1
|
Zhao S, Kvale KF, Zhu L, Zettler ER, Egger M, Mincer TJ, Amaral-Zettler LA, Lebreton L, Niemann H, Nakajima R, Thiel M, Bos RP, Galgani L, Stubbins A. The distribution of subsurface microplastics in the ocean. Nature 2025; 641:51-61. [PMID: 40307520 PMCID: PMC12043517 DOI: 10.1038/s41586-025-08818-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2023] [Accepted: 02/20/2025] [Indexed: 05/02/2025]
Abstract
Marine plastic pollution is a global issue, with microplastics (1 µm-5 mm) dominating the measured plastic count1,2. Although microplastics can be found throughout the oceanic water column3,4, most studies collect microplastics from surface waters (less than about 50-cm depth) using net tows5. Consequently, our understanding of the microplastics distribution across ocean depths is more limited. Here we synthesize depth-profile data from 1,885 stations collected between 2014 and 2024 to provide insights into the distribution and potential transport mechanisms of subsurface (below about 50-cm depth, which is not usually sampled by traditional practices3,6) microplastics throughout the oceanic water column. We find that the abundances of microplastics range from 10-4 to 104 particles per cubic metre. Microplastic size affects their distribution; the abundance of small microplastics (1 µm to 100 µm) decreases gradually with depth, indicating a more even distribution and longer lifespan in the water column compared with larger microplastics (100 µm to 5,000 µm) that tend to concentrate at the stratified layers. Mid-gyre accumulation zones extend into the subsurface ocean but are concentrated in the top 100 m and predominantly consist of larger microplastics. Our analysis suggests that microplastics constitute a measurable fraction of the total particulate organic carbon, increasing from 0.1% at 30 m to 5% at 2,000 m. Although our study establishes a global benchmark, our findings underscore that the lack of standardization creates substantial uncertainties, making it challenging to advance our comprehension of the distribution of microplastics and its impact on the oceanic environment.
Collapse
Affiliation(s)
- Shiye Zhao
- Japan Agency for Marine-Earth Science and Technology, Yokosuka, Japan.
| | - Karin F Kvale
- Aotearoa Blue Ocean Research, Lower Hutt, New Zealand
| | - Lixin Zhu
- State Key Laboratory of Estuarine and Coastal Research, East China Normal University, Shanghai, China
- Department of Marine and Environmental Sciences, Northeastern University, Boston, MA, USA
| | - Erik R Zettler
- NIOZ Royal Netherlands Institute for Sea Research, Den Burg, The Netherlands
| | - Matthias Egger
- The Ocean Cleanup, Rotterdam, The Netherlands
- Empaqtify, St Gallen, Switzerland
| | - Tracy J Mincer
- Harriet Wilkes Honors College, Florida Atlantic University, Boca Raton, FL, USA
| | - Linda A Amaral-Zettler
- NIOZ Royal Netherlands Institute for Sea Research, Den Burg, The Netherlands
- Department of Freshwater and Marine Ecology, Institute for Biodiversity and Ecosystem Dynamics, University of Amsterdam, Amsterdam, The Netherlands
| | | | - Helge Niemann
- NIOZ Royal Netherlands Institute for Sea Research, Den Burg, The Netherlands
- Department of Earth Sciences, Faculty of Geosciences, Utrecht University, Utrecht, The Netherlands
| | - Ryota Nakajima
- Japan Agency for Marine-Earth Science and Technology, Yokosuka, Japan
| | - Martin Thiel
- Facultad Ciencias del Mar, Universidad Catolica del Norte, Coquimbo, Chile
- MarineGEO Program, Smithsonian Environmental Research Center, Edgewater, MD, USA
- Centre for Ecology and Sustainable Management of Oceanic Island (ESMOI), Coquimbo, Chile
| | - Ryan P Bos
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA, USA
| | - Luisa Galgani
- Department of Biotechnology, Chemistry and Pharmacy, University of Siena, Siena, Italy
- National Biodiversity Future Center (NBFC), Palermo, Italy
| | - Aron Stubbins
- Department of Marine and Environmental Sciences, Northeastern University, Boston, MA, USA
- Department of Chemistry and Chemical Biology, Northeastern University, Boston, MA, USA
- Department of Civil and Environmental Engineering, Northeastern University, Boston, MA, USA
| |
Collapse
|
2
|
Santana MFM, Tonin H, Vamvounis G, van Herwerden L, Motti CA, Kroon FJ. Predicting microplastic dynamics in coral reefs: presence, distribution, and bioavailability through field data and numerical simulation analysis. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2025; 32:9655-9675. [PMID: 40133747 PMCID: PMC11991954 DOI: 10.1007/s11356-025-36234-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/08/2024] [Accepted: 03/03/2025] [Indexed: 03/27/2025]
Abstract
Understanding distribution and bioavailability of microplastics is vital for conducting ecological risk assessments (ERA) and developing mitigation strategies in marine environments. This study couples in situ data from Lizard Island (Great Barrier Reef) and numerical modelling and simulations to determine microplastic abundances in abiotic (water and sediment) and biotic (planktivorous fish, sea squirts, sponges, corals, and sea cucumbers) compartments and predict their trajectories within this ecosystem. Results show microplastics predominantly (75%) originate from beached plastics from nearby islands and coastal areas, dispersing northward without local entrapment and settlement likely occurring on northern beaches (> 50%), including Papua New Guinea. Concentrations increased by three orders of magnitude with depth, with distinct profiles: surface waters contained more fragments and low-density polymers at concentrations of < 1 microplastics m-3, and deeper layers more fibres and high-density polymers, with concentrations peaking at the seafloor at > 100 microplastics m-3. Reflecting ecological and physiological traits of each taxon, fish exhibited microplastic contamination levels nearly twice that observed in invertebrates, and while polymers and colours had no stronger evidences on influencing bioavailability, shape and size did, with fish more susceptible to contamination by microplastic fibres and all taxa to smaller-sized microplastic particles.
Collapse
Affiliation(s)
- Marina F M Santana
- Australian Institute of Marine Science (AIMS), Cape Cleveland Road, Cape Cleveland 4810, Townsville, QLD, 4810, Australia.
- College of Science and Engineering, James Cook University (JCU), Townsville, QLD, 4811, Australia.
- AIMS@JCU, Division of Research and Innovation, James Cook University, Townsville, QLD, 4811, Australia.
| | - Hemerson Tonin
- Australian Institute of Marine Science (AIMS), Cape Cleveland Road, Cape Cleveland 4810, Townsville, QLD, 4810, Australia
| | - George Vamvounis
- College of Science and Engineering, James Cook University (JCU), Townsville, QLD, 4811, Australia
- AIMS@JCU, Division of Research and Innovation, James Cook University, Townsville, QLD, 4811, Australia
| | - Lynne van Herwerden
- College of Science and Engineering, James Cook University (JCU), Townsville, QLD, 4811, Australia
- AIMS@JCU, Division of Research and Innovation, James Cook University, Townsville, QLD, 4811, Australia
| | - Cherie A Motti
- Australian Institute of Marine Science (AIMS), Cape Cleveland Road, Cape Cleveland 4810, Townsville, QLD, 4810, Australia
- AIMS@JCU, Division of Research and Innovation, James Cook University, Townsville, QLD, 4811, Australia
| | - Frederieke J Kroon
- Australian Institute of Marine Science (AIMS), Cape Cleveland Road, Cape Cleveland 4810, Townsville, QLD, 4810, Australia
- AIMS@JCU, Division of Research and Innovation, James Cook University, Townsville, QLD, 4811, Australia
| |
Collapse
|
3
|
Xu L, Bai X, Li K, Zhang G, Zhang M, Wu Z, Huang Y, Hu M. Sandstorms contribute to the atmospheric microplastic pollution: Transport and accumulation from degraded lands to a megacity. JOURNAL OF HAZARDOUS MATERIALS 2024; 480:136427. [PMID: 39522213 DOI: 10.1016/j.jhazmat.2024.136427] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/25/2024] [Revised: 10/10/2024] [Accepted: 11/05/2024] [Indexed: 11/16/2024]
Abstract
Surface dust from degraded lands is a major global aerosol source, mobilized by meteorological events like sandstorms. Microplastics (MPs) in dust can be enriched in the atmosphere and transported over long distances to sensitive regions during sandstorms. This study was conducted in a megacity frequently impacted by sandstorms in spring, exploring the influx, characteristics, enrichment mechanism, and transport pathway of sandstorm-derived MPs. The deposition rate of these MPs reached 1823.65 ± 892.53 items·m-2·d-1, predominantly consisting of low-density polymers and those mainly used in synthetic fiber, with an average size of 60.75 µm. Compared to MPs in annual atmospheric deposition, these MPs were smaller and contained a higher proportion of potentially harmful polymers. These factors could increase exposure risks for residents from sandstorm-derived MPs, along with distinct meteorological and ecological effects. Backward trajectory analysis suggested the observed sandstorms originated from the Mongolian Plateau, over 1000 km away. Comparisons of MPs from surface-collected dust on the Mongolian Plateau with sandstorms-delivered MPs revealed the transport was determined by MP shape, size, and density. This study highlights the critical role of sandstorms in the MP atmospheric cycling, emphasizing the extensive impacts of MPs and the need for coordinated mitigation efforts across regions.
Collapse
Affiliation(s)
- Libo Xu
- State Key Joint Laboratory of Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, Peking University, Beijing 100871, China
| | - Xinyi Bai
- State Key Joint Laboratory of Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, Peking University, Beijing 100871, China
| | - Kang Li
- State Key Joint Laboratory of Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, Peking University, Beijing 100871, China
| | - Guangbao Zhang
- State Key Joint Laboratory of Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, Peking University, Beijing 100871, China
| | - Mengjun Zhang
- Marine Institute for Bioresources and Environment, Peking University Shenzhen Institute, Shenzhen, Guangdong 518057, China; PKU-HKUST Shenzhen-Hongkong Institution, Shenzhen, Guangdong 518057, China
| | - Zhijun Wu
- State Key Joint Laboratory of Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, Peking University, Beijing 100871, China
| | - Yi Huang
- State Key Joint Laboratory of Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, Peking University, Beijing 100871, China; Marine Institute for Bioresources and Environment, Peking University Shenzhen Institute, Shenzhen, Guangdong 518057, China; PKU-HKUST Shenzhen-Hongkong Institution, Shenzhen, Guangdong 518057, China.
| | - Min Hu
- State Key Joint Laboratory of Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, Peking University, Beijing 100871, China.
| |
Collapse
|
4
|
Wang Y, Zhang L, Sun H, Zhang J, Guo Z. Nanoplastics Distribution during Ice Formation: Insights into Natural Surface Water Freezing Conditions. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2024; 58:20245-20255. [PMID: 39467813 DOI: 10.1021/acs.est.4c10211] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/30/2024]
Abstract
The migration characteristics of nanoplastics (NPs) in the natural freezing process are complex and have attracted increasing attention in simulating natural freezing in recent years. However, simulated freezing conditions often fall short of replicating natural freezing processes, and studies on the vertical distribution of NPs remain inadequate. This study established a more realistic simulation of the natural freezing process in surface water by controlling both the air temperature (T1) and the water temperature (T2). Additionally, we introduced a new parameter, the local distribution coefficient (Kiw1), to compare with the effective distribution coefficient (Kiw2). The values of Kiw1 and Kiw2 for PS-500 nm were 0.18 and 0.21, respectively, at T1 = -20 °C and T2 = 1 °C. The results revealed the NPs concentration differed in ice, near-ice liquid, and far-ice liquid. Both properties of NPs and environmental factors could regulate the vertical distribution of NPs. The findings underscored the importance of freezing temperature regulated by T1 and T2, elucidating the roles of various influencing factors on the vertical distribution characteristics of NPs and unraveling the mechanisms of NPs distribution in the ice-water system. This study can provide valuable insights for understanding the migration of NPs in surface water in cold regions.
Collapse
Affiliation(s)
- Yakun Wang
- Key Laboratory of Groundwater Resources and Environment, Ministry of Education, Jilin Provincial Key Laboratory of Water Resources and Environment, College of New Energy and Environment, Jilin University, Changchun 130012, China
| | - Liwen Zhang
- Key Laboratory of Groundwater Resources and Environment, Ministry of Education, Jilin Provincial Key Laboratory of Water Resources and Environment, College of New Energy and Environment, Jilin University, Changchun 130012, China
| | - Heyang Sun
- Key Laboratory of Groundwater Resources and Environment, Ministry of Education, Jilin Provincial Key Laboratory of Water Resources and Environment, College of New Energy and Environment, Jilin University, Changchun 130012, China
| | - Jing Zhang
- Key Laboratory of Groundwater Resources and Environment, Ministry of Education, Jilin Provincial Key Laboratory of Water Resources and Environment, College of New Energy and Environment, Jilin University, Changchun 130012, China
| | - Zhiyong Guo
- Key Laboratory of Groundwater Resources and Environment, Ministry of Education, Jilin Provincial Key Laboratory of Water Resources and Environment, College of New Energy and Environment, Jilin University, Changchun 130012, China
| |
Collapse
|
5
|
Gerolin CR, Zornio B, Pataro LF, Labuto G, Semensatto D. Microplastic pollution responses to spatial and seasonal variations and water level management in a polymictic tropical reservoir (São Paulo, Brazil). ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2024; 31:42388-42405. [PMID: 38874755 DOI: 10.1007/s11356-024-33960-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/01/2023] [Accepted: 06/06/2024] [Indexed: 06/15/2024]
Abstract
We assessed microplastic (μP) pollution in water and sediment samples during the dry and rainy season (October/2018 and March/2019, respectively) from the Guarapiranga Reservoir in the Metropolitan Region of São Paulo, Brazil, which provides drinking water for up to 5.2 million people. The concentration of mPs varied spatially and seasonally, with the higher concentrations observed near the urbanized areas and during the dry season. Water column concentrations ranged from 150 to 3100 particles/m3 and 0.07-25.05 mm3 plastic/m3 water during the dry season, and 70-7900 particles/m3 and 0.06-4.57 mm3 plastic/m3 water during the rainy season. Sediment samples were collected only during the rainy season, with concentrations ranging from 210 to 22,999 particles/kg dry weight and 0.15-111.46 mm3/kg dry weight. The particle size distribution exhibited seasonal variation, with μPs >1 mm predominating during the dry season, constituting 60-75% of all particles. In terms of quantity, fibers accounted for the majority of microplastics, comprising 55-95% during the dry season and 70-92% during the rainy season. However, when considering particle volume, irregular particles dominated in some samples, accounting for up to 95% of the total amount. The predominant colors of microplastics were white/crystal, black, and blue, with the main compositions identified as polypropylene (PP) and polyethylene terephthalate (PET), suggesting the influence of untreated domestic sewage discharge. Additionally, some additives were detected, including the pigments Fast RED ITR and phthalocyanine blue. The management of reservoir water levels appears to influence the quantity of μPs in the water column. As the water level increases up to 90% of the reservoir capacity during the rainy season, the amount of μPs in the water decreases, despite the higher influx of particles resulting from surface runoff caused by rainy conditions. This suggests a "dilution" effect combined to the polymictic mixing hydrodynamics. Our results may contribute to the creation and improvement of monitoring programs regarding mP pollution and to the adoption of specific public policies, which are still lacking in legislation.
Collapse
Affiliation(s)
- Cristiano Rezende Gerolin
- Laboratory of Integrated Sciences (LabInSciences), Universidade Federal de São Paulo, Diadema, SP, 09972-270, Brazil
| | - Bruno Zornio
- Thermo Fisher Scientific, São Paulo, SP, 05425-000, Brazil
| | | | - Geórgia Labuto
- Laboratory of Integrated Sciences (LabInSciences), Universidade Federal de São Paulo, Diadema, SP, 09972-270, Brazil
- Department of Chemistry, Universidade Federal de São Paulo, Diadema, SP, 09972-270, Brazil
| | - Décio Semensatto
- Laboratory of Integrated Sciences (LabInSciences), Universidade Federal de São Paulo, Diadema, SP, 09972-270, Brazil.
- Department of Environmental Sciences, Universidade Federal de São Paulo, Diadema, SP, 09972-270, Brazil.
| |
Collapse
|
6
|
Li Y, Ke S, Xu D, Zhuo H, Liu X, Gao B. Preferential deposition of buoyant small microplastics in surface sediments of the Three Gorges Reservoir, China: Insights from biomineralization. JOURNAL OF HAZARDOUS MATERIALS 2024; 468:133693. [PMID: 38367432 DOI: 10.1016/j.jhazmat.2024.133693] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/19/2023] [Revised: 01/25/2024] [Accepted: 01/31/2024] [Indexed: 02/19/2024]
Abstract
Sediments act as sinks of microplastics (MPs) derived from terrestrial ecosystems. However, the fate and transport of MPs at the zone of sediment-overlying water in reservoir environment are poorly understood. Here, the MPs distribution patterns in surface sediments of the Three Gorges Reservoir (TGR) and dominant mechanisms responsible for the sinking of MPs at the zone of sediment-overlying water were comprehensively investigated. The predominant occurrence of small microplastics (<300 µm, SMPs) in surface sediments of the TGR was found, with buoyant polyethene (PE) was dominant polymer types. Interestingly, the high abundance of SMPs in sediments correlated well with the Ca2+/Mg2+ in overlying water, suggesting that divalent cations in overlying water may enhance the preferential deposition of SMPs. Simulation sinking experiments under the presence of Microcystis aeruginosa and two divalent cations using different-sized PE MPs demonstrated that the greater deposition of SMPs was mainly the result of the formation of biogenic calcite on the surface of MPs rather than magnesium minerals, which provides stronger ballasting effects for SMPs than for large MPs. This study first highlights that the impact of biomineralization on preferential sinking of SMPs and enhances the understanding of the transport behaviour of MPs in aquatic environment.
Collapse
Affiliation(s)
- Yang Li
- State Key Laboratory of Water Environment Simulation, School of Environment, Beijing Normal University, Beijing 100875, China; State Key Laboratory of Simulation and Regulation of Water Cycle in River Basin, China Institute of Water Resources and Hydropower Research, Beijing 100038, China
| | - Sun Ke
- State Key Laboratory of Water Environment Simulation, School of Environment, Beijing Normal University, Beijing 100875, China
| | - Dongyu Xu
- State Key Laboratory of Simulation and Regulation of Water Cycle in River Basin, China Institute of Water Resources and Hydropower Research, Beijing 100038, China
| | - Haihua Zhuo
- Changjiang Basin Ecology and Environment Monitoring and Scientific Research Center, Changjiang Basin Ecology and Environment Administration, Ministry of Ecology and Environment, Wuhan 430010, China
| | - Xiaobo Liu
- State Key Laboratory of Simulation and Regulation of Water Cycle in River Basin, China Institute of Water Resources and Hydropower Research, Beijing 100038, China
| | - Bo Gao
- State Key Laboratory of Simulation and Regulation of Water Cycle in River Basin, China Institute of Water Resources and Hydropower Research, Beijing 100038, China.
| |
Collapse
|
7
|
Xu L, Bai X, Li K, Zhang G, Zhang M, Hu M, Huang Y. Human Exposure to Ambient Atmospheric Microplastics in a Megacity: Spatiotemporal Variation and Associated Microorganism-Related Health Risk. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2024; 58:3702-3713. [PMID: 38356452 DOI: 10.1021/acs.est.3c09271] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/16/2024]
Abstract
Microplastics are found in various human tissues and are considered harmful, raising concerns about human exposure to microplastics in the environment. Existing research has analyzed indoor and occupational scenarios, but long-term monitoring of ambient atmospheric microplastics (AMPs), especially in highly polluted urban regions, needs to be further investigated. This study estimated human environmental exposure to AMPs by considering inhalation, dust ingestion, and dermal exposure in three urban functional zones within a megacity. The annual exposure quantity was 7.37 × 104 items for children and 1.06 × 105 items for adults, comparable with the human microplastic consumption from food and water. Significant spatiotemporal differences were observed in the characteristics of AMPs that humans were exposed to, with wind speed and rainfall frequency mainly driving these changes. The annual human AMP exposure quantity in urban green land spaces, which were recognized as relatively low polluted zones, was comparable with that in public service zones and residential zones. Notably, significant positive correlations between the AMP characteristics and the pathogenicity of the airborne bacterial community were discovered. AMP size and immune-mediated disease risks brought by atmospheric microbes showed the most significant relationship, where Sphingomonas might act as the potential key mediator.
Collapse
Affiliation(s)
- Libo Xu
- State Key Joint Laboratory of Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, Peking University, Beijing 100871, China
| | - Xinyi Bai
- State Key Joint Laboratory of Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, Peking University, Beijing 100871, China
| | - Kang Li
- State Key Joint Laboratory of Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, Peking University, Beijing 100871, China
| | - Guangbao Zhang
- State Key Joint Laboratory of Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, Peking University, Beijing 100871, China
| | - Mengjun Zhang
- Peking University Shenzhen Institute, Shenzhen, Guangdong 518057, China
- PKU-HKUST Shenzhen-Hongkong Institution, Shenzhen, Guangdong 518057, China
| | - Min Hu
- State Key Joint Laboratory of Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, Peking University, Beijing 100871, China
| | - Yi Huang
- State Key Joint Laboratory of Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, Peking University, Beijing 100871, China
- Peking University Shenzhen Institute, Shenzhen, Guangdong 518057, China
| |
Collapse
|
8
|
Liu F, Rasmussen LA, Klemmensen NDR, Zhao G, Nielsen R, Vianello A, Rist S, Vollertsen J. Shapes of Hyperspectral Imaged Microplastics. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2023; 57:12431-12441. [PMID: 37561646 PMCID: PMC10448723 DOI: 10.1021/acs.est.3c03517] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/10/2023] [Revised: 07/25/2023] [Accepted: 07/26/2023] [Indexed: 08/12/2023]
Abstract
Shape matters for microplastics, but its definition, particularly for hyperspectral imaged microplastics, remains ambiguous and inexplicit, leading to incomparability across data. Hyperspectral imaging is a common approach for quantification, yet no unambiguous microplastic shape classification exists. We conducted an expert-based survey and proposed a set of clear and concise shapes (fiber, rod, ellipse, oval, sphere, quadrilateral, triangle, free-form, and unidentifiable). The categories were validated on images of 11,042 microplastics from four environmental compartments (seven matrices: indoor air; wastewater influent, effluent, and sludge; marine water; stormwater; and stormwater pond sediments), by inviting five experts to score each shape. We found that the proposed shapes were well defined, representative, and distinguishable to the human eye, especially for fiber and sphere. Ellipse, oval, and rod were though less distinguishable but dominated in all water and solid matrices. Indoor air held more unidentifiable, an abstract shape that appeared mostly for particles below 30 μm. This study highlights the need for assessing the recognizability of chosen shape categories prior to reporting data. Shapes with a clear and stringent definition would increase comparability and reproducibility across data and promote harmonization in microplastic research.
Collapse
Affiliation(s)
- Fan Liu
- Department
of the Built Environment, Aalborg University, 9220 Aalborg Ø, Denmark
| | - Lasse A. Rasmussen
- Department
of the Built Environment, Aalborg University, 9220 Aalborg Ø, Denmark
| | | | - Guohan Zhao
- Research
Centre for Built Environment, Energy, Water and Climate, VIA University College, 8700 Horsens, Denmark
| | - Rasmus Nielsen
- Department
of the Built Environment, Aalborg University, 9220 Aalborg Ø, Denmark
| | - Alvise Vianello
- Department
of the Built Environment, Aalborg University, 9220 Aalborg Ø, Denmark
| | - Sinja Rist
- National
Institute of Aquatic Resources, Technical
University of Denmark, 2800 Kongens Lyngby, Denmark
| | - Jes Vollertsen
- Department
of the Built Environment, Aalborg University, 9220 Aalborg Ø, Denmark
| |
Collapse
|