Análise sazonal dos resíduos plásticos em praias urbanas de Fortaleza

The world's coastal beaches are affected by various contaminants, the vast majority being different types of solid waste, with particular emphasis on plastics, which take many years to degrade. Oceanic waste is widely distributed across multiple marine biomes and is commonly found on sandy beaches. Such waste has a severe impact on ocean ecosystems, biodiversity, and the interconnected trophic chains. This study aims to analyze plastic waste collected from two beaches along the coast of Fortaleza during both rainy and dry periods. The objective is to assess the distribution of this waste on these densely frequented beaches using qualitative and quantitative indices. The research methodology involved collecting solid waste from 150-meter-long sections using an adapted version of the OSPAR guideline at two tourist beaches in Fortaleza, Ceará—one collection during the rainy season and another during the dry season. For material analysis, four indices were applied. Three of these—Clean Coast Index, Clean Environment Index, and Plastic Abundance Index—are already used by researchers in environmental studies to assess beach cleanliness. Additionally, a new index is introduced in this study, the Current Environmental Status Index, which aims to classify the environmental state of beach coasts using two distinct weighting factors without requiring repeated collections. By the end of the study, it was observed that the analyzed beaches exhibited apparent similarity in their environmental state during both rainy and dry periods, except for a curious change at Praia do Futuro during the dry season, where hydrodynamic currents emerged as an external influencing factor. Furthermore, a positive correlation was found between the studied indices. The new index proved to be stricter than the others. Future studies should conduct further collections and research using this index to better establish its efficacy and assess its competence in different environments. Additionally, previous studies indicate that researchers working with similar indices on different beaches often use only partially comparable methods, making it challenging to use their data for fully reliable comparisons. Nevertheless, it is believed that these indices can be extremely useful for coastal managers.