Preliminary assessment of microplastic in rhizosphere and non-rhizosphere region of mangrove at four locations along Karachi coast, Pakistan.

Mangrove ecosystem faces significant threats from the various pollutants including microplastic (MPs). The aim of this study was to assess variations in MP distribution in mangrove sediments of rhizosphere (R) and non-rhizosphere (NR) regions. A total of 14,960 MP particles were identified from Sandspit backwater (SS-1 & SS-2) and Creek areas (PQ & KC). Notably, the NR showed higher MP counts (7848) compared to the R region (7112). Analysis revealed variations in MP types, with beads being predominant in both R and NR, followed by film, fiber, and fragments. KC exhibited highest MP contamination, followed by PQ, SS-2, and SS-1. Fourier-transform infrared (FTIR) analysis confirmed the presence of polyethylene terephthalate and polyethylene in sediments samples. This first detailed report on MP in mangrove sediments and other limited studies from Pakistan establishes the widespread distribution of MPs in the coastal area and provide a baseline for further elaboration in future.