Spatial and temporal distribution of microplastics in the surface waters of Barranglompo Island, Makassar

Microplastic (MP) pollution is emerging as a potential threat to the marine environment. The distribution of microplastics in marine waters can interact with the abiotic and biotic environment. This study aimed to investigate the spatial and temporal occurrence of microplastics in the waters around Barranglompo Island, Makassar, South Sulawesi, Indonesia. Five sampling points were determined in the inner and outer zones, respectively. Samples were collected three times at 10 day intervals through volume reduced sampling using neuston nets (volume 10L) in each zone (N=30). The seawater was filtered through 47 mm diameter Whatman filter papers (0.45 µm). MP characteristics (colour, shape, and size) were observed visually under a stereomicroscope. MP polymer types were analysed using Fourier-transform infrared spectroscopy (FTIR, N=4). The results showed no significant spatial difference in MP abundance, but a significant temporal difference in both the inner and outer zones with ranges of 3800 – 10040 MP/m3 and 3540 – 11260 MP/m3, respectively. The most common MP colour was blue, the shape was predominantly line, and the most abundant size range was 0.1 – 0.5 mm. Three plastic polymer types were detected: polyester, polypropylene, and rayon. The temporal increase in MP abundance may indicate an increase in improper plastic waste disposal in this area. However, further studies are needed to investigate the vertical distribution of MPs.