Temporal variability of microplastics contaminant ingested by striped barnacles Amphibalanus amphitrite in tidal flat of the Tsurumi River estuary, Tokyo Bay Area, Japan

Abstract

Microplastic pollution is an emergent and serious environmental threat to the aquatic environment, hence, understanding their fate, transportation and concentrations is vital for addressing such threat. The knowledge of bio-contamination of microplastics in continuous time scale within specific location area is limited. Therefore, in this study, we investigated the temporal variability of microplastics contaminant ingested by striped barnacle Amphibalanus amphitrite over a one-year period in the Tsurumi River Tidal Flat within the Tokyo Bay area, Japan. The overall mean MPs concentration in striped barnacles was 14.07 ± 1.44 MPs /wet weight (g⁻¹) or 3.88 ± 0.42 MPs/ individual. The highest concentration was observed in November (26.60 ± 7.07 MPs number/body weight (g⁻¹) or 8.90 ± 2.34 MPs/ individual), whereas, the lowest concentration was observed in July (4.53 ± 1.78 MPs number/body weight (g⁻¹) or 1.50 ± 0.60 MPs/ individual). Statistical analysis detected significant differences in the overall MPs concentration (p = 0.005). The dominant type of MPs was fragment (66 %), followed by fiber (17 %), pellet (12 %) and film (5 %). A total of 23 polymer types were identified with µFT-IR. Polyethylene was the most abundant polymer type with 33 % of the total particles identified, followed Polyamide with 13 %, Melamine Urea-Formaldehyde with 12 %, Phenol Formaldehyde with 10 % and Polyether 7 % respectively. The results obtained in this study confirms the exposure of microplastics contaminant to stripped barnacles in their natural environment and highlights that concentration values fluctuate over time even within a specific area.