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Tuuri EM, Gascooke JR, Leterme SC. Efficacy of chemical digestion methods to reveal undamaged microplastics from planktonic samples. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 947:174279. [PMID: 38942303 DOI: 10.1016/j.scitotenv.2024.174279] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/31/2023] [Revised: 06/22/2024] [Accepted: 06/23/2024] [Indexed: 06/30/2024]
Abstract
Standardisation and validation of methods for microplastics research is essential. A major methodological challenge is the removal of planktonic organisms from marine water samples allowing for the identification of microplastics associated to planktonic communities. To improve the reproducibility and accuracy of digestion methods for the removal of planktonic biomass, we compared and modified existing chemical digestion methods. These digestion methods included an acidic digestion using nitric acid, alkaline digestions with potassium hydroxide (alkaline 1 digestion) and sodium hydroxide from drain cleaner (alkaline 2 digestion), an oxidative digestion using sodium dodecyl sulfate with hydrogen peroxide, and an enzymatic digestion using enzyme drain clean pellets. Chemical digestion of three densities of zooplankton communities (high, medium, and low) in the presence of five commonly found environmental microplastic pollutants (polyamide, polyethylene, polyethylene terephthalate, polypropylene, and polystyrene) were performed for each treatment. The chemical treatments were assessed for (i) their digestion efficiency of zooplankton communities by different biomass densities, and (ii) their impact on microplastic particles through the comparison of both chemical (Raman spectroscopy) and physical (length, width, and visual) changes, between the pre-treatment and post-treatment microplastic particles. The alkaline 1, alkaline 2 and oxidative methods demonstrated significantly better digestion efficiency (p < 0.05) than the modified enzymatic and acidic treatments. The acidic, alkaline 1, and alkaline 2, treatments caused the most damages to the microplastic particles. We suggest future studies to implement the oxidative digestion method with sodium dodecyl sulfate and hydrogen peroxide because of its high digestion efficiency, and low damage to microplastic particles. This method is similar to the wet peroxide oxidation digestion method used throughout the literature but can be implemented at a lower cost.
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Affiliation(s)
- Elise M Tuuri
- College of Science and Engineering, Flinders University, GPO Box 2100, Adelaide, South Australia 5001, Australia; Institute for Nanoscale Science and Technology, Flinders University, GPO Box 2100, Adelaide, South Australia 5001, Australia.
| | - Jason R Gascooke
- College of Science and Engineering, Flinders University, GPO Box 2100, Adelaide, South Australia 5001, Australia; Institute for Nanoscale Science and Technology, Flinders University, GPO Box 2100, Adelaide, South Australia 5001, Australia
| | - Sophie C Leterme
- College of Science and Engineering, Flinders University, GPO Box 2100, Adelaide, South Australia 5001, Australia; Institute for Nanoscale Science and Technology, Flinders University, GPO Box 2100, Adelaide, South Australia 5001, Australia; ARC Training Centre for Biofilm Research and Innovation, Flinders University, Bedford Park, SA 5042, Australia
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de Carvalho AR, Riem-Galliano L, Ter Halle A, Cucherousset J. Interactive effect of urbanization and flood in modulating microplastic pollution in rivers. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2022; 309:119760. [PMID: 35850317 DOI: 10.1016/j.envpol.2022.119760] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/20/2022] [Revised: 06/17/2022] [Accepted: 07/08/2022] [Indexed: 06/15/2023]
Abstract
Freshwater ecosystems play an important role in transporting and accumulating microplastics. Spatial and temporal variability in microplastic pollution can create critical spots and moments of elevated pollution, however, the consequences of their interaction are still poorly understood. This study aimed to assess the interaction between urbanization and flood episodes on river microplastic pollution. The water surface was sampled in two sites of the Garonne River, upstream and downstream a large urban area, during two flood episodes. Samples were chemically digested to facilitate particles isolation, and microplastics (700 μm-5 mm) were characterized through infrared spectroscopy (ATR-FTIR). Microplastic concentration increased by 5-8 fold during flood episodes, driven by river discharge. This increase was more significant in the downstream site. During the flood, there was an overall increase of larger particles on water surface, but only in the downstream site microplastic colours and polymeric compositions significantly varied. Principal component analysis of infrared spectra from polyethylene microplastics revealed that the main variance in the spectral region corresponded to hydroxyl and carbonyl groups. The carbonyl content in microplastics was significantly higher for particles collected during the flood, likely indicating a higher level of degradation. Urbanization modulates freshwater microplastic pollution during floods, and changes in microplastic physicochemical profile should be further integrated within toxicity studies to evaluate risks potentially elevated to animal and human health.
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Affiliation(s)
- Aline Reis de Carvalho
- UMR 5174 EDB (Laboratoire Évolution and Diversité Biologique), CNRS, Université Toulouse III Paul Sabatier, IRD, 118 Route de Narbonne, 31062, Toulouse, France; UMR 5623 IMRCP (Laboratoire des Interactions Moléculaires et Réactivité Chimique et Photochimique), CNRS, Université Toulouse III Paul Sabatier, 118 Route de Narbonne, 31062, Toulouse, France.
| | - Louna Riem-Galliano
- UMR 5174 EDB (Laboratoire Évolution and Diversité Biologique), CNRS, Université Toulouse III Paul Sabatier, IRD, 118 Route de Narbonne, 31062, Toulouse, France
| | - Alexandra Ter Halle
- UMR 5623 IMRCP (Laboratoire des Interactions Moléculaires et Réactivité Chimique et Photochimique), CNRS, Université Toulouse III Paul Sabatier, 118 Route de Narbonne, 31062, Toulouse, France
| | - Julien Cucherousset
- UMR 5174 EDB (Laboratoire Évolution and Diversité Biologique), CNRS, Université Toulouse III Paul Sabatier, IRD, 118 Route de Narbonne, 31062, Toulouse, France
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John J, Nandhini AR, Velayudhaperumal Chellam P, Sillanpää M. Microplastics in mangroves and coral reef ecosystems: a review. ENVIRONMENTAL CHEMISTRY LETTERS 2022; 20:397-416. [PMID: 34642583 PMCID: PMC8495182 DOI: 10.1007/s10311-021-01326-4] [Citation(s) in RCA: 30] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/26/2021] [Accepted: 09/08/2021] [Indexed: 05/13/2023]
Abstract
Microplastic pollution has recently been identified as a major issue for the health of ecosystems. Microplastics have typically sizes of less than 5 mm and occur in various forms, such as pellets, fibres, fragments, films, and granules. Mangroves and coral reefs are sensitive and restricted ecosystems that provide free ecological services such as coastal protection, maintaining natural cycles, hotspots of biodiversity and economically valuable goods. However, urbanization and industrial activities have started contaminating even these preserved ecosystems. Here we review sources, occurrence, and toxicity of microplastics in the trophic levels of mangrove and coral reef ecosystems. We present detection methods, such as microscopic identification and spectroscopy. We discuss mitigating measures that prevent the entry of microplastics into the marine environment.
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Affiliation(s)
- Juliana John
- Department of Civil Engineering, National Institute of Technology, Tiruchchirappalli, India
| | - A R Nandhini
- Environmental Science and Technology, Anna University, Chennai, India
| | | | - Mika Sillanpää
- Chemistry Department, College of Science, King Saud University, Riyadh, 11451 Saudi Arabia
- Faculty of Science and Technology, School of Applied Physics, University Kebangsaan Malaysia, 43600 Bangi, Selangor Malaysia
- International Research Centre of Nanotechnology for Himalayan Sustainability (IRCNHS), Shoolini University, Solan, Himachal Pradesh 173212 India
- School of Chemical and Metallurgical Engineering, University of the Witwatersrand, 2050 Johannesburg, South Africa
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Alfonso MB, Takashima K, Yamaguchi S, Tanaka M, Isobe A. Microplastics on plankton samples: Multiple digestion techniques assessment based on weight, size, and FTIR spectroscopy analyses. MARINE POLLUTION BULLETIN 2021; 173:113027. [PMID: 34627037 DOI: 10.1016/j.marpolbul.2021.113027] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/07/2021] [Revised: 09/29/2021] [Accepted: 09/30/2021] [Indexed: 06/13/2023]
Abstract
Digestion protocols are needed to determine microplastics abundance and features. This study assessed the organic matter (OM) digestion efficiency on plankton samples and the MPs' weight, size, and polymer changes under different digestion techniques. For this, 2-step (KOH and H2O2 + Fe2+) and 3-step (2-step and enzymes) digestion techniques were assessed under different duration and temperature conditions. The results obtained for OM digestion with 2-step and 3-step techniques were satisfactory. Weight changes were registered for polyethylene terephthalate (PET), polystyrene foam, polyvinyl chloride, and polycarbonate with 2-step digestion, but with inconsistent values. Significant size changes were registered only for PET applying 2-step digestion techniques at 60 °C. Using 40 °C for 72 h prevailed all polymers from size changes. Polyethylene weathered MPs were also preserved, including an enzymatic step. Polymer fingerprints were not affected by any digestion technique. Based on these results, any method applying high temperatures will damage MPs.
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Affiliation(s)
- María B Alfonso
- Research Institute for Applied Mechanics, Kyushu University, 6-1 Kasuga-Koen, Kasuga 816-8580, Japan; Instituto Argentino de Oceanografía (IADO-CONICET-UNS), Bahía Blanca, Argentina, Florida 8000, Complejo CCT CONICET Bahía Blanca, Edificio E1, B8000BFW, Bahía Blanca, Argentina.
| | - Kayoko Takashima
- Research Institute for Applied Mechanics, Kyushu University, 6-1 Kasuga-Koen, Kasuga 816-8580, Japan
| | - Sayaka Yamaguchi
- Research Institute for Applied Mechanics, Kyushu University, 6-1 Kasuga-Koen, Kasuga 816-8580, Japan
| | - Mie Tanaka
- Research Institute for Applied Mechanics, Kyushu University, 6-1 Kasuga-Koen, Kasuga 816-8580, Japan
| | - Atsuhiko Isobe
- Research Institute for Applied Mechanics, Kyushu University, 6-1 Kasuga-Koen, Kasuga 816-8580, Japan
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