Characterization of urban park litter pollution.

Abstract

Monitoring campaigns to collect and characterize urban park litter have been carried out in Italy annually from 2018 to 2023. A total of 274 urban parks in 108 cities (with 745 inhabitants to 2.7 million) were monitored. The citizen science approach was applied, and each campaign involved yearly an average of 416 volunteers coordinated by Legambiente. An adaptation of the sampling protocol proposed by the Marine Strategy Framework Directive (MSFD) Technical Group on Marine Litter (2008/56/CE) was applied. In total 161,293 (mean value 26,882.2 ± 4,743.4) items were collected within 42,300 m² (density 3.82 items/m²). Cigarette butts are the most widespread waste: 36.3 % ± 5.5 % and up to 25 butts/m² were found. Significant amounts of metal (16.2 %), glass/ceramics (13.0 %) and paper/cardboard (10.7 %) were found. Despite the COVID emergency having ended in 2021, during the 2022 monitoring campaign face masks only represent 0.2 % of the total waste items. No correlation was found between the amount of waste and the number of inhabitants or the geographical position of the city. The population density was poorly correlated with the quantity of waste collected while a slight correlation was evidenced by the presence of plastic bottles which seem to have decreased in recent years. Using the FTIR Spectroscopy 19 different polymers were identified. The most common were cellulose acetate (cigarette butts) polyethylene and polypropylene. Following the application of recent SUP regulations, polylactic acid and starch blended biopolymers were found (till 0.3 %). Finally, the presence of highly degraded polymers was observed.