Marine beach litter monitoring strategies along Mediterranean coasts. A methodological review

Marine litter pollution in a subantarctic beach of the Strait of Magellan, Punta Arenas, Chile

This study assessed the presence of marine litter along the beach of the city of Punta Arenas, Chile. The sampling period coincided with the COVID-19 pandemic. A total of 239 plastic waste items were identified out of a total of 638 litter items. The Clean Coast Index reported within this study ranged from Clean (CCI 2-5) to Extremely dirty (CCI >20), especially near the port. The majority of litter items has been classified as originating from varied origins, as it is not possible to pinpoint a precise origin in most items. The results indicate that the predominant plastic litter in Punta Arenas is PVC. The results are discussed in relation to the sources and composition of the residues, the morpho dynamics of the coast, and the CCI is compared with other locations around the globe.

Marine litter weight estimation from UAV imagery: Three potential methodologies to advance macrolitter reports

In the context of marine litter monitoring, reporting the weight of beached litter can contribute to a better understanding of pollution sources and support clean-up activities. However, the litter scaling task requires considerable effort and specific equipment. This experimental study proposes and evaluates three methods to estimate beached litter weight from aerial images, employing different levels of litter categorization. The most promising approach (accuracy of 80 %) combined the outcomes of manual image screening with a generalized litter mean weight (14 g) derived from studies in the literature. Although the other two methods returned values of the same magnitude as the ground-truth, they were found less feasible for the aim. This study represents the first attempt to assess marine litter weight using remote sensing technology. Considering the exploratory nature of this study, further research is needed to enhance the reliability and robustness of the methods.

Assessment of beach macrolitter using unmanned aerial systems: A study along the Bulgarian Black Sea Coast

Over the years, the Black Sea has been impacted by the issue of marine litter, which poses ecological and health threats. A mid-term monitoring program initiated in 2018 assessed the abundance, density, and composition of beach litter (BL) on 40 frequently visited beaches. From 2018 to 2022, there was a significant increase in average abundance, rising by 261 %. Artificial polymer materials accounted for the majority (84 %) of the litter. Land-based sources dominated 77 % of the litter. The Clean Coast Index (CCI) categorized the beaches as "moderate" with an average value of 8.9 for the period between 2018 and 2022. However, the years 2021 and 2022, during the COVID-19 epidemic, were identified as the "dirtiest period" with 11 beaches classified as "extremely dirty" due to high domestic tourist pressure. The study demonstrates a successful combination of standard in situ visual assessment supported by unmanned aerial systems for beach litter surveys.

Assessing marine macrolitter on the coastline of the Asterousia Biosphere Reserve: Insights from a community-based study

Even in pristine and remote environments of the Mediterranean, marine litter is building up threatening habitats and species and inhibiting sustainable development. The present study reports the findings of beach litter surveys carried out by 250 local community members in nine sites along the coastline of the Asterousia Biosphere Reserve, situated in the southernmost end of Europe. The average recorded litter density along these sites amounted to 125 items per 100 meters of coastline (range: 22-510) and to 0.05 items per square meter of beach (range: 0.01-0.13). Only two of the nine surveyed beaches were found to be in good environmental status, in compliance with the European threshold value for beach litter. The other seven studied beaches surpassed the European threshold value. The primary sources of the litter identified in the study can be attributed to unsustainable practices and inadequate waste management by individuals, communities and municipalities using the coastal and marine environment. Additionally, unsustainable waste management practices within the agricultural sector were also found to be a significant contributor to marine litter pollution.

Fishing for litter for the reduction of marine plastic debris: What benefits and costs do Italians perceive?

As marine plastic litter (MPL) accumulates in the ocean, the need for remediation solutions, such as fishing for litter (FFL) schemes, is very crucial. In order to support the implementation of FFL schemes, the opinion of some Italians were sampled. The present study investigates Italians' opinions about the contribution of FFL in reducing MPL, and the perceived benefits and costs of the scheme. Descriptive statistics, test analyses and a logit regression were carried out. The key findings show a high sensitivity and concern toward MPL, and a good knowledge of FFL experiences. In Italians' opinion, potential FFL costs incurred by fishers should be mainly borne by public institutions. Considering FFL benefits, Italians have no doubts about the effectiveness of fishing for litter in reducing MPL. Female and coastal residence, FFL knowledge and concern about MPL positively affected the perceptions of FFL benefits, while education has a negative effect on the beneficial perceptions of FFL.