Marine litter pollution on Amazonian beaches: A risk assessment study with focus on non-urban beaches

To better understand the impacts of marine litter, this study focused on the development and application of the Macro-Litter Risk Index-MLRI using two Amazonian beaches, rural and village beaches. This index facilitates comparisons between different beaches, offering a detailed classification of risks and contributing to impact assessment and mitigation through the formulation of appropriate public policies. The MLRI is based on five sub-indices, of which two were adapted for non urban beach settings to ensure its applicability. No weighting was assigned to the sub indices, reinforcing their equal importance in the final result. Each sub-index was rated on a scale from 1 (Very High risk) to 5 (Very Low risk), with the MLRI value calculated as the arithmetic mean of these ratings. On each beach, macro-litter was manually collected in four pre-defined areas, each measuring 400 m². These areas were located within the intertidal zone, with their upper boundary set at the high tide line. The items were quantified and characterized according to marine litter survey and monitoring protocols. According to the MLRI, the rural beach was classified as Low risk (score 4) due to its low level of impact, while the village beach was classified as Moderate risk (score 3), indicating moderate environmental, public health, and economic impacts. The results highlight the vulnerability of each beach according to the sub-indices and emphasize the need for public policy implementation. Overall, this index can be applied to any non-urban beach worldwide, providing valuable insights to support the development of public policies.