Accumulation of microplastic in the marine environment is of great concern and has been considered to be a growing problem in the coastal sediments of Bangladesh. This research represents the large-scale abundance, characterization of microplastic contamination, and its type of polymer in the beach sediment of Cox’s Bazar. To understand the potential impacts associated with microplastic pollution in Cox’s Bazar coastal area, quantification, identification, and spatial distribution of the types of microplastic and polymer were done from the collected samples of Cox’s Bazar coastal regions. All sediments analyzed through visual and Scanning Electron Microscope (SEM) identification contained microplastic particles (<5 mm). The majority of the detected microplastics were found to be fibrous (< 1 mm), which accounted for more than 70% of the total microplastics. Through the use of Attenuated total reflectance-Fourier transform infrared (ATR-FTIR) spectroscopy, the study identified the type of polymer present. Evaluation of qualitative measurements of various polymer types has been done, including rayon, nylon, polyethylene (PE), polystyrene (PS), polypropylene (PP), polyurethane (PU), alkyd, epoxy, and the polyethylene–polypropylene copolymer (PE + PP). Quantitative analysis performed and illustrated using analytical tools to document the amount of microplastic (particles 100 g⁻¹). Rayon, nylon, and polyethylene are the most abundant polymers throughout the sampled regions whereas polypropylene which were found to be the least abundant. Microplastic concentration is highest in the regions of Laboni point (111) and Kolatoli (97) in the Cox’s Bazar beach. On the contrary, Himchori (6) and Bardeil (5) areas show the lowest abundance of microplastic that can be correlated with the growth of tourism centered urbanization. The findings of this work can help identify potential sources of microplastics that can be utilized to improve the coastal environment and provide valuable clues to coastal zone management in Cox’s Bazar regions.

Dengue fever is a tropical viral disease mostly spread by the Aedes aegypti mosquito across the globe. Each year, millions of people have dengue fever, and many die as a result. Since 2002, the severity of dengue in Bangladesh has increased, and in 2019, it reached its worst level ever. This research used satellite imagery to determine the spatial relationship between urban environmental components (UEC) and dengue incidence in Dhaka in 2019. Land surface temperature (LST), urban heat-island (UHI), land-use–land-cover (LULC), population census, and dengue patient data were evaluated. On the other hand, the temporal association between dengue and 2019 UEC data for Dhaka city, such as precipitation, relative humidity, and temperature, were explored. The calculation indicates that the LST in the research region varies between 21.59 and 33.33 degrees Celsius. Multiple UHIs are present within the city, with LST values ranging from 27 to 32 degrees Celsius. In 2019, these UHIs had a higher incidence of dengue. NDVI values between 0.18 and 1 indicate the presence of vegetation and plants, and the NDWI identifies waterbodies with values between 0 and 1. About 2.51%, 2.66%, 12.81%, and 82% of the city is comprised of water, bare ground, vegetation, and settlement, respectively. The kernel density estimate of dengue data reveals that the majority of dengue cases were concentrated in the city’s north edge, south, north-west, and center. The dengue risk map was created by combining all of these spatial outputs (LST, UHI, LULC, population density, and dengue data) and revealed that UHIs of Dhaka are places with high ground temperature and lesser vegetation, waterbodies, and dense urban characteristics, with the highest incidence of dengue. The average yearly temperature in 2019 was 25.26 degrees Celsius. May was the warmest month, with an average monthly temperature of 28.83 degrees Celsius. The monsoon and post-monsoon seasons (middle of March to middle of September) of 2019 sustained higher ambient temperatures (>26 °C), greater relative humidity (>80%), and at least 150 mm of precipitation. The study reveals that dengue transmits faster under climatological circumstances characterized by higher temperatures, relative humidity, and precipitation.