Characterization and Assessment of Micro and Macroscopic Litter in Sardinian Beaches (Western Mediterranean Sea)

摘要

The presence of beach litter along the coast is due to the indirect input by waves, wind, rivers and currents and to the direct deposition by beach users. This study, conducted in Sardinia (Western Mediterranean Sea), aims to quantify and characterize beach litter all around the island and to suggest the main sources of impact. Five monitoring campaigns (autumn 2013; spring 2014; autumn 2015; spring 2016; autumn 2016) were conducted considering 3 "exposed" and 4 "sheltered" beaches by means of 33.3-m linear transects in which all "macroscopic" items (5 mm) were collected. "Micro" litter (5 mm) sampling was performed in 6 beaches through 10-m linear transects. For both sampling designs, abundance and litter typologies were assessed following the protocols of the Marine Strategy Framework Directive (MSFD) and BASEMAN project. Repeated measures permutational analysis of variance was performed to detect any difference in abundance and composition of marine litter according to season, wind exposure and site. Exposure was the factor that better explains the distribution of litter: higher values were found on the "exposed" (E) sites with respect to the "sheltered" (S) ones, both for macroscopic (E: 1696.56plus/minus219.25 items/100 m; S: 420.5 +/- 74.73 items/100 m) and micro litter (E: 7990.67 +/- 2319.44 items/10 m; S: 111.78 +/- 25.91 items/10 m). All the 8 typologies were recorded, and litter composition significantly varied according to exposure and site over time. This work provides key information about litter presence and sources, useful to suggest possible mitigation measures.