Fate and behavior of microplastics in biosolids: pollution characteristics and environm ental risks

2022 Fiscal Year Annual Research Report

• Project/Area Number: 22F22054
• Allocation Type: Single-year Grants
• Research Institution: Gifu University
• Principal Investigator: 李 富生 岐阜大学, 流域圏科学研究センター, 教授 (10332686)
• Co-Investigator(Kenkyū-buntansha): BHAT SARTAJ 岐阜大学, 流域圏科学研究センター, 外国人特別研究員
• Project Period (FY): 2022-09-28 – 2025-03-31
• Keywords: Earthworms / microplastics / cow dung / microbes / vermicomposting

Outline of Annual Research Achievements

Vermireactors were used for treating three different concentrations (0.5%, 1% and 2%) of LDPE and PBSA of <2 mm size with the addition of cow dung (CD). The CD supported the growth and hatchlings of earthworms, and the toxicity effect of both LDPE and PBSA microplastics on earthworm Eisenia fetida was analysed. For vermicomposting, the mixtures were kept for thermo stabilization for at least a week. After that, clitellated Eisenia fetida species of earthworms were incubated separately @ 5 worms’ 250 g-1 of the CD for a period of 120 days. Experimental samples of both CD and earthworms were collected at 60 and 120 days of vermicomposting and analyzed for various physico-chemical parameters, like the moisture content measured by drying the samples to a constant weight at 105 °C (24 h) in an oven. The organic matter content was determined by combusting the dried samples in a muffle furnace at 600 °C for 2 h. The pH and electrical conductivity (EC) were also determined by using the aqueous solution of dry sample with deionized water (w/v = 1/10) after shaken for 2 h. Scanning Electron Microscopy (SEM), and Fourier Transform Infrared Spectroscopy (FTIR) analysis were also conducted following standard protocols. The initial results suggested that the LDPE microplastics pose more threat to earthworm Eisenia fetida as compared to the PBSA microplastics.

Current Status of Research Progress

2: Research has progressed on the whole more than it was originally planned.

Reason

We have completed the vermicomposting part of the study for 120 days of treatment period. The study is going according to the plan, and we will further study the samples for their physico-chemical analysis and microbial analysis.

Strategy for Future Research Activity

The next plan for the study will to be conduct the microbial analysis of the samples using 16srDNA by the quantitative PCR method. The physico-chemical analysis for the 120 day of vermicomposting samples will also be conducted. After that all data of vermicomposting, SEM, FT-IR and microbial analysis will be compiled for the writing of the research paper.

Research Products

• [Book] Chapter 14: Removal potential of microplastics in organic solid wastes via biological treatment approaches. In Microbial Biotechnology: Role in Ecological Sustainability and Research (2022)
  • Author(s): Bhat, S. A., Cui, G., Yaseera, N., Lei, X., Ameen, F., & Li, F.
  • Total Pages: 465
  • Publisher: John Wiley & Sons, Inc
  • ISBN: 9781119834458