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Microplastic release from the degradation of polypropylene feeding bottles during infant formula preparation


Microplastic release from the degradation of polypropylene feeding bottles during infant formula preparation

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Polypropylene-based products are commonly used for food preparation and storage, but their capacity to release microplastics is poorly understood. We investigated the potential exposure of infants to microplastics from consuming formula prepared in polypropylene (PP) infant feeding bottles (IFBs). Here, we show that PP IFBs release microplastics with values as high as 16,200,000 particles per litre. Scenario studies showed that PP IFB sterilization and exposure to high-temperature water significantly increase microplastic release. A 21-d test of PP IFBs showed periodic fluctuations in microplastic release. To estimate the potential global exposure to infants up to 12 months old, we surveyed 48 regions, finding values ranging from 14,600– 4,550,000 particles per capita per day, depending on the region. We demonstrate that infant exposure to microplastics is higher than was previously recognized due to the prevalence of PP-based products used in formula preparation and highlight an urgent need to assess whether exposure to microplastics at these levels poses a risk to infant health.
IFB sample preparation and establishment and validation of the MP analysis protocol a, Schematic of IFB sample preparation. b–e, Identification and mapping of PP MPs. b, Optical microscope image of particles released from IFBs using a 100× microscope objective. c, Raman mapping of the same region obtained using the PP Raman bands at 2,830–2,870 cm⁻¹. The colour scale bar indicates the intensity of the integrated spectral band in arbitrary units. d, AFM image of the same region to determine the morphology of released MPs. The colour scale bar indicates the height of MPs. e, Three-dimensional (3D) AFM topographic image. f, MPs per litre as determined by the third party versus our laboratory. IFB product 1 was used in this test (n = 5 independent bottles for each laboratory test; P = 0.66). g, MPs released from PP IFBs using tap water versus deionized water. For the control samples, no PP MPs were found when using tap water (n = 5 independent bottles of products 1 and 2 (P1 and P2, respectively) in both the tap water and deionized water tests). The P values obtained using products 1 and 2 were 0.13 and 0.18, respectively. h, Raman spectra of PP MPs, formula particles and the filter background. i, MPs released from PP IFBs using formula versus deionized water. For the control samples, the PP IFBs were replaced by a glass beaker and the same procedure was followed for formula and deionized water sample preparation. For the control samples, no PP MPs were found when using formula while only very small amounts of MPs were found in the deionized water, which was probably due to the plastic tubing used in the deionized water-making process (n = 5 independent bottles of products 1 and 2 were used in the formula and deionized water tests). The P values obtained using products 1 and 2 were 0.89 and 0.96, respectively. In f–i, statistical significance was determined by two-sided t-test with a confidence interval of 95% (for details, see Methods). The black horizontal lines and x marks in the box plots represent the median and mean values, respectively, the boxes represent the 25th to 75th percentile, and the whiskers represent the range of data. Source data
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1AMBER Research Centre and Centre for Research on Adaptive Nanostructures and Nanodevices (CRANN), Trinity College Dublin, Dublin, Ireland.
2Department of Civil, Structural and Environmental Engineering, Trinity College Dublin, Dublin, Ireland. 3TrinityHaus, Trinity College Dublin, Dublin, Ireland.
4School of Chemistry, Trinity College Dublin, Dublin, Ireland. 5BiOrbic Bioeconomy SFI Research Centre, University College Dublin, Dublin, Ireland.
6These authors contributed equally: Dunzhu Li, Yunhong Shi. e-mail:;;
Microplastics (MPs) are a global concern15 due to their
potential risk to human health69. The estimated MP con-
sumption via food chain and inhalation pathways ranges
from 74,000–211,000 particles annually in the United States10 and
MPs have been detected in human stools11. Exposure to MPs can
induce gut microbiota dysbiosis and lipid metabolism disorder in
mice12,13 and sub-micrometre MPs can penetrate the fish blood–
brain barrier, inducing brain damage and behavioural disorders14.
Research on MPs has focused on major food and water sources
(for example, fish) and the potential transfer of MPs from the ocean
to humans through the food chain10, but little is known about the
direct release of MPs from plastic products. Two specific products
with plastic containers (polyethylene terephthalate (PET) water bot-
tles and PET/nylon teabags1518) were found to release high levels of
MPs under daily use conditions. Polypropylene (PP) MPs accounted
for 62.8% of all MPs detected in adult stools, but the origin of these
MPs is unknown11. The annual production of PP accounts for about
20% of all non-fibre plastic production19 and PP is considered to be
a safe plastic that is suitable for many applications20, such that it is
the most widely used plastic in food preparation21.
PP infant feeding bottles (IFBs) are widely used for the preparation
of infant formula. IFBs are routinely exposed to high-temperature
water and endure shaking during formula preparation procedures.
Since mechanical friction force can break down PP into MPs2225,
there is the potential for MP release from PP IFBs. To assess the
prevalence of PP IFBs, we mined IFB sales data from local leading
e-commerce sites (data from each Amazon site were mined using
the Jungle Scout platform while data from non-Amazon sites were
directly collected via the site’s web page) from 48 regions, covering
77.6% of the global population (Fig. 1). We identified that PP IFBs
in the form of PP bottles, PP accessories or both (Fig. 1a) account
for 82.5% of the global IFB market, with regional differences in
the preference for PP IFBs, accessories and non-PP products. The
balance of the market share is dominated by glass IFBs. Next, we
estimated infant MP exposure by developing a protocol to quan-
tify and characterize the PP MPs release from PP IFBs using ten
representative PP IFB products, accounting for 68.8% of the global
market (Fig. 1b). The effects of water temperature, sterilization and
repeated use over a 21-d period on the levels of MP release were
assessed. Combining the MP release data from PP IFBs with local
non-breastfeeding rates and milk intake volumes, we estimated the
exposure of 12-month-old infants to MPs in 48 regions.
Sample preparation and measurement protocol. We tested
the quantity of MPs released from PP IFBs during standard for-
mula preparation steps involving World Health Organization
(WHO)-recommended26 cleaning, sterilizing and mixing tech-
niques (Fig. 2a). After thoroughly cleaning each of the brand-new
PP IFBs (products 1–10), we soaked them in 95 °C deionized water
for 5 min (cleaning and sterilizing). After air drying, we poured
70 °C deionized water (the recommended temperature for infant
formula preparation26) into the IFBs, which were then mechanically
shaken for 60 s to simulate the formula mixing process (180 r.p.m. in
a reciprocating shaker). After cooling, we filtered the water samples
from the PP IFBs using a gold-coated filter with a pore size of 0.8 µm.
The quantity and topography of the released PP MPs were deter-
mined by Raman spectroscopy and atomic force microscopy (AFM)
(see Fig. 2c,d; details in Supplementary Figs. 2 and 3 and Notes 2,
3 and 6). To confirm the reliability of this protocol (Supplementary
Figs. 4–6 and Supplementary Note 4), we first conducted a recov-
ery test employing standard polystyrene microplastic samples
Microplastic release from the degradation of
polypropylene feeding bottles during infant
formula preparation
Dunzhu Li1,2,6, Yunhong Shi2,6, Luming Yang1,2, Liwen Xiao 2,3 ✉ , Daniel K. Kehoe1, Yurii K. Gun’ko4,5,
John J. Boland 1,4 ✉ and Jing Jing Wang 1 ✉
Polypropylene-based products are commonly used for food preparation and storage, but their capacity to release microplastics
is poorly understood. We investigated the potential exposure of infants to microplastics from consuming formula prepared
in polypropylene (PP) infant feeding bottles (IFBs). Here, we show that PP IFBs release microplastics with values as high as
16,200,000 particles per litre. Scenario studies showed that PP IFB sterilization and exposure to high-temperature water sig-
nificantly increase microplastic release. A 21-d test of PP IFBs showed periodic fluctuations in microplastic release. To estimate
the potential global exposure to infants up to 12 months old, we surveyed 48 regions, finding values ranging from 14,600–
4,550,000 particles per capita per day, depending on the region. We demonstrate that infant exposure to microplastics is
higher than was previously recognized due to the prevalence of PP-based products used in formula preparation and highlight an
urgent need to assess whether exposure to microplastics at these levels poses a risk to infant health.
NATURE FOOD | VOL 1 | NOVEMBER 2020 | 746–754 |
Content courtesy of Springer Nature, terms of use apply. Rights reserved
... The guts of aquatic organisms constitute another natural aqueous system with organic molecules that can function as solubilizers when plastic materials (micro or macro) and water encounter loci of energetic mixing (Benson, Agboola et al., 2022). Foods and drinks in plastic containers that require vigorous shaking, including baby formula in plastic bottles, often provide the necessary conditions for creation of sM&NP (Li, Shi et al., 2020). Human digestive systems may also be capable of converting the microplastics that are ingested or inhaled to sM&NP by this mechanism (Lu, Luo et al., 2019). ...
Full-text available
The immense production of plastic polymers combined with their discordancy with nature has led to vast plastic waste contamination across the geosphere, from the oceans to freshwater reservoirs, wetlands, remote snowpacks, sediments, air and multiple other environments. These environmental pollutants include microplastics (MP), typically defined as small and fragmented plastics less than 5 mm in size, and nanoplastics (NP), particles smaller than a micrometer. The formation of micro and nanoplastics in aqueous media to date has been largely attributed to fragmentation of plastics by natural (i.e., abrasion, photolysis, biotic) or industrial processes. We present a novel method to create small microplastics (≲ 5 μm) and nanoplastics in water from a wide variety of plastic materials using a small volume of a solubilizer liquid, such as n-dodecane, in combination with vigorous mixing. When the suspensions or solutions are subjected to ultrasonic mixing, the particle sizes decrease. Small micro- and nanoparticles were made from commercial, real world and waste (aged) polyethylene, polystyrene, polycarbonate and polyethylene terephthalate, in addition to other plastic materials and were analyzed using dark field microscopy, Raman spectroscopy and particle size measurements. The presented method provides a new and simple way to create specific size distributions of micro- and nanoparticles, which will enable expanded research on these plastic particles in water, especially those made from real world and aged plastics. The ease of NP and small MP formation upon initial mixing simulates real world environments, thereby providing further insight into the behavior of plastics in natural settings.
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Size and concentration are two important parameters for the analysis of microplastics (MPs) in water. The analytical tools reported so far extract this information in a single-particle analysis mode, dramatically increasing the analysis time. Here, we present a combination of multi-angle static light scattering technique, called "Goniophotometry", with chemometric multivariate data processing for the batch analysis of size and concentration of MPs in water. Nine different sizes of polystyrene (PS) MPs with diameters between 500 nm and 20 μm are investigated in two different scenarios with uniform (monodisperse) and non-uniform (polydisperse) size distribution of MPs, respectively. It is shown that Principal Component Analysis (PCA) can reveal the existing relationship between the scattering data of mono- and polydisperse samples according to the size distribution of MPs in mixtures. Therefore, a Linear Discriminant Analysis (LDA) model is constructed based on the PCA of scattering data of PS monodisperse samples and is subsequently employed to classify the size of MPs not only in unknown mono- and polydisperse PS samples, but also for other types of MPs such as Polyethylene (PE) and Polymethylmethacrylate (PMMA). When the size of MPs is classified, their concentration is measured using a simple linear fit. Finally, a Linear Least Square (LLS) model is used to evaluate the reproducibility of the measurements.
Take-out food has become increasingly prevalent due to the fast pace of people's life. However, few study has been done on microplastics in take-out food. Contacting with disposable plastic containers, take-out food may be contaminated with microplastics. In the present study, abundance and characteristics of microplastics in total of 146 take-out food samples including solid food samples and beverage samples (bubble tea and coffee) were determined and identified. The mean abundance of microplastics in take-out food was 639 items kg⁻¹, with the highest value in rice and the lowest value in coffee. Fragments shape, transparent color and sizes ≤500 μm were the main characteristics of microplastics in those food, and polyethylene was the main polymer type. Our results indicated that microplastics in take-out food was influenced by food categories and cooking methods, as well as food packaging materials. Approximately 170–638 items of microplastics may be consumed by people who order take-out food 1–2 times weekly.
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Microplastic (MP) contamination is a public issue for the environment and for human health. Plastic-based food filter bags, including polyethylene terephthalate, polypropylene, nylon 6 (NY6), and polyethylene, are widely used for soft drink sub-packaging, increasing the risk of MPs in foods and the environment. Three types of commercially available filter bags, including non-woven and woven bags, were collected, and MPs released after soaking were mapped using Raman imaging combined with chemometrics. Compared with peak area imaging at a single characteristic peak, Raman imaging combined with direct classical least squares calculation was more efficient and reliable for identifying MP features. Up to 94% of the bags released MPs after soaking, and there was no significant correlation with soaking conditions. Most MPs were tiny fragments and particles, and a few were fibrous MPs 620–840 μm in size. Woven NY6 filter bags had the lowest risk of releasing MPs. Source exploration revealed that most MPs originated from fragments and particles adsorbed on the surface of bags and strings. The results of this study are applicable to filter bag risk assessment and provide scientific guidance for regulating MPs in food.
Despite the huge success of commercial stabilizers (antioxidants, UV absorbers, etc.) on the functionality enhancement and lifetime prolonging of polymers, their toxicity on the environment has been raising severe concerns. Therefore, producing environmentally benign stabilizers via green chemistry has been attracting researchers’ attention. In this work, we demonstrated the potential of mussel-inspired polydopamine nanoparticles (PDA-NPs) with intrinsic biocompatibility for the enhancement of both thermo- and photo-oxidation stability of polypropylene (PP). The effects of PDA-NPs size on the antioxidative performance of PP were systematically explored. PDA-NPs with different sizes of 471 nm, 284 nm, and 98 nm were synthesized first by tuning the pH values of initial dopamine solutions. The antioxidation ability of PDA-NPs for PP increased remarkably with the decreasing size, which was attributed to a higher specific area and more available semiquinone structure of smaller PDA-NPs. Compared with pure PP, the oxidation induction time (OIT) and onset thermal decomposition temperature of optimized PP composites can be increased significantly from 9.8 min to 26.0‍‍ min by 165% with the addition of only 0.5 wt.% PDA-NP (98 nm), while the thermo- and photo-oxidative degree (formation of carbonyl products) on the surface can be decreased by 53% and 92% at most, respectively. However, the dependence of UV protection ability of PDA-NPs for PP on their size is non-monotonic. As indicated by cross-sectional fluorescence and modulus imaging, the shallowest degradation depth was observed for PP composites with the PDA-NP size of 284 nm other than that of 98 nm. These results have demonstrated the feasibility of PDA-NPs as robust stabilizers and the importance of size design for optimizing the anti-aging efficiency of PDA-NPs, providing valuable insights into the development of multifunctional stabilizers for environmental sustainability.
Pregnancy and infancy are sensitive windows for environmental exposures. However, no study has investigated the presence of microplastics (MPs) in mother-infant pairs, and the exposure sources. Therefore, we aim to assess MPs exposure in placenta, meconium, infant feces, breast milk and infant formula samples, and assess the potential sources of pregnancy and lactational exposure to MPs. A total of 18 mother-infant pairs were recruited, and placentas and meconium samples were collected. Infant feces, breast milk and infant formula samples were collected at 6 months of age. We also collected data on plastic use and feeding habits through two questionnaires to determine the source of exposure. We used an Agilent 8700 laser infrared imaging spectrometer to analyze samples. Sixteen types of MPs were identified, and polyamide (PA) and polyurethane (PU) were dominant. >74 % of the MPs found were 20–50 μm in size. The water intake and usage of scrub cleanser or toothpaste may be exposure sources of pregnant women. The breastfeeding and usage of feeding bottles and plastic toys may be exposure sources for infants. Given the lack of relevant studies, our results highlight the need of investigating the contribution of plastic products to the MPs exposure during the lactational period.
Microplastics in food are receiving increasing attention because they are directly ingested by humans and pose a health threat. However, little attention has been paid to the microplastics resulting from the disposable drink cups. Here, we analyzed the microplastic contamination in beverages in three commonly used plastic cups (PP, PET, and PE cups). Effects of the cup materials, the residence time of the drink in the cup, shaking, and water temperatures on the microplastic release were systematically investigated. The results showed that the microplastic abundance in water reached 723–1,489 particles cup⁻¹ after 5 min exposure and increased significantly with increasing residence time. The size of released microplastics was mainly in the range of <50 μm. The shaking applied during transport promoted the release of microplastics from plastic cups. Besides, the results showed that cups released more microplastics when serving hot drinks than serving cold drinks. Based on the results, we estimated that people may unconsciously ingest 37,613–89,294 microplastics a year due to the use of one plastic cup every 4–5 days. Considering the potential harm of microplastics, the contamination of microplastics resulting from the use of plastic cups for drinks needs to be taken seriously.
The plastic materials are converted into microplastics (MPs) and nanoplastics (NPs) by oxidation, hydrolysis, mechanical corrosion, photodegradation, and biodegradation. The actual sources of MPs and NPs are difficult to trace because of their small size, degradation nature, and fragmentation of the debris. The MPs sources in the marine environment are from land and include industrial waste, runoff, beach visitors, and wastewater from research stations. Ecocline is the process of MPs transportation from terrestrial sources to the seas and oceans through rivers and estuaries. The fibers and fragments type MPs are found around 80% in the ocean and constitute more than the granules and pellets. MPs and NPs concentrations are higher in coastal sediments when compared with the sea surface and water column. MPs and plastic materials are consumed by marine biotas such as zooplankton, phytoplankton, fishes, seabirds, cetaceans, sea turtles, echinoderms, and invertebrates. The interaction of MPs and NPs with compounds such as heavy metals, aromatic hydrocarbons, pharmaceutical compounds, pesticides, nanoparticles, organohalogens, organotins, and plastic additives cause adverse effects and are toxic to aquatic organisms. It is necessary to reduce the MPs and NPs pollution from wastewater treatment plants by using renewable or biodegradable materials and removing plastic waste from various sources.
Microplastics (MPs) and nanoplastic (NPs) pollution is a global concern due to the massive use of plastic products. Although there have been many studies on the treatments of animals with MPs/NPs, there are few systematic summaries of MPs/NPs translocation and hazards in animals. This review comprehensively summarizes the pathways by which animals are exposed to MPs/NPs in the environment, in particular, to summarize in detail their translocation and hazards in vivo. Studies have shown that MPs/NPs enter the animals' body through water, food, breath and even skin, enter the blood circulation through the lungs and digestive tract, and eventually accumulate in various tissues. After a summary of the studies, we found a high correlation between the tissue accumulation of MPs/NPs and their particle size, with 4–20 μm MPs appearing to be more prone to accumulate in tissues. These MPs/NPs accumulated in animal tissues may be transferred to humans through the food chain. Thus, we summarized the studies on the accumulation of MPs/NPs in livestock and poultry products, showing that MPs/NPs in livestock and poultry products gradually increased with the complexity of processing and packaging processes. There are few reports related to direct contamination of livestock products by MPs/NPs, we hope that this review will bring together the growing body of evidence that MPs/NPs can directly harm human health through the food chain.
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Background: In contrast with the ample literature on within- and between-country inequalities in breastfeeding practices, there are no multi-country analyses of socioeconomic disparities in breastmilk substitute (BMS) consumption in low- and middle-income countries (LMICs). Objective: This study aimed to investigate between- and within-country socioeconomic inequalities in breastfeeding and BMS consumption in LMICs. Methods: We examined data from the Demographic Health Surveys and Multiple Indicator Cluster Surveys conducted in 90 LMICs since 2010 to calculate Pearson correlation coefficients between infant feeding indicators and per capita gross domestic product (GDP). Within-country inequalities in exclusive breastfeeding, intake of formula or other types of nonhuman milk (cow/goat) were studied for infants aged 0-5 mo, and for continued breastfeeding at ages 12-15 mo through graphical presentation of coverage wealth quintiles. Results: Between-country analyses showed that log GDP was inversely correlated with exclusive (r = -0.37, P < 0.001) and continued breastfeeding (r = -0.74, P < 0.0001), and was positively correlated with formula intake (r = 0.70, P < 0.0001). Continued breastfeeding was inversely correlated with formula (r = -0.79, P < 0.0001), and was less strongly correlated with the intake of other types of nonhuman milk (r = -0.40, P < 0.001). Within-country analyses showed that 69 out of 89 did not have significant disparities in exclusive breastfeeding. Continued breastfeeding was significantly higher in children belonging to the poorest 20% of households compared with the wealthiest 20% in 40 countries (by ∼30 percentage points on average), whereas formula feeding was more common in the wealthiest group in 59 countries. Conclusions: BMS intake is positively associated with GDP and negatively associated with continued breastfeeding in LMICs. In most countries, BMS intake is positively associated with family wealth, and will likely become more widespread as countries develop. Urgent action is needed to protect, promote, and support breastfeeding in all income groups and to reduce the intake of BMS, in light of the hazards associated with their use.
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Although infant nanomaterial exposure is a worldwide concern, breastfeeding transfer of transition metal-oxide nanoparticles to as well as their toxicity to offspring are still unclear. Breastfeeding transmits nutrition and immunity from mothers to their offspring; it also provides a portal for maternal toxins to enter offspring. Thus, a toxicology assessment of both mothers and their offspring should be established to monitor nanomaterial exposure during lactation. Here, we determined the effects of the exposure route on the biodistribution, biopersistence, and toxicology of nanoparticles (titanium dioxide, zinc oxide, and zirconium dioxide) in both mouse dams and their offspring. Oral and airway exposure routes were tested using gavage and intranasal administration, respectively. Biodistribution in the main organs (breast, liver, spleen, lung, kidney, intestine, and brain) and biopersistence in the blood and milk were determined using inductively coupled plasma mass spectrometry. Hematology and histomorphology analyses were performed to determine the toxicology of the nanoparticles. A reduced offspring body weight was found with the reduced nanoparticle size. Furthermore, both oral and airway exposure increased the nanoparticle concentrations in the main tissues and milk. More nanoparticles were transferred into maternal tissues and milk via airway exposure than via oral exposure. During the transfer of the metal from the exposed nanoparticles to milk, the immune cell pathway played a more important role in the airway route than in the oral exposure route. Finally, maternal exposure via both the oral and airway routes reduced the body weight and survival rate of their breastfeeding offspring, which could possibly be attributed to the toxicity of nanoparticles to blood cells and organs. In conclusion, maternal exposure to nanoparticles led to a reduced body weight and survival rate in breastfed offspring, and nanoparticle exposure via the airway route led to a higher immune response and tissue injury than that via the oral exposure route. This study suggests that the use of products containing metal nanoparticles in breastfeeding mothers and their offspring should be reconsidered to maintain a safe breastfeeding system.
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Plastics are known sources of chemical exposure and few, prominent plastic-associated chemicals, such as bisphenol A and phthalates, have been thoroughly studied. However, a comprehensive characterization of the complex chemical mixtures present in plastics is missing. In this study, we benchmark plastic consumer products, covering eight major polymer types, according to their toxicological and chemical signatures using in vitro bioassays and nontarget high-resolution mass spectrometry. Most (74%) of the 34 plastic extracts contained chemicals triggering at least one end point, including baseline toxicity (62%), oxidative stress (41%), cytotoxicity (32%), estrogenicity (12%), and antiandrogenicity (27%). In total, we detected 1411 features, tentatively identified 260, including monomers, additives, and nonintentionally added substances, and prioritized 27 chemicals. Extracts of polyvinyl chloride (PVC) and polyurethane (PUR) induced the highest toxicity, whereas polyethylene terephthalate (PET) and high-density polyethylene (HDPE) caused no or low toxicity. High baseline toxicity was detected in all “bioplastics” made of polylactic acid (PLA). The toxicities of low-density polyethylene (LDPE), polystyrene (PS), and polypropylene (PP) varied. Our study demonstrates that consumer plastics contain compounds that are toxic in vitro but remain largely unidentified. Since the risk of unknown compounds cannot be assessed, this poses a challenge to manufacturers, public health authorities, and researchers alike. However, we also demonstrate that products not inducing toxicity are already on the market.
The increasing presence of micro- and nano-sized plastics in the environment and food chain is of growing concern. Although mindful consumers are promoting the reduction of single-use plastics, some manufacturers are creating new plastic packaging to replace traditional paper uses, such as plastic teabags. The objective of this study was to determine whether plastic teabags could release microplastics and/or nanoplastics during a typical steeping process. We show that steeping a single plastic teabag at brewing temperature (95 °C) releases approximately 11.6 billion microplastics and 3.1 billion nanoplastics into a single cup of the beverage. The composition of the released particles is matched to the original teabags (nylon and polyethylene terephthalate) using Fourier-transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS). The levels of nylon and polyethylene terephthalate particles released from the teabag packaging are several orders of magnitude higher than plastic loads previously reported in other foods. An initial acute invertebrate toxicity assessment shows that exposure to only the particles released from the teabags caused dose-dependent behavioral and developmental effects.
Background: Microplastics are ubiquitous in natural environments. Ingestion of microplastics has been described in marine organisms, whereby particles may enter the food chain. Objective: To examine human feces for the presence of microplastics to determine whether humans involuntarily ingest them. Design: Prospective case series in which participants completed a food diary and sampled stool according to step-by-step instructions. Setting: Europe and Asia. Participants: Eight healthy volunteers aged 33 to 65 years. Measurements: After chemical digestion, Fourier-transform infrared microspectroscopy was used to analyze the presence and shape of 10 common types of microplastic in stool samples. Results: All 8 stool samples tested positive for microplastics. A median of 20 microplastics (50 to 500 µm in size) per 10 g of human stool were identified. Overall, 9 plastic types were detected, with polypropylene and polyethylene terephthalate being the most abundant. Limitations: There were few participants, and each provided only 1 sample. The origin and fate of microplastics in the gastrointestinal tract were not investigated. Conclusion: Various microplastics were detected in human stool, suggesting inadvertent ingestion from different sources. Further research on the extent of microplastic intake and the potential effect on human health is needed. Primary funding source: None.
Microplastics (MPs) contamination has been recognized as one of major threats to coastal marine environments. Although studies evidenced severe MPs contaminations to the Pacific Ocean, environmental implications of MPs concentrations, distributions, and characteristics have not been evaluated in sufficient detail. Here, we report on the distribution, abundance, and characteristics of MPs at the surface of the Northwestern Pacific Ocean, from which environmental implications are assessed. A manta trawl with a mesh size of ~330 μm and a rectangular net opening of 0.45 × 1 m was used to collect MPs samples on May 11-June 3, 2018. The MPs samples were sequentially isolated, digested, filtered, and characterized using an optical microscope, micro-Raman spectroscopy, and scanning electron microscopy. The results indicate the heterogeneity in abundance, shapes, color, and sizes of MPs. The study provides strong environmental implications such as sources, environmental degradation, residence time, transportation routes, and biological interactions.
The role of rivers as a major transport pathway for all sizes of plastic debris into the ocean is widely recognized. Global modelling studies ranked the Changjiang River as the largest contributor of plastic waste to the marine environment, but these estimates were based on insufficient empirical data. To better understand the role of rivers in delivering terrestrial plastic debris to the ocean, the spatial and temporal patterns of microplastics (MP) in the Changjiang Estuary (CE) and the East China Sea (ECS) were studied based on surface water samples in February, May, and July 2017. A total of 3225 MP (60-5000 μm) were identified by Fourier-transform infrared (FTIR) spectrometry. MP abundance in July was higher than in February and May due to higher river discharge. Density stratification in CE significantly influenced the surface MP abundances. A temporal accumulation zone within the river-sea interface for plastics was indicated by stations with apparently higher abundances in the river plume. Fibers were the most common MP (>80%) over three months. Small MP (<1000 μm) composed 75.0% of the total plastics on average. The average mass of MP was 0.000033 g/particle, which was two orders of magnitude lower than the empirical mass in literature. Without considering tidal effects, we estimate 16-20 trillion MP particles, weighing 537.6-905.9 tons, entered the sea through the surface water layer of the Changjiang River in 2017. These findings of this study provide reliable information on MP waste in a large river, which should be considered in further studies for estimating the riverine plastic loads.
Microplastics are ubiquitous across ecosystems, yet the exposure risk to humans is unresolved. Focusing on the American diet, we evaluated the number of microplastic particles in commonly consumed foods in relation to their recommended daily intake. The potential for microplastic inhalation and how the source of drinking water may affect microplastic consumption were also explored. Our analysis used 402 data points from 26 studies, which represents over 3600 processed samples. Evaluating approximately 15% of Americans' caloric intake, we estimate that annual microplastics consumption ranges from 39000 to 52000 particles depending on age and sex. These estimates increase to 74000 and 121000 when inhalation is considered. Additionally, individuals who meet their recommended water intake through only bottled sources may be ingesting an additional 90000 microplastics annually, compared to 4000 microplastics for those who consume only tap water. These estimates are subject to large amounts of variation; however, given methodological and data limitations, these values are likely underestimates.
On account of environmental concerns, the fate and adverse effects of plastics have attracted considerable interest in the last years. Recent studies have indicated the potential for fragmentation of plastic materials into nanoparticles, i.e., “nanoplastics” and their possible accumulation in the environment. Nanoparticles can show markedly different chemical and physical properties than their bulk material form. Therefore, possible risks and hazards to the environment need to be considered and addressed. However, the fate and effect of nanoplastics in the (aquatic) environment has so far been little explored. In this review, we aim to provide an overview of the literature on this emerging topic, with an emphasis on the reported impacts of nanoplastics on human health, including the challenges involved in detecting plastics in a biological environment. We first discuss the possible sources of nanoplastics, their fates and effects in the environment and then describe the possible entry routes of these particles into the human body, as well as their uptake mechanisms at the cellular level. Since the potential risks of environmental nanoplastics to humans have not yet been extensively studied, we focus on studies demonstrating cell responses induced by polystyrene nanoparticles. In particular, the influence of particle size and surface chemistry are discussed, in order to understand the possible risks of nanoplastics for humans and provide recommendations for future studies.