RESUMO
The objective of the present study was to test whether the Atlantic ghost crab Ocypode quadrata is a reliable biomonitor of microplastic (MP) pollution of beach sediments. To test the hypothesis (H1) that the sediment is the main source of MP ingestion, the proportion of MP types (hard plastic, microfibers, pellet, soft plastic, and extruded polystyrene foam) in the gut content was compared with that on the strandline. The types of MPs in the gut content and sediment had similar proportions; black (~49%) and blue (~45%) microfibers were responsible for this similarity (55%), hence confirming H1. However, the second hypothesis (H2) that prevalence of MP in the gut content is related to its density on beach with distinct urbanization degree was not accepted. These results indicate that high trophic plasticity of the ghost crab and, consequently, multiple-sources of contamination may interfere with its use as a biomonitor of MP pollution.
Assuntos
Braquiúros/crescimento & desenvolvimento , Sedimentos Geológicos/análise , Poluentes da Água/análise , Animais , Praias , Braquiúros/efeitos dos fármacos , Braquiúros/metabolismo , Monitoramento Ambiental/métodos , Plásticos/análise , Plásticos/farmacologia , Urbanização , Poluentes da Água/farmacologiaRESUMO
Waters entering the small estuaries of the Brazilian north-east originate from drainage basins that cross semi-arid and tropical rainforest areas at various levels of use and conservation. Such rivers are often under heavy demand for water supply and other services, such as effluent dilution. The present study examines four consecutive years (2006-2009) of water quality-monitoring data divided by season (rainy and dry) just before the Goiana River enters its estuary. The environmental variables are largely controlled by rainfall patterns. The water temperatures are consistently above 25 °C, which impairs dissolved oxygen levels (3.1 to 6.7 mg L-1) and may suggest eutrophication. By contrast, biochemical oxygen demand, percentage O2 saturation and total phosphorous (which are eutrophication indicators) do not show non-compliant levels, according to local legislation. Although the monitoring stations surround a municipal centre, the estuary is downstream from this area, the main uses of which are artisanal fisheries, nature conservation, leisure and aquaculture. Therefore, continuous monitoring and long-term analysis of the resulting water quality are important.
Assuntos
Monitoramento Ambiental/métodos , Estuários , Poluição da Água/estatística & dados numéricos , Brasil , Eutrofização , Oxigênio/análise , Fósforo/análise , Chuva , Rios , Estações do Ano , Temperatura , Poluição da Água/análise , Qualidade da Água , Abastecimento de ÁguaRESUMO
INTRODUCTION: Artisanal fisheries in tropical estuaries are an important economic activity worldwide. However, gear (e.g. ropes, nets, buoys, crates) and vessels are often in use under dangerous conditions. Polyfilament nylon ropes are used until they are well beyond human and environmental safety limits. Severe wear and tear results in the contamination of the environment with micro-fragments. The spread of these fragments in the marine environment and their ingestion by the biota are documented in the scientific literature and are increasing concerns. The aim of this study was to evaluate the ingestion of plastic fragments by two fish (drum) species in relation to seasonal, habitat and fish size-class variation. MATERIALS AND METHODS: The stomach contents of 569 individuals of Stellifer brasiliensis and Stellifer stellifer from the main channel of the Goiana Estuary were examined to identify variation in the number and the weight of plastic fragments and relate this variation to differences among the seasons (early dry, late dry, early rainy and late rainy), the habitats within the estuary (upper, middle and lower) and the size classes of the fish (juveniles, sub-adults and adults). RESULTS: Plastic fragments were found in 7.9% of the individuals of these two drum species captured from December 2005 to August 2008. Nylon fragments occurred in 9.2% of S. stellifer and 6.9% of S. brasiliensis stomachs. The highest number of nylon fragments ingested was observed in adults during the late rainy season in the middle estuary. DISCUSSION: Blue polyfilament nylon ropes are used extensively in fisheries and can be lost, inappropriately discarded or damaged during use in the estuary. These fragments were the only type of plastic detected during this study. The ingestion of nylon fragments by fish probably occurred during the animals' normal feeding activities. During the rainy season, the discharge of freshwater transports nylon fragments to the main channel and makes the fragments more available to fish. Fishery activities are responsible for a significant amount of the marine debris found in the estuary. CONCLUSIONS: The ingestion of fragments of nylon threads by fish is a demonstrated form of pollution in the Goiana Estuary. The physiological and toxicological consequences of the ingestion of this type of debris are unknown, as is the actual extent of the problem worldwide. The solutions to the problem are in the hands of authorities and communities alike because the good care and timely replacement of gear requires education, investment and effective policies.
Assuntos
Monitoramento Ambiental/métodos , Nylons/análise , Perciformes/metabolismo , Estações do Ano , Poluentes Químicos da Água/análise , Animais , Ingestão de Alimentos , Ecossistema , Água Doce , Conteúdo Gastrointestinal/química , Nylons/química , Chuva , América do Sul , Poluentes Químicos da Água/química , Poluição Química da Água/estatística & dados numéricosRESUMO
Beaches are subject to solid waste contamination at the strandline. Litter depositional dynamics is influenced by specific beach morphology and sources of solid wastes. The amount of items on the strandline of Boa Viagem beach (Recife, Brazil) was evaluated during dry and rainy seasons of 2005 to characterize their sources and depositional patterns. The strandline was surveyed once a month to count and classify all visible solid waste items within a belt-transect. Plastics were used for detailed analysis of the wastes accumulated. There were quantitative, but not qualitative, differences in litter accumulation during the year and parts of the beach. The main source of debris was land-based. In general, the beach was low-polluted in the dry season and medium-polluted during the rainy season. The method is a low-cost and highly efficient characterization of solid wastes contamination of urban beaches.
Assuntos
Praias , Poluição Ambiental , Oceano Atlântico , Brasil , Cidades , Meio Ambiente , Estações do Ano , Movimentos da ÁguaRESUMO
The solid waste accumulation patterns on Tamandaré beach, Pernambuco State (Brazil), was assessed from February 2001 to July 2002. This beach is easily accessible, frequently used, and there is a public cleaning service. The beach is under the influence of three small coastal drainage basins. The study visually divided the beach into 15 segments according to the level of solid waste contamination into absent (A), trace (B), unacceptable (C) and objectionable (D). The lowest levels of contamination were found at the middle part of the study area, the most vulnerable in respect to coastal erosion presenting numerous interventions on the beach, absence of native vegetation and lesser width. The highest levels of contamination were at the northern and southern ends of the area, where there are no developments, the beach morphology favours deposition of sediments, there is native vegetation and the beach is wider. The D level did not occur within the area.