Investigating the presence of microplastics in the water and sediment of Qeshm mangrove ecosystem beach (Case study of Tabl mangrove forest)

The increasing production and consumption of plastic in the world has caused environmental problems. Monitoring of microplastics in natural ecosystems is needed. In the intertidal area of Qeshm mangrove forest beach, three sites were selected and water and runoff were sampled in 3 repetitions. The sediments were placed in an oven at 50 C˚ for 72 hours and passed through a 7 mm sieve. Then the sediment and water samples were first mixed with NaCl saturated solution and then with NaI saturated solution. The upper part of the saline solutions was filtered using Whatman filter paper (Cat No. 1442) and the filter paper was placed in an oven at 60 C˚ for 12 hours. Finally, the filters were examined by a stereoscope. Also, the amount of difference between the groups was investigated using variance analysis and F statistics. The highest and lowest number of microplastics in sediments were observed in site 1 with 54.67±19.14 MPs/Kg and in site 3 with 9.67±3.06 MPs/Kg, respectively. Also, the number of microplastics in water was the highest in site 1 with 17.33±6.51 MPs/L, and the lowest in site 3 with 3.33±1.53 MPs/L. A correlation was observed between microplastics in water and sediments (R2=0.96). The similarity based on the presence of microplastics in water and sediment was observed in sites 2 and 3 (ρ=0.95). In general, it can be said that the number of microplastics in water and sediment was higher in areas with more human activity and presence.