Microplastic pollution in the surface water and sediments from Kallar Kahar wetland, Pakistan: occurrence, distribution, and characterization by ATR-FTIR

This study reports the distribution of microplastics in surface water and sediments collected from Kallar Kahar wetland, Punjab, Pakistan, which is a game reserve and hosts migratory birds during winter season. Microplastics were extracted using density separation and wet oxidation method. The microplastics identification was done under a stereo-microscope, and their polymer compositions were characterized using an attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopy. The average abundance of microplastics in water and sediment samples was 88 ± 14.5 items/L and 5720 ± 2580 items/kg, respectively. The dominant shape groups of microplastics in water were fiber (58.7%), irregular fragments (32.4%), and beads (8.7%) with dominant colors as transparent > black > yellow ≈ white > red > green > pink > blue. Similar distribution in sediments was found, i.e., fiber (61.2%), irregular fragments (28.4%), and beads (10.3%) with dominant colors as transparent > pink > white > red ≈ black > blue > brown > green ≈ yellow. The ATR-FTIR spectra of visible microplastics were identified to be polypropylene (PP), high density polyethylene (HDPE), ethylene vinyl acetate (EVA), low density polyethylene (LDPE), nitrile, polymethyl methacrylate (PMMA), latex, and polyethylene terephthalate (PETE). In the study area, recreational activities, improper waste disposal, and runoff from catchment areas are the main reasons for the contamination of microplastics in the Lake. The pollution load can be minimized by taking measures such as creating awareness, promotion of ecotourism, and reducing plastic use.