Tracking microplastics contamination in drinking water in Zahedan, Iran: From source to consumption taps

Methods to optimize the collection, pretreatment, extraction, separation, and examination of microplastics in soil, groundwater, and human samples

Microplastics (MPs) in soil, groundwater, and human (SGH) present a significant global challenge due to their ecological and human health impacts. However, current protocols for detecting MPs in these environments and humans are limited, inconsistently applied, and vary significantly, particularly during the pretreatment stages of MP analysis. Moreover, no study has investigated the impact of methodological flaws on MP detection. This study conducted a thorough global assessment of the existing soil and groundwater (SG) pretreatment methods, using statistical tests to evaluate their effectiveness. It also reviewed filtration and analytical techniques for MPs in SGH samples. The analysis included research articles from PubMed, Google Scholar, Scopus, and Web of Science published between 2015 and 2024. Findings show that pretreatment using more than 100 g of soil can impact MP quantification, likely due to soil heterogeneity, while groundwater volume did not significantly affect MP quantification, likely due to the homogeneity of groundwater. During SGH pretreatment, various salts (e.g., ZnCl2 and NaCl) can be used for density flotation. Fenton's reagent was found to be a better choice than H2O2 for organic material removal because less heat was released. Post treatment MPs in SGH samples can be analyzed using various instruments and resolutions such as FTIR down to 1-5 µm, ATR-FTIR down to 2 µm, micro-Raman down to 500 nm, and LDIR down to 1 µm. This study lays the foundation for developing an effective MP analysis in SGH.

Microplastics and phthalate esters in yogurt and buttermilk samples: characterization and health risk assessment

The contamination of yogurt and buttermilk (doogh), two widely consumed dairy products, with microplastics (MPs) and phthalic acid esters (PAEs), and subsequently the health effects caused by the contamination of these products on humans, is a potential concern. In this study, the abundance and characteristics of MPs as well as the PAEs concentration in different types of yogurts and buttermilk available in the Iranian market were investigated. The average abundance of MPs in different types of yogurts and buttermilk was between 0.63 and 0.76 and 0.52-0.7 items/mL, respectively. Most detected MPs in yogurt and buttermilk samples were in the size range of 1000-5000 μm with the predominant color and shape of transparent and fiber, respectively. Polyethylene terephthalate (PET) and polyamide (PA) were the dominant polymers in yogurt and buttermilk samples, respectively. The average concentrations of PAEs in different types of yogurt and buttermilk samples were between 5.79 and 11.36 and 1.46-6.93 µg/L, respectively. The findings showed that Di(2-ethylhexyl) phthalate (DEHP) levels in yogurt and buttermilk samples may have a carcinogenic risk for adults and adolescents. According to the results of this study, the intake of MPs and PAEs through high consumption of yogurt and buttermilk should be recognized as a significant source of MPs in the human body.

Supplementary Information

The online version contains supplementary material available at 10.1007/s40201-025-00939-z.

Unseen toxins: Exploring the human health consequences of micro and nanoplastics

Micro and nanoplastics (MNPs) contamination constitute a pressing global issue with considerable ramifications for human health. Particles originating from the decomposition of plastic waste permeate ecosystems and disturb biological systems, especially the gastrointestinal (GI) tract. MNPs compromise the intestinal barrier, provoke oxidative stress, inflammation, and immunological dysfunction, and modify gut microbiota, which is associated with metabolic problems, inflammatory bowel disease (IBD), and colorectal cancer. MNPs traverse biological barriers beyond the gastrointestinal system, including the blood-brain barrier, colonic mucus layer, and placental barrier, resulting in accumulation in essential organs such as the liver, kidneys, and brain. This results in inflammatory damage, metabolic abnormalities, and oxidative stress, specifically affecting liver disease due to microbiota metabolite alteration and nephrotoxicity in the kidneys. Airborne MNPs pose an additional risk to respiratory health, aggravating ailments such as asthma, chronic obstructive pulmonary disease (COPD), and pulmonary fibrosis. At-risk groups, such as pregnant women, newborns, and the elderly, encounter increased dangers, as MNPs traverse the placental barrier and may induce neurological and intergenerational health consequences. These particles function as vectors for environmental pollutants, exacerbating their cardiovascular and neurological effects. Addressing the long-term consequences of MNP exposure necessitates interdisciplinary collaboration to enhance comprehension and alleviate their growing risk to human health.

Occurrence, sampling, identification and characterization of microplastics in tap water: A systematic review and meta-analysis

Identifying microplastics (MPs) in tap water has recently attracted considerable attention. The present study aimed to systematically review MPs contamination and characteristics in tap water. All techniques used for sampling, processing, and analyzing MPs in tap water were also assessed. Furthermore, the characteristics of MPs, including abundance, type, color, and shape, were summarized. Various databases, including Web of Science, PubMed, ScienceDirect, Scopus, Springer, and MDPI, were searched to find published articles up to January 2025. The occurrence of MPs in tap water was meta-analyzed using a random-effects model. A total of 6100 articles were found, of which 43 were included in the systematic review. The results indicated that the pooled mean concentration of MPs in tap water was 56.98 particles per liter (P/L). Manual sampling with a sample volume of less than 1 liter was most commonly used, and microscopic, Raman, and Fourier-transform infrared spectroscopy (FTIR) methods were frequently applied for extracting and identifying MPs. The most abundant polymer identified was polyethylene (PE), followed by polyethylene terephthalate (PET) and polypropylene (PP). Fibers and fragments were the dominant forms of MPs found in water. The lack of a harmonized protocol and the difficulty in validating MP analysis methods in tap water have led to inconsistent and sometimes contradictory results, making comparisons unreliable. The findings of this systematic review can support the development of a comprehensive protocol and promote standardized, harmonized methods for MP analysis in tap water.

Nanoplastics disrupt hepatic lipid metabolism via the inhibition of PPARγ: a study based on digestive system exposure

Nanoplastics (NPs) are emerging environmental contaminants capable of crossing biological barriers and accumulating in organs such as the liver, raising growing concerns about their potential contribution to nonalcoholic fatty liver disease (NAFLD). Notably, bottled water has been recognised as a major daily source of NP exposure. However, the associations between NP exposure and NAFLD onset, as well as the mechanistic basis, remain unclear. To investigate this, we analysed data from the National Health and Nutrition Examination Survey (NHANES) 2013-2016 cycles, using daily bottled water intake to estimate NP exposure and the hepatic steatosis index (HSI) as an indicator of liver fat accumulation. Animal and cellular experiments were conducted to evaluate NP-induced hepatic alterations. Additionally, transcriptomic analysis of liver tissues was performed, and integration with DisGeNET and the Comparative Toxicogenomics Database (CTD) enabled bioinformatic analyses and identification of key regulatory pathways. Epidemiological results revealed a significant positive correlation between bottled water consumption and HSI. Experimental findings demonstrated that NP exposure induced liver vacuolisation, oxidative damage, metabolic disruption, and inflammation in both in vivo and in vitro models. Transcriptomic and database integration revealed that NP exposure suppressed the PPAR signalling pathway, particularly by downregulating PPARγ expression, with excessive ROS generation likely contributing to this inhibition. These results were summarised in an adverse outcome pathway (AOP) framework, illustrating how NP exposure may impair PPARγ signalling and promote hepatic lipid accumulation. In conclusion, this study provides evidence that environmental NP exposure may be a contributing factor to NAFLD development and highlights the potential public health impact of the intake of NPs from bottled water.

Investigation of heavy metals adsorbed on microplastics in drinking water and water resources of Zabol

This study investigates the presence and adsorption of heavy metals (HMs) on microplastics (MPs) in the drinking water and water resources of Zabol, Iran. Sampling was conducted at five stations in Zabol and two Chah-Nimeh reservoirs (CHWRs), the primary drinking water sources, using glass samplers and polyvinylidene fluoride membrane filters. Fourier-transform infrared spectroscopy, scanning electron microscopy, and optical microscopy identified MPs, while inductively coupled plasma optical emission spectrometry quantified heavy metals. Results revealed that polyethylene, polystyrene, polyamide, and polypropylene were the predominant polymers, with Fe, Mn, Zn, Cu, and Ni adsorbed on their surfaces. Iron (Fe) exhibited the highest concentration, reaching 84 µg.L⁻¹ in CHWRs and 85 µg.L⁻¹ in the distribution network. In CHWRs the highest percentage (61%) of size of MPs were between 500 and 1000 μm, while in water distribution network maximum range of obtained MPs were between 50 and 100 μm. The average concentration of the other detected heavy metals were as: zinc (Zn) 43.9 µg.L- 1 and 7.75 µg.L- 1, manganese (Mn) 11.48 µg.L- 1 and 6.5 µg.L- 1, arsenic (As) 20.22 µg.L- 1 and 0.26 µg.L- 1, cadmium (Cd) 3.16 µg.L- 1 and 2.8 µg.L- 1, copper (Cu) 15.18 µg.L- 1 and 0.03 µg.L- 1, and nickel (Ni) 0.10 µg.L- 1 and 2.25 µg.L- 1 in distribution network and CHWRs, respectively. World Health Organization recommended the permissible limit of these cations in drinking water as 10 µg.L- 1 for As, 5 µg.L- 1 for Cd, 50 µg.L- 1 for Cr, 20 µg.L- 1 for Ni, 10 µg.L- 1 for Mn, 500 µg.L- 1 for Zn, 300 µg.L- 1, 2000 µg.L- 1 for Cu and 300 µg.L- 1 for Fe. The study highlights MPs as carriers of toxic heavy metals, presenting significant health and environmental risks. This novel research emphasizes the impact of secondary pollution and water treatment processes on MP fragmentation and HM contamination. Recommendations include adopting enhanced water treatment protocols to mitigate MP and HM risks, implementing stricter quality monitoring at all stages of water distribution, and promoting public awareness of plastic pollution. Future studies should explore the health effects of MPs and HMs, optimize sampling methods, and focus on long-term monitoring under diverse environmental conditions to address this emerging issue comprehensively.

Measurement and daily consumption of microplastics in drinking water from a Small Island Developing State-Fiji: from freshwater to groundwater sources

The occurrence of microplastics (MPs) in drinking water has emerged as a significant source of this contaminant, posing an increased risk to human health. These MPs are now of extreme concern, especially on the possible harmful effects it may have on human health. This study is the first baseline MPs data in drinking water from Fiji. Raw, treated, tap, rain, ground, and bottled water were investigated for the presence of MPs and the ingestion rate by the different age groups. The analytical procedure was validated by determining recovery rates and analyses of blanks. The detection limit of the MPs was 10 µm, while fibers and particles ≥ 100 µm were analyzed on 100% of the filter area. The abundance of MPs in drinking water was source-dependent. Percentage removal of MPs from water treatment plants was 45-67%, resulting in the presence of 0.10 ± 0.03 to 2.90 ± 0.57 MPs L-1 in tap water. The presence of MPs in bottled, rain, and groundwater was in the range of 0 to 2.20 ± 0.41 MPs L-1. Fiber MPs predominated in all water sources except for bottled water. Main types of polymer identified were polyethylene, polypropylene, and poly(ethylene terephthalate). Estimated daily intake of MPs in tap water by children and adults were 0.0031-0.1813 and 0.0021-0.0829 MPs/kg bw/day, respectively. Information from this work in combination with information from the health sector will help to fully understand microplastic impact on human health and the actions that are required to mitigate it.

Investigating the antibiotic resistance genes and mobile genetic elements in water systems impacted with anthropogenic pollutants

A wide range of pollutants, including heavy metals, endocrine-disrupting chemicals (EDCs), residual pesticides, and pharmaceuticals, are present in various water systems, many of which strongly drive the proliferation and dissemination of antimicrobial resistance genes (ARGs), heightening the antimicrobial resistance (AMR) crisis and creating a critical challenge for environmental and health management worldwide. This study addresses the impact of anthropogenic pollutants on AMR through an extensive analysis of ARGs and mobile genetic elements (MGEs) in urban wastewater, source water, and drinking water supplies in India. Results indicated that blaTEM and blaCTXM-32 were the dominant ARGs across all water systems, underscoring the prevalence and dominance of resistance against β-lactam antibiotics. Moreover, transposase genes such as tnpA-02, tnp-04, and tnpA-05 were detected across all water systems, indicating potential mechanisms for genetic transfer. The ubiquitous presence of intI-1 and clin-intI-1 genes underscores the widespread dissemination of MGEs, posing challenges for water quality management. Besides, human pathogenic bacteria such as Clostridium, Acinetobacter, and Legionella were also detected, highlighting potential health risks associated with contaminated water. The identified pathogenic bacterial genera belong to the phyla Pseudomonadota and Firmicutes. Leveraging linear regression to analyze correlations between EDCs and ARG-MGEs provides deeper insights into their interconnected dynamics. DMP showed a significant influence on tnpA-02 (p = 0.005), tnpA-07 (p = 0.015), sul-1 (p = 0.008), intI-1 (p = 0.03), and clin-intI1 (p = 0.012), while DiNOP demonstrated a very high impact on tnpA-05 (p = 0). Redundancy analysis revealed significant correlations between resistance genes and EDCs. Additionally, environmental parameters such as pH were highly correlated with the majority of MGEs and blaCTXM-32. Furthermore, we found that F-, NO-3, and SO4-2 were significantly correlated with sul-1, with F- exhibiting the highest impact, emphasizing the intricate interplay of pollutants in driving AMR. Understanding these interconnected factors is crucial for developing effective strategies and sustainable solutions to combat antibiotic resistance in environmental settings.

The aging and pollution behavior of microplastics in tap water supply system subjected to residual chlorine exposure

This study investigated the aging and pollution behavior of acrylonitrile butadiene styrene (ABS) and polycarbonate (PC) microplastics (MPs) exposed to residual chlorine in tap water distribution systems. The ABS and PC MPs in the aging processes were analyzed using scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS). Results revealed that 0.4 mg/L residual chlorine could induce morphological changes, increase surface oxygen-containing functional groups, and enhance the hydrophilicity of MPs at the CT value of 9216 mg·min/L. Additionally, both ABS and PC MPs released dissolved organic matter (DOM) into water, with higher DOM concentrations observed in the presence of residual chlorine. Besides, this interaction also led to the formation of trichloromethane (TCM). And the TCM production increased with higher MPs concentrations, smaller particle size, and longer chlorine exposure time.

Assessment and treatment of microplastics in different environmental compartments of Kallar Kahar Lake-a case study

Microplastic pollution has garnered global attention in recent decades due to its recognized ecological concerns through previous studies. However, in Pakistan, scarce information has been reported on MP pollution concerning the freshwater ecosystem. The current study was conducted on Kallar Kahar Lake, Punjab, Pakistan for (1) quantification, characterization, and distribution of MPs in surface water, sediments, and fish samples and (2) two treatment processes (magnetization and coagulation + flocculation) for the removal of MPs from the water. Samples were collected from each point by grab sampling method to investigate the MPs according to their type, shape, and color. The MP quantification and analysis were accomplished via the counting method by a stereomicroscope and Fourier transform infrared spectroscopy for their polymer type and composition. Results indicated the average MP abundance as 49.6 ± 11.14 MP/500 mL, 143 ± 48.18 MP/100 g, and 79 ± 12.2 items for water, sediments, and fish correspondingly. The dominant MP colors were blue, transparent, and green in all three environmental compartments. The ATR-FTIR identified the polymer types in lake water, sediment, and fish were PPS, PIB, and PLF; PET, PE, PP, and Natural Latex Rubber; and PET, respectively. The MP removal rate was observed high in both treatments. The average % removal rate of iron ore magnetization treatment was observed to be 80% at 1300 mg/L dosage of Fe2O3. Similarly in chemical coagulation processes, the highest MP removal efficiency was 85% (PET), 83% (PPS) and 80% (PIB) at the different concentration dosages of 150 + 15 mg/L, 111 + 15 mg/L, and 150 + 111 + 15 mg/L for Combination 1, Combination 2, and Combination 3, respectively. Overall, this study provided an integrative and novel approach for the removal of MP from surface water, which also holds an explicit commercial utilization prospect to overpower the MP pollution in water bodies. Also, the current findings serve as baseline data for the study of local freshwater systems.

Isolation and characterization of microplastics from the human respiratory system: Sputum, broncho-alveolar lavage fluid, and pleural fluid simultaneously

Microplastics (MPs) are emerging pollutants found in all ecosystems. While extensive research has focused on MP pollution across ecosystems, investigating their effect on the human body is still in its early stages. This study, conducted for the first time in Iran, specifically investigates MPs in the respiratory system, including sputum, broncho-alveolar lavage fluid (BALF), and pleural fluid. In this study, 34 patients participated after signing the consent form. Professional physicians collected 13 sputum samples, 11 BALF samples, and 10 pleural fluid samples. Patients' demographic information, lifestyle, occupation, exposed environment, and type of disease were evaluated through a questionnaire. The combination of digestion techniques, density separation, observation, Micro-Raman, and SEM/EDS analysis was performed to recognize MPs. The study results confirmed the presence of MPs in the respiratory system of all participants. MPs abundance in sputum, BALF, and pleural fluid varied between 156 and 468, 28-133, and 21-210 particles/100 mL, respectively. Generally, 22 types of MPs were identified and polyester (62-72%) was predominant. Fiber-shaped MPs were dominant in sputum (77%) and BALF (70%), and fragment-shaped in pleural fluid (63%). Particles <100 μm were the most abundant in all samples [in sputum (75.9%), BALF (50%), and pleural fluid (94.4%)]. Sampling type, occupational exposure, smoking, exposure to cigarette smoke, and wearing masks have affected the abundance of MPs (P < 0.05). Also, the shape and size of MPs affect their deposition in the respiratory system (P < 0.05). Hence, minimizing exposure to MPs is essential for safeguarding the environment and human health.

Occurrence and risk of microplastics and hexabromocyclododecane in urban drinking water systems: From source water to tap water

The widespread presence of microplastics (MPs) in drinking water systems and their risk of releasing additives have caused widespread concern. However, current research on the migration and risks of MPs and additives in the complete drinking water supply chain remains inadequate. In this study, micro-Raman spectrometer was used to track the entire transport process of MPs from the water source to the tap water, with concentrations ranging from 805 to 4960 items/L, and polyethylene and Polyethylene terephthalate were dominant. The removal efficiency of MPs at the drinking water treatment plant was 85.0 ± 5.2 %. However, chlorination increased the proportion of polystyrene by 40.1 ± 5.3 %. Chlorination increases the surface roughness and carbonyl index of polystyrene standards, and promotes the release of hexabromocyclododecane (HBCD) (482.0 ng/g-2208.7 ng/g). The non-carcinogenic risk index of HBCD ingestion through drinking water remains well below 1 for residents. Complete water treatment processes significantly reduce the risks posed by MPs, achieving reductions of 54.3 % in the pollution load index and 82.1 % in the potential ecological risk index. The estimated daily intake of MPs ingested by residents through tap water ranges from 33.4 to 45.6 items/kg/d. This study investigated the occurrence of MPs in the complete drinking water supply chain and the risk of chlorine disinfection for HBCD release, which could help develop more effective MPs control measures and risk management strategies.

Fibrous foes: First report on insidious microplastic contamination in dietary fiber supplements

Regular consumption of health supplements to balance dietary intake has gained popularity worldwide. One such supplement that has gained popularity among consumers is dietary fibers. Microplastic (MPs) contamination in various food products is being reported worldwide. However, there is a paucity of understanding of the occurrence of MPs in dietary supplements. This study addresses this gap by investigating the degree of MPs contamination in dietary fiber supplements. Nine commonly consumed (powder and gummy-based) over-the-counter dietary fiber supplements in Australia were tested in this study. Microscopic examination revealed the presence of MPs fibers and fragments in all the tested products. Further categorization showed that MPs particles were of various colours, including black, blue, red, green, and white. The order of polymer abundance was Polyamide > Polydiallyl Phthalate > polyethylene polypropylene diene > Polyurethane = Polyethylene terephthalate > Polyethylene = Ethylene acrylic acid copolymer. Among the supplements, powder-based samples had higher MPs (at the adult dosage suggested by the manufacturer) than gummy-based product. The average predicted ingestion of microplastics from these supplements (all nine samples) was 5.89 ± 2.89 particles day-1. The dietary exposure for children and adults ranged from 0.1-0.48 and 0.18-4.08 particles day-1, respectively. Based on the microplastic contamination factor (MCF), among the nine samples tested, 69.81% exhibited a moderate level, while 20.76% showed a significant level of microplastic contamination. The polymer risk index (pRi) indicates products with very high and high-risk categories. The possible sources of MPs contamination in the products were studied. To our knowledge, this is the first study to record and quantify the presence of MPs in dietary fiber supplements, which is a direct source of MPs exposure to humans via., ingestion.

Comprehensive systematic review and meta-analysis of microplastic prevalence and abundance in freshwater fish species: the effect of fish species habitat, feeding behavior, and Fulton's condition factor

Microplastics are emerging pollutants that cause health problems for aquatic organisms. Fish is one of the important organisms because of its consumption by humankind. The present study examines the abundance and prevalence of microplastics in freshwater fish species through a systematic review study while considering five important factors, i.e. water resources, habitat, feeding behavior, Fulton's condition factor, and microplastic characteristics. A comprehensive meta-analysis was undertaken to evaluate relevant publications in terms of microplastic abundance. Articles published up to July 30, 2022 were found through Global search engines including, Web of Science, Scopus, and PubMed. In total, 786 articles were found that 53 and 42 articles were used for qualitative review and meta-analysis, respectively. This was carried out by a random-effects model with high heterogeneity (I2 = 99.76%). According to the data, the highest attention in microplastic research in body part and water sources are related to gastrointestinal tract (n = 259 (~ 80%)) and rivers (n = 189 (~ 58%)), respectively. According to the results, the average microplastic prevalence range was 5 -100%, and microplastic abundance was within the 0.04-204 items range per individual. The difference between microplastic prevalence and abundance for the key factors for parametric and nonparametric data were analyzed using Analysis of variance (ANOVA) and the Kruskal-Wallis test, respectively. According to the Baujat plot, two studies (ID: 27 and 25) revealed the minimal influence of microplastics abundance. Conclusively, the average microplastics abundance according to the pooled data, varied between 2.23 and 2.48, with a mean of 2.35 items per individual in the studies overall. It is concluded that the amount of ingested microplastics by fish is related only to physiology (height, weight, and body structure) but not feeding behavior, habitat, and surrounding water.

Supplementary Information

The online version contains supplementary material available at 10.1007/s40201-024-00907-z.

The Detection and Analysis of Microplastics in a Typical Mountainous Drinking Water System in China

Microplastics (MPs) are widely detected in urban drinking water systems. However, the presence and characteristics of MPs in mountainous drinking water systems with independent and simple filtration facilities have been overlooked. In this study, we revealed the ubiquity of MPs and demonstrated that their concentrations increased along with the pipeline length in Bainitan Village, Tiantai County, China. The simple filtration facility in this village did not effectively remove most MPs. Polyethylene, polyurethane, and polyethylene terephthalate were the dominant polymers in water samples (72.32% in total), while polyvinylchloride, polyurethane, and polyethylene were the most prevalent in the sediment (74.00% in total) of the reservoir. Long fragments were the predominant shape of MPs in all samples, with the majority being smaller than 100 μm. The estimated daily intake of MPs through drinking water ingestion was highest in infants (2.14-31.26 MPs/kg bw/day), compared to children (1.41-20.67 MPs/kg bw/day) and adults (1.05-15.35 MPs/kg bw/day), highlighting their increased vulnerability. This emphasizes the need for advanced water treatment systems in mountainous regions. It also underscores the necessity for government attention to improve water safety in remote areas. Our research will contribute valuable baseline data for further research on MP exposure, particularly in mountainous communities.

Tracking Microplastics Contamination in Drinking Water Supply Chain in Haikou, China: From Source to Household Taps

The presence of microplastics (MPs) in aquatic environments has become a significant global concern due to their potential adverse effects on human health. This study aimed to investigate the contamination of MPs throughout the drinking water supply chain in Haikou City, China, and to conduct risk assessments regarding the relationship between MPs contamination and human health. The results revealed that the abundance of MPs in raw, treated, and tap water was 0.6 ± 0.6, 5.2 ± 2.7, and 1.2 ± 1.1 particles·L-1, respectively. Fragments were identified as the most prevalent shape across all samples, with the size category of 20-50 μm showing the highest abundance of MPs. Among the 11 types of polymers identified, polyethylene and polypropylene accounted for 50% and 29%, respectively. The potential risk index values were significantly higher for treated water (370.26) and tap water (303.85) compared to raw water (13.46), suggesting that plastic pipes may be a key contributor to MPs contamination in drinking water. Therefore, efforts should be directed toward developing pipes with low release rates of MPs, as well as improving detection methods for smaller particles and accurately assessing associated risks.

A systematic review and quality assessment of estimated daily intake of microplastics through food

Plastic waste enters the oceans and soil and is consumed by organisms and humans. Some of the ingested microplastics may remain in the human body and cause toxicity. We conducted a systematic review to estimate the extent to which humans are exposed to microplastics through consumption and performed a quality assessment of research results. We searched for studies published up to December 2023 and included studies that reported on the characteristics and estimated intake of microplastics. The quality assessment tool reported in previous studies was used for food and drinking water studies. We included 76 studies in the analysis, and the types of foods were classified into seven categories: seafood, drinking water, table salt, fruits and vegetables, beverages, condiments, and meat. The estimated daily intake of microplastics via food was 0.0002-1,531,524 MP/day, with the highest value in bottled water. The quality of food and drinking water studies was evaluated using a quantitative tool to assess reliability. The quality of food studies was 11.50 out of 20 points and the quality of drinking water studies was 11.16 out of 19 points. These results indicate that the closer the score is to the maximum, the more reliable the research findings. The quantitative assessment can be used as an indicator for evaluating the risks of microplastics and can help reduce biases that may occur during the research process. This study confirmed microplastics in foods and human exposure to up to one million microplastics daily. Our study emphasizes the potential for microplastic exposure through food intake and subsequent accumulation in the human body; therefore, efforts are needed to reduce exposure to microplastics in daily life.

Microplastics abundance and potential ecological risk assessment in sediment, water and fish of Deepor Beel-a Ramsar Wetland of the Brahmaputra plain, India

Microplastics (MPs) are increasingly recognized as environmental contaminants with complex impacts on fish and other aquatic organisms. This study determined the microplastics abundance and the induced-ecological risks of microplastics in water, sediment, and commonly harvested fishes of a Ramsar site, Deepor Beel of Assam, India. Six samples of water and sediment were collected with nine individuals of two commonly harvested fish species Puntius sophore (Pool Barb) and Gudusia chapra (Indian River Shad). The abundance of microplastics in water and sediments were analyzed through organic matter digestion using hydrogen peroxide (H2O2, 30%) and sodium chloride (NaCl) for density separation. Potassium hydroxide (KOH, 10%) was used for digestion of fish gut. The microplastics were identified visually and chemically characterized through micro-Raman spectroscopy. Total 467 microplastic particles in water and sediment, and 62 particles in fish were identified. An average concentration of 0.55 ± 0.06 particles/L in water, 4.03 ± 0.41 particles/100 g in sediment samples, 3.83 ± 2.26 particles/individual in Puntius sophore, and 6.5 ± 3.40 particles/individual in Gudusia chapra were detected. Fibers accounted to the major shape of microplastic in water (54%) and sediment (50%), whereas fragments (65%) were the major shapes detected in both fishes. The color composition includes blue, black, red, green, brown, yellow, and transparent. Fiber particles size ranged between 150 and 1782 µm, fragments within 85-325 µm, and sphere within 85-220 µm. Chemical characterization of microplastics revealed polymer types including polypropylene (PP = 27%), polyvinyl chloride (PVC = 25%), acrylonitrile-butadiene-styrene (ABS = 18%), polycarbonate (PC = 13%), polyethylene (12%), and polystyrene (PS = 5%). PHI levels were at hazard level III and V for water and sediment samples and at level IV for both fish species. The PLI at hazard level I indicated low pollution levels, whereas the PERI were within danger and extreme danger levels. This study is the first report in abundances of microplastics and the ecological risk assessment of microplastics in surface waters, sediments and fishes of Deepor Beel wetland.

Polyamide 6 microplastics as carriers led to changes in the fate of bisphenol A and dibutyl phthalate in drinking water distribution systems: The role of adsorption and interfacial partitioning

Microplastics (MPs) co-exist with plastic additives and other emerging pollutants in the drinking water distribution systems (DWDSs). Due to their strong adsorption capacity, MPs may influence the occurrence of additives in DWDSs. The article investigated the occurrence of typical additives bisphenol A (BPA) and dibutyl phthalate (DBP) in DWDSs under the influence of polyamide 6 (PA6) MPs and further discussed the partitioning of BPA/DBP on PA6s, filling a research gap regarding the impact of adsorption between contaminants on their occurrence within DWDSs. In this study, adsorption experiments of BPA/DBP with PA6s and pipe scales were conducted and their interaction mechanisms were investigated. Competitive adsorption experiments of BPA/DBP were also carried out with site energy distribution theory (SEDT) calculations. The results demonstrated that PA6s might contribute to the accumulation of BPA/DBP on pipe scales. The adsorption efficiencies of BPA/DBP with both PA6s and pipe scales were 26.47 and 2.61 times higher than those with only pipe scales. It was noteworthy that BPA had a synergistic effect on the adsorption of DBP on PA6s, resulting in a 26.47 % increase in DBP adsorption. The article provides valuable insights for the compounding effect of different types of additives in water quality monitoring and evaluation.

Transforming pollution into solutions: A bibliometric analysis and sustainable strategies for reducing indoor microplastics while converting to value-added products

Microplastics (MPs), as emerging indoor contaminants, have garnered attention due to their ubiquity and unresolved implications for human health. These tiny particles have permeated indoor air and water, leading to inevitable human exposure. Preliminary evidence suggests MP exposure could be linked to respiratory, gastrointestinal, and potentially other health issues, yet the full scope of their effects remains unclear. To map the overall landscape of this research field, a bibliometric analysis based on research articles retrieved from the Web of Science database was conducted. The study synthesizes the current state of knowledge and spotlights the innovative mitigation strategies proposed to curb indoor MP pollution. These strategies involve minimizing the MP emission from source, advancements in filtration technology, aimed at reducing the MP exposure. Furthermore, this research sheds light on cutting-edge methods for converting MP waste into value-added products. These innovative approaches not only promise to alleviate environmental burdens but also contribute to a more sustainable and circular economy by transforming waste into resources such as biofuels, construction materials, and batteries. Despite these strides, this study acknowledges the ongoing challenges, including the need for more efficient removal technologies and a deeper understanding of MPs' health impacts. Looking forward, the study underscores the necessity for further research to fill these knowledge gaps, particularly in the areas of long-term health outcomes and the development of standardized, reliable methodologies for MP detection and quantification in indoor settings. This comprehensive approach paves the way for future exploration and the development of robust solutions to the complex issue of microplastic pollution.

Microplastic contamination in some beverages marketed in türkiye: Characteristics, dietary exposure and risk assessment

In this study, microplastic contamination in water, natural mineral water and mineral water, sparkling soft drinks, cold tea and some traditional beverages marketed in Türkiye were assessed. Microplastics physically and chemically characterized by microscope and ATR/FT-IR, respectively. Microplastics were detected in 9 out of 47 beverage samples. A total of 250 microplastics with 5 different polymers, 2 different shapes, and 7 different colours were detected in 47 beverage samples. The average microplastic concentration was 2.24 ± 9.86 particles/L for all beverages analysed. The highest average microplastic concentration was found in mineral waters in glass bottles (average 11.3 particles/L). No microplastics were found in cold tea and other drinks. The total annual microplastic exposure from beverage consumption in male and female individuals aged >15 years was 2029 and 1786 particles/mL/year, respectively. The microplastic load index category of all beverage samples was determined as "moderate". The average pRi level of all beverages was 117 ± 260 and the risk level was determined as "low". The study provides evidence that microplastics are common in beverages and that microplastics are directly ingested by humans.

Mapping Microplastics in Humans: Analysis of Polymer Types, and Shapes in Food and Drinking Water-A Systematic Review

Microplastics (MPs) pervade the environment, infiltrating food sources and human bodies, raising concerns about their impact on human health. This review is focused on three key questions: (i) What type of polymers are humans most exposed to? (ii) What are the prevalent shapes of MPs found in food and human samples? (iii) Are the data influenced by the detection limit on the size of particles? Through a systematic literature analysis, we have explored data on polymer types and shapes found in food and human samples. The data provide evidence that polyester is the most commonly detected polymer in humans, followed by polyamide, polyurethane, polypropylene, and polyacrylate. Fibres emerge as the predominant shape across all categories, suggesting potential environmental contamination from the textile industry. Studies in humans and drinking water reported data on small particles, in contrast to larger size MPs detected in environmental research, in particular seafood. Discrepancies in size detection methodologies across different reports were identified, which could impact some of the discussed trends. This study highlights the need for more comprehensive research on the interactions between MPs and biological systems and the effects of MPs on toxicity, together with standardised analytical methodologies to accurately assess contamination levels and human exposure. Understanding these dynamics is essential for formulating effective strategies to mitigate the environmental and health implications of MP pollution.

Global prevalence of microplastics in tap water systems: Abundance, characteristics, drivers and knowledge gaps

Tap water is a main route for human direct exposure to microplastics (MPs). This study recompiled baseline data from 34 countries to assess the current status and drivers of MP contamination in global tap water systems (TWS). It was shown that MPs were detected in 87 % of 1148 samples, suggesting the widespread occurrence of MPs in TWS. The detected concentrations of MPs spanned seven orders of magnitude and followed the linearized log-normal distribution (MSE = 0.035, R2 = 0.965), with cumulative concentrations at 5th, 50th and 95th percentiles of 0.028, 4.491 and 728.105 items/L, respectively. The morphological characteristics were further investigated, indicating that particles smaller than 50 μm dominated in global TWS, with fragment, polyester and transparent as the most common shape, composition and color of MPs, respectively. Subsequently, the SHapley Additive exPlanations (SHAP) algorithm was implemented to quantify the importance of variables affecting the MP abundance in global TWS, showing that the lower particle size limit was the most important variables. Subgroup analysis revealed that the concentration of MPs counted at the size limit of 1 μm was >20 times higher than that above 1 μm. Ultimately, current knowledge gaps and future research needs were elucidated.

Microplastics in drinking water: A review on methods, occurrence, sources, and potential risks assessment

Microplastics in drinking water captured widespread attention following reports of widespread detection around the world. Concerns have been raised about the potential adverse effects of microplastics in drinking water on human health. Given the widespread interest in this research topic, there is an urgent need to compile existing data and assess current knowledge. This paper provides a systematic review of studies on microplastics in drinking water, their evidence, key findings, knowledge gaps, and research needs. The data collected show that microplastics are widespread in drinking water, with large variations in reported concentrations. Standardized methodologies of sampling and analysis are urgently needed. There were more fibrous and fragmented microplastics, with the majority being <10 μm in size and composed of polyester, polyethylene, polypropylene, and polystyrene. Little attention has been paid to the color of microplastics. More research is needed to understand the occurrence and transfer of microplastics throughout the water supply chain and the treatment efficiency of drinking water treatment plants (DWTPs). Methods capable of analyzing microplastics <10 μm and nanoplastics are urgently needed. Potential ecological assessment models for microplastics currently in use need to be improved to take into account the complexity and specificity of microplastics.

Occurrence and fate of microplastics from a water source to two different drinking water treatment plants in a megacity in eastern China

The widespread presence of microplastics (MPs) contamination in drinking water has raised concerns regarding water safety and public health. In this study, a micro-Raman spectrometer was used to trace the occurrence of MP transport from a water source to a drinking water treatment plant (DWTP)1 with an advanced treatment process and DWTP2 with a conventional treatment process and the contributions of different processes to the risk reduction of MPs were explored. Six types of MPs were detected: polyethylene terephthalate, polyethylene, polypropylene, polystyrene, polyamide, and polyvinyl chloride. 2-5 μm (35.8-41.2%) and polyethylene terephthalate (27.1-29.9%) were the most frequently detected MP sizes and types of water source samples, respectively. The abundance of MPs in treated water decreased by 72.7-83.0% compared to raw water. Ozonation and granular activated carbon (52.7%), and sand filtration (47.5%) were the most effective processes for removing MPs from DWTP1 and DWTP2, respectively. Both DWTPs showed significant removal effects on polyethylene terephthalate, with 80.0-88.1% removal rates. The concentrations of polystyrene increase by 30.0-53.4% after chlorination. The dominant components in the treated water of DWTP1 and DWTP2 were polypropylene (24.7%) and polyethylene 27.7%, respectively, and MPs of 2-5 μm had the highest proportion (55.3-64.3%). Pollution load index and potential ecological risk index of raw water treated by DWTPs were reduced by 48.0-58.7% and 94.5-94.7%, respectively. The estimated daily intake of MPs in treated water for infants was 45.5-75.0 items/kg/d, respectively, approximately twice that of adults. This study contributes to the knowledge gap regarding MP pollution in drinking water systems.

Regulatory Science Perspective on the Analysis of Microplastics and Nanoplastics in Human Food

Microplastics are increasingly reported, not only in the environment but also in a wide range of food commodities. While studies on microplastics in food abound, the current state of science is limited in its application to regulatory risk assessment by a continued lack of standardized definitions, reference materials, sample collection and preparation procedures, fit-for purpose analytical methods for real-world and environmentally relevant plastic mixtures, and appropriate quality controls. This is particularly the case for nanoplastics. These methodological challenges hinder robust, quantitative exposure assessments of microplastic and nanoplastic mixtures from food consumption. Furthermore, limited toxicological studies on whether microplastics and nanoplastics adversely impact human health are also impeded by methodology challenges. Food safety regulatory agencies must consider both the exposure and the risk of contaminants of emerging concern to ascertain potential harm. Foundational to this effort is access to and application of analytical methods with the capability to quantify and characterize micro- and nanoscale sized polymers in complex food matrices. However, the early stages of method development and application of early stage methods to study the distribution and potential health effects of microplastics and nanoplastics in food have largely been done without consideration of the stringent requirements of methods to inform regulatory activities. We provide regulatory science perspectives on the state of knowledge regarding the occurrence of microplastics and nanoplastics in food and present our general approach for developing, validating, and implementing analytical methods for regulatory purposes.

Incidence and exposure to microplastics in table salt present in the Iran market

Plastics and microplastics (MPs) are toxic, pervasive and threatening the biotic and abiotic components of the earth, and they threaten food safety and food security by moving in the food chain. In this study, the amounts and characteristics of 40 table salt samples with different brands, including sea salt (No = 13), rock (No = 13), bulk (No = 8) and non-standard (No = 6), were investigated with a combination of sieving, filtration, observation and FTIR, Micro-Raman and SEM techniques. The results showed that all the salts were contaminated with MPs. In general, the abundance range of detected particles was 700-5470 MPs/kg. The abundance of MPs was higher in counterfeit and non-standard salts (1825 ± 1808 MPs/kg). Investigating the relationship between the effect of the purification process (Kruskal-Wallis Test, P = 0.841), the type of packaging (Kruskal-Wallis Test, P = 0.609), and the type of salt (Kruskal-Wallis Test, P = 0.942), on the abundance of MPs using a comparison test Kruskal-Wallis was not significant. However, the numerical difference was recognizable. The most identified polymer in the salts was cellulose acetate, which probably causes by unmanaged plastic litter in the environment (especially cigarette butts). The dominant form of particles was fragment-shaped, which is the most abundant form of identified MPs in the environment. Both environmental pollution and secondary pollution (during production and packaging), respectively, contribute to the contamination of salts with MPs. The estimated human dietary intake (EDI) and the amount of estimated annual intake (EAI) for different ages in Iran were obtained EDI = 5-59 MPs/capita/day and EAI = 1967-21563 MPs/capita/year. The surface morphology of the particles showed that the MPs were affected by continuous weathering, mechanical fracture and oxidation. MPs are a threat to human health due to the absorption and transmission of dangerous pollutants and their inherent toxicity. Therefore, a solution must be thought of to prevent the contamination of the food chain through salts by MPs, (with protective measures at the salt source, and by improving its production processes.

Removal of most frequent microplastic types and sizes in secondary effluent using Al2(SO4)3: choosing variables by a fuzzy Delphi method

Microplastics (MPs) as an emerging pollutant can affect aquatic organisms through physical ingestion, chemical problems and possible creation of biological layers on their surfaces in the environment. One of the significant ways for MPs to enter the aquatic environment is through the effluent discharge of wastewater treatment plants (WWTPs). In this study, first, the concentration and characteristics of MPs in secondary wastewater effluent, and the influential variables related to the coagulation process, for MPs removal were identified using systematic reviews of previous studies. Then, the most proper MPs characterization and coagulation variables were chosen by experts' opinions using a fuzzy Delphi method. Therefore, the experiment tested in conditions close to the full-scale wastewater treatments. Finally, in the laboratory removal of MPs by coagulation of polyamide (PA), polystyrene (PS), and polyethylene (PE), < 125 and 300-600 μm in size, was tested by a jar test applying Al2(SO4)3 in doses of 5 to 100 mg/L plus 15 mg/L polyacrylamide as a coagulant aid. Using R and Excel software, the results were analyzed statistically. It was concluded that the maximum and minimum removal efficiency was 74.7 and 1.39% for small PA and large PE, respectively. Smaller MPs were found to have higher removal efficiency. The MPs type PA achieved greater removal efficiency than PS, while PE had the least removal efficiency.

The Behavior of Polymeric Pipes in Drinking Water Distribution System-Comparison with Other Pipe Materials

The inner walls of the drinking water distribution system (DWDS) are expected to be clean to ensure a safe quality of drinking water. Complex physical, chemical, and biological processes take place when water comes into contact with the pipe surface. This paper describes the impact of leaching different compounds from the water supply pipes into drinking water and subsequent risks. Among these compounds, there are heavy metals. It is necessary to prevent these metals from getting into the DWDS. Those compounds are susceptible to impacting the quality of the water delivered to the population either by leaching dangerous chemicals into water or by enhancing the development of microorganism growth on the pipe surface. The corrosion process of different pipe materials, scale formation mechanisms, and the impact of bacteria formed in corrosion layers are discussed. Water treatment processes and the pipe materials also affect the water composition. Pipe materials act differently in the flowing and stagnation conditions. Moreover, they age differently (e.g., metal-based pipes are subjected to corrosion while polymer-based pipes have a decreased mechanical resistance) and are susceptible to enhanced bacterial film formation. Water distribution pipes are a dynamic environment, therefore, the models that are used must consider the changes that occur over time. Mathematical modeling of the leaching process is complex and includes the description of corrosion development over time, correlated with a model for the biofilm formation and the disinfectants-corrosion products and disinfectants-biofilm interactions. The models used for these processes range from simple longitudinal dispersion models to Monte Carlo simulations and 3D modeling. This review helps to clarify what are the possible sources of compounds responsible for drinking water quality degradation. Additionally, it gives guidance on the measures that are needed to maintain stable and safe drinking water quality.

Insights into Anthropogenic Micro- and Nanoplastic Accumulation in Drinking Water Sources and Their Potential Effects on Human Health

Anthropogenic microplastics (MPs) and nanoplastics (NPs) are ubiquitous pollutants found in aquatic, food, soil and air environments. Recently, drinking water for human consumption has been considered a significant pathway for ingestion of such plastic pollutants. Most of the analytical methods developed for detection and identification of MPs have been established for particles with sizes > 10 μm, but new analytical approaches are required to identify NPs below 1 μm. This review aims to evaluate the most recent information on the release of MPs and NPs in water sources intended for human consumption, specifically tap water and commercial bottled water. The potential effects on human health of dermal exposure, inhalation, and ingestion of these particles were examined. Emerging technologies used to remove MPs and/or NPs from drinking water sources and their advantages and limitations were also assessed. The main findings showed that the MPs with sizes > 10 μm were completely removed from drinking water treatment plants (DWTPs). The smallest NP identified using pyrolysis-gas chromatography-mass spectrometry (Pyr-GC/MS) had a diameter of 58 nm. Contamination with MPs/NPs can occur during the distribution of tap water to consumers, as well as when opening and closing screw caps of bottled water or when using recycled plastic or glass bottles for drinking water. In conclusion, this comprehensive study emphasizes the importance of a unified approach to detect MPs and NPs in drinking water, as well as raising the awareness of regulators, policymakers and the public about the impact of these pollutants, which pose a human health risk.

Microplastics removal from aquatic environment by coagulation: Selecting the best coagulant based on variables determined from a systematic review

The present study was carried out in the two phases of systematic review and experimental research. First, for the systematic review phase, Web of Science, Scopus, and PubMed as electronic databases were utilized to find research articles distributed up to March 5, 2021, related to the removal of microplastics by coagulation. In total, 104 publications were found, of which 14 were reviewed for deriving the variables and research design. Then, in the experimental phase, the experiment was carried out based on the variables derived from the systematic phase for three microplastic types (polyethylene, polystyrene, and polyamide) and five coagulants (polyaluminum chloride (PAC), ferric chloride (FeCl₃), aluminum chloride (AlCl₃), alum (Al(OH)₃) and aluminum sulfate (Al₂(SO₄)₃)) in bench scale study. The differences between removal efficiencies in terms of type, shape, concentration, and size of microplastics within the looked into article was analyzed utilizing ANOVA or Kruskal-Wallis test (for parametric or nonparametric analysis, respectively). The results of experimental phase show that the removal efficiency of different microplastics was significantly different, and it was equal to 65, 22, and 12% on average for PA, PS, and PE, respectively. These averages are much lower than the average removal efficiency calculated in the reviewed articles (78 and 52% for PS and PE, respectively). The removal efficiency of microplastics types by coagulants was not significantly different. As a result, a coagulant that has the lowest dose can be selected as the most suitable coagulant, which is Al(OH)₃ in this study.