Anthropogenic litter in a Mediterranean coastal wetland: A heterogeneous spatial pattern of historical deposition

Coastal wetlands represent areas that can testify historical accumulation of litter. We analyzed the anthropogenic litter deposited on the channel bottom of a coastal wetland area that experienced water stress due to extreme summer dryness after about 20 years. We hypothesize that the litter accumulated in the different areas over the years reflects the different social user categories (i.e., fishermen, beach users, hunters) and exposure to meteomarine events. Our findings highlight that historically accumulated litter is composed of plastics (78.8 %), clothes (8.9 %), and glass (4.9 %). Moreover, litter concentration averages 53.6 items/ha in the 8 sectors. The most found categories were common household items (25.4 %), diverse (professional and consumer) items (24.2 %), and food and beverages packaging (21.4 %). Finally, litter diversity indices and the Detrended Correspondence Analysis showed sector and litter type similarities. We reported for the first time the presence of litter accumulated for 20 years testifying non-more occurring recreational activities.