Microplastic pollution impact on the Gulf of Thailand: insights from water samples assessment and ingestion by zooplankton as complementary tools

2023 Fiscal Year Annual Research Report

• Project/Area Number: 22K21328
• Research Institution: Kyushu University
• Principal Investigator: ALFONSO MARIA・BELEN 九州大学, 応用力学研究所, 准教授 (70961944)
• Project Period (FY): 2022-08-31 – 2024-03-31
• Keywords: microplastic / plastic pollution / zooplankton / ingestion / marine

Outline of Annual Research Achievements

Throughout the second year of the project, I successfully finalized the sample processing to determine the ingestion of microplastics by zooplankton collected on Si Chang Island in the Gulf of Thailand from August 2022 to April 2023. Sampling was carried out during different seasons, including wet, intermediate, and dry, and at varying tidal intervals (spring and neap tides), with a one to two-week gap between each sampling. I characterized the size, shape, and polymer types of the SMPs ingested. Mps were also characterized in water samples. 750 individuals of the calanoid Centropages furcatus were analyzed, an average ingestion value of 0.41 ± 0.13 particles ind-1. All the particles were fragments, with a predominant size under 50 um, and polymer types as Polypropylene (PP, 71 %), followed by Ethylene-Propylene-Diene-Monomer (EPDM, 16 %) and Polyethylene (PE, 7 %). Up to 470.2 particles m-3 were estimated to be retained by this calanoid species and potentially available for trophic transfer. The effect of rainfall on SMPs ingestion was inconclusive, with a non-significant observed tendency to higher ingestion values near the coastal area than offshore area. The results are under review for the publication journal Science of the Total Environment (top 10%). Two papers were published as a result of this research project Alfonso et al., 2023 and Nakano et al., 2024.

Research Products

• [Int'l Joint Research] Instituto Argentino de Oceanografia/Universidad Nacional del Sur(アルゼンチン)
  • Country Name: ARGENTINA
  • Counterpart Institution: Instituto Argentino de Oceanografia/Universidad Nacional del Sur
• [Int'l Joint Research] Chulalongkorn University(タイ)
  • Country Name: THAILAND
  • Counterpart Institution: Chulalongkorn University
• [Journal Article] Influence of monsoon seasonality and tidal cycle on microplastics presence and distribution in the Upper Gulf of Thailand (2024)
  • Author(s): Nakano, H., Alfonso, M. B., Jandang, S., Phinchan, N., Chavanich, S., Viyakarn, V., & Isobe, A.
  • Journal Title: Science of the Total Environment Volume: 920 Pages: 170787
  • DOI: 10.1016/j.scitotenv.2024.170787
  • Peer Reviewed / Open Access / Int'l Joint Research
• [Journal Article] Zooplankton as a suitable tool for microplastic research (2023)
  • Author(s): Alfonso, M. B., Lindsay, D. J., Arias, A. H., Nakano, H., Jandang, S., & Isobe, A
  • Journal Title: Science of the Total Environment Volume: 905 Pages: p. 167329.
  • DOI: 10.1016/j.scitotenv.2023.167329
  • Peer Reviewed / Open Access / Int'l Joint Research
• [Presentation] Addressing plastic pollution: COPS’ international research activities (2024)
  • Author(s): Haruka Nakano, Maria Bleen Alfonso and Suppakarn Jandang
  • Organizer: KYUDAI NOW Thailand
  • Int'l Joint Research / Invited
• [Presentation] Highlights of Key Activities in the SATREPS Project during FY2023 (2023)
  • Author(s): Maria Belen Alfonso, Haruka Nakano, and Suppakarn Jandang
  • Organizer: meeting with JICA representatives at Thailand
  • Int'l Joint Research / Invited