https://www.selleckchem.com/products/ars-1620.html This study aims to determine the degradation of plastic polypropylene (PP) and identify the presence of microplastic in sediments and seawater along the Tambak Lorok coastal area. The study was conducted by collecting samples from the sea surface area, at 50 cm and 170 cm depths, while seawater and sediments were collected from six stations. The results showed an early stage of degradation because of abiotic factors. The surface morphology of plastic changed, indicating the disorientation of the plastic. Furthermore, the results demonstrated that organic carbon decreased by 3.15%, 6.67%, and 16.76% for the PP applied on surface water, at 50 cm depth and at 170 cm depth, respectively. From six stations, PP microplastic was the dominant type, where microplastic in sediment was bio-fouled fiber ranging in size from 255.23 to 1245.71 μm; however, in seawater, it was 7-111 particles/10 mL and ranged from 270.27 to 1279.12 μm in size. We report the first large-scale investigation of microplastic contamination in beach sediments across Auckland, New Zealand's most populous region. Sediment samples were taken from the high tide and intertidal zones at 39 sites across estuary, harbour and ocean environments of the East and West Coasts. Microplastic contamination was present at the majority of beaches studied with a mean abundance of 459 particles.m-2 ranging from 0 to 2615 particles.m-2. High variability was observed between the sites, indicating the importance of small-scale factors on microplastic contamination. Samples from high and intertidal zones showed no significant difference in microplastic contamination (p = 0.225). The West Coast beaches exhibited higher microplastic contamination compared with East Coast beaches (p = 0.004). Microplastics were predominately fibres (88%), with lower proportions of fragments (8%) and films (4%). The majority of the microplastics analysed were regenerated cellulose (34%), polyethyl