Study of the litter in the urban environment as primary and secondary microplastics sources

Microplastic is one of the most important environmental challenges of recent decades. Although the abundance of microplastics in water sources and water bodies such as the marine were investigated in many studies, knowing the sources of microplastics requires more studies. In this study, litter was investigated as one of the challenges of urban management and the sources of primary microplastic and secondary microplastic in the urban environment. For this purpose, Clean Environment Index and Cigarette Butt Pollution Index, were used to interpret the density of litter and estimate the abundance of microplastic resources in Khuzestan province, Iran. The results showed that the density of litter in the studied cities was 0.0001-0.6502 items/m². The calculated clean environment index and cigarette butt pollution index were 0.211-35.05 and 0.112-12.897, respectively. The density of primary microplastic and secondary microplastic sources in the studied cities was 47,207-62,767 µg/m² (average = 52782) and 2127-3140 µg/m² (average = 2570), respectively. The abundance of primary microplastic due to littering in the studied cities was estimated at 150 g/year. Reducing the ratio of littering waste in the urban environment and increasing the efficiency of the urban cleaning service is necessary to manage the most dispersed source of microplastics in the urban environment.