Chlorinated pesticides, polychlorinated biphenyls and polycyclic aromatic hydrocarbons in the fat tissue of seabirds from King George Island, Antarctica

Abstract

Persistent organic pollutants (POPs), such as chlorinated pesticides, polychlorinated biphenyls (PCBs) and polycyclic aromatic hydrocarbons (PAHs), have been detected worldwide, including in the Antarctic region. The Antarctic continent can no longer be considered pristine, as there has been a localized but considerable human impact on the region (UNEP, 2002). Local pollution caused by research stations, tourism and long-range transport account for the presence of these compounds in the biota (Risebrough and Carmignani, 1972; Lukowski,1983a,b; Montone et al., 2001b; Corsolini et al., 2002), atmosphere (Bidleman et al., 1993; Montone et al., 2005), water (Gupta et al., 1996; Bicego et al., 1996; Bicego et al., 2002) and sediment (Montone et al., 2001a; Martins et al., 2004; Curtosi et al., 2007) in Antarctica. Several organisms may be used to investigate local pollution. Birds have a number of advantages in this respect. The ecology and behavior of birds are particularly well understood and the background knowledge of their biology enhances their usefulness as biomonitors (Furness and Greenwood, 1993). Antarctica has over 40 species of nesting birds. Many are natives to this remote region of Earth (e.g., Adelie penguin, Antarctic petrel, Snow petrel) and others come to the Antarctic continent and sub Antarctic islands to breed and then migrate to lower latitudes the rest of the year (e.g., Southern fulmar, Cape petrel, South Polar skua). As long-range migratory and top predators, skuas can accumulate high concentrations of anthropogenic contaminants as they forage over large areas. In contrast, penguins show greater fidelity to the Antarctic and sub Antarctic region. This baseline report presents the concentration of selected chlorinated pesticides, polychlorinated biphenyls and polycyclic aromatic hydrocarbons (PAHs) measured in archived fat samples from Brown skuas (Catharacta antarctica, n = 6) and three species of penguins [Adelie (Pygoscelis adeliae; n = 2), Chinstrap (Pygoscelis antarctica; n = 2) and Gentoo (Pygoscelis papua; n = 3)] captured in the vicinity of a Brazilian and a Polish Antarctic Station on King George Island. Opportunistic samples of Antarctic tern (Sterna vittata; n = 2), Snowy sheathbill (Chionis alba; n = 1) and Blue-eyed shag (Phalacrocorax atriceps; n = 1) were also analyzed. Subcutaneous fat samples from these birds were collected near the Comandante Ferraz (62 050S–58 230W; Brazil) andH. Arctowski (62 090S–58 280W; Poland) Antarctic Stations, located in Admiralty Bay during the summer of 1997–1998 (Fig. 1), wrapped in aluminium foil and immediately frozen at 15 C. The analytical procedure followed that described by MacLeod et al. (1985). Briefly, after the addition of anhydrous Na2SO4, approximately 0.5 g of wet tissue was extracted withmethylene chloride using a tissumizer. Prior to extraction, 4,40-dibromooctafluorbiphenyl (DBOFB), 2,20,4,50,6-pentachlorobiphenyl (PCB 103); 2,20,3,30,4, 5,50,6-octachlorobiphenyl (PCB 198); d8-naphthalene, d10-acenaphthene, d10-phenanthrene, d12-chrysene and d12-perylene were added to samples, blanks and reference material (SRM 1945 from the National Institute of Standards and Technology) as surrogates for chlorinated pesticides, PCBs and PAHs, respectively. Extracts were initially cleaned by using partially deactivated silica:alumina column chromatography eluted with a 1:1 mixture of pentane and methylene chloride. The fraction was further purified by high-performance liquid chromatography (HPLC) to remove excess lipids and finally concentrated to a volume of 0.5 mL in hexane. Internal standards (2,4,5,6-tetrachlorometaxylene (TCMX) for chlorinated pesticides and PCBs; and d10-fluorene and d10-benzo[a]pyrene) for PAHs) were added prior to gas chromatographic analysis. Chlorinated pesticides and PCBs were analyzed through gas chromatography using an electron capture detector (ECD). PAHs were quantitatively analyzed through a gas chromatograph coupled to a mass spectrometer (GC–MS) in a selected ion mode (SIM). Table 1 displays mean concentrations (±standard deviation) on a lipid weight (lw) basis for HCHs, HCB, DDTs, chlordanes, dieldrin, mirex, total PCBs and total PAHs in the seabirds studied. Except for HCHs and HCB, the concentrations of most chlorinated pesticides were significantly higher in skuas than in the other species of birds (Fig. 2). In contrast, no significant differences in the concentrations of these compounds were found among the three species of penguins studied (Fig. 3). Lukowski (1983a) found a similar profile of DDTs in adipose tissue of the same three species of penguins collected in the proximity of the Arctowski Station in Admiralty Bay, but at significantly lower concentrations (0.548 ± 0.314, 0.340 ± 0.238, 0364 ± 0.155 ng g 1 w for P. adeliae, P. antarctica and P. papua, respectively). Average concentrations of oxychlordane, dieldrin, mirex and p,p0-DDE in skuas (408 ± 169, 254 ± 158, 2210 ± 1590 and 5840 ± 4020 ng g 1 lw, respectively) were approximately 15, 10, 25 and 30 times higher than in penguins. Lukowski (1983b) also found DDT contents approximately 15 times higher in skua than in penguins. This difference demon-