Time to Safeguard the Future Generations from the Omnipresent Microplastics

Review and future outlook for the removal of microplastics by physical, biological and chemical methods in water bodies and wastewaters

Microplastics (MPs) have become a major global environmental problem due to their accelerated distribution throughout different environments. Their widespread presence is a potential threat to the ecosystems because they alter the natural interaction among their constituent elements. MPs are considered as emergent pollutants due to the huge amount existing in the environment and by the toxic effects they can cause in living beings. The removal of MPs from water bodies and wastewaters is a control strategy that needs to be implemented from the present on and strictly constantly in the near future to control and mitigate their distribution into other environments. The present work shows a detailed comparison of the current potential technologies for the remediation of the MPs pollution. That is, physical, biological, and chemical methods for the removal of MPs from water bodies and wastewaters. Focusing mainly on the discussion of the perspective on the current innovative technologies for the removal or degradation of the MPs, rather than in a deep technical discussion of the methodologies. The selected novel physical methods discussed are adsorption, ultrafiltration, dynamic membranes and flotation. The physical methods are used to modify the physical properties of the MPs particles to facilitate their removal. The biological methods for the removal of MPs are based on the use of different bacterial strains, worms, mollusks or fungus to degrade MPs particles due to the hydrocarbon chain decrease of the particles, because these kinds of microorganisms feed on these organic chains. The degradation of MPs in water bodies and wastewaters by chemical methods is focusing on coagulation, electrocoagulation, photocatalysis, and ozonation. Chemical methods achieve the degradation of MPs by the modification of the chemical structure of the particles either by the change of the surface of the particles or by attacking radicals with a high oxidation capacity. Additionally, some interesting combinations of physical, chemical, and biological methods are discussed. Finally, this work includes a critical discussion and comparison of several novel methods for the removal or degradation of MPs from water bodies and wastewaters, emphasizing the areas of opportunity and challenges to be faced.

Postbiotic Sodium Butyrate Mitigates Hypertension and Kidney Dysfunction in Juvenile Rats Exposed to Microplastics

BACKGROUND

Plastic production has led to widespread microplastic (MP) pollution, with children more vulnerable to MPs than adults. However, the mechanisms linking MP exposure to hypertension and kidney disease in children remain unclear. This study explored whether sodium butyrate, a short-chain fatty acid (SCFA) with antioxidant and anti-inflammatory properties, could mitigate MP-induced hypertension and kidney damage in juvenile rats.

METHODS

Male Sprague-Dawley rats (3 weeks old) were randomly assigned to four groups (n = 8/group): control, low-dose MP (1 mg/L), high-dose MP (10 mg/L), and high-dose MP with sodium butyrate (400 mg/kg/day). Rats were euthanized at 12 weeks.

RESULTS

High-dose MP exposure impaired kidney function and increased blood pressure, which were alleviated by sodium butyrate through reduced oxidative stress, modulation of gut microbiota, increased plasma butyric acid levels, and enhanced renal SCFA-sensing G protein-coupled receptor 43 expression.

CONCLUSIONS

Sodium butyrate holds potential for mitigating MP-induced hypertension by reducing oxidative stress, modulating the gut microbiota, and elevating butyric acid levels.

Factors affecting microplastic pollution of sandboxes in urban residential areas: Simple methodology for quality control in the context of potential exposure assessment for children

Occurrence of microplastics in the environment is well studied, but our knowledge of their distribution in specific locations, such as the sandboxes, which are integral parts of popular playgrounds for children, is limited. Pioneering research on the factors affecting the microplastic pollution of sandboxes in urban residential areas was conducted within three estates in Kielce, Poland. Sand samples (Σ27) were collected from nine sandboxes and examined for the presence of microplastics, using a simple quality control methodology proposed by the authors. Microplastics were found in each sample and their contents ranged from 60 to 5,540 items/kg of sand. Fragments and fibers were the most prevalent types of microplastics in the samples. They contributed to approximately 95% of all microplastics found. Transparent fibers were the most abundant among fibers (63%) and red particles (57%) among fragments. A strong, positive, and significant correlation (rSpearman = 0.90) was found between the number of microplastic items and the location of sandboxes (above sea level). There was no correlation between the population density of the estates (rSpearman  =  0.03), the distance of the estates from the center (rSpearman  =  0.02), and the distance of the estates from main roads (rSpearman  =  0.43). Considering that sandboxes can be a potential source of microplastics for children, and assuming that sand ingestion by children is similar to the estimated daily soil ingestion rate, our results indicate that the number of microplastics ingested could be 1,106. Inhalation, dermal transport, and ingestion of microplastic particles from sandboxes pose a potential threat to children's health. However, more research is needed to better understand the health risks associated with this source of microplastics.

Toy building bricks as a potential source of microplastics and nanoplastics

Microplastics and nanoplastics have become noteworthy contaminants, affecting not only outdoor ecosystems but also making a notable impact within indoor environments. The release of microplastics and nanoplastics from commonly used plastic items remains a concern, and the characterisation of these contaminants is still challenging. This study focused on evaluating the microplastics and nanoplastics produced from plastic building bricks. Using Raman spectroscopy and correlation analysis, the plastic material used to manufacture building blocks was determined to be either acrylonitrile butadiene styrene (correlation value of 0.77) or polycarbonate (correlation value of 0.96). A principal component analysis (PCA) algorithm was optimised for improved detection of the debris particles released. Some challenges in microplastic analysis, such as the interference from the colourants in the building block materials, was explored and discussed. Combining Raman results with scanning electron microscopy - energy-dispersive X-ray spectroscopy, we found the scratches on the building blocks to be a significant source of contamination, estimated several thousand microplastics and several hundred thousand nanoplastics were generated per mm2 following simulated play activities. The potential exposure to microplastics and nanoplastics during play poses risks associated with the ingestion and inhalation of these minute plastic particles.

Dynamics of microplastic abundance under tidal fluctuation in Musi estuary, Indonesia

Tidal dynamics contribute to fluctuations in microplastic abundance (MPs). This is the first study to characterize MPs under the influence of tidal fluctuations in the Musi River Estuary. MPs samples were collected during flood and ebb tides at 10 research stations representing the inner, middle and outer parts of the Musi River Estuary. MPs were extracted to identify the shape, color and size. MP abundances were 467.67 ± 127.84 particles/m3 during flood tide and 723.67 ± 112.05 particles/m3 during ebb tide. The concentration of MPs in the outer zone of the estuary (ocean) was detected to be higher than in the inner zone of the estuary (river). The MPs found were dominated by black color, film shape and size 101-250 μm. A greater abundance of MPs at ebb tide than at flood tide implies that the Musi Estuary's largest source of emissions is discharge from the river.

Are Microplastics Toxic? A Review from Eco-Toxicity to Effects on the Gut Microbiota

Emerging studies have presented an initial picture of the toxic effects of exposure to environmental micro- and nanoplastics. They have indicated that micro- and nanoplastics may induce toxicity by leading to oxidative stress, energy metabolism disorders, gene damage, and so forth in environmental organisms, marine invertebrates and vertebrates, and laboratory mouse models. In recent years, micro- and nanoplastics have been discovered in human fecal samples, placentas, lung tissue, and even blood; thus, micro- and nanoplastics pose an alarming and ever-increasing threat to global public health. However, current research on the health effects of micro- and nanoplastics and the possible adverse outcomes in humans has only presented the tip of the iceberg. More robust clinical data and basic experiments are still warranted to elucidate the specific relationships and mechanisms. In this paper, we review studies on micro- and nanoplastic toxicity from the perspectives of eco-toxicity, the adverse effects on invertebrates and vertebrates, and the impact of micro- and nanoplastics on the gut microbiota and its metabolites. In addition, we evaluate the toxicological role of micro- and nanoplastic exposure and its potential implications in respect to human health. We also summarize studies regarding preventive strategies. Overall, this review provides insights on micro- and nanoplastic toxicity and its underlying mechanisms, opening up scientific avenues for future in-depth studies.

Polystyrene microplastics induced nephrotoxicity associated with oxidative stress, inflammation, and endoplasmic reticulum stress in juvenile rats

Introduction

Unintended intake of microplastic particles has been demonstrated to exert adverse health effects, however, studies on relevant nephrotoxicity in juvenile mammals are lacking.

Methods

Therefore, we investigated the potential nephrotoxicity of oral-exposed polystyrene microplastics (PSMPs) (1,000 nm, 2.0 mg/kg/d) for 28 days in juvenile rats. Levels of oxidative stress, inflammation, and endoplasmic reticulum (ER) stress in kidneys were analyzed.

Results and discussion

Results revealed that PSMPs noticeably decreased the growth rate of bodyweight, and organ index of the kidney, cardiac, and ovary. The intestinal injury caused by PSMPs exposure was also observed, which was distinctly alleviated with N-acetyl-cysteine (NAC) and Salubrinal (Sal) treatment compared with the single PSMPs group. PSMPs caused histological lesions of the kidney via disrupting the serum blood urea nitrogen (BUN), creatinine (CRE), and pro-inflammatory mediators IL-1β, IL-6, and TNF-α. Furthermore, PSMPs exposure induced ER stress and inflammation presumably potentially mediated by oxidative stress in kidneys of rats. Eventually, PSMPs also promoted renal cells apoptosis, manifested as an obvious increase in the number of positive cells for the dUTP nick end labeling of Terminal deoxynucleotidyl transferase, which also can be confirmed by the elevated expression of genes associated with apoptosis Bcl-2, Bax, Caspase-12, Caspase-9, Caspase-3, and IHC score of Caspase-12 in the PSMPs group. Supplementation of NAC and Sal not only ameliorated the PSMPs-induced oxidative stress and ER stress but also the inflammation and apoptosis in the kidney. Collectively, this study suggested that PSMPs caused nephrotoxicity in juvenile rats potentially through oxidative damage and ER stress, which call for greater efforts to be taken on regulating the PSMPs ingestion in children.

Hazard index of microplastics contamination in various fishes collected off Parangipettai, Southeast coast of India

The authors of the present research aimed to assess microplastics (MPs) contamination in the gills and gut of selected fishes from various aquatic zones and also to bring out the risks of the identified polymers. Accordingly, about 200 fish specimens of 10 different species were collected from the landing center at Parangipettai, southeast coast of India. The fishes were dissected to investigate MPs contamination in their gills and gut. The dissected tissues were acid digested and filtered to observe its microplastic contamination using a stereozoom microscope. In gills, Cynoglossus arel had the least contamination (0.4 ± 0.01 particles/ind) and Mugil cephalus had highest microplastic contamination (1.7 ± 0.01 particles/ind). In gut, C. arel had the minimum contamination (0.7 ± 0.09 particles/ind) and Rastrelliger kanagurta had maximum contamination (2.3 ± 0.26 particles/ind). The size of microplastics isolated from the present study ranged from 100 to 1000 μm. Among microplastic shapes, fibers (97%) and pellets (3%) were observed. About eight colours of microplastics were observed in the fishes among which black was dominant. Three polymers such as LDPE, PP and PS were identified by μFTIR, among which LDPE (57%) was dominant. Polymer Hazard Index denotes that LDPE (6.27), PP (3.4) and PS (2.7) have a PHI score of 1-10 classifying them in the hazard category II which has a medium risk. These polymers may directly enter the human body when consumed and cause health implications which require further investigation.

A scoping review protocol on in vivo human plastic exposure and health impacts

BACKGROUND

Global plastic production has increased exponentially since the 1960s, with more than 6300 million metric tons of plastic waste generated to date. Studies have found a range of human health outcomes associated with exposure to plastic chemicals. However, only a fraction of plastic chemicals used have been studied in vivo, and then often in animals, for acute toxicological effects. With many questions still unanswered about how long-term exposure to plastic impacts human health, there is an urgent need to map human in vivo research conducted to date, casting a broad net by searching terms for a comprehensive suite of plastic chemical exposures and the widest range of health domains.

METHODS

This protocol describes a scoping review that will follow the recommended framework outlined in the 2017 Guidance for the Conduct of Joanna Briggs Institute (JBI) Scoping Reviews, to be reported in accordance with Preferred Reporting Items for Systematic Reviews and Meta-Analyses extension for Scoping Reviews (PRISMA-ScR) Checklist. A literature search of primary clinical studies in English from 1960 onwards will be conducted in MEDLINE (Ovid) and EMBASE (Ovid) databases. References eligible for inclusion will be identified through a quality-controlled, multi-level screening process. Extracted data will be presented in diagrammatic and tabular form, with a narrative summary addressing the review questions.

DISCUSSION

This scoping review will comprehensively map the primary research undertaken to date on plastic exposure and human health. Secondary outputs will include extensive databases on plastic chemicals and human health outcomes/impacts.

SYSTEMATIC REVIEW REGISTRATION

Open Science Framework (OSF)-Standard Pre-Data Collection Registration, https://archive.org/details/osf-registrations-gbxps-v1 , https://doi.org/10.17605/OSF.IO/GBXPS.