Marine litter composition and sources on coasts of south-eastern Black Sea: A long-term case study.

Long-term monitoring of marine litter composition and density has been conducted between 2009 and 2018 on eleven beaches of Trabzon city located on the south-eastern Black Sea coast in Turkey. All unnatural litter items were collected from randomly selected transects on the beaches. A total of litter items 4138 in number and 108.75 kg in weight were collected during the study. The highest litter density was 22.00 items/m which is categorized as extremely dirty by Clean-Coast Index. The ANOVA results revealed that there was a significant difference in density between years (p< 0.05). However, no significant difference was found between stations, substratum and whether the station is located on a river mouth (p> 0.05). Plastic (79.69%) was the most commonly found litter followed by metal (7.37%) and glass (5.58%). The main source of the litter items was found to be river transportation (21.96%).