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- Title
Variação sazonal, espacial e composicional de lixo ao longo das praias da margem oriental da Baía de Guanabara (Rio de Janeiro) no período de 1999-2008.
- Authors
Neto, José Antônio Baptista; da Fonseca, Estefan Monteiro
- Abstract
Guanabara Bay is one of the largest bays on the Brazilian coastline and has an area of approximately 384 km2, including it islands, however, has been identified as one of the main polluted coastal environments on the Brazilian coastline. In the last 100 years the catchment area around Guanabara Bay has been strongly modified by human activities, in particular deforestation and uncontrolled settlement, which increased the amounts of contaminants introduced from sewage effluents, industrial discharge, urban and agricultural runoff, atmospheric fallout, and the combined inputs from the rivers. This study quantifies the distribution and composition of beach debris during surveys of beaches in the eastern margin of Guanabara Bay during the years of 1999-2008, field surveys was carried out using transects, all of the transects with the same measurement (10 X 1 meters), and it were set parallel to the water line and located on top of the high tide mark, in three stations of each beach, the extremities of the beach arc and in the central part of the beach, the surveys was carried out in two distinct seasons of the year, one representing the rainy period (summer) and one in the dry period (winter). Debris was categorized into 13 predetermined types of anthropogenic debris: plastic bag, plastic bottles, glass bottles, metal, paper, fishing material, modified wood, fabrics, footwear, construction material, light bulbs, cans and expanded polystyrene. A total of 21841 items were quantified on the Guanabara Bay beaches during the ten years of surveying, with an annual average of more then 2000 item. Temporal differences in the accumulation of debris were also assessed, a total of 14505 items were quantified in the summer and 7336 items in the winter, reflecting the increase capacity of the rivers in the debris transport during the rainy season (summer). Plastic comprised 70.6% of debris deposited in the Guanabara bay beaches, significantly higher than construction material, which was the second most abundant debris type at 10%, followed by glass (8.1%), expanded polystyrene (7.0%), paper (6.7%), cans (4.8%), modified wood (4.6%), fabrics (3.6%), diverse metals (3.2%), footwear (1.6%), remaining fishing material (1.3%) and light bulbs (1.1%). Comparisons, based on debris counts average across transects and areas, indicated that the Brandoas beach was the most contaminated site, followed by Pedrinhas, Boas Viagem, Luz, Charitas and São Francisco. However, 77% of all the catalogued items were counted in the São Gonçalo Municipality, and the Brandoas beach the most contaminated site, representing 52% of counted items, indicating that this beach was the main site for debris deposition, and it can also be source of debris for the other sites. Differently from others areas of the world where the debris has its origin in activities based in the ocean, such as ships, recreation and fishing. The abundance and distribution of debris through the Guanabara Bay beaches appears to be from local land-based or near shore sources, where the rivers represent the main source of debris, due to the use of the rivers by the municipally inhabitant to discard their garbage. The results gotten in these surveys in relation to the amount and composition of the debris deposited on beaches also reflect the cleanness practice by the municipality. One another factor that has great influence in the composition of the debris, found in beaches, is the buoyancy capacity of the materials, since the heaviest material tends to concentrate and remain closer to the source areas. Anthropogenic debris constitutes a significant threat to the marine environment, represent a hazard not only for the marine animals, but also for human activities, health and tourism.
- Subjects
RIO de Janeiro (Brazil); GUANABARA Bay (Brazil); BRAZIL; COASTAL zone management; ECOSYSTEM management; NATURAL resources management; MARINE debris; COASTS
- Publication
Journal of Integrated Coastal Zone Management / Revista de Gestão Costeira Integrada, 2011, Vol 11, Issue 1, p31
- ISSN
1646-8872
- Publication type
Article
- DOI
10.5894/rgci189