Exploring the impact of polystyrene microplastics on human health: unravelling the health implications of polystyrene microplastics (PS-MPs): a comprehensive study on cytotoxicity, reproductive health, human exposure, and exposure assessment

Abstract

This investigation explores the various impacts that polystyrene microplastics (PS-MPs) have on human health. As most of the plastic materials affect human health when they release leachable toxic substances that affect human health, this causes a negative effect that determines poor health conditions and leads to health hazards associated with plastic toxins routed in the human body, such as: Polychlorinated Biphenyls, Polybrominated Biphenyls etc. The study includes micro-plastic exposure assessment on testicular structure analysis, and cytotoxicity evaluations of different human cell types. The findings clarified the possible dangers of PS-MPs exposure from food, medications, and common products, emphasising the necessity of standard specimen handling procedures for precise biomonitoring.

Introduction

Global plastic production has surpassed 300 million tons annually.¹ The global issue of environmental pollution stemming from plastic waste has raised significant concerns. Plastic in various forms, including macroparticles, microparticles, and nanoparticles, poses a potential threat to both marine ecosystems and human well-being.^2,3

In recent times, a growing body of research has concentrated on investigating the presence and ecological dynamics of microplastics in terrestrial and freshwater ecosystems. Various forms of microplastics have been identified in both environmental settings and within consumables such as: food and drinking water.¹

The current processes for creating, utilising, disposing of, and manufacturing plastics have a significant detrimental influence on the environment. The negative effects affect many different areas, including biodiversity, human health, climate change, sustainable livelihoods, ecosystem equilibrium, cultural variety, and, in the end, human dimensions. It emphasises how widely accepted it is that the current use of plastics is having a negative impact on society, is seriously harming the environment, and aspects of human health.⁴

Nevertheless, the insufficient natural breakdown and inadequate recycling of plastic waste have led to its accumulation in both terrestrial and marine ecosystems. Reports from the 1970s by scientists highlighted the presence of tiny plastic particles in the ocean.¹

Microplastics refer to diminutive plastic fragments measuring less than 5 mm.¹ Their extensive presence in diverse environmental domains, as well as in food and potable water, has garnered escalating global scrutiny.¹ The assessment of raw recycling wash water revealed microplastic counts ranging from 5.97 × 10^6 to 1.12 × 10^8 MP m⁻³, as determined through fluorescence microscopy analysis. Implementation of microplastic pollution mitigation measures, specifically filtration, proved effective in removing the majority of microplastics exceeding 5 μm, particularly exhibiting high removal efficiencies for those exceeding 40 μm. Microplastics less than 5 μm were typically not eliminated by filtering and were therefore released into the environment, with an annual potential release of 59–1,184 tonnes. The findings highlights the necessity of additional filtration targeting smaller microplastics before wash water discharge, advocating for an integrated approach to address microplastics in water quality regulations.⁵

Additionally, plastic serves as a vital packaging material in the realms of both food and pharmaceuticals. The importance of utilising high-quality plastic containers cannot be overstated. The significance of high-quality plastic containers remains paramount, serving crucial roles in packaging and storing not only food and pharmaceuticals but also household goods.

Additionally, it’s essential to consider plastic particles within the size range of 1 to 1,000 nm, or potentially even as small as 100 nm, as nanoplastics. These particles may demonstrate colloidal characteristics. It’s crucial to provide this context when discussing small particles to highlight the specific category of nanoplastics and their unique properties, particularly their colloidal nature. This context becomes important in understanding the potential environmental and health implications associated with nanoplastic particles.¹

Microplastics (MP), defined as plastic particles ranging from 1 μm to 5 mm, are now ubiquitous across global ecosystems. Studies reveal that these particles traverse water systems, moving from urban environments to freshwater bodies and eventually reaching the oceans. Additionally, atmospheric systems play a role in transporting microplastics from terrestrial environments to the oceans, utilising the sea as a conduit for global MP dissemination.⁵

Firstly, studies indicate that these particles traverse water systems, implying that microplastics move within urban environments and make their way into freshwater bodies. This movement could occur through various means, such as: runoff from urban areas, industrial discharges, or wastewater effluents, ultimately contributing to the presence of microplastics in freshwater ecosystems.

Secondly, the statement highlights that these microplastics, once in terrestrial environments, can be transported to the oceans through atmospheric systems. This suggests that microplastics in the form of airborne particles may be carried by wind or other atmospheric processes, ultimately reaching the sea. The ocean acts as a conduit for the global dissemination of microplastics.

In summary, the statement emphasised the interconnectedness of environmental systems, illustrating how microplastics move through water systems within urban and freshwater environments. Further, it emphasises the role of atmospheric systems in transporting microplastics from terrestrial areas to the oceans, highlighting the potential for a global impact on marine environments.⁵

Safety usage of plastic in food and pharmaceuticals

Plastic containers and closures

The safe utilisation of plastic in the context of food and pharmaceuticals is significant therefore pharmaceutical and food grade manufacturing is vital. Plastic closures and containers designated for pharmaceutical use, whether directly holding a pharmaceutical product or having potential indirect contact, are termed pharmaceutical-grade plastic containers. These containers and closures, specifically designed for pharmaceutical applications, are crafted from materials that may include additives. Importantly, these materials are selected to ensure that no substances capable of being extracted by the product in quantities that could alter its stability, efficacy, or pose any risk of toxicity are present.⁶

Containers are in close contact with the product and, at present, no container is entirely unresponsive, especially when dealing with aqueous solutions. Both the chemical and physical attributes impact product stability, with a preference for emphasising physical characteristics when choosing a protective container.⁷

As per British pharmacopoeia plastic containers designed for parenteral infusion of aqueous solutions are crafted from one or more polymers, potentially incorporating additives as needed. The predominant polymers employed in their manufacture include polyethylene, polypropylene, and poly(vinyl chloride). These containers, which can take the form of bags or bottles, are specifically tailored for the purpose of containing and delivering aqueous solutions for parenteral infusion.⁶

As per United States Pharmacopoeia; the container is that which holds the article and is or may be in direct contact with the article. The immediate container is that which is in direct contact with the article at all time.⁸

Additionally, details regarding containers and closures can be located in the British Pharmacopoeia Codex (B.P.C), the British National Formulary (B.N.F.), and the British Pharmacopeia (B.P.). The Pharmaceutical Society of Great Britain issued recommendations on dispensing containers in 1972, while its Department of Pharmaceutical Sciences has made noteworthy contributions to understanding containers for tablets and semi-solid preparations. British standards 1679, 1965, 1967, 1968, and 1969 provide specifications for a wide range of containers utilised in dispensing (Table 1).⁹

Table 1.

Application: Use of plastic in food and pharmaceuticals; this table provides a brief overview of how plastic is utilised in various aspects of the food and pharmaceutical industries.

Application	Use of plastic in food and pharmaceuticals
I. Packaging	a. Plastic containers are widely used for packaging food and pharmaceutical products, ensuring protection, and preserving freshness. b. Plastic films and wraps provide a convenient and lightweight solution for wrapping food items and securing pharmaceutical products.
II. Storage containers	c. High-quality plastic containers serve as effective storage solutions for both perishable and non-perishable food items. They also contribute to organised storage in pharmaceutical settings.
III. Single-use packaging	d. Single-use plastic packaging, such as: bottles, pouches, and blister packs, is prevalent in the pharmaceutical industry for individual dosage units and in the food industry for convenient portions.
IV. Safety and hygiene	e. Plastic packaging in the form of bottles and blister packs enhances product safety and hygiene, preventing contamination and ensuring product integrity.
V. Transportation and distribution	f. Plastic materials are commonly used for lightweight and durable packaging during transportation and distribution, minimising the risk of breakage and damage.
VI. Compliance with regulations	g. Many plastic materials used in food and pharmaceutical packaging comply with regulatory standards, ensuring that they meet safety and quality requirements.

Action of contents on polyvinyl chloride medication bottles containing B.P.C. tincture and chloroform. Peppermint, clove, or anise oil. The combination or individual use of preparations containing free (undissolved) chloroform or ether can quickly soften and distort B.P.C. morphine tincture. Very quick softening and distorting for oils containing peppermint, clove, or anise. Even at low solvent concentrations, preparations containing free (undissolved) ether or chloroform, either separately or in combination, cause softening.⁹

Rationale of the study

The global proliferation of plastic waste, particularly in the form of microplastics, has emerged as a pressing environmental and public health concern. Amidst this backdrop, the study aims to comprehensively investigate the potential impacts of polystyrene microplastics (PS-MPs) on human health.

This study addresses the pervasive issue of plastic pollution, specifically focusing on the ubiquitous presence of PS-MPs in various ecosystems, including food and water sources. The study aims to comprehensively understand the consequences of human exposure to PS-MPs and their potential health risks (Fig. 1).

Fig. 1.

Exploring the impact of polystyrene microplastics on human health: Cytotoxicity, testicular effects, etc.

The rationale for this study is rooted in several key factors

In summary, this study is motivated by the imperative to bridge existing knowledge gaps, unravel the complexities of PS-MP exposure, and pave the way for evidence-based recommendations to safeguard human health in the face of escalating plastic pollution and packaging usage in food and pharmaceuticals.

The text highlights the limited understanding of the cytotoxic effects of PS-MPs on different human cell types, emphasising the importance of systematically evaluating cellular responses. Further, there is a growing concern about the potential impact of PS-MPs on male reproductive health, prompting an investigation into alterations in testosterone levels, testicular morphology, and hormonal pathways.

In addition to cytotoxicity and reproductive health, the study takes a comprehensive approach to assess PS-MP exposure through various channels, including food, pharmaceuticals, and personal care products. The goal is to quantify and qualify the extent of human exposure to PS-MPs and contribute to a better understanding of the associated risks.

The study also examines the necessity for standardised specimen collection, handling, and analysis procedures to ensure the reliability of biomonitoring results. This approach enables meaningful comparisons across studies and reinforces the importance of responsible plastic usage. Overall, the text advocates for informed decision-making in industries utilising plastic, with a focus on minimising adverse health and environmental impacts for safer and healthier products that are more safe and non-toxic.

Study of methodology and scientific understanding

Prolonged exposure to polystyrene microplastics (PS-MPs) has adverse effects on male reproductive health. The human body is exposed to plastic, including plastic bottles, liquid carry bags, and plastic food containers, leading to the ingestion of microplastics. The surge in the use of single-use plastic drinking straws during the COVID-19 pandemic has contributed to pollution. The increased utilisation of such straws necessitates an evaluation of their impact on the male testicular system, as microplastics have been found to influence sperm production and erectile processes. The effects of microplastic-polluted water on mice, focusing on testosterone levels and associated abnormalities were studied. The results indicate that microplastics have a significant impact on male reproductive functions, affecting both sperm production and erectile processes. As the usage of everyday plastic items continues to rise, the absorption and accumulation of microplastics pose a serious threat to human and animal health. However, it remains uncertain whether direct microplastic contamination from plastic packaging poses a risk to human health.¹⁰ After thorough investigations, it has been determined that particle plastic pollution does not predominantly originate from drinking water, food, food containers, common personal care items, or biomedical products, though they may still contribute to plastic debris. This context highlights various items that, while not primary sources, can continue to contribute to plastic pollution and potentially contaminate human food and drink supplies. This sets the stage for a scientific study unveiling potential adverse effects on male reproductive health resulting from prolonged exposure to polystyrene microplastics (PS-MPs). Testosterone levels and abnormalities in the LH-mediated LHR/cAMP/PKA/StAR pathway, specifically linking the discussion to a particular type of plastic waste. The information presented emphasises the necessity for further investigations to ascertain the extent of contamination caused by polystyrene microplastics and its potential association with COVID-19. This highlights a knowledge gap concerning the relationship between plastic pollution, particularly from drinking straws, and the ongoing pandemic. In conclusion, transitioning from a broad understanding of various plastic pollution sources to a specific focus on polystyrene microplastics and their potential impact on male reproductive health, the concluding statement emphasises the importance of threats associated with the exposure of micro-plastics and practical solutions to address pollution issues, particularly in the context of drinking straw pollution and its potential health risks.^2,4,11 A research study has uncovered minuscule plastic fragments in both disposable and reusable plastic bottles, citing facial scrubs as specific examples. This suggests that microscopic plastic particles are present in a variety of plastic bottles, irrespective of their intended single-use or reusable nature. Additionally, the study emphasises facial scrubs, commonly used for exfoliation, as additional instances of products contributing to the presence of these minute plastic particles. The inference drawn is that the concern of microplastic contamination goes beyond the packaging of beverages and encompasses personal care items such as facial scrubs, highlighting a broader issue of worry regarding plastic pollution in everyday products.

Additionally, it is pointed out that facial scrubs containing lower-quality microplastic beads can adversely impact the face by depositing plastic remnants, causing damage to facial skin texture and hindering skin regeneration.² Cosmetic products, particularly facial scrubs, have been identified as significant contributors to microplastic pollution.¹² Study aimed to investigate, quantify, and characterise the sorptive properties of plastic microbeads commonly employed as exfoliants in cosmetics. The mean diameters of polyethylene microbeads, extracted from various products, varied widely, ranging from 164 to 327 μm. The research reveals that a single use of these microbeads can release a substantial number, ranging from 4,594 to 94,500 microbeads. The microbeads underwent testing involving a binary mixture of [(14)C-DDT and (3)H-phenanthrene] to assess their capacity to accumulate and transport compounds. The study found that the potential for sorbed compounds to be transferred by microbeads closely resembled outcomes observed in prior sorption tests using polythene (PE) particles. In conclusion, this research emphasises that exfoliants commonly used in cosmetics represent a significant and avoidable source of microplastic pollution. Poorly formulated products have the potential to introduce contaminants that may adversely impact facial structure.¹³

“Rinse-off” cosmetics, like toothpaste, that purposefully contain microbeads and are intended to cleanse or exfoliate the skin are covered by the regulation

Implemented regulatory actions

Put into effect regulatory measures; an act was passed by Congress in response to concerns about microbeads in the water supply. The main cause for concern is the infiltration of small plastic beads into drainage systems from personal hygiene practices like face washing and tooth brushing. There’s concern that these microbeads may end up in lakes and oceans because they may not be filtered out thoroughly in water treatment systems. These microbeads pose a concern to small fish and other species in aquatic situations where they may be mistaken for food. It is imperative to acknowledge that the recently passed legislation is not intended to tackle issues pertaining to consumer safety. At this time, there is no proof that plastic microbeads, which are frequently found in cosmetic items, are harmful to people’s health.¹⁴ Although a number of states have separately outlawed microbead-containing items, Congress decided that a single federal law was required. The goal of this national legislation is to ensure a uniform approach to tackling the issue of microbeads in cosmetic items across the nation by streamlining rules, as the current state laws vary. The recently passed law defines a “plastic microbead” as any solid plastic particle that satisfies two requirements: it must be 5 millimetres in size or less, and it must be intended for use in cleaning or exfoliating the body, in whole or in part.^14,15

Throughout history, humans have employed various drinking techniques for diverse reasons. The use of straws has been popularised with the assumption that it minimises contact with teeth, thereby reducing health risks and promoting dental well-being. By positioning the straw to ensure liquids bypass the teeth and directly reach the throat, it is believed to prevent cavities caused by sugary or acidic beverages, offering a safeguard against potential discolouration from harmful substances. While initially designed for dental protection, disposable plastic straws have evolved into perceived luxurious and convenient accessories, commonly embraced in recreational settings such as: restaurants, cafeterias, and bars.⁴

Also, microplastics can be found in three of the four body exfoliants available. Just 25% of these primary plastic particles are filtered out of water sewage treatment plants, and they have the potential to enter the sewage system. As a result, coming into direct contact with microplastic particles found in common products could be very dangerous.²

Ingested microplastic particles can cause a variety of issues depending on their size, shape, and chemistry of functional groups. Aggregates containing biomolecules and microplastics or nanoplastics can cause gastrointestinal dysmotility or obstruction because microplastic particles cannot be digested. Size is widely recognised as a crucial in-vitro cytotoxicity parameter.² Remarkably, microplastics have been identified in human faeces.¹

Given the ongoing surge in plastic production and the escalating challenge of worldwide plastic pollution, there is an imperative demand for heightened plastic recycling efforts. A notable gap exists in our understanding and evaluation of microplastic pollution originating from specific points, such as: plastic recycling facilities, on a global scale.⁵

Additionally, microplastics can act as carriers for diverse hazardous pollutants, encompassing heavy metals, polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), dichlorodiphenyltrichloroethane (DDT), polybrominated diphenyl ethers (PBDEs), and other contaminants like polyfluoroalkyl substances (PFAS), pharmaceuticals, and personal care products.^1,5

Microbeads are artificial polymer particles that are produced in a range of sizes between 0.1 μm and 5 mm, with variations in their size, shape, density, and intended use. These microbeads are made for certain uses, such as: adding them to toothpaste, bath bombs, scrubs, and face cleansers, among other personal hygiene products. Further, they find use in a wide range of consumer goods like printer toners and cleaning agents, as well as in industrial settings for abrasive media (plastic blasting, for example), different industrial processes (such as: oil and gas exploration, textile printing, and automotive moulding), other plastic products (such as those used in anti-slip and anti-blocking applications), and even in medical settings.¹⁶ The study calculated the amount of PS particles consumed through meals, everyday goods, and pharmaceuticals. Based on a 3 μm PS particle weight of 1.5 × 10^8 mg, the maximum amount of plastic particles that an individual could potentially consume annually through food is 11,000 micro-plastic particles. Microplastic and nanoplastic particles annually by consuming seafood, such as: oysters, crabs, and fish.^2,13,17 The term “microplastics” broadly refers to smaller plastic particles, originally coined to distinguish them from larger plastics (macro) that are visible without a microscope. Researchers have adopted varying definitions, often tied to the sampling methods employed in characterising these minuscule plastic particles. For instance, some define microplastics using 500 μm and 67 μm sieves as upper and lower limits, while others opt for <5 mm to 333 μm based on the Neuston nets utilised in their sampling procedures.¹⁶

A person’s drinking water may include up to 237,250 plastic particles every year. If particles were larger than 100 μm in diameter, additional calculations that took into consideration the different features of the particles indicated that the maximum yearly personal consumption may surpass 133 mg. An estimated 35 × 10⁶ primary plastic particles are produced annually by personal care or biomedical goods, which have the potential to introduce between 4,594 and 94,500 particles daily.²

The substantial presence of microplastics can induce toxicity in organisms, leading to significant ecological risks. Additionally, these microplastics have the potential to be transferred and concentrated through food chains, posing a threat to human health (Tables 2 and 3).¹

Table 2.

PS particle source and the estimated annual intake.

PS particle source	Estimated annual intake
Food-related (3 μm PS particles)	11,000 plastic particles per person
Drinking water (3 μm PS particles)	Up to 237,250 plastic particles per year
Maximum personal consumption (varying characteristics)	Exceeding 133 mg/year if particles >100 μm in diameter

Table 3.

Personal care or biomedical products intake with estimated annual consumption.

Personal care or biomedical products intake	Estimated annual consumption
5 mL volume of product	4,594 to 94,500 particles per day
Estimated annual primary plastic particle usage	Up to 35 × 10^6 particles

The World Health Organisation (WHO) urged academics worldwide to intensify their studies on the effects of microplastics on human health.¹ In the contemporary era, scholars, policymakers, and practitioners are increasingly focusing on the issue of pollution caused by single-use plastics. Examinations of existing literature have revealed that, unlike personal protective equipment (PPE), the impact of plastic drinking straws on pollution during the COVID-19 pandemic has not been thoroughly investigated (Table 4).⁴

Table 4.

Overall human exposure to primary plastic particles and estimated total human exposure.

Overall human exposure to primary plastic particles	Estimated total human exposure
Considering less than 10% of plastic waste comprises PS particles	0–19 mg/year, or 0–19 μg/mL
Assumptions involve applying PS particles at the maximum concentration	Heightened to 0–19,000 mg/year

Mice were exposed to drinking water with 100 μg/L and 1,000 μg/L PS-MPs (0.5 μm, 4 μm, and 10 μm particles) for 180 days in a row as part of an in vivo experiment. Testicular morphology was altered, blood levels of testosterone, LH, and FSH were lowered, sperm viability was lowered, and the number of aberrant sperm increased as a result of this prolonged exposure. Testicular tissues showed a reduction in the expression of steroidogenic enzymes and StAR.

In vitro studies with primary Leydig cells unveiled the mechanism underlying PS-MP-induced reduction in testosterone. Notably, PS-MPs attached themselves to Leydig cells and internalised them, resulting in a concentration-dependent drop in testosterone in the cell supernatant. Additionally, the activation of the AC/cAMP/PKA pathway was inhibited by PS-MPs, resulting in the downregulation of StAR, LHR, and steroidogenic enzymes. The reduction in StAR and steroidogenic enzyme levels was lessened by the overexpression of LHR, which ultimately prevented the drop in testosterone caused by PS-MPs. Persistent exposure of mice to ecologically pertinent concentrations of PS-MPs had detrimental effects on testicular histology, spermatogenesis, and hormonal equilibrium. The reduction in testosterone levels was attributed to the suppression of the LH-mediated LHR/cAMP/PKA/StAR pathway (Fig. 2)¹¹.

Fig. 2.

The impact of PS-MPs on testis structures was examined by H&E staining. Arrows: Abnormal structure. Data represent means ± SD. ^*P < 0.05, ^**P < 0.01, ^***P < 0.001 vs. control. ^#P < 0.05, ^##P < 0.01 vs. 100 μg/L group.

Tests for polystyrene cytotoxicity investigated how different human cell types, such as: HDFs, HMC-1 cells, and PBMCs, responded to PS particles. The emphasis was on HDFs, which are abundant in stromal tissue, essential for wound healing, and serve as a barrier to prevent the absorption of PS particles. To investigate possible connections between PS microparticles, the human immune system, and hypersensitivity, human mast cells were selected to mimic tissue mast cells in terms of histamine, tryptase, and heparin expression. One of the most distinctive discoveries into the human immune response to PS particles came from the behaviour of isolated PBMCs, which reflected the production of cytokines.²

During treatment, PS particles (1 mg/mL) were completely coated on the cells. Interestingly, HDFs showed no discernible cytotoxicity at 500 μg/mL, indicating that main PS particles may not be as damaging to skin and organs. The viability of HDFs treated with 3 μm PS particles at 1,000 μg/mL decreased by 40% (^**P < 0.001) in experiments where the concentration of PS exceeded 500 μg/mL, but the viability of PBMCs was unchanged (Table 5).²

Table 5.

PS particle concentration and cytotoxicity response for cell types.

Cell type	PS particle concentration	Cytotoxicity response
HDFs	Up to 500 μg/mL	No significant cytotoxicity observed
PBMCs	Up to 500 μg/mL	No significant cytotoxicity observed
HDFs	1,000 μg/mL	40% reduction in viability (**P < 0.001)
PBMCs	1,000 μg/mL	No significant decrease in viability

Standardised methods for the collection, processing, storage, and analysis of specimens are necessary for the precise assessment of toxicant exposure and biomonitoring. A phlebotomist or a commercial blood draw station took blood samples from registered anglers in Michigan with the goal of analysing the amounts of organochlorines in the sample. The specimens collected by phlebotomists in glass containers were transferred to plastic containers at the central facility of the commercial laboratory for freezing purposes. Subsequently, the Michigan Department of Community Health’s Analytical Chemistry Section Laboratory conducted the analysis, providing insights into sample storage in glass containers (n = 28) as opposed to plastic containers (n = 113). This was done to investigate PCB’s, PBB’s, and DDE in the study ahead.¹⁸

To investigate the factors influencing the amounts of polychlorinated biphenyls (PCBs), polybrominated biphenyls (PBBs), and dichlorodiphenyldichloroethylene (DDE), linear regression analyses were performed. The results showed that while DDE or PBB concentrations were unaltered, serum stored in plastic containers changed the overall concentrations of PCBs, particularly the higher chlorinated PCBs like PCB-180 and PCB-199. It’s interesting to note that no other sample features could explain the increased PCB concentrations (0.75 micro g/L vs. 0.45 micro g/L; P = 0.025) seen in those housed in plastic containers. There was no difference in the percentage of PCB detects between the two subsamples. While a considerable number of earlier studies have not disclosed whether specimens were kept in glass or plastic containers, while some have. As a result, it was suggest that a thorough of review procedure be started in order to verify that previous reports based on impartial PCB determinations were accurate. Thus, it was recommend standardising specimen collection, handling, storage, and measurement in order to improve the reliability of future research. This is especially important for recently discovered analytes (Tables 6 and 7).¹⁸

Table 6.

Analysed substances and effects on concentrations.

Analysed substances	Effects on concentrations
Polychlorinated Biphenyls (PCBs)	Alterations in total concentrations, especially higher chlorinated PCBs (PCB-180, PCB-199)
Dichlorodiphenyldichloroethylene (DDE)	Unaffected
Polybrominated Biphenyls (PBBs)	Unaffected

Table 7.

Linear regression analyses and its results.

Linear Regression Analyses	Results
Impact of Storage Container on PCBs	Storing serum in plastic containers led to higher concentrations, especially for higher chlorinated PCBs
Impact on DDE and PBBs	No significant impact
Other influencing factors	No other sample characteristics explained the observed higher PCB values in plastic containers (0.75 micro g/L vs. 0.45 micro g/L; P = 0.025)

Conclusion

This study provides valuable revelations regarding the potential health hazards associated with polystyrene microplastics. Cytotoxicity assessments demonstrate diverse reactions across various human cell types, emphasising the necessity of evaluating distinct tissues. Testicular effects indicate adverse impacts on male reproductive health, emphasising the need for further research into the long-term consequences. Additionally, the toxicant exposure assessment accentuate the widespread presence of PS-MPs in food, pharmaceuticals, and personal care products, calling for heightened awareness and standardised protocols in specimen handling to ensure reliable biomonitoring and accurate risk assessment. The findings prompt a critical reevaluation of plastic usage in various industries to mitigate potential health and environmental hazards.

The World Health Organisation (WHO) has urged intensified studies on the effects of microplastics on human health, indicating a recognised need for a more comprehensive understanding. The study concludes by emphasising the need for a critical reevaluation of plastic usage in various industries to mitigate potential health hazards.

Standardised protocols in specimen handling are recommended for reliable biomonitoring and accurate risk assessment, highlighting the importance of understanding and addressing the potential health risks associated with microplastics. Microplastics, including PS-MPs, can act as carriers for diverse hazardous pollutants, encompassing heavy metals, polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), and other contaminants.

Ingested microplastic particles can cause gastrointestinal dysmotility or obstruction. The potential transfer and concentration of these pollutants through food chains pose a threat to human health.

The text implies that exposure to microplastics, particularly PS-MPs, may lead to gastrointestinal issues, hormonal imbalances, cytotoxicity, and the transfer of hazardous pollutants, all of which collectively suggest potential health risks for humans. Cytotoxicity tests on human cell types reveal varying responses, emphasising the importance of assessing different tissues.

PS particles may not be as damaging to skin and organs, but certain concentrations can affect the viability of specific cell types.

Prolonged exposure to PS-MPs, as demonstrated in in vivo experiments with mice, can lead to altered testicular morphology and lowered blood levels of testosterone, luteinising hormone (LH), and follicle-stimulating hormone (FSH).

A reduction in testosterone levels is attributed to the suppression of the LH-mediated LHR/cAMP/PKA/StAR pathway.

Thus, in vivo experiments on mice exposed to PS-MPs show altered testicular morphology, hormonal imbalances, and reduced sperm viability. In vitro studies reveal the mechanism of PS-MP-induced reduction in testosterone, which is one of the major findings that can individually affect humans in the presence of such toxicants.

List of abbreviations

1. AC/cAMP/PKA/StAR: Adenylate cyclase/cyclic AMP/protein kinase A/steroidogenic acute regulatory protein,

2. B.N.F.: British National Formulary,

3. B.P.: British Pharmacopeia,

4. B.P.C: British Pharmacopoeia Codex,

5. DDE: Dichlorodiphenyldichloroethylene,

6. FSH: Follicle-Stimulating Hormone,

7. H&E: Hematoxylin and Eosin,

8. Human Dermal Fibroblasts (HDFs),

9. Human Mast Cell line (HMC-1),

10. Human Peripheral Blood Mononuclear Cells (PBMCs),

11. LH: Luteinising Hormone,

12. PBBs: Polybrominated Biphenyls,

13. PCBs: Polychlorinated Biphenyls,

14. Polystyrene (PS).

Glossary

1. Adenylate cyclase: An enzyme that catalyses the conversion of ATP to cyclic AMP (cAMP).

2. Adverse health effects: Harmful consequences or impacts on health.

3. Biomolecules: Organic molecules that are essential for life, including proteins, nucleic acids, lipids, and carbohydrates.

4. Biomonitoring: The process of measuring and assessing the concentration of specific substances, such as pollutants or toxins, in biological samples to evaluate human or environmental exposure.

5. Cytotoxicity: The degree to which a substance is toxic to cells, often measured by its ability to cause cell damage or death.

6. Ecosystems: A biological community of interacting organisms and their physical environment.

7. Environmental pollution: The introduction of contaminants into the natural environment, leading to adverse changes.

8. Follicle-stimulating hormone (FSH): A hormone that regulates the development, growth, pubertal maturation, and reproductive processes of the body.

9. Food packaging: The materials and techniques used to enclose and protect food products.

10. Gastrointestinal dysmotility: Impaired movement of the digestive tract, affecting the normal functioning of the gastrointestinal system.

11. In Vitro: Processes that are performed or take place outside a living organism, often in a laboratory setting.

12. Intimate contact: Close or direct association between plastic materials and consumables.

13. Luteinising hormone (LH): A hormone that plays a role in the regulation of the reproductive system, including the stimulation of testosterone production.

14. Microplastics: Extremely small pieces of plastic debris, often less than five millimeters in length.

15. Nanoplastics: Extremely small plastic particles on the nanometer scale.

16. Pharmaceutical grade: Refers to materials that meet specific quality and safety standards for use in pharmaceutical products.

17. PS-MPs: Polystyrene microplastics.

18. Reproductive health: Concerns the function and systems of the male and female reproductive organs and the well-being of the reproductive process.

19. Responsibility plastic usage: The conscious and mindful use of plastic materials to minimise negative impacts on health and the environment.

20. Responsible plastic usage: Mindful and sustainable practices in the production, consumption, and disposal of plastic materials.

21. Specimen collection: The process of gathering and preparing samples, often biological, for analysis or examination.

22. Standardisation: The process of developing and implementing standards to ensure consistency and reliability in procedures, methods, or materials.

23. Toxicant exposure: The exposure of an organism to toxic substances, which can have harmful effects on health.

24. Ubiquitous: Present, appearing, or found everywhere.

Author contributions

The author of this work, Dr Saurabh Dilip Bhandare, contributed to all aspects of the manuscript, including conceptualisation, literature review, data collection and analysis, interpretation of results, drafting and revising the manuscript, and final approval for submission. Responsibility for the work’s intellectual content and integrity rests only with Dr Saurabh Dilip Bhandare.

Funding

No funding has been provided to support this study. All expenses associated with this research have been borne by the individual author involved.

Conflict of interest statement. The authors declare no conflicts of interest related to the study, authorship, or publication of this article. No financial or personal relationships with individuals or organisations that could potentially influence the work have been disclosed. This study was conducted with the highest degree of integrity and objectivity, and the author have adhered to ethical standards throughout the entire study process.

Affiliated to SPPU; formerly known as: university of Pune. Visit at website address: https://cop.brahmavalley.com/