Littering in population centers along the Latin American Pacific coast

Urban areas are major sources of anthropogenic litter, as solid waste (SW) generated by daily activities can reach adjacent ecosystems when inadequately managed. This study evaluates whether SW disposal equipment and pedestrian disposal behavior are associated with macrolitter abundance and composition in public spaces across 20 population centers in seven Latin American Pacific countries. SW receptacle abundance ranged from 1 to 14 units 1000 m^-2; 3.3% were overflowing, 6.7% full, 60.0% half full, and 30.0% empty, suggesting recent maintenance. A total of 35.9% of the waste items held by the surveyed pedestrians were disposed of improperly, either dropped on the ground or left behind at the location. Among waste types, cigarette butts had the highest proportion of improper disposal (90.5%), followed by plastics (11.5%), and paper (11.1%). All evaluated public spaces were contaminated with macrolitter, with abundances ranging from 0.08 (in Antofagasta, Chile) to 0.61 items m^-2 (in Santiago, Panamá). Plastics (37.8%) and cigarette butts (33.9%) dominated macrolitter, followed by paper (15.9%), suggesting a link with improperly discarded waste. Macrolitter abundance showed weak negative and positive relationships with SW receptacle abundance and the proportion of improper disposal, respectively, although neither was statistically significant. Our findings highlight cigarette butt littering and the need for improved disposal equipment and management to prevent urban and nearby ecosystem pollution. This study provides an initial assessment of urban littering in the Latin American Pacific region, offering preliminary insights and a multidisciplinary methodology applicable across diverse contexts, serving as a foundation for future research.