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ABSTRACT
Ivar do Sul, J.A. and Costa, M.F. Plastic pollution risks in an estuarine conservation unit. In: Conley, D.C., Masselink, G., Russell, P.E. and O'Hare, T.J. (eds.), Proceedings 12th International Coastal Symposium (Plymouth, England), Journal of Coastal Research, Special Issue No. 65, pp. 48-53, ISSN 0749-0208.
Plastics enter the marine environment mostly from land-based sources, often via estuaries. However, studies related to plastic debris pollution remain rare within these environments. An estuarine beach comprised within a Marine Conservation Unit (MCU) in the Northeast coast of Brazil was studied during one year regarding plastic pollution. Petroleum derived products were >95% of all items, as commonly reported for other coastal and marine habitats. Monthly totals of marine debris presented an average of 10.8±1.63 items.100m^sup -2^, much lower than reported in the literature for other estuarine beaches. Three main sources were identified: fisheries, local users and human settlements along the river basin. The most frequent (56%) size category was 11-100cm^sup 2^, but fragmented items alone were 83% of observed items. The main impact on the estuarine and visiting biota expected is the ingestion of plastic items and fragments, which was corroborated by recent works on estuarine fishes. Interactions with fishing gear are highlighted in the context of this MCU. To protect the traditional livelihoods in the Goiana Estuary, the guarantee of a healthy ecosystem, inclusive free from plastic pollution, must be included in management plans.
ADDITIONAL INDEX WORDS: Environmental monitoring, pollution control, ecosystem management, fisheries, physical fragmentation, ingestion, nylon.
INTRODUCTION
Coastal areas concentrate most of the World's population and, since the first human settlements, estuarine environments have been intensely used to urban, agro-industrial and recreational activities. Consequently, these regions have been heavily impacted (Ridgwaya and Shimmield, 2002), inclusive with the presence of plastic marine debris, especially since the 1930s (Spokas, 2008). The occurrence of different types of marine pollution (i.e. sewage; organic and inorganic compounds in sediments and water) is well documented in heavily occupied estuarine ecosystems (Kennish and Elliot, 2012) but, even there, the behaviour of plastics is poorly known (Thornton and Jackson, 1998; Williams and Simmons, 1997; 1999; Araújo and Costa, 2007; Browne et al., 2010). Once in estuaries, plastics stand a quite high chance of reaching continental platforms and the open ocean. But also...