Small cetaceans found stranded or accidentally captured in southeastern Brazil: Bioindicators of essential and non-essential trace elements in the environment Leila Soledade Lemos a,b,n , Jailson Fulgencio de Moura a,b , Rachel Ann Hauser-Davis c , Reinaldo Calixto de Campos d,1 , Salvatore Siciliano a a Escola Nacional de Saúde Pública/FICORUZ, Departamento de Endemias Samuel Pessoa—DENSP, Grupo de Estudos de Mamíferos Marinhos da Região dos Lagos, GEMM-Lagos. Rua Leopoldo Bulhões, 1.480, 61 andar, Sala 611, Manguinhos, Rio de Janeiro, RJ 21041-210, Brazil b Programa de Pós-Graduação em Saúde Pública e Meio Ambiente, ENSP/Fiocruz, Rua Leopoldo Bulhões, 1480 Manguinhos, Rio de Janeiro, RJ 21041-210, Brazil c Instituto de Química/UNICAMP, Grupo de espectrometria, Preparo de amostras e Mecanização-GEPAM, C. Postal 6154, 13084-971 Campinas, SP, Brazil d Departamento de Química, Pontifícia Universidade Católica do Rio de Janeiro, Rua Marquês de São Vicente, 225 Gávea, Rio de Janeiro, RJ 22453-900, Brazil article info Article history: Received 27 April 2013 Received in revised form 24 July 2013 Accepted 29 July 2013 Available online 29 August 2013 Keywords: Small cetaceans Marine mammals Trace-elements Rio de Janeiro abstract Essential (Cu, Mn, Se and Zn) and non-essential (Cd and Hg) elements were analyzed in the hepatic tissue of 22 individuals of seven different species of small cetaceans (Feresa attenuata; Orcinus orca; Pontoporia blainvillei; Sotalia guianensis; Stenella frontalis; Steno bredanensis; Tursiops truncatus) accidentally caught in fishing nets or found stranded along the northern coast of the state of Rio de Janeiro, Brazil, between 2001 and 2010. Atlantic spotted dolphin (S. frontalis) showed the highest levels of Cd (20.23 μgg À1 , dry weight), while rough-toothed dolphin (S. bredanensis) showed the highest levels of Hg (825.9 μgg À1 dw) and Se (221.9 μgg À1 dw). Killer whale (O. orca) presented the highest levels of Cu (64.80 μgg À1 dw) and Zn (2220 μgg À1 dw), and Guiana dolphin (S. guianensis), the highest level of Mn (13.05 μgg À1 dw). Cu, Hg, Mn and Zn in the hepatic tissue of killer whale (O. orca), Cu, Hg, Mn, Se and Zn in the hepatic tissue of rough-toothed dolphin (S. bredanensis) and Cd and Zn in the hepatic tissue of Guiana dolphin (S. guianensis) were significantly higher when compared to other studies with these species around the world. No significant correlations were observed between element accumulation and sex, sexual maturity and body length. An analysis of the interelemental relationships in the Guiana dolphin specimens showed strong positive correlations between Cd and Se, Cu and Zn, and Hg and Se. Differences were observed in the bioaccumulation of elements between the analyzed species, probably related to each species feeding habit, and differences between different element concentrations in the different dolphin species were probably due to the preference for certain preys and their bioavailability in the environment. Thus, the bioavailability of the analyzed elements in the marine environment should also be taken in consideration. This study also presents the first data ever reported for pygmy killer whale (F. attenuata) regarding trace element concentrations in hepatic tissue. & 2013 Elsevier Inc. All rights reserved. 1. Introduction Growing human populations, urbanization, rapid economic development and bad planning of coastal areas have placed increasing pressure on marine and coastal ecosystems, causing several environmental impacts, such as the release of alarming levels of trace elements into the environment Some natural sources contribute to the concentrations of these elements in the aquatic environment, but the great majority comes from anthro- pogenic activities that increase their mobilization, circulation and release into the environment (Nriagu and Pacyna, 1988; Caussy et al., 2003; Audry et al., 2004; Eggleton and Thomas, 2004). The northern coast of Rio de Janeiro, located in southeastern of Brazil, is characterized by the presence of different aquatic bodies, such as rivers and lagoons that present important features collaborating to generate inflow of fluvial water, organic matter and significant loads of contaminants to the coast. The main river of the region is the Paraíba do Sul river, that presents several Contents lists available at ScienceDirect journal homepage: www.elsevier.com/locate/ecoenv Ecotoxicology and Environmental Safety 0147-6513/$ - see front matter & 2013 Elsevier Inc. All rights reserved. http://dx.doi.org/10.1016/j.ecoenv.2013.07.025 n Corresponding author at: Grupo de Estudos de Mamíferos Marinhos da Região dos Lagos—GEMM-Lagos, Departamento de Endemias Samuel Pessoa, DENSP, Escola Nacional de Saúde Pública/FICORUZ, Rua Leopoldo Bulhões, 1.480, 61 andar, Sala 611, 21041-210 Manguinhos, Rio de Janeiro, RJ, Brazil. E-mail addresses: leslemos@hotmail.com, leslemos@gmail.com (L.S. Lemos). URL: http://www.gemmlagos.com.br (L.S. Lemos). 1 In memorian. Ecotoxicology and Environmental Safety 97 (2013) 166–175