Occurrence of microplastics and trace metals in fish and shrimp from Songkhla lake, Thailand during the COVID-19 pandemic

ABSTRACT

The study was carried out in the beginning of May, 2020 during the COVID-19 pandemic lockdown period in Thailand. This study reported on the occurrence of microplastic debris in stomachs of fish (Arius maculatus) and shrimps (Parapenaeopsis hardwickii and Metapenaeus brevicornis) from Songkhla Lake. The average occurrences of microplastic pieces per stomach in fish and shrimps according to 10% digested KOH reagent were 2.73 ± 0.15, 4.11 ± 1.12 and 3.78 ± 1.12, respectively. The most common shape of microplastics in fish and shrimp was fiber. Black was the most frequent color found followed by blue, white and red. Microplastic size found in this study ranged from 150 μm to 5 mm and 70% of microplastic size was less than 1 mm. Five polymer types were reported including polyester, rayon, polyvinyl alcohol, polyethylene and paint. It is worth noting that textile fiber also appeared in stomachs of fish and shrimp. It might have been caused by the fact that during the lockdown period people change their way of life such as doing more laundry thus, releasing more cloth fibers (microplastics) into sewer and lake. This study found anomalous correlation coefficients between the number of microplastic particles in the organisms’ stomachs and most of the metal concentrations in their tissues. © 2021, ALÖKI Kft., Budapest, Hungary.