Microplastics in Sediment of Kuakata Beach, Bangladesh: Occurrence, Spatial Distribution, and Risk Assessment

Abstract

Kuakata beach, known as Daughter of Sea in Bangladesh, has drawn a growing number of tourists from all over the world, leading to the higher use of single plastic products. This study was a first attempt to describe the occurrence, spatial distribution, and ecological risk of microplastics (MPs) in Kuakata beach sediments. A total of 24 surface sediment samples were collected from the intertidal zone of the beach, and MPs were extracted using the density separation method and a stereomicroscope. Fourier transform infrared (FTIR) spectroscopy was used for qualitative and quantitative identification. The results revealed that the average MPs in the beach sediment were 232 ± 52 items kg–1 dry weight, which was much higher than many other sandy beaches throughout the world. Analyses of variance showed a significant (p < 0.01) difference among the mean abundance of MPs in sampling points. Fibers were dominated in every sampling point with an average of 123 ± 27 item kg–1. Most of the MPs observed were colored (60%), and the rest were transparent (40%). It was found that the size range of 1–5 mm MPs constituted over half (55%) of total MPs covering an average value of 127 ± 34 items kg–1. Three polymer types were identified in the sediment samples through FTIR analysis which followed the decreasing order of polyethylene terephthalate > polyethylene > polypropylene. Correlation analysis showed a positive relationship between the abundance of MPs and the finer grain size of sediment (p = 0.055; r = 0.7), indicating grain size-controlled the density of MPs. The pollution load index was assessed to estimate the ecological risk and found that the beach sediment of Kuakata belonged to the risk category I of the pollution index. This investigation provided preliminary information on MPs pollution in the marine ecosystem that the policymakers can use to take appropriate management approaches.

Microplastics in fish culture ponds: abundance, characterization, and contamination risk assessment

“…With certain adjustments, the MP isolation procedure in this investigation was carried out in accordance with the approaches described by Banik et al (2022) and Hossain et al (2021). The water samples were subjected to drying in a hot air oven at a temperature of 90 °C until complete dryness, along with 400 g of wet sediment samples from the bed.…”

“…Using ImageJ software (version 2.0.0) and a high-resolution camera (DP software) mounted to the microscope, measurements of MPs were carried out (Hossain et al, 2021). A hot needle test was also performed for any suspicious plastic particles (Banik et al, 2022). The categorization of MP particles in terms of their types, shapes, colors, and sizes adhered to the existing literature guidelines (Hidalgo-Ruz et al, 2012;Frias and Nash, 2019;Hossain et al, 2021).…”

“…Subsequently, larger-sized MP particles were separated from the filter papers to identify their chemical composition (polymer type). The specific details of the Fourier-transform infrared (FTIR) analysis can be found in Banik et al (2022).…”

“…Approximately 390.7 million tons of plastic products were generated globally in 2021, of which 4.8 and 12.7 million tons were discharged into aquatic environments each year (PEMRG, 2022). Due to the effects of wave-induced mechanical abrasion, photochemical oxidation, and biological processes, larger plastic items undergo fragmentation into smaller microscopic fragments (<5 mm in size), commonly denoted as "microplastics" (MPs) (Cole et al, 2011;Rilling, 2012;Corcoran et al, 2015;Banik et al, 2022). The buoyant nature, durability, widespread presence, resistance to weather, and chemicals are attributes that cause plastics to float at the water surface within aquatic ecosystems, where they tend to persist for extended periods (Geyer et al, 2017).…”

“…Through processes of degradation or fragmentation, secondary MPs are created from bigger plastic debris (Barnes et al, 2009;Andrady, 2011). As MPs are hardly removed from polluted environments, launching a proper and an efficient waste management system to diminish the risk of MP pollution on aquatic ecosystems and human food web (Anderson et al, 2016;Estahbanati and Fahrenfeld, 2016;Banik et al, 2022) is necessary.…”