Marine Pollution Bulletin 81 (2014) 242–247 Contents lists available at ScienceDirect Marine Pollution Bulletin journal homepage: www.elsevier.com/locate/marpolbul Baseline Influence of proximity to an urban center in the pattern of contamination by marine debris ⇑ A.S. Leite, L.L. Santos, Y. Costa, V. Hatje Instituto de Química, Universidade Federal da Bahia, Bahia 40170-290, Brazil article info abstract Keywords: In order to test the relationship between the occurrence of marine debris and the distance from urban Solid waste areas, nine beaches in the metropolitan area of Salvador, Bahia, Brazil and the adjacent northern coast Contamination were studied. Marine debris were collected, sorted in several categories and weighed. It was observed Salvador that plastics were numerically the most abundant component of the collected debris. As expected, the Regression analyses beaches closest to Salvador presented the largest density of debris, with the exception of the Porto da Bahia Barra beach, which has an efficient public cleaning system and does not have any vegetation, making it difficult to accumulate solid waste. Linear regression analyses showed significant relationships between the distance from the urban center (Salvador) and the number of marine debris per m2, the total number of debris per beach (abundance), and the diversity of debris types (richness). The results showed that proximity to urban regions was a key factor in the marine debris distribution along the coast. Ó 2014 Elsevier Ltd. All rights reserved. Marine debris represent one of the most important environ- trends, marine debris pollution is ubiquitous in the coast of Brazil mental pollutants of the XXIst century and can be considered a seri- (Hatje et al., 2013). The lack of urban planning to support high hu- ous threat to sustainable use of marine and coastal resources (e.g., man density along the coast is primarily responsible for the impro- Goldberg, 1995; Ivar do Sul and Costa, 2007). Among marine deb- per disposal of domestic, industrial and even hospital solid and ris, plastics deserve special attention. The versatility of these mate- liquid waste in these areas (Buenrostro and Bocco, 2003; Sharholy rials has led to a great increase in their use in a wide range of et al., 2007). A review by Ivar do Sul and Costa (2007) showed that products over the past decades, and consequently has led to an in- there are only a small number of studies regarding the problem of crease in plastic marine debris. marine debris in the extensive coast of Bahia (1180 km) (Fig. 1), Along with plastics, the large majority of marine debris found in which represents one of the main leisure and tourism areas of Bra- the environment is composed of nylon, rubber, polystyrene and zil. Salvador, the capital of the State, is the third biggest metropol- foam (Spengler and Costa, 2008). These materials share important itan area in the country, with more than 2.7 million inhabitants. characteristics such as lightweight, durability, and buoyancy, which Several studies showed that the urbanization and the industrial facilitate their transport and dispersion (de Araújo and Costa, 2006; developments in the Salvador metropolitan area, including the larg- Ivar do Sul and Costa, 2007; Ivar do Sul et al., 2011; Moore et al., est petrochemical complex in the Southern hemisphere and two 2011). Numerous studies report the negative impacts caused by important ports, has resulted in the contamination of estuaries, marine debris, among which are deleterious effects on wildlife beaches and the mangroves of the Todos os Santos Bay by metals and habitat quality, the economy, aesthetics and even human and organic contaminants (e.g. Eça et al., 2013; Hatje and Barros, health and safety (e.g. Derraik, 2002; Ivar do Sul and Costa, 2007). 2012; Hatje et al., 2009, 2010). Studies on marine debris, however, More recently Ivar do Sul and Costa (2014) critically analyzed the remain sparse for the coast of Bahia, which makes it difficult to pro- recent literature regarding specifically microplastics contamination vide conclusive arguments for policy and management action. and their effects on the marine biota. Although pollution by marine Santos et al. (2005) realized the first semi-quantitative analyses debris can impact remote areas, there is a high concentration and of marine debris in the non-urbanized northern beaches of Bahia. accumulation of debris in the coastal zones. Following global Later, it was reported that the total number of items presented in developed and undeveloped beaches in this region was not signif- icantly different from each other (Ivar do Sul et al., 2011). Santos ⇑ Corresponding author. Current address: Dept. of Ocean Sciences, University of et al. (2009) examined composition, quantities and distributions California Santa Cruz, Santa Cruz, USA. Tel.: +1 8314594736. of marine debris along 150 km of relatively undeveloped beaches E-mail address: [email protected] (V. Hatje). http://dx.doi.org/10.1016/j.marpolbul.2014.01.032 0025-326X/Ó 2014 Elsevier Ltd. All rights reserved. A.S. Leite et al. / Marine Pollution Bulletin 81 (2014) 242–247 243 Fig. 1. Location of studied beaches in Bahia, northeastern Brazil. PB = Porto da Barra; OND = Ondina; JA = Jardim de Alá; ART = Praia dos Artistas; JAG = Jaguaribe; ALE = Aleluia; GEN = Genipabu; ITA = Itacimirim and PF = Praia do Forte. located South of Bahia. The latter showed that marine debris in this some degree, whereas the beaches localized close to Salvador (Por- area were threefold higher than the amounts observed in relatively to da Barra, Ondina, Jardim de Alá, Praia dos Artistas, Jaguaribe and well preserved beaches located at least 60 km north of Salvador Aleluia) presents retaining walls. (Santos et al., 2005). It was suggested that the main source of deb- Beach selection was performed using satellite imagery to delin- ris was the rivers draining from populous areas and the alongshore eate transects parallel to the coastline with a length of 300 m. This current that flows southward along the coast (Santos et al., 2005). transect was divided in thirty 10 m wide subtransects perpendicular This is the first study that evaluated the marine debris occur- the coast. Sampling was conducted in 3 transects randomly selected rence in the exposed sandy beaches of Salvador. This study aimed for each beach. The sampling dates were chosen to combine the time to test the hypothesis that there is a negative relationship between of the low tide with the time of the highest visitation. Sampling on the distance from the urban center Salvador (i.e. area with high the beaches was limited to the zones stretching from the low tide density of buildings, resident populations and urbanized land- mark to the berm on each beach. Cables and poles were used to de- scapes) with the abundance (absolute number of items on a beach), limit each transect from the low-water line to its upper limit. Sam- richness (number of categories of debris) and mass of marine deb- ples were collected during two weekends, during spring tides. All ris found on beaches. The approach employed here is pioneer, and debris (>1 cm) inside each transect were collected, manually with highlight the importance of this study. the aid of gloves, packed in 50 L plastic bags, labeled and stored. Nine beaches located in Salvador and in the adjacent northern In the laboratory, the material was separated into categories shore (Fig. 1) were chosen to assess whether there is a significant (Table 1). The classified material was counted and weighed and difference in the quantity and type of marine debris. To choose the richness and abundance of items were calculated according the beaches two factors were considered, the degree of visitation to their type. The items in the ‘‘construction materials’’ category, and also the distance from Salvador. The beaches Porto da Barra usually made of heavy items such as cement blocks and wood (closest to downtown), Ondina, Jardim de Alá, Praia dos Artistas, boards, had their weight estimated in the field to the nearest kg. Jaguaribe and Aleluia are located in urbanized areas of Salvador, Items made of more the one type of material (e.g., nylon line with whereas Genipabu, Itacimirim and Praia do Forte are located on hook), were classified as the type with the slowest decomposition the adjacent coast around 60 and 80 km North from downtown. rate (Araújo and Costa, 2004). Vegetation debris (i.e., seeds, roots Beaches in Salvador are intermediate to reflective (de Carvalho, and algae) were not collected or considered marine debris due to 2002), whereas beaches at the northern shore are dissipative, with their natural origin. Concentration of debris was expressed as extensive areas of surfing, flat topography and fine-grained sand number of debris (abundance), number of debris per m2, weight (Ivar do Sul et al., 2011). From all studied beaches, Porto da Barra of items per m2, and richness (number of categories of debris). is the only one protected, once it is located inside Todos os Santos To assess whether the distribution of these variables followed a Bay. The backshore of all studied beaches is occupied at least in significant gradient along the distance from downtown, linear 244 A.S. Leite et al. / Marine Pollution Bulletin 81 (2014) 242–247 Table 1 Classification of marine debris. Category Subcategories Plastic Bucket, shaver, floaters, rubber, toys, DVD’s cover, pens, straws, carpet, cigarettes, dispenser, strings, tapes, bandages, packaging, toothbrush, foams, unidentifiable hard