Citizen scientists study beach litter along 12,000 km of the East Pacific coast: A baseline for the International Plastic Treaty.

Anthropogenic Marine Litter (AML) accumulating on beaches causes damage to coastal ecosystems and high costs to local communities. Volunteers sampled AML on 130 beaches along the central and southern East Pacific coasts, with AML densities ranging from 0.46 to 2.26 items m-2 in the different countries. AML composition was dominated by plastics and cigarette butts, the latter especially in Mexico and Chile. The accumulation of AML in the upper zones of the beaches and substantial proportions of cigarette butts, glass and metal pointed mainly to local sources. Statistical modelling of litter sources on continental beaches revealed that tourism, access and related infrastructure (e.g. parking lots) best explained AML densities, while plastic densities were also influenced by the distance from river mouths and national Gross Domestic Product. Large-scale monitoring can be a useful tool to evaluate the effectiveness of public policies that should primarily focus on land sources.

Bottle with a message: The role of story writing as an engagement tool to explore children's perceptions of marine plastic litter.

As human behaviors play a crucial role in addressing the global threat of plastic pollution, it is vital to understand perceptions about marine plastic litter (MPL) and to develop interventions encouraging pro-environmental behaviors (PEBs). This study evaluates story writing as a window to explore perceptions and as an engagement activity to boost PEBs. During the COVID-19 lockdowns, schoolchildren from the East Pacific coast participated in this activity, each creating a story and answering a pre-post survey. Qualitative and quantitative analysis of 81 stories and 79 surveys show awareness of sources and impacts. Participants identified land and local pollution as significant contributors to MPL and emphasized bio-ecological impacts, reflecting concern for landscape and wildlife. While the stories presented a diversity of solutions, recycling dominated the surveys. As participants reported an increase in self-assessed knowledge and improved PEBs after this activity, it can be seen as an engagement tool to encourage behavior change.