various human biological samples, such as lungs, stool, placenta, sputum, breast milk, liver, and blood. MPs can cause various illnesses in humans, depending on how they enter the body. Healthy and sustainable ecosystems depend on the proper functioning of microbiota, however, MPs disrupt the balance of microbiota. Also, due to their high surface area compared to their volume and chemical characteristics, MPs act as pollutant absorbers in different environments. Multiple policies and initiatives exist at both the domestic and global levels to mitigate pollution caused by MPs. Various techniques are currently employed to remove MPs, such as biodegradation, filtration systems, incineration, landfill disposal, and recycling, among others. In this review, we will discuss the sources and types of MPs, the presence of MPs in different environments and food, the impact of MPs on human health and microbiota, mechanisms of pollutant adsorption on MPs, and the methods of removing MPs with algae and microbes.

Deleterious effects of polypropylene released from paper cups on blood profile and liver tissue of Clarias gariepinus: bioremediation using Spirulina

Despite numerous studies on microplastics, the biological impacts of polypropylene microplastics (PP-MPs) and its toxicity on freshwater fish have yet to be fully revealed. The purpose of this research was to look at the potentially harmful effects of PP-MPs in freshwater African catfish Clarias gariepinus and bioremediation using Spirulina. After acclimatization to laboratory conditions, 108 fish (125 ± 3 gm and 27 ± 2 cm) were assigned into triplicate six experimental groups (12 fish/group), a control group, Spirulina group (SP), PP-MP-treated groups (0.14 and 0.28 mg/l PP-MPs), and PP-MP + Spirulina-treated groups (0.14 mg/l PP-MPs + 200 mg/L SP and 0.28 mg/l PP-MPs +200 mg/L SP) for 15-day exposure and 45-day recovery after that. The hematological parameters exhibiting significance (RBCs, Hct, Hb, and MCV) or non-significance (MCH and MCHC) either decreased with the increase in PP-MP doses from 0.0 in the control to 0.28 mg/L red blood cells (RBCs), hematocrit (Hct), mean corpuscular hemoglobin (MCH), mean corpuscular hemoglobin concentration (MCHC), hemoglobin (Hb) and platelets or increased with such an increase in doses (mean corpuscular volume (MCV)). The liver enzyme activity, aspartate aminotransferase (AST), alkaline phosphatase (ALP), and alanine aminotransferase (ALT) exhibited non-significant (p ≥ 0.05) or significant (p < 0.05) increases in (0.14 and 0.28 mg/L) PP-MP-exposed groups, respectively, except ALP. Furthermore, there was a significant (p < 0.05) or non-significant (p ≥ 0.05) increase in 0.14 and 0.28 mg/l PP-MP +200 mg/L-exposure groups, respectively, compared to the control group and the same exposure group without Spirulina. In comparison to the control group, PP-MPs (0.14 and 0.28 mg/L) induced a significant (p < 0.05) increase in the percentage of poikilocytosis and nuclear abnormalities of RBCs. The liver tissue from fish exposed to PP-MPs exhibited varying degrees of pathological changes. These results indicated that these pathological changes increased with PP-MP concentration, suggesting that the effect of PP-MPs was dose-dependent. After 45 days of recovery under normal conditions, it was obvious that there was a significant improvement in the percentage of poikilocytosis and nuclear abnormalities of RBCs, as well as a non-significant improvement in hemato-biochemical parameters and liver tissue.

Microplastic contamination in salt-cured fish and commercial sea salts: an emerging food safety threat in relation to UN Sustainable Development Goals (SDGs)

Microplastic (MP) contamination in seafood, particularly processed varieties like dried and salt-cured fish, poses a significant threat to human health. This study investigated MP levels in 22 salt-cured fish species and commercial sea salts along the Indian east coast. Results showed substantially higher MP concentrations compared to global averages, with fragments and fibres (< 250 µm) composing 70% of identified MPs, primarily PVC and PS polymers (> 55%). Station 2 exhibited high pollution levels, with salt-cured fish averaging 54.06 ± 14.48 MP items/g and salt containing 23.53 ± 4.2 MP items/g, indicating a high hazard risk index. A modest correlation was observed between MP abundance, morphotypes, polymer composition in the salt, and their impact on fish products. Given the critical link between food safety, security, and public health, further research is imperative to mitigate MP contamination, aligning with UN Sustainable Development Goals (Goal 2, Goal 3, Goal 14, and Goal 15) for enhanced food safety and security.

Bacterial screening in Indian coastal regions for efficient polypropylene microplastics biodegradation

Polypropylene based medical devices significantly increased production and usage in COVID-19 pandemic states, and this material is very resilient in the environment. Thus, more than ever, rapid action is needed to reduce this pollution. This study focuses on the degradation of polypropylene microplastics (PP MPs) by unique marine bacterial strains obtained from the Thoundi (Bacillus tropicus, Bacillus cereus, Stenotrophomonas acidaminiphila, and Brucella pseudintermedia) and Rameshwaram coasts (Bacillus cereus). Those above five bacterial strains were chosen after preliminary screening of their hydrophobicity, biofilm-forming capabilities, and responsiveness to the zone of clearance technique. During the biodegradation process (28 days), the growth, metabolic activity, and viability of these five isolates were all raised. After the post-biodegradation process, the weight loss percentages of the mentioned bacterial strains treated with PP MPs gradually decreased, with values of 51.5 ± 0.5 %, 47.5 ± 0.5 %, 33 ± 1 %, 28.5 ± 0.5 and 35.5 ± 0.5 %, respectively. UV-Vis DRS and SEM analysis confirmed that bacterial strains adhering to MPs cause cracks and cavities on their surface. The degradation of PP MPs can be inferred from alterations in the FT-IR spectrum, specifically in the carbonyl group range of 1100-1700 cm-1, as well as changes in the 1H NMR spectrum, including chemical shift and proton peak pattern alterations. Bacterial strains facilitated the degradation of PP MPs through the secretion of hydrolase-categorized enzymes of protease, lipase, and esterase. The findings of this study indicate that marine bacteria may possess distinctive characteristics that facilitate the degradation of plastic waste and contribute to environmental conservation.

Recognition and detection technology for microplastic, its source and health effects

Microplastic (MP) is ubiquitous in the environment which appeared as an immense intimidation to human and animal health. The plastic fragments significantly polluted the ocean, fresh water, food chain, and other food items. Inadequate maintenance, less knowledge of adverse influence along with inappropriate usage in addition throwing away of plastics items revolves present planet in to plastics planet. The present study aims to focus on the recognition and advance detection technologies for MPs and the adverse effects of micro- and nanoplastics on human health. MPs have rigorous adverse effect on human health that leads to condensed growth rates, lessened reproductive capability, ulcer, scrape, and oxidative nervous anxiety, in addition, also disturb circulatory and respiratory mechanism. The detection of MP particles has also placed emphasis on identification technologies such as scanning electron microscopy, Raman spectroscopy, optical detection, Fourier transform infrared spectroscopy, thermo-analytical techniques, flow cytometry, holography, and hyperspectral imaging. It suggests that further research should be explored to understand the source, distribution, and health impacts and evaluate numerous detection methodologies for the MPs along with purification techniques.

Assessment of polystyrene nano plastics effect on human salivary α-amylase structural alteration: Insights from an in vitro and in silico study

The study found that the enzyme activity of human salivary α-amylase (α-AHS) was competitively inhibited by nanoplastic polystyrene (PS-NPs), with a half-inhibitory concentration (IC50) of 92 μg/mL, while the maximum reaction rate (Vmax) remained unchanged at 909 μg/mL•min. An increase in the concentration of PS-NPs led to a quenching of α-AHS fluorescence with a slight red shift, indicating a static mechanism. The binding constant (Ka) and quenching constant (Kq) were calculated to be 2.92 × 1011 M-1 and 1.078 × 1019 M-1• S-1 respectively, with a hill coefficient (n) close to one and an apparent binding equilibrium constant (KA) of 1.54 × 1011 M-1. Molecular docking results suggested that the interaction between α-AHS and PS-NPs involved π-anion interactions between the active site Asp197, Asp300 residues, and van der Waals force interactions affecting the Tyr, Trp, and other residues. Fourier transform infrared (FT-IR) and circular dichroism (CD) analyses revealed conformational changes in α-AHS, including a loss of secondary structure α-helix and β-sheet. The study concludes that the interaction between α-AHS and PS-NPs leads to structural and functional changes in α-AHS, potentially impacting human health. This research provides a foundation for further toxicological analysis of MPs/NPs in the human digestive system.

Microplastics in Ecuador: A review of environmental and health-risk assessment challenges

Pollution from plastic debris and microplastics (MPs) is a worldwide issue. Classified as emerging contaminants, MPs have become widespread and have been found not only in terrestrial and aquatic ecosystems but also within the food chain, which affects both the environment and human health. Since the outbreak of COVID-19, the consumption of single-use plastics has drastically increased, intensifying mismanaged plastic waste in countries such as Ecuador. Therefore, the aim of this review is to 1) summarize the state of MP-related knowledge, focusing on studies conducted with environmental matrices, biota, and food, and 2) analyze the efforts by different national authorities and entities in Ecuador to control MP contamination. Results showed a limited number of studies have been done in Ecuador, which have mainly focused on the surface water of coastal areas, followed by studies on sediment and food. MPs were identified in all samples, indicating the lack of wastewater management policies, deficient management of solid wastes, and the contribution of anthropogenic activities such as artisanal fishing and aquaculture to water ecosystem pollution, which affects food webs. Moreover, studies have shown that food contamination can occur through atmospheric deposition of MPs; however, ingredients and inputs from food production, processing, and packaging, as well as food containers, contribute to MP occurrence in food. Further research is needed to develop more sensitive, precise, and reliable detection methods and assess MPs' impact on terrestrial and aquatic ecosystems, biota, and human health. In Ecuador specifically, implementing wastewater treatment plants in major cities, continuously monitoring MP coastal contamination, and establishing environmental and food safety regulations are crucial. Additionally, national authorities need to develop programs to raise public awareness of plastic use and its environmental effects, as well as MP exposure's effects on human health.

"Microplastic seasoning": A study on microplastic contamination of sea salts in Bangladesh

This study investigated microplastics (MPs) in commercial sea salts from Bangladesh. The presence of MPs in the 18 sea salt bands was 100 %, where the mean MPs abundance was 471.67 MPs/kg, ranging between 300 and 670 MPs/kg. The maximum number of MPs in the 300-1500 μm size class was significantly higher than the 1500-3000 μm and 3000-5000 μm size class. The most dominant color was black. Fibers and foams were the dominant shapes. The highest number of MPs was 41 %, obtained from coarse salt grains. Four types of polymers were mainly identified from the analyzed samples: PP, PE, PET, and PA. The mean polymer risk index value among these sea salts was 539 to 1257. The findings of this study can be helpful for consumers, salt industries, and policymakers to be aware of or reduce MP contamination levels in sea salts during production and consumption.

Assessment of microplastic contamination in the gastrointestinal tracts of indigenous fishes from north eastern hill regions of Bhogdoi, a tributary of River Brahmaputra, India

Microplastic (MP) pollution in freshwater environments has drawn considerable attention over the decades due to the risk posed by MPs to the aquatic fauna and human health. In this study, the occurrence of MPs was assessed from the gastrointestinal tracts (GIT) of indigenous fishes from Bhogdoi River, a tributary of River Brahmaputra, northeast hill region, Assam, India. All the fish species (n = 180) analysed showed 100% occurrence of MPs sampled from three stations of River Bhogdoi. A total of 488 microplastic particles were recorded from GIT of fishes collected. The mean abundance of MPs was highest in Station-II (7.64 ± 2.77 numbers individual-1) with lowest in S-I (3.17 ± 0.99 numbers individual-1). The MP size of 100-500 μm, MP shape of fibre (43.33%) and fragments (35.33%), blue colour MPs (26-37%) and polymer type PA (23-30%) were most prevalent in fishes analysed from River Bhogdoi. The mean abundance of MPs was higher in herbivore fishes (8.52 ± 1.22 numbers individual-1) as compared to carnivorous and omnivorous fish species with highest abundance in Labeo rohita (12.11 ± 2.13 numbers individual-1). Fibre and fragments with size range of 100-500 μm were dominant among all the feeding habits. Blue and black colour MPs were abundant among herbivore and carnivore fishes. Fourier transform infrared spectroscopy results confirmed that polyamide and polypropylene were the most abundant MP polymer in the fishes analysed. The present study provides baseline information of MPs in River Bhogdoi, Assam, for its future monitoring and assessment of contaminants.

Microplastic contamination in commercial fish feeds: A major concern for sustainable aquaculture from a developing country

Plastic pollution has become a global issue nowadays. Due to the increased population in developing countries, we largely depend on fish from our aquaculture industry to meet the required protein demand. Though several studies documented plastic ingestion in freshwater and marine organisms, very limited studies have been conducted to elucidate microplastic (MP) contamination in commercial fish feed. Therefore, this study was designed to identify, quantify, and characterize microplastics (MPs) in commercial fish feeds in Bangladesh and assess possible health risks in fish consuming different commercial fish feeds. All fish feed samples were 100 % contaminated with MPs, where the mean abundance of MPs ranged between 500 and 2200 MPs/kg. No significant differences among different types of feeds (e.g., starter, grower, and finisher) were observed in terms of MPs abundance (F = 0.999, p = 0.385). This study revealed that fiber was the most dominant shape of MPs (90 %), while the most dominant color of MPs was red (34 %), followed by black (31 %) and blue (19 %). The 100-1500 µm size class covers 88 % of the total MPs in the collected fish feed samples. Identified polymers in the samples were polyethylene (PE, 37.71 %), polyvinyl chloride (PVC, 27.14 %), polypropylene (PP, 22.08 %), and polyethylene terephthalate (PET, 13.07 %), respectively, where PE and PVC fall under the risk category IV to V. The Pollution load index (PLI) values of all fish feed samples were <10, indicating the risk category of I (low risk). Therefore, this study highly recommended avoiding plastic materials in the packaging and storing purposes of feed ingredients in the feed mills to ensure contamination-free fish feed for sustainable aquaculture.

Are Microplastics a Macro Issue? A Review on the Sources of Contamination, Analytical Challenges and Impact on Human Health of Microplastics in Food

In recent years, human populations' exposure to microplastics via foods is becoming a topic of concern. Although microplastics have been defined as "emerging contaminants", their occurrence in the environment and food is quite dated. This systematic review aims to investigate the discrepancies which are characterizing the research in the microplastics field in foods, with particular regard to sample preparations, microplastics' concentrations and their effect on humans. For the selection of papers, the PRISMA methodology was followed. Discrepancies in the methodological approaches emerged and in the expression of the results as well, underlying the urgency in the harmonization of the methodological approaches. Uncertainties are still present regarding the adverse effects of microplastics on the human body. The scientific evidence obtained thus far is, in fact, not sufficient to demonstrate a concrete negative effect. This review has clearly underlined the need to standardise laboratory approaches to obtain useful results for better food safety management.

Application of Infrared and Near-Infrared Microspectroscopy to Microplastic Human Exposure Measurements

Microplastic pollution is a global issue for the environment and human health. The potential for human exposure to microplastic through drinking water, dust, food, and air raises concern, since experimental in vitro and in vivo toxicology studies suggest there is a level of hazard associated with high microplastic concentrations. However, to infer the likelihood of hazards manifesting in the human population, a robust understanding of exposure concentrations is needed. Infrared and near-infrared microspectroscopies have routinely been used to analyze microplastic in different exposure matrices (air, dust, food, and water), with technological advances coupling multivariate and machine learning algorithms to spectral data. This focal point article will highlight the application of infrared and Raman modes of spectroscopy to detect, characterize, and quantify microplastic particles, with a focus on human exposure to microplastic. Methodologies and state-of-the-art approaches will be reported and potential confounding variables and challenges in microplastic analysis discussed. The article provides an up-to-date review of the literature on microplastic exposure measurement using (near) infrared spectroscopies as an analytical tool, highlighting the recent advances in this rapidly advancing field.

Microplastics, a Global Issue: Human Exposure through Environmental and Dietary Sources

Plastic production has grown dramatically over the years. Microplastics (MPs) are formed from the fragmentation of larger plastic debris by combining chemical, physical, and biological processes and can degrade further to form nanoplastics (NPs). Because of their size, MPs and NPs are bioavailable to many organisms and can reach humans through transport along the food chain. In addition to the risk from ingesting MPs themselves, there are risks associated with the substances they carry, such as pesticides, pathogenic microorganisms, and heavy metals, and with the additives added to plastics to improve their characteristics. In addition, bioaccumulation and biomagnification can cause a cumulative exposure effect for organisms at the top of the food chain and humans. Despite the growing scientific interest in this emerging contaminant, the potential adverse effects remain unclear. The aim of this review is to summarize the characteristics (size, shape, color, and properties) of MPs in the environment, the primary sources, and the transport pathways in various environmental compartments, and to shed more light on the ecological impact of MPs and the potential health effects on organisms and humans by identifying human exposure pathways.

Microplastics contamination in fish feeds: Characterization and potential exposure risk assessment for cultivated fish of Bangladesh

Fish feed is becoming an increasingly vital source of nourishment for farmed fish, which are mainly coming from marine fish and agricultural sources. Anthropogenic particles, such as microplastics, are abundant in both marine fish and agricultural byproducts that are utilized to make fish feed. This study investigated whether fish feed could be a source of microplastic contamination, and revealed that a 20 weeks adult farmed tilapia fish might consume up to 268.45 ± 1.438 microplastic particles via fish feed where finisher type feeds were found to be mostly contributory in this number. The microplastics were initially observed with a stereomicroscope and FESEM-EDS. Polymeric composition of microplastics was determined to be polypropylene (PP), nylon-6 (NY-6), polyethylene terephthalate (PET), polystyrene (PS), polyvinyl alcohol (PVA), polyethylene (PE), high- and low-density polyethylene (HDPE, LDPE), ethylene vinyl acetate (EVA), polycarbonate (PC), poly vinyl acetate (PVAc), poly urethane (PU) and polyvinyl chloride (PVC) by FTIR. Results also revealed that the size of microplastic particles in all fish feed ranged from 14 μm to 4480 μm, with 550 ± 45.45 to 11,600 ± 56.1 microplastic particles/kg of fish feed. The FESEM-EDS data demonstrated to overlook the microplastic surface along with attachment of heavy metals onto that surface such as Pb, Ni, and Co in finisher type feed that could create additional health risks.

Microplastics: Human exposure assessment through air, water, and food

BACKGROUND

Microplastics (MP) are plastic particles with dimension up to 5 mm. Due to their persistence, global spread across different ecosystems and potential human health effects, they have gained increasing attention during the last decade. However, the extent of human exposure to MP through different pathways and their intake have not been elucidated.

OBJECTIVES

The objective of this review is to provide an overview on the pathways of exposure to MP through inhalation, ingestion, and dermal contact considering data from the open bibliography on MP in air, dust, food, water and drinks.

METHODS

A bibliographic search on Scopus and PubMed was conducted using keywords on MP in outdoor and indoor air, indoor dust, food including beverages and water and human intake (n = 521). Articles were sorted by their title and abstract (n = 213), and only studies reporting MP identification and quantification techniques were further considered (n = 168). A total of 115 articles that include quality assurance and quality control (QA/QC) procedures are finally discussed in the present review. Based on MP concentration data available in literature, we estimated the potential inhaled dose (ID), dust intake (DI), the estimated daily intake (EDI) via food and beverages. Finally, the total daily intake (TDI) considering both inhalation and ingestion routes are provided for adults, infants and newborns.

RESULTS

The concentrations of MP in outdoor and indoor air, dust, and in food and water are provided according to the bibliography. Human exposure to MP through dust ingestion, inhalation of air and food/drinks consumption revealed that indoor air and drinking waters were the main sources of MP.

CONCLUSIONS

This study reveals that humans are constantly exposed to MP, and that the indoor environment and the food and water we ingest decisively contribute to MP intake. Additionally, we highlight that infants and newborns are exposed to high MP concentrations and further studies are needed to evaluate the presence and risk of MP in this vulnerable age-population.

Characterization of microplastics and its Pollution load index in freshwater Kumaraswamy Lake of Coimbatore, India

Microplastics are less than 5mm in diameter that enters the ecosystem through the breakdown of large plastic particles or climate and human activity. This study examined the geographical and seasonal distribution of microplastics in the surface water of Kumaraswamy Lake, Coimbatore. During seasons, including summer, pre-monsoon, monsoon, and post-monsoon, samples were collected from the lake's inlet, centre, and outlet. All sampling points contained linear low-density polyethylene, high-density polyethylene, polyethylene terephthalate, and polypropylene microplastics. Water samples contained fibre, thin, fragment, and film microplastics in black, pink, blue, white, transparent, and yellow colours. Lake's microplastic pollution load index was under 10, indicating risk I. Over four seasons, microplastic content was 8.77±0.27 particles per litre. The monsoon season had the highest microplastic concentration, followed by pre-monsoon, post-monsoon, and summer. These findings imply that the spatial and seasonal distribution of microplastics may be harmful to the fauna and flora of the lake.

Contribution of plastic and microplastic to global climate change and their conjoining impacts on the environment - A review

Plastics are fossil fuel-derived products. The emissions of greenhouse gases (GHG) during different processes involved in the lifecycle of plastic-related products are a significant threat to the environment as it contributes to global temperature rise. By 2050, a high volume of plastic production will be responsible for up to 13 % of our planet's total carbon budget. The global emissions of GHG and their persistence in the environment have depleted Earth's residual carbon resources and have generated an alarming feedback loop. Each year at least 8 million tonnes of discarded plastics are entering our oceans, creating concerns regarding plastic toxicity on marine biota as they end up in the food chain and ultimately affect human health. The unsuccessful management of plastic waste and its presence on the riverbanks, coastlines, and landscapes leads to the emission of a higher percentage of GHG in the atmosphere. The persistence of microplastics is also a significant threat to the fragile and extreme ecosystem containing diverse life forms with low genetic variation, making them vulnerable to climatic change. In this review, we have categorically discussed the contribution of plastic and plastic waste to global climate change covering the current plastic production and future trends, the types of plastics and plastic materials used globally, plastic lifecycle and GHG emission, and how microplastics become a major threat to ocean carbon sequestration and marine health. The conjoining impact of plastic pollution and climate change on the environment and human health has also been discussed in detail. In the end, we have also discussed some strategies to reduce the climate impact of plastics.

Microplastics in European sea salts - An example of exposure through consumer choice and of interstudy methodological discrepancies

Microplastics are contaminants of emerging concern, not least due to their global presence in marine surface waters. Unsurprisingly, microplastics have been reported in salts harvested from numerous locations. We extracted microplastics from 13 European sea salts through 30% H₂O₂ digestion and filtration over 5-µm filters. Filters were visually inspected at magnifications to x100. A subsample of potential microplastics was subjected to Raman spectroscopy. Particle mass was estimated, and human dose exposure calculated. After blank corrections, median concentrations were 466 ± 152 microplastics kg^-1 ranging from 74 to 1155 items kg^-1. Traditionally harvested salts contained fewer microplastics than most industrially harvested ones (t-test, p < 0.01). Approximately 14 µg of microplastics (< 12 particles) may be absorbed by the human body annually, of which a quarter may derive from a consumer choosing sea salt. We reviewed existing studies, showing that targeting different particle sizes and incomplete filtrations hinder interstudy comparison, indicating the importance of method harmonisation for future studies. Excess salt consumption is detrimental to human health; the hazardousness of ingesting microplastics on the other hand has yet to be shown. A portion of microplastics may enter sea salts through production processes rather than source materials.

Biochemical, Genotoxic and Histological Implications of Polypropylene Microplastics on Freshwater Fish Oreochromis mossambicus: An Aquatic Eco-Toxicological Assessment

In recent years, polypropylene microplastic has persisted in freshwater ecosystems and biota, forming ever-growing threats. This research aimed to prepare polypropylene microplastics and evaluate their toxicity to the filter feeder Oreochromis mossambicus. In this research, fish were given a dietary supplement of polypropylene microplastics at 100, 500, and 1000 mg/kg for acute (96 h) and sub-acute (14 days) durations to assess toxic effects on liver tissues. FTIR results revealed the presence of polypropylene microplastic in their digestion matter. The ingestion of microplastics in O. mossambicus led to fluctuations in homeostasis, an upsurge in reactive oxygen species (ROS) levels, an alteration in antioxidant parameters, including superoxide dismutase (SOD), catalase (CAT), glutathione-S-transferase (GST), and glutathione peroxidase (GPx); a promotion in the oxidation of lipid molecules; and a denaturation in the neurotransmitter enzyme acetylcholinesterase (AChE). Our data indicated that sustained exposure to microplastics (14 days) produced a more severe threat than acute exposure (96 h). In addition, higher apoptosis, DNA damage (genotoxicity), and histological changes were found in the liver tissues of the sub-acute (14 days) microplastics-treated groups. This research indicated that the constant ingestion of polypropylene microplastics is detrimental to freshwater environments and leads to ecological threats.

Microplastics in different fish and shellfish species in the mangrove estuary of Bangladesh and evaluation of human exposure

The water bodies in Bangladesh thrive from plastic pollution. Estuaries are pools of environmental contaminants, and the world's largest mangrove forest, Sundarbans' estuary, is no exception. Thus, for the first time, we investigate MPs abundance in the muscle and gastrointestinal tract (GIT) of twenty estuarine species of fish and shellfish of the Sundarbans, as well as the human health risk. MPs abundance was evident in all the samples ranging from 5.37 ± 1.07 to 54.30 ± 16.53 MP items/g wet body weight (dw) in muscle samples and 7.33 ± 1.89 to 205.61 ± 136.88 MP items/g (dw) in GIT samples. The estimated health risk from MPs is substantial, where the average human intake will be 85,710.08 items of MPs per year per capita for the population of Bangladesh. The dominant polymer types observed using ATR-FTIR are PP and PE (17.5 %), PA (17.5 %) in the muscle tissues, and PP and PE (11.11 %), and EVA (11.11 %) in the GITs. Bottom-feeding species, such as demersal and benthic species, are more contaminated. However, the level of MPs in the species shows a negative correlation with the length and weight of the species. This study reveals that MP pollution is widespread and concerning in Bangladesh's Sundarban mangrove estuarine zone.

Cost-effective remedial to microfiber pollution from wash effluent in Kolkata and Ranaghat

The microfibers generated from Polyester and Nylon based materials during washing cause serious environmental pollution by both contaminating the aquatic environment and the livelihood of the underwater creatures as well. This study aims at investigating the microfiber-pollution in wash effluents collected from different regions of Kolkata which is believed to be one of the microfiber-polluted cities in the South-east Asia in recent times. In this work, packed bed microfiltration (PBMF) was adopted in an economic and eco-friendly manner to arrest adequate amounts of microfibers and non-biodegradable matters present in the water samples collected from different regions of Kolkata and its surrounding areas. Moreover, effective parameters such as packed bed height to diameter ratio (H/D), mess size of the adopted filtration unit were varied from 0.71 to 2.85 and 60 to 100, respectively to understand the efficacy of the approach and to justify the potential of such alternative in order to alleviate the concern as well. The present study reveals that the microfiltration efficiency of the proposed PBMF unit was achieved maximum 93.5% for sample A and 92.2% for sample D respectively to reduce the microfiber count from 7614 to 543 in an hour operation at a flow rate of 60 L h^-1. Besides, the cost of such system was found to be promising as much as 5 US$ on a yearly basis.

Microplastics and plastics-associated contaminants in food and beverages; Global trends, concentrations, and human exposure

Microplastics has become a global concern due to their ubiquitous presence which poses unavoidable human exposure risks. Geographical distribution and yearly trends of research on microplastics, food, and beverages do not exist. Thus, no overall account is available regarding the presence of microplastics and plastics-associated contaminants in food and beverages. Hence, this attempt is to review the geographical distribution of studies through a brief bibliometric analysis and the plastics-associated contaminants including plasticizers and microplastics in food and beverages. Estimated microplastic consumption has been listed for the pool of publications reviewed here. Further, this review discusses the ingestion potency of micropollutants associated with microplastics, possible health impacts, and existing challenges. Global trend in research exponentially increased after 2018 and China is leading. Studies on microplastics were limited to a few beverages and food; milk, beer, tea, refreshing drinks, salt, sugar, honey, etc., whereas seafood and drinking water have been extensively studied. Publications on plastic-additives were reported in two ways; migration of plastic-additives from packaging by leaching and the presence of plastic-additives in food and beverages. Bisphenol A and bis(2-Ethylhexyl) phthalate were the most frequently reported both in food and beverages. Exposure of packaging material to high temperatures predominantly involves plastic-additive contamination in food and beverages. Microplastics-bound micropollutants can also be ingested through food and beverages; however, a lack of knowledge exists. The complex matrix of food or beverages and the absence of standard procedures for analysis of microplastics and micropollutants exist as challenges. More investigations on the presence of microplastics and plastic-additives in food and beverage are urgent needs to a better assessment of potential human exposure and human health risk.

Ingestion and impacts of water-borne polypropylene microplastics on Daphnia similis

Polypropylene microplastics are the leading contaminant in aquatic environments, although research on their toxicity remains scarce. The proposed research focuses on the harmful consequences of acute exposure to polypropylene microplastics in Daphnia similis. This work converts widely available polypropylene bags into microplastics using xylene. FTIR findings demonstrated the lack of xylene residue in the produced polypropylene microplastic particles, which were spherical and ranged in size from 11.86 to 44.62 µm (FE-SEM). The results indicate that acute exposure to polypropylene microplastics causes immobility in D. similis. Ingestion of microplastics enhances the generation of reactive oxygen species (ROS), as shown by biochemical studies. Due to the production of free radicals in D. similis, the antioxidant enzymes superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx) and glutathione-S-transferase (GST) and a non-antioxidant enzyme of reduced glutathione (GSH) and also oxidative stress effects in lipid (lipid peroxidation - LPO), protein (carbonyl protein - CP) were increased. Additionally, the amount of the neurotransmitter enzyme acetylcholinesterase (AChE) activity was decreased. These findings indicate that the accumulation of polypropylene microplastics in the bodies of filter-feeding organisms should aggravate toxicity in the freshwater environment.

Consuming microplastics? Investigation of commercial salts as a source of microplastics (MPs) in diet

The omnipresence of microplastics (MPs) in marine and terrestrial environments as a pollutant of concern is well established and widely discussed in the literature. However, studies on MP contamination in commercial food sources like salts from the terrestrial environment are scarce. Thus, this is the first study to investigate various varieties of Australian commercial salts (both terrestrial and marine salts) as a source of MPs in the human diet, and the first to detect MPs in black salt. Using Nile red dye, the MPs were detected and counted under light microscopy, further characterised using attenuated total reflectance Fourier transformed infrared spectroscopy (ATR-FTIR) and scanning electron microscopy and energy-dispersive X-ray spectroscopy (SEM-EDS). Of all the 90 suspected particles, 78.8% were identified as MPs with a size ranging between 23.2 µm and 3.9 mm. The fibres and fragments constituted 75.78% and 24.22% respectively. Among the tested samples, Himalayan pink salt (coarse) from terrestrial sources was found to have the highest MP load, i.e. 174.04 ± 25.05 (SD) particle/kg, followed by black salt at 157.41 ± 23.13 particle/kg. The average concentration of detected MPs in Australian commercial salts is 85.19 ± 63.04 (SD) per kg. Polyamide (33.8%) and polyurethane (30.98%) were the dominant MP types. Considering the maximum recommended (World Health Organization) salt uptake by adults daily at 5 g, we interpret that an average person living in Australia may be ingesting approximately 155.47 MPs/year from salt uptake. Overall, MP contamination was higher in terrestrial salts (such as black and Himalayan salt) than the marine salt. In conclusion, we highlight those commercial salts used in our daily lives serve as sources of MPs in the diet, with unknown effects on human health.

Dietary consumption of polypropylene microplastics alter the biochemical parameters and histological response in freshwater benthic mollusc Pomacea paludosa

One of the most common environmental pollutant in aquatic ecosystems are polypropylene microplastics and their impacts on aquatic organisms are still scarce. The study aimed to prepare polypropylene microplastics using organic solvent (spherical and 11.86-44.62 μm) and then test their toxicity on the freshwater benthic mollusc grazer Pomaceae paludosa. The present study investigated chronic (28 days) exposure of polypropylene microplastics via dietary supplements (250 mg kg^-1, 500 mg kg^-1 & 750 mg kg^-1) in P. paludosa, and the toxic effect was evaluated in digestive gland tissue. The FTIR results revealed no change in polypropylene microplastics during ingestion or after egestion. On the other hand, Ingestion causes accumulation in their bodies and disrupts redox homeostasis. Meanwhile, alteration occurs in oxidative stress-related biomarkers such as increased reactive oxygen species level (ROS), impaired the biochemical parameters of antioxidant system catalase (CAT), glutathione peroxidase (GPx), reduced glutathione (GSH), and glutathione - S- transferase (GST), deterioration of oxidative stress effects in lipid peroxidation (LPO) and carbonyl protein (CP) and changed the digestive enzymes such as amylase, pepsin, esterase and alkaline phosphatase that are measured in hepatopancreas tissue. The histology results revealed that ingesting these microplastics caused severe damage to the digestive gland cells. According to the findings, ingestion of polypropylene microplastics in benthic freshwater mollusc causes more serious harm and impacts energy acquisition. This finding represents the ecological risk of polypropylene microplastic pollution in the freshwater ecosystem.

Microplastic contamination in commercially important bivalves from the southwest coast of India

Due to the ever-increasing production of plastic litter and its subsequent accumulation as microplastic in the environment, the pollution caused by microplastics is considered as a global menace, especially in the coastal ecosystem. Occurrence of microplastics in water and three commercially important bivalves, Viz. green mussel (Perna viridis), edible oyster (Magallana bilineata) and black clam (Villorita cyprinoides) from five different locations of southwest coast of India was studied. The highest abundance of microplastics was observed in water samples from Periyar River (163.67 items L^-1). Among bivalves, the highest abundance of microplastics was observed in clams from Periyar River (digestive gland: 22.8 g^-1; gill: 29.6 g^-1), whereas the lowest abundance was observed in mussels sampled from Vembanad estuary (digestive gland: 5.6 g^-1; gill: 8.5 g ^-1). Fibers were the most prevalent type of microplastics found in bivalve tissues across each location. Microplastics less than 2 mm were the most prevalent based on size. Polypropylene and high-density polyethylene were the two types of microplastics observed based on the results of Raman spectroscopy. No relationship was observed between shell length, tissue weight and microplastic abundance. A strong positive correlation was observed between the microplastic presence in water and bivalve tissues. The usefulness of sedentary bivalves in assessing the aquatic pollution has been validated through this study.

Surface water, sediment, and biota: The first multi-compartment analysis of microplastics in the Karnafully river, Bangladesh

The Karnafullly River, which flows through Chattogram and falls into the Bay of Bengal, Bangladesh, is vulnerable to microplastic contamination. In this study, we looked at microplastics in the Karnafully River's surface water (5 sites), sediment (9 sites), and biota (4 species). Microplastic concentrations ranged from 0.57 ± 0.07 to 6.63 ± 0.52 items/L in surface water, 143.33 ± 3.33 to 1240 ± 5.77 items/kg dry weight in sediment, and 5.93 ± 0.62 to 13.17 ± 0.76 items/species in biota. A significant difference (P < 0.05) was found in the concentration of MPs in the Karnafully River's sediment, biota, and surface water. High percentage of fiber-shaped and small-sized MPs (<1 mm) were detected throughout the samples. Water and sediment MPs were often transparent/white and blue, whereas biota MPs were mostly black and red, indicating a color preference during biological uptake. The Bay of Bengal received 61.3 × 10⁹ microplastic items per day. The feeding zone of biota influenced the level of microplastics, with a trend of pelagic > demersal > benthic > benthopelagic. Polyethylene and polyethylene terephthalate were the most abundant polymer. Using the average fish intake rate in Bangladesh, we computed a possible consumption of 4015-7665 items of MPs/person/year.

Toxicity evaluation of polypropylene microplastic on marine microcrustacean Artemia salina: An analysis of implications and vulnerability

Polypropylene microplastic particles are one of the predominant pollutants in marine ecosystems and their toxic effects are unknown in aquatic biota. The study aims to prepare the spherical shaped polypropylene microplastics (size range 11.86 μm-44.62 μm) and assess their toxic effects (1, 25, 50, 75 and 100 μg/mL) in various life stages (nauplii, metanauplii and juvenile) of marine microcrustacean Artemia salina within 48 h. In addition, microplastics ingestion by Artemia nauplii was proved by FTIR analysis. The results revealed, microplastics accumulation in their tract leads to change in their homeostasis, as followed increase in the oxidative burst causes mortality in nauplii (LC₅₀ 40.947 μg/mL) and meta nauplii (LC₅₀ 51.954 μg/mL). In juvenile, swimming behaviour was changed. Moreover, microplastic consumption disturbs the antioxidant biomarkers such as superoxide dismutase (SOD), catalase (CAT), reduced glutathione (GSH), glutathione -S- Transferase (GST) and reduces the neurotransmitter enzyme acetylcholinesterase (AChE) activity. In addition, histology of juvenile Artemia showed damage in epithelial cells. This study indicates that exposure to polypropylene microplastics is more harmful to zooplanktonic organisms of the marine ecosystem.

Litter and plastic monitoring in the Indian marine environment: A review of current research, policies, waste management, and a roadmap for multidisciplinary action

Environmental contamination due to plastic waste mismanagement is a growing global concern. Plastic problem is of particular concern to the Indian Ocean nations as Asia currently contributes to the highest share of mismanaged plastic waste. Consequently, there is a worldwide interest to understand the distribution and transboundary movement of plastic from this region, which is crucial for implementing management measures. This review article focuses on current knowledge of plastic research, policies, waste management, socio-economics, challenges, and research opportunities. To date, marine plastic studies have focused on a few locations, providing an analysis of distribution and plastic-organism interactions in the Indian marine system. Along with scientific investigation, enforcement, improvisation, and, if necessary, framing new policies, integrated technologies to manage plastic waste, and behavioural changes are essential to mitigate plastic pollution. Such measures will be effective through a combination of actions among national and international researchers, industries, environmental managers, and the public.

The impact of nano/micro-plastics toxicity on seafood quality and human health: facts and gaps

Contamination of the food and especially marine environment with nano/micro-plastic particles has raised serious concern in recent years. Environmental pollution and the resulting seafood contamination with microplastic (MP) pose a potential threat to consumers. The absorption rate of the MP by fish is generally considered low, although the bioavailability depends on the physical and chemical properties of the consumed MP. The available safety studies are inconclusive, although there is an indication that prolonged exposure to high levels of orally administered MP can be hazardous for consumers. This review details novel findings about the occurrence of MP, along with its physical and chemical properties, in the marine environment and seafood. The effect of processing on the content of MP in the final product is also reviewed. Additionally, recent findings regarding the impact of exposure of MP on human health are discussed. Finally, gaps in current knowledge are underlined, and the possibilities for future research are indicated in the review. There is an urgent need for further research on the absorption and bioavailability of consumed MP and in vivo studies on chronic exposure. Policymakers should also consider the implementation of novel legislation related to MP presence in food.

Microplastics: A review of analytical methods, occurrence and characteristics in food, and potential toxicities to biota

Microplastics (MPs) are ubiquitous in various environment compartments, including food. Here, we collected research reports of MPs in food published during 2010-2020, and summarized the analytical methods developed and utilized by researchers (e.g., digestion, separation and identification, as well as related QA/QC measures implemented), the occurrence, and the characteristics of MPs in six kinds of food. The potential effects on biota from exposure to MPs were also reviewed. The results showed that most researchers digested food samples using chemical solutions such as HNO₃, H₂O₂, KOH, or NaOH. FT-IR and Raman spectroscopy were the main technique for identifying MPs, and microscopes were used to count MP particles. The abundances MPs were in the ranges of 0-5860, 2.00-1100, 0-698, 4.00-18.7, 0-5.68 × 10⁴ and 900-3000 particles/kg in beverages, condiments, honey, meat, seafood and vegetables, respectively. The "maximum" annual human intake of MPs from these foods is approximately 1.42 × 10⁵-1.54 × 10⁵ particles/capita, equivalent to the consumption of 50 plastic bags (size: 0.04 mm × 250 mm × 400 mm, density: 0.98 g/cm³) each year. Blue-colored and fiber-shaped MP particles were the most commonly observed in food, predominated by PA, PE, PES, PET and PP types. Toxicity studies indicated that MPs, additives of MPs and adsorbents or microorganisms on the surfaces of MPs were all somewhat toxic to cells or biota. Exposure to MPs may induce oxidative stress, inflammation, neurotoxicity, and reproductive toxicity, and change the structure of intestinal microflora in cells or biota. Therefore, we call for more investigation into the residual, excretion and bioavailability of MPs or related absorbents/additives in biota and humans.

High levels of microplastics in commercial salt and industrial salterns in Sri Lanka

This study provides the first analysis and quantification of MPs in salt products in Sri Lanka. Commercial table salt brands, rock salt, lab-grade NaCl and raw salt from three salterns were analysed using microscopy and Fourier transform infrared spectroscopy. All salt samples were contaminated with MPs: in commercial salts products it ranged from 11 to 193 items/kg, rock salts had 64 items/kg and lab grade NaCl had 253 ± 8.9 items/kg. The MP levels in salterns varied significantly: Hambantota 3345.7 ± 311.4 items/kg, Puttalam 272.3 ± 10.6 items/kg, and Elephant Pass 36.3 ± 4.5 items/kg. Predominantly, MPs were presented as fibres, followed by fragments. Of the 23 polymer types identified; low-density polyethylene (LDPE; 17%), resin dispersion (15%) and high-density polyethylene (HDPE; 12%) were notable. This study provides the first comparison of MPs in raw salt and commercial salt. This information is important to trace the pollutant sources and then to take steps to eliminate MPs in food products consumed.

Microplastics as contaminants in Indian environment: a review

The increased production and consumption scale of plastic items has led to the generation of microplastics (MPs), an emerging class of contaminants, in our environment. MPs are plastic particles less than 5 mm in size and could originate due to primary and secondary sources. The primary ones are generated as such in the MP size range while the secondary MPs are a result of fragmentation of larger plastic particles which eventually enters the aquatic, terrestrial and atmospheric environments. The increasing concern of MP pollution in every compartment of our environment is being globally explored, with relatively fewer studies in India. Among the total studies published on MP prevalence in the Indian environments, marine systems have received significantly higher attention compared to the other compartments like freshwater, atmosphere, terrestrial and human consumables. This review article is an effort to present current understanding of MP pollution in aquatic systems, terrestrial systems, atmosphere and human consumables of India by reviewing available scientific literature. Along with this, the review also focuses on identification of the gap areas in current knowledge and highlights way forward for future research. This would further help in meeting the goals of this emergent pollutant management.

A comprehensive review on assessment of plastic debris in aquatic environment and its prevalence in fishes and other aquatic animals in India

The presence of meso, macro, and microplastics (MPs) in aquatic environments has raised concerns due to their potential risks to aquatic as well as human life. Though plastics are considered to be inert in nature, MPs with toxic additives and accumulated contaminants have harmful ecological effects. Reports of absorption of MPs by internal tissues and toxicity in vital organs such as lung cells, liver, and brain cells have proved its serious health hazards. The study of plastic debris in the aquatic environment deserves special attention due to its ecotoxicological impact. This review presents a detailed account of the assessment of plastic debris in marine as well as freshwater environments. The formation of MPs and their sources, sampling, isolation, identification and characterization methods adopted, and the prevalence of MPs in aquatic life are discussed. To the best of our knowledge, the present article is a first-ever comprehensive review covering the entire of India. Our review finds that, so far, very few studies have been carried out, and there is a paucity of information, especially on the prevalence of plastic debris in the freshwater environment, fish, and other aquatic animals in India. While major studies have been done at various coastal locations in the southern part of India and a few studies in the rest of India, south-eastern states remain neglected. Toxicological studies on various life forms, including humans, are lacking. The present review also fills the gap in our knowledge of the various locations studied across India and can guide future research.

Microplastics and other harmful substances released from disposable paper cups into hot water

Disposable paper cups are popular for consuming beverages. These paper cups have an interior that is laminated with a hydrophobic film made of mostly plastic (polyethylene) and sometimes of copolymers. The objective of this study was to evaluate the degradation of these films as a result of exposure to hot water (85-90 °C). Due to deterioration of the films, ions like fluoride, chloride, sulfate, and nitrate were released into the water contained in the paper cups. Microplastic particles leaching into the liquid were identified and quantified. Fluorescence microscopy indicated the release of approximately 25,000 micron-sized microplastic particles into one cup of hot water in 15 min (100 ml) while scanning electron micrographs indicate 102 + 21.1 × 10⁶ sub-micron-sized particles/ml into the same volume of liquid. Toxic heavy metals like Pb, Cr, and Cd were detected in the films which can be transferred into hot water. Elemental analysis shows a decrease in the percentage of elements like C, H, and N (by weight) due to exposure to hot water. Ingestion of microplastics, ions, and heavy metals regularly while consuming our daily dose of hot beverages like tea and coffee can expose us to potential health risks in the future.

Environmental prevalence, fate, impacts, and mitigation of microplastics-a critical review on present understanding and future research scope

Microplastics are considered to be ubiquitous and widespread emerging contaminants. They are persistent in the nature and pose considerable harm to the environment. Their omnipresence is documented in almost all aquatic habitats, several atmospheric and terrestrial environments, and also in human consumables. The objective of this review is to provide an overview of the environmental prevalence of the microplastics in all environmental compartments, and their possible adverse impacts. It also presents review of the studies conducted in India and the epitome of potential mitigation measures. The need and direction of future research are highlighted. The review will help in determining the exposure levels, environmental consequences, and risk estimations, and will guide the researchers and policymakers.

Microplastic contamination of salt intended for human consumption: a systematic review and meta-analysis

Microplastics (MPs) are an emerging contaminant ubiquitous in the environment. There is growing concern regarding potential human health effects, a major human exposure route being dietary uptake. We have undertaken a systematic review (SR) and meta-analysis to identify all relevant research on MP contamination of salt intended for human consumption. Three thousand nine hundred and nineteen papers were identified, with ten fitting the inclusion criteria. A search of the databases MEDLINE, EMBASE and Web of Science, from launch date to September 2020, was conducted. MP contamination of salt varied significantly between four origins, sea salt 0–1674 MPs/kg, lake salt 8–462 MPs/kg, rock and well salt 0–204 MPs/kg. The majority of samples were found to be contaminated by MPs. Corresponding potential human exposures are estimated to be 0–6110 MPs per year (for all origins), confirming salt as a carrier of MPs. A bespoke risk of bias (RoB) assessment tool was used to appraise the quality of the studies, with studies demonstrating moderate to low RoB. These results suggest that a series of recurring issues need to be addressed in future research regarding sampling, analysis and reporting to improve confidence in research findings.