Abstract:
The purpose of this study was to investigate the types and distribution of
microplastics around Map Ta Phut Industrial Estate, Rayong Province. The data was collected in
the period from October 2019 to April 2020 by dividing into 3 times for representing the rainy,
summer, and winter seasons. Blue swimming crab samples were collected within a kilometer
away from the lowest tide and the environmental factors data such as salinity and electricity
conductivity at 3 stations including Nong Fab, Ta Kuan, and Saeng Chan were recorded.
Microplastics were extracted from the stomach and gastrointestinal tract of the
Blue swimming crab using a 30% hydrogen peroxide (H2O2) solution. The obtained contaminants
were then observed under a stereo microscope to analyze and record the microplastics quantity,
shape, color, and size. Moreover, Fourier-transform infrared spectroscopy (FT-IR) analysis was
used to confirm and identify the type of microplastics. From the results of this study, the types
and distribution of microplastics around Map Ta Phut Industrial Estate, Rayong province were
reported. The contaminants in the stomach of Blue swimming crabs were averaged 5.5 ± 2.3
pieces/individual. The average microplastic was 1.1 ± 1.0 pieces/individual or 21.5 percentage of
contaminants was confirmed by FT-IR. The highest abundance of microplastics was found in the
summer as 2.2 ± 3.2 pieces/individual, followed by in the rainy season as 0.8 ± 1.7
pieces/individual, and the lowest in winter as 0.6 ± 1.2 pieces/individual. Four types of
microplastics including PET (56.7%), PP (21.0%), Other (16.9%), and PS (5.5%) were found.
The abundances of microplastics in shape were fiber (90.3%), fragment (5.8%) and sphere
(3.9%). The highest size of microplastics were 501 - 1,000 μm (35.4%), followed by 1- 500 μm
(35.0%), and the lowest size 1,001 -5,000 μm (29.6%). The microplastics were found in a variety
of color with black (33.3%), blue (23.8%), brown (19.0%), red (14.3%), green (4.8%), and white
(4.8%), respectively.