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Fs in Antarctic fur seal pups and penguin eggs
Chemosphere 76 (2009) 264–269
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Contamination profiles of selected PCB congeners, chlorinated pesticides, PCDD/Fs in Antarctic fur seal pups and penguin eggs Alessandra Schiavone *, Simonetta Corsolini, Nicoletta Borghesi, Silvano Focardi Department of Environmental Science ‘‘G. Sarfatti”, University of Siena, via P.A. Mattioli, 4, I-53100 Siena, Italy
a r t i c l e
i n f o
Article history: Received 3 December 2008 Received in revised form 5 February 2009 Accepted 1 March 2009 Available online 16 April 2009 Keywords: PCB PCDD/Fs DDT Antarctic Penguin Seal pup
a b s t r a c t The aim of this study was to investigate levels of some major environmental contaminants, such as polychlorinated biphenyls (PCBs), polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) and organochlorine pesticides in Antarctic samples. Concentrations of some persistent organic pollutants (POPs) were investigated in Antarctic fur seal pups and eggs of three species of penguins. Dichloro-diphenyl-trichloroethane (DDT) was the main pollutant, followed by PCBs; other organochlorine compounds such as hexachlorobenzene (HCB) and PCDD/Fs were usually found only in minor quantities. Adélie penguin eggs had significantly higher mean PCB concentrations (p < 0.05) compared to the other two penguin species, but there was no difference in DDT levels (p > 0.05). TEQ values in fur seal blubber in our study were one order of magnitude lower than those considered to elicit physiological effects in aquatic mammals. In general, POP concentrations in our samples suggested that likely the study populations were not currently at risk for adverse health effects, but indicated a clear need for further monitoring to assess the presence and time trend of a broad range of contaminants, mainly emerging POPs thought to be increasing in polar regions. Ó 2009 Elsevier Ltd. All rights reserved.
1. Introduction Polar regions are reported to be a final sink for contaminants (AMAP, 2000). In fact, global distillation or fractionation by condensation in cold polar environments has been proposed as mechanisms whereby the polar regions may become sinks for persistent organic pollutants (POPs) (Wania and Mackay, 1993). Moreover, the presence of persistent and toxic industrial contaminants in the Antarctic environment is also attributed to local sources, with the activities of scientific stations, in particular concentrated in the Antarctic peninsula, where the samples analyzed in this study come from. Chlorinated pesticides were first discovered in Antarctic wildlife in the 1960s (Sladen et al., 1966). Recent studies continue to demonstrate the presence of organochlorine pesticides in the Antarctic marine food web (Gupta et al., 1996; Weber and Goerke, 1996; Corsolini et al., 2006), despite bans or restrictions on use of many of these compounds. Cold conditions of the Antarctic environment favour persistence of POPs with respect to temperate and tropical environments. The storage of lipids as an energy source makes Antarctic food webs vulnerable to bioaccumulative chemicals, and top predators are the species exposed to greatest risk (Loganathan et al., 1990; Loganathan and Kannan, 1991). In mammals, lipid soluble and persistent POPs are transferred from * Corresponding author. Tel.: +39 3472748692. E-mail address: [email protected] (A. Schiavone). 0045-6535/$ - see front matter Ó 2009 Elsevier Ltd. All rights reserved. doi:10.1016/j.chemosphere.2009.03.007
maternal lipid stores to offspring through lactation (Tanabe et al., 1987). Marine mammals are special from this point of view, because their milk is often very rich in lipids. The lipid content of Antarctic fur seal milk can be up to 39.8% (Goldsworthy and Crowley, 1999). Although there might be some in utero transfer of contaminants from mother to pup in mammals, transfer through lactation is considered as quantitatively far more important (Nakashima et al., 1997). Water bird eggs have proven particularly useful as bioindicators of organochlorines in aquatic environments (Pastor et al., 1995). Further, pollutant concentrations in eggs may help in assessment of hazards faced by embryos during development and their composition directly reflects that of maternal tissues (Drouillard and Norstrom, 2001). Russell et al. (1999) found that the initial in ovo exposure to persistent hydrophobic organic pollutants of the developing embryos in various classes of oviparous organisms is approximately similar to the exposure of the adults who deposit the eggs. The developing embryos of oviparous organisms at the top of the food chain are therefore exposed to the same contaminant levels as the female adults from which they originate. If developing embryos are more susceptible to chemical contaminants than the adult organisms, toxic effects are more likely to occur in developing embryos than in the adult organisms. Limited information is available on POPs levels in Antarctic fur seals (Arctocephalus gazella) and penguins from the Antarctic peninsula. Objectives of this study was to provide contamination profiles of selected PCB congeners, chlorinated pesticides, dioxins and
A. Schiavone et al. / Chemosphere 76 (2009) 264–269
furans in Antarctic fur seal pups and eggs of three species of penguins, Adélie penguin (Pygoscelis adéliae), Chinstrap penguin (Pygoscelis antarcticus) and Gentoo penguin (Pygoscelis papua). The results will help evaluate the status of contamination and toxic potential and possible risks to these organisms.
2. Materials and methods 2.1. Samples Antarctic fur seal (A. gazella) pup tissues were collected between January and February 2004. Samples were collected at Livingston Island, South Shetland, Antarctic Peninsula, (62°390 S, 60°300 W). The pups were found dead and the tissue samples were obtained from the carcasses at the time of necropsy. Sampling location, gender (11 male and 9 female), body weight (3.4 ± 2 Kg) and body length (11.3 ± 26 cm) were recorded. Unhatched eggs of Adélie penguins (P. adéliae, n = 13), Gentoo penguins (P. papua, n = 13) and Chinstrap penguins (P. antarcticus, n = 9) were collected at King George Island, South Shetland, Antarctic Peninsula (62°100 S, 58°670 W), during the 2004/05 field season. All samples were wrapped in polyethylene bags and stored at 20 °C until analysis. 2.2. Chemical analysis Twenty seal liver and twenty muscle samples were analyzed for hexachlorobenzene (HCB), dichloro-diphenyl-trichloroethanes (DDTs: o,p0 -p,p0 -DDE, o,p0 -p,p0 -DDD, o,p0 -p,p0 -DDT), and forty-three PCB congeners. The same samples and more five seal blubber samples, were analyzed for polychlorinated dibenzo-p-dioxins (PCDDs), and polychlorinated dibenzofurans (PCDFs). The assessment of health risks posed by the dioxin, and furan congeners was assessed as Toxicity Equivalents (TEQs) (Van den Berg et al., 2006). Penguin eggs were analyzed for twenty-three PCB congeners, DDTs and HCB. All the samples were analyzed following the methods described elsewhere (Kannan et al., 2001) with some modifications. Approximately 4 g of liver and muscle and 1.5 g of blubber were homogenized with sodium sulphate and spiked with 50 ng of CBs 30 and 209 as internal standards; they were Soxhlet extracted for 16 h with n-hexane and dichloromethane (1:3). The extract was rotary evaporated to 10 mL. Interfering substances were removed by fractionation with multilayer silica gel column, prepared by packing a glass column (20 mm i.d.) with a series of layers of silica gel in the following order: 2 g silica gel, 2–6 g 40% acidic-silica gel, 2 g silica gel and a thin layer of sodium sulphate at the top. The column was cleaned with 150 mL of hexane (discarded fraction), prior to transfer of sample extracts. Samples were then eluted with 200 mL of hexane and rotary evaporated to 1 mL for HR-GC analysis. Subsequently the eluted fractions were passed through a glass column (10 mm i.d.) packed with 1 g of silica gel impregnated carbon (Wako Pure Chemical Industries, Tokyo, Japan) for separation of sixteen 2,3,7,8-substituted PCDD/F congeners. The first fraction, which was eluted with 150 mL of hexane, contained major PCB congeners which interfere with analysis of PCDD/Fs. The second fraction, eluted with 200 mL of toluene, contained PCDDs and PCDFs. Blank samples, prepared by the procedure used for the samples, was included every ten samples and when needed, results were blank corrected. Recovery rates for PCB congeners ranged from 86% to 97% and for PCDDs and PCDFs ranged from 65% to 94%. PCB congeners, HCB and DDTs were identified and quantified by a gas chromatograph (Perkin–Elmer mod. Autosystem) equipped with 63Ni electron capture detector (HRGC–ECD). Concentrations were calculated from the peak area of the sample to that of the cor-
265
responding external standard. Aroclor 1260 and 1254 (AccuStandard Inc., Niederbipp, Europe) and a mixture of organochlorine pesticides (Dr. Ehrenstorfer GmbH., Augsburg, Germany) of known compound composition were used in the identification of chemicals. PCB congeners are presented by their IUPAC numbers throughout the manuscript. The concentrations of individually resolved peaks were summed to obtain total PCB concentrations on a wet weight basis (ww). DDTs refers to the sum of o,p0 - p,p0 -DDE, o,p0 -p,p0 -DDT and o,p0 -p,p0 -DDD. The methodological limit of detection (LOD) of individual PCB congeners and organochlorine pesticides was determined to be 0.01 ng/g ww. Determinations of PCDD/Fs by isotope dilution were performed by a Trace gas chromatograph equipped with an AS 2000 autosampler (ThermoFinnigan) and fitted with a Rtx-5MS capillary column (30 m 0.25 mm i.d., 0.25 lm) from Restek (Bellefonte, PA, USA). The samples were analyzed with a GCQ plus ion trap mass spectrometer (MS) from Thermo Finnigan in selected ion monitoring mode (SIM). A Cambridge Isotope Laboratory (Andover, MA, USA) certified stock solution containing 2 tetra- and hexa-PCDD (13C12, 99%) in nonane was used as an internal standard. LODs of individual PCDDs and PCDFs, calculated as mean blank + 3SD, were 0.1– 0.15 pg/g. Statistical analyses were performed with STATISTICA 7 for Windows (Ver 7.1; Statsoft, Italia srl) at a significance level of p = 0.05. Statistically significant differences between the mean concentrations of contaminants were investigated by single factor one-way analysis of variance (ANOVA). Data were log-transformed for achieving normal distribution before running ANOVAs. Posthoc Tukey compromise tests were used to determine statistical differences among species and tissues. Correlation are expressed using the Pearson correlation coefficient r.
3. Results and discussion 3.1. Levels of PCBs and chlorinated pesticides in seal tissues PCB fingerprints (Fig. 1a) showed a notable presence of low chlorinated PCBs. The most abundant PCB congeners were IUPAC numbers 183 > 134 > 146 > 153 > 138 in muscle and 183 > 134 > 153 > 138 > 118 in liver samples. These congeners, which accounted for the majority of total PCB concentrations, are normally found as the dominant PCB congeners in marine mammals (Kannan et al., 1993; Fillmann et al., 2007; Ylitalo et al., 2008). The presence of some high chlorinated congeners (the most persistent and widespread type) may also be associated with local sources (waste burning and dumping sites) (Montone et al., 2003). The mean PCB and DDT concentrations in liver did not show statistical difference from those in muscle (p > 0.05). 1,1-Dichloro-2,2bis (p-chlorophenyl)-ethylene (p,p0 -DDE), which is the major breakdown/metabolic product of DDT, accounted for 64% and 59% of total DDT concentrations in liver and muscle respectively. p,p0 -DDE values were one order of magnitude higher than those reported by Miranda-Filho et al. (2007) in blubber of southern elephant seal pups, but of the same order as those reported for adult southern elephant seals. Since the present samples were from seal pups, higher pesticide concentrations in adult southern fur seals may be presumed. p,p0 -DDE seems to be easily transferred through the placenta than the various DDT forms (Borrell et al., 1995), which may explain our finding of high concentrations of p,p0 -DDE also in stillborn seal pups. HCB concentrations were one or two orders of magnitude lower P than those of PCBs and DDT, both in seal pups and penguin eggs (Table 1). HCB accounted for 1% of the total POP residues. The concentrations of HCB observed in fur seals in this study were similar to those detected in other Antarctic pinnipeds (Vetter et al., 2001; Miranda-Filho et al., 2007).
A. Schiavone et al. / Chemosphere 76 (2009) 264–269
b
Blubber
Liver
206
205
194
207
195
189
201
196
170
199
180
172
177
156+202+171
174
185
128
183
Muscle
178
138
137
176
141
105
153
146
134
118+149
151
144+135
99
110
101
95
60+56
70+76
%
16 14 12 10 8 6 4 2 0
158
Liver
a 18
187
266
M uscle
60 50 40
%
30 20 10 1234678 9-OCDF
1234678HpCDF
123789HxCDF
234678HxCDF
123678HxCDF
123478HxCDF
23478PeCDF
12378PeCDF
2378TCDF
1234678 9-OCDD
1234678HpCDD
123789HxCDD
123678HxCDD
123478HxCDD
12378PeCDD
2378TCDD
0
Fig. 1. Percentage contribution of each congener to the total PCB residue (a) and PCDDs and PCDFs (b) in different tissues of seal pups.
Contaminant toxicity and risk in pinnipeds are little understood. Kannan et al. (2000) recommended a safe upper PCB threshold concentration of 8700 ng/g lw for marine mammals’ blood or liver and a threshold of 17 000 ng/g lw for PCBs in the blubber due to adverse effects on immune function, based on several studies that measured a range of toxicological endpoints (e.g. natural killer cell activity, thyroid hormone concentrations) and levels of PCBs. PCB burdens in the pups in this study were found to be much lower. These observations suggest that the population is not currently at risk for adverse health effects due to PCBs, but there is a clear need for further monitoring and research to assess the average levels and the future trend of a broad range of organochlorines (OCs) and other halogenated compounds in Antarctic seals. Moreover, these contaminant threshold values were derived for species other than Antarctic fur seals, and fur seals may be more or less sensitive to the effects of these compounds. 3.2. Levels of PCDDs and PCDFs in seal tissues Several PCDDs and PCDFs were not detected in the tissues of fur seal pups at a detection limit of 0.1–0.15 pg/g ww. Residue concentrations of planar halogenated aromatic hydrocarbons occurred in the order PCDFs > PCDDs in all seal pup tissues (Table 1). A similar pattern was found by Senthil Kumar et al. (2002) in Weddell seal
liver, fish, Adélie penguin and skua egg samples from Terra Nova Bay, by Corsolini et al. (2002) in Weddell seal blubber and skua liver from the Ross Sea; and by Jimènez et al. (1999) in the subcutaneous fat of sea lions from Punta Bermeja (Argentina). On the other hand, samples from the northern hemisphere have generally shown a different trend, with PCDDs > PCDFs (Addison et al., 2005; Kajiwara et al., 2008). This suggests that the two hemispheres are affected by different sources of contamination. The frequency of occurrence of PCDD and PCDF residues was too sporadic in samples to show any clear statistical correlation between the tissues. Our results were one to three orders of magnitude greater than those found in previous studies on Antarctic seals (Table 2). Relatively higher values obtained in this study may also be due to local sources. Livingston Island, where our seal samples were collected, is the second largest island of the South Shetlands, and hosts three permanent scientific bases, while there are nine research stations on nearby King George Island. Research bases in Antarctica may contribute to PCDD/F contamination through incineration activities (Miller et al., 1999), although atmospheric transport from other continents is recognized as a major pathway for their dispersal and is thought to be the primary source (UNEP, 2003). 2,3,4,7,8-PeCDF and 1,2,3,7,8-PeCDD were the congeners exhibiting the highest levels both in the tissues of fur seal pups (Fig. 1b).
Table 1 Mean (± standard deviation) organochlorine concentrations (ng/g wet weight) and PCDD/Fs (pg/g wet weight) in the tissues of Antarctic fur seal pups collected from Livingstone Island (Antarctic Peninsula) and in the eggs of Pygoscelis penguins collected from King George Island (Antarctic Peninsula). Tissues
n
RPCBs
RDDTse (p,p0 -DDE)
HCB
RPCDD (TEQ PCDD)
RPCDF (TEQ PCDF)
PCDD/Fs (TEQ)
Antarctic Fur seal blubber Antarctic Fur seal liver Antarctic Fur seal muscle Adélie penguin egg Chinstrap penguin egg Gentoo penguin egg
5 20 20 9 9 9
na 59 ± 43d 33 ± 22d 12 ± 4c 6 ± 4c 5 ± 3c
na 191 ± 106 (123 ± 52) 103 ± 55 (60 ± 26) 23 ± 10 (18 ± 10) 17a ± 15 (15 ± 12.2) 15b ± 9 (12.5 ± 10.4)
na 2.2 ± 0.88 1.37 ± 0.69 7.63 ± 1.8 3.8 ± 3.7 3.7 ± 3.5
54 ± 55.6 (17) 10.6 ± 17.6 (4.2) 3.5 ± 8.8 (0.4) na na na
96.4 ± 114.7 (13.3) 153.7 ± 211 (22.6) 85 ± 76.6 (8.2) na na na
150 (30.6) 164 (26.8) 88.5 (8.6) na na na
na: not analyzed. a n = 7. b n = 6. c Sum of 23 congeners (Aroclor 1254). d Sum of 44 congeners (Aroclor 1260). e RDDTs: sum of o,p0 -p,p0 -DDE, o,p0 -p,p0 -DDT and o,p0 -p,p0 -DDD.
267
A. Schiavone et al. / Chemosphere 76 (2009) 264–269 Table 2 Planar halogenated aromatic hydrocarbons, PCDD/Fs, (pg/g lw; ng/g ww) in tissues of Pinnipeds from Antarctica. Tissue
Date of collection
Species
Age/Sex class
n
Location
PCDDs
Blubber
1986
Lobodon carcinophagus (Crabeater seal) Arctocephalus gazella (Antarctic fur seal) Leptonychotes weddelli (Weddell seal) Arctocephalus gazella (Antarctic fur seal)
m+f
17
Antarctic Ocean
nd
f
11
Adult
1
Pup m + f
5
Bird Island (South Gorgia) Terra Nova Bay (Ross sea) Livingston Island
f
1
Pup m + f
19
Adult
1
Pup m + f
20
lw
96.4
30.6
This study
0.65
Terra Nova Bay (Ross sea)
31
12
18
Corsolini et al. (2002)
Livingston Island
3.5
8.5
8.6
This study
0.11
3.8
0.12
23
due to the different lactation period between age groups. The frequency of occurrence of PCDD residues was too sporadic in the samples for a correct correlation analysis and scatterplots showed a negative linear regression in muscle samples and no significant correlation (p > 0.05) in liver samples. Iwata et al. (2004) found an increasing trend of PCDD/Fs with age in the liver of male Baikal seals. Moreover, in our samples the PeCDF congeners showed a significant increase with age (p < 0.05) in liver and muscle, indicating lower metabolic capability for this compound, as also found by Iwata et al. (2004) in Baikal seals. In the case of highly chlorinated congeners, no increasing trend was observed in either type of fur seal tissue. Interestingly, Iwata et al. (2004) reported a declining tendency with age of some PCDD/F congeners in the liver of adult female seals, suggesting the maternal transfer of PCDD/Fs to pups through lactation. This author also found a significant regression with negative slope values for a limited number of congeners, including 2,3,4,7,8-PeCDF, which showed a significant increase with age in the liver of our seal pup samples. 3.4. Levels of PCBs and chlorinated pesticides in penguin eggs
Chinstrap
Gentoo
138
Adélie penguin eggs had significantly higher mean PCB concentrations (p < 0.05) than eggs of other two penguin species, but there was no difference in DDT levels (p > 0.05). No statistically different (p > 0.05) concentrations were found between Gentoo and Chinstrap eggs for any compounds. Chinstrap and Gentoo penguin eggs showed the same PCBs patterns (Fig. 2), with hexachlorobiphenyls as the major homologues, followed by hepta- > penta> tetra-CBs, while Adélie penguin eggs showed different patterns, with pentachlorobiphenyls as the major homologues, followed by hepta- > tri- > hexa-CBs. The differences observed between Adélie penguins and the other Pygoscelis penguins, which inhabit the same area, may be related to diet, reproductive status, ecological niches, and migration.
118
123
105
114
101
66
44
52
53.6
26.8
Adèlie
28
Corsolini et al. (2002)
153.7
No difference was found in OC and PCDD/F concentrations between male and female seal pups (p > 0.05), probably due to their immature state, while levels of PCBs, DDTs and PCDFs in both liver and muscle increased significantly with the age of pups (p < 0.05). In contrast, HCB did not differ between age groups (p > 0.05). The same results were found in a study of exposure to organohalogens during the lactation period in harbor seal pups (Neale et al., 2005). In the initial stage of a seal’s life the higher levels detected are only
18
17
10.6
3.3. Correlations between different seal groups
8
17
Senthil Kumar et al. (2002) This study
The main sources of 2,3,4,7,8-PeCDF in the environment are technical PCB mixtures and combustion processes (Rappe et al., 1989). Significant concentrations of 1,2,3,7,8-PeCDD have been attributed to chlorophenol related sources from waste incineration (Senthil Kumar et al., 2002). Moreover, our samples came from seal pups and limited pharmacokinetic information is available on transfer of dioxin and furan congeners other than TCDD to fetus, placenta, and pups. The TEQ concentrations (Table 1) were in the following decreasing order: blubber > liver > muscle. TEQ values in fur seal blubber in our study were one order of magnitude lower than those considered to elicit immune dysfunction in adult harbor seals (209 pg TEQ/g lw) (Iwata et al., 2004). The threshold concentration for TEQs to elicit physiological effects in the liver of aquatic mammals has been estimated to range from 160 to 1400 (mean: 520) pg/g lw (Kannan et al., 2000). Our values were one order of magnitude lower. This estimate does not include the safety factors that are generally applied for inter-specific comparison, and it should be borne in mind that our values came from seal pups, and higher TEQ values are expected for adult Antarctic fur seals. In fact, it has been estimated that mean total PCDD concentrations in pup blubber samples are usually about 60% of those of their mothers (Addison et al., 1999).
16 14 12 10 % 8 6 4 2 0
3.7
Fig. 2. Percentage contribution of each congener to the total PCB residue in the three species of penguin eggs.
206
Arctocephalus gazella (Antarctic fur seal)
Oehme et al. (1995)
195
2004
2
189
Muscle
Bignert et al. (1989)
7
170
1996
5.1
ww
15.7
180
2004
Terra Nova Bay (Ross sea) Livingston Island
lw
References
1–3
157
Leptonychotes weddelli (Weddell seal) Arctocephalus gazella (Antarctic fur seal) Leptonychotes weddelli (Weddell seal)
ww
3.7–6.1
156
1995–1996
TEQs
lw
167
Liver
ww
128
2004
187
1996
153
1987
PCDFs
268
A. Schiavone et al. / Chemosphere 76 (2009) 264–269
Table 3 Organochlorine concentrations (ng/g lw; ng/g ww) in eggs of Penguins from Antarctica. Matrix Date of collection
Species
Egg
Pygoscelis Pygoscelis Pygoscelis Pygoscelis Pygoscelis Pygoscelis Pygoscelis Pygoscelis Pygoscelis
1995 1981 1978 2004
1988-1990 1995/6 1981 1983 1978
a
adéliae (Adélie penguin) adéliae (Adélie penguin) adéliae (Adélie penguin) papua (Gentoo penguin) adéliae (Adélie penguin) antarctica (Chinstrap penguin) papua (Gentoo penguin) adéliae (Adélie penguin) adéliae (Adélie penguin)
Pygoscelis adéliae (Adélie penguin) Aptenodytes forsteri (Emperor penguin) Pygoscelis papua (Gentoo penguin) Eudyptes chrysocome (Rockhopper penguin) Eudyptes schlegeli (Royal penguin)
n
Location
5 1
Terranova Bay (Ross sea) Syowa Station Falkland Island
9 9 9 27 6
King Gorge Island (South Shetland)
PCBs
DDTs
HCB
lw ww
lw ww
lw ww
20 Prydz Bay 11 5 Macquarie Island 6
<100 <100 <100 <100
<0.1a 98.2a 197.5a 130a 23 17 15 (7.1) 6.3a 23 (20.7a) 5a 10a 40a 20a
10
<100
40a
Cape Bird (Ross Island) Edmonson Point (Ross sea)
2.8 19.6 110 <10 12 6 5 8.8
References
<0.1 Corsolini et al. (2002) Tanabe et al. (1986) nd Ballschmiter et al. 30 (1981) 7.63 This study 3.8 3.7 5.6 Court et al. (1997) 18.7 Corsolini et al. (2006)
10
10 20 10 20
Luke et al. (1989)
Only p,p0 -DDE.
Comparing our results to previous works on egg samples, a clear tendency of increasing levels of PCBs in Antarctic penguin eggs was lacking (Table 3). Total DDTs and p,p0 -DDE values were higher than those reported in previous works in Adèlie eggs (Luke et al., 1989; Court et al., 1997) while they were similar to those reported by Corsolini et al. (2006) in Adélie eggs from the Wood Bay area (Ross Sea). A same increasing trend was reported by Weber and Goerke (2003), who investigated p,p0 -DDE concentrations in Antarctic fish species and found a significant increase in p,p0 -DDE between 1987 and 1996. p,p0 -DDE is the most persistent metabolite of p,p0 -DDT, which has been used extensively in the southern hemisphere (Connell et al., 1999) and is still employed in significant amounts for vector control against malaria in the lower latitudes. It is known that the avian egg has proved to be an advantageous tool for monitoring contaminant exposure in a multitude of species as its composition directly reflects that of maternal tissues (Drouillard and Norstrom, 2001; Verreault et al., 2006). The are many risks associated with an increased pollutant burden in birds – even subtle changes in behaviour have been seen and associated with pollution. As far as we know, only one recent study has been carried P out on Antarctic birds (Bustnes et al., 2007). HCB and PCB concentrations found in penguin eggs in this study were similar to those found by Bustnes et al. (2007) in blood of female south polar skuas during breeding (6.17 ng/g ww for HCB, and 6.94 ng/g ww P for PCB), while p,p0 -DDE concentrations were one order of magnitude higher in penguin eggs than in skua blood (4.87 ng/g ww in female blood). Bustnes et al. (2007) found associations between these OC concentrations and fitness components in skuas for the first time. The timing of reproduction and the hatching mass of chicks were both adversely related to the mothers’ blood residues of OCs. Bustnes et al. (2007) concluded that such changes may affect the population parameters in long-lived birds. In our three penguin species, pollutant burdens in reproductive specimens were greater than those found in the skua population. Moreover, the three penguin species share the same environment and have adopted a fine ecological segregation to reduce niche overlap and competition. For this reason penguins may be more sensitive to the adverse effects of OCs. In fact, while all the Pygoscelis species are very synchronous in nesting, the breeding cycles of the three species are quite asynchronous (Trivelpiece et al., 1987). Chicks hatched at approximately 2 week intervals, with Adélie p. being the earliest and Chinstrap p. the latest to hatch annually. Asynchronous breeding cycles greatly reduce competition for food between Adélie penguins and their congeners during chick rearing, so, a
subtle change in the timing of reproduction can also noticeably affect reproduction success. 4. Conclusions Our data contribute to the limited literature on concentrations of persistent organic contaminants in marine mammals and birds from the Antarctic region. DDE is the main pollutant, followed by PCBs; other organochlorine compounds such as HCB and PCDD/Fs are usually found only in minor quantities. Seal liver did not show a significantly different degree of contamination from muscle. The eggs study indicated that Adélie penguins were more susceptible to accumulation of contaminants from their environment than Gentoo and Chinstrap penguins. The concentrations of organochlorines in penguin eggs and seal tissues reported here may be toxicologically insignificant, but more studies are needed to assess the real health risks associated with these levels of pollutants. Seals and penguins are particularly sensitive to contaminants, since the natural stress on wildlife in extreme environments, such as the Antarctic, is often more severe than in temperate regions, rendering such species more vulnerable to the effects of pollutants. Acknowledgments This research was funded by the Italian National Program of Research in Antarctica (PNRA). The National Science Foundation supported S. Corsolini’s stay and travel to and from King George Is. We are very grateful to Daniel Torres and Daniel Torres jr (Instituto Antarctico Chileno, Santiago, Chile) for collecting the fur seal samples during the 2003/04 expedition, and to Wayne Trivelpiece, and Susan Trivelpiece for collecting the penguin egg samples. We thank Roger Hewitt, Agunsa (Punta Arenas, Chile) and Raytheon (USA) for their friendly logistic support. References Addison, R.F., Ikonomou, M.G., Stobo, W.T., 1999. Polychlorinated dibenzo-p-dioxins and non-ortho- and mono-ortho-chlorine substituted polychlorinated biphenyls in grey seals (Halichoerus grypus) from Sable Island, Nova Scotia, in 1995. Mar. Environ. Res. 47, 225–240. Addison, R.F., Ikonomou, M.G., Fernandez, M.P., Smith, T.G., 2005. PCDD/F and PCB concentrations in Artic ringed seals (Phoca hispida) have not change between 1981 and 2000. Sci. Total Environ., 301–311. AMAP Workshop on Persistent Organic Pollutants (POPs) in the Arctic: Human Health and Environmental Concerns, Artic Monitoring and Assessment Programme Report 2000, 1,
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Miller, H.C., Mills, G.N., Bembo, D.G., Macdonald, J.A., Evans, C.W., 1999. Induction of cytochrome P4501A (CYP1A) in Trematomus bernacchii as an indicator of environmental pollution in Antarctica: assessment by quantitative RT-PCR. Aquat. Toxicol. 44, 183–193. Miranda-Filho, K.C., Metcalfe, T.L., Metcalfe, C.D., Robaldo, R.B., Muelbert, M.M.C., Colares, E.P., Martinez, P.E., Bianchini, A., 2007. Residues of persistent organochlorine contaminants in Southern Elephant seals (Mirounga leonina) from Elephant Island, Antarctica. Environ. Sci. Technol. 41, 3829–3835. Montone, R.C., Taniguchi, S., Weber, R.R., 2003. PCBs in the atmosphere of King Gorge Island, Antarctica. Sci. Total Environ. 308, 167–173. Neale, J.C.C., Schmelzer, K.R., Gulland, F.M.D., Berg, E.A., Tjeerdema, R.S., 2005. Organohalogen levels in harbor seal (Phoca vitulina) pups increase with duration of nursing. J. Toxicol. Environ. Health Part A 68 (9), 687–691. Nakashima, Y., Ohsawa, S., Umegaki, K., Ikegami, S., 1997. Hexachlorobenzene accumulated by Dams during pregnancy is transferred to suckling rats during early lactation. J. Nutr. 127 (4), 648–654. Pastor, D., Jover, L., Ruiz, X., Albaigés, J., 1995. Monitoring organochlorine pollution in Audouin’s gull eggs: the relevance of sampling procedures. Sci. Total Environ. 162, 215–223. Rappe, C., Marklun, S., Kjeller, L.-O., Lindskog, A., 1989. PCDDs and PCDFs in emissions from various incinerators. Chemosphere 18, 1283–1290. Russell, R.W., Gobas, F.A.P.C., Haffner, G.D., 1999. Maternal transfer and in ovo exposure of organochlorines in oviparous organisms: a model and field verification. Environ. Sci. Technol. 33, 416–420. Senthil Kumar, K., Kannan, K., Corsolini, S., Evans, T., Giesy, J.P., Nakanishi, J., Masunaga, S., 2002. Polychlorinated dibenzo-p-dioxins, dibenzofurans and polychlorinated biphenyls in polar bear, penguin and south polar skua. Environ. Pollut. 119, 151–161. Sladen, W.J.L., Menzie, C.M., Reichel, W.L., 1966. DDT residues in Adelie penguins and crabeater seal from Antarctica. Nature 210, 670–673. Tanabe, S., Subramanian, A.N., Hidaka, H., Tatsukawa, R., 1986. Transfer rates and pattern of PCB isomers and congeners and p,p’ -DDE from mother to egg in Adélie penguin (Pygoscelis adéliae). Chemosphere 15 (3), 343–351. Tanabe, S., Loganathan, B.G., Subramaniam, A.N., Tatsukawa, R., 1987. Organochlorine residues in shot-finned pilot whale: possible use as tracer of biological parameters. Mar. Pollut. Bull. 18, 561–563. Trivelpiece, W.Z., Trivelpiece, S.G., Volkman, N.J., 1987. Ecological segregation of Adélie, Gentoo and Chinstrap penguins at King George Island, Antarctica. Ecology 68, 351–361. UNEP (United Nations Environment Programme), 2003. Global Report 2003. Regionally Based Assessment of Persistent Toxic Substances, Geneve. Van den Berg, M., Birnbaum, L.S., Denison, M., De Vito, M., Farland, W., Feeley, M., Fiedler, H., Hakansson, H., Hanberg, A., Haws, L., Rose, M., Safe, S., Schrenk, D., Tohyama, C., Tritscher, A., Tuomisto, J., Tysklind, M., Walker, N., Peterson, R.E., 2006. The 2005 World Health Organization re-evaluation of human and mammalian Toxic equivalency factors for dioxins and dioxin-like compounds. Toxicol. Sci. 93 (2), 223–241. Verreault, J., Villa, R.A., Gabrielsen, G.W., Skaare, J.U., Letcher, R., 2006. Maternal transfer of organohalogen contaminants and metabolites to eggs of Arcticbreeding glaucous gulls. Environ. Pollut. 144, 1053–1060. Vetter, W., Klobes, U., Luckas, B., 2001. Distribution and levels of eight toxaphene congeners in different tissues of marine mammals, birds and cod livers. Chemosphere 43, 611–621. Wania, F., Mackay, D., 1993. Global fractionation and cold condensation of low volatility organochlorine compounds in polar regions. Ambio 22, 10–18. Weber, K., Goerke, H., 1996. Organochlorine compounds in fish off the Antarctic Peninsula. Chemosphere 33, 377–392. Weber, K., Goerke, H., 2003. Persistent organic pollutants (POPs) in Antarctic fish: levels, patterns, changes. Chemosphere 53 (6), 667–678. Ylitalo, G.M., Myers, M., Stewart, B.S., Yochem, P.K., Braun, R., Kashinsky, L., Boyd, D., Antonelis, G.A., Atkinson, S., Aguirre, A.A., Krahn, M.M., 2008. Organochlorine contaminants in endangered Hawaiian monk seals from four subpopulations in the Northwestern Hawaiian Islands. Mar. Pollut. Bull. 56 (2), 231–244.
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Contamination profiles of selected PCB congeners, chlorinated pesticides, PCDD/Fs in Antarctic fur seal pups and penguin eggs Alessandra Schiavone *, Simonetta Corsolini, Nicoletta Borghesi, Silvano Focardi Department of Environmental Science ‘‘G. Sarfatti”, University of Siena, via P.A. Mattioli, 4, I-53100 Siena, Italy
a r t i c l e
i n f o
Article history: Received 3 December 2008 Received in revised form 5 February 2009 Accepted 1 March 2009 Available online 16 April 2009 Keywords: PCB PCDD/Fs DDT Antarctic Penguin Seal pup
a b s t r a c t The aim of this study was to investigate levels of some major environmental contaminants, such as polychlorinated biphenyls (PCBs), polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) and organochlorine pesticides in Antarctic samples. Concentrations of some persistent organic pollutants (POPs) were investigated in Antarctic fur seal pups and eggs of three species of penguins. Dichloro-diphenyl-trichloroethane (DDT) was the main pollutant, followed by PCBs; other organochlorine compounds such as hexachlorobenzene (HCB) and PCDD/Fs were usually found only in minor quantities. Adélie penguin eggs had significantly higher mean PCB concentrations (p < 0.05) compared to the other two penguin species, but there was no difference in DDT levels (p > 0.05). TEQ values in fur seal blubber in our study were one order of magnitude lower than those considered to elicit physiological effects in aquatic mammals. In general, POP concentrations in our samples suggested that likely the study populations were not currently at risk for adverse health effects, but indicated a clear need for further monitoring to assess the presence and time trend of a broad range of contaminants, mainly emerging POPs thought to be increasing in polar regions. Ó 2009 Elsevier Ltd. All rights reserved.
1. Introduction Polar regions are reported to be a final sink for contaminants (AMAP, 2000). In fact, global distillation or fractionation by condensation in cold polar environments has been proposed as mechanisms whereby the polar regions may become sinks for persistent organic pollutants (POPs) (Wania and Mackay, 1993). Moreover, the presence of persistent and toxic industrial contaminants in the Antarctic environment is also attributed to local sources, with the activities of scientific stations, in particular concentrated in the Antarctic peninsula, where the samples analyzed in this study come from. Chlorinated pesticides were first discovered in Antarctic wildlife in the 1960s (Sladen et al., 1966). Recent studies continue to demonstrate the presence of organochlorine pesticides in the Antarctic marine food web (Gupta et al., 1996; Weber and Goerke, 1996; Corsolini et al., 2006), despite bans or restrictions on use of many of these compounds. Cold conditions of the Antarctic environment favour persistence of POPs with respect to temperate and tropical environments. The storage of lipids as an energy source makes Antarctic food webs vulnerable to bioaccumulative chemicals, and top predators are the species exposed to greatest risk (Loganathan et al., 1990; Loganathan and Kannan, 1991). In mammals, lipid soluble and persistent POPs are transferred from * Corresponding author. Tel.: +39 3472748692. E-mail address: [email protected] (A. Schiavone). 0045-6535/$ - see front matter Ó 2009 Elsevier Ltd. All rights reserved. doi:10.1016/j.chemosphere.2009.03.007
maternal lipid stores to offspring through lactation (Tanabe et al., 1987). Marine mammals are special from this point of view, because their milk is often very rich in lipids. The lipid content of Antarctic fur seal milk can be up to 39.8% (Goldsworthy and Crowley, 1999). Although there might be some in utero transfer of contaminants from mother to pup in mammals, transfer through lactation is considered as quantitatively far more important (Nakashima et al., 1997). Water bird eggs have proven particularly useful as bioindicators of organochlorines in aquatic environments (Pastor et al., 1995). Further, pollutant concentrations in eggs may help in assessment of hazards faced by embryos during development and their composition directly reflects that of maternal tissues (Drouillard and Norstrom, 2001). Russell et al. (1999) found that the initial in ovo exposure to persistent hydrophobic organic pollutants of the developing embryos in various classes of oviparous organisms is approximately similar to the exposure of the adults who deposit the eggs. The developing embryos of oviparous organisms at the top of the food chain are therefore exposed to the same contaminant levels as the female adults from which they originate. If developing embryos are more susceptible to chemical contaminants than the adult organisms, toxic effects are more likely to occur in developing embryos than in the adult organisms. Limited information is available on POPs levels in Antarctic fur seals (Arctocephalus gazella) and penguins from the Antarctic peninsula. Objectives of this study was to provide contamination profiles of selected PCB congeners, chlorinated pesticides, dioxins and
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furans in Antarctic fur seal pups and eggs of three species of penguins, Adélie penguin (Pygoscelis adéliae), Chinstrap penguin (Pygoscelis antarcticus) and Gentoo penguin (Pygoscelis papua). The results will help evaluate the status of contamination and toxic potential and possible risks to these organisms.
2. Materials and methods 2.1. Samples Antarctic fur seal (A. gazella) pup tissues were collected between January and February 2004. Samples were collected at Livingston Island, South Shetland, Antarctic Peninsula, (62°390 S, 60°300 W). The pups were found dead and the tissue samples were obtained from the carcasses at the time of necropsy. Sampling location, gender (11 male and 9 female), body weight (3.4 ± 2 Kg) and body length (11.3 ± 26 cm) were recorded. Unhatched eggs of Adélie penguins (P. adéliae, n = 13), Gentoo penguins (P. papua, n = 13) and Chinstrap penguins (P. antarcticus, n = 9) were collected at King George Island, South Shetland, Antarctic Peninsula (62°100 S, 58°670 W), during the 2004/05 field season. All samples were wrapped in polyethylene bags and stored at 20 °C until analysis. 2.2. Chemical analysis Twenty seal liver and twenty muscle samples were analyzed for hexachlorobenzene (HCB), dichloro-diphenyl-trichloroethanes (DDTs: o,p0 -p,p0 -DDE, o,p0 -p,p0 -DDD, o,p0 -p,p0 -DDT), and forty-three PCB congeners. The same samples and more five seal blubber samples, were analyzed for polychlorinated dibenzo-p-dioxins (PCDDs), and polychlorinated dibenzofurans (PCDFs). The assessment of health risks posed by the dioxin, and furan congeners was assessed as Toxicity Equivalents (TEQs) (Van den Berg et al., 2006). Penguin eggs were analyzed for twenty-three PCB congeners, DDTs and HCB. All the samples were analyzed following the methods described elsewhere (Kannan et al., 2001) with some modifications. Approximately 4 g of liver and muscle and 1.5 g of blubber were homogenized with sodium sulphate and spiked with 50 ng of CBs 30 and 209 as internal standards; they were Soxhlet extracted for 16 h with n-hexane and dichloromethane (1:3). The extract was rotary evaporated to 10 mL. Interfering substances were removed by fractionation with multilayer silica gel column, prepared by packing a glass column (20 mm i.d.) with a series of layers of silica gel in the following order: 2 g silica gel, 2–6 g 40% acidic-silica gel, 2 g silica gel and a thin layer of sodium sulphate at the top. The column was cleaned with 150 mL of hexane (discarded fraction), prior to transfer of sample extracts. Samples were then eluted with 200 mL of hexane and rotary evaporated to 1 mL for HR-GC analysis. Subsequently the eluted fractions were passed through a glass column (10 mm i.d.) packed with 1 g of silica gel impregnated carbon (Wako Pure Chemical Industries, Tokyo, Japan) for separation of sixteen 2,3,7,8-substituted PCDD/F congeners. The first fraction, which was eluted with 150 mL of hexane, contained major PCB congeners which interfere with analysis of PCDD/Fs. The second fraction, eluted with 200 mL of toluene, contained PCDDs and PCDFs. Blank samples, prepared by the procedure used for the samples, was included every ten samples and when needed, results were blank corrected. Recovery rates for PCB congeners ranged from 86% to 97% and for PCDDs and PCDFs ranged from 65% to 94%. PCB congeners, HCB and DDTs were identified and quantified by a gas chromatograph (Perkin–Elmer mod. Autosystem) equipped with 63Ni electron capture detector (HRGC–ECD). Concentrations were calculated from the peak area of the sample to that of the cor-
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responding external standard. Aroclor 1260 and 1254 (AccuStandard Inc., Niederbipp, Europe) and a mixture of organochlorine pesticides (Dr. Ehrenstorfer GmbH., Augsburg, Germany) of known compound composition were used in the identification of chemicals. PCB congeners are presented by their IUPAC numbers throughout the manuscript. The concentrations of individually resolved peaks were summed to obtain total PCB concentrations on a wet weight basis (ww). DDTs refers to the sum of o,p0 - p,p0 -DDE, o,p0 -p,p0 -DDT and o,p0 -p,p0 -DDD. The methodological limit of detection (LOD) of individual PCB congeners and organochlorine pesticides was determined to be 0.01 ng/g ww. Determinations of PCDD/Fs by isotope dilution were performed by a Trace gas chromatograph equipped with an AS 2000 autosampler (ThermoFinnigan) and fitted with a Rtx-5MS capillary column (30 m 0.25 mm i.d., 0.25 lm) from Restek (Bellefonte, PA, USA). The samples were analyzed with a GCQ plus ion trap mass spectrometer (MS) from Thermo Finnigan in selected ion monitoring mode (SIM). A Cambridge Isotope Laboratory (Andover, MA, USA) certified stock solution containing 2 tetra- and hexa-PCDD (13C12, 99%) in nonane was used as an internal standard. LODs of individual PCDDs and PCDFs, calculated as mean blank + 3SD, were 0.1– 0.15 pg/g. Statistical analyses were performed with STATISTICA 7 for Windows (Ver 7.1; Statsoft, Italia srl) at a significance level of p = 0.05. Statistically significant differences between the mean concentrations of contaminants were investigated by single factor one-way analysis of variance (ANOVA). Data were log-transformed for achieving normal distribution before running ANOVAs. Posthoc Tukey compromise tests were used to determine statistical differences among species and tissues. Correlation are expressed using the Pearson correlation coefficient r.
3. Results and discussion 3.1. Levels of PCBs and chlorinated pesticides in seal tissues PCB fingerprints (Fig. 1a) showed a notable presence of low chlorinated PCBs. The most abundant PCB congeners were IUPAC numbers 183 > 134 > 146 > 153 > 138 in muscle and 183 > 134 > 153 > 138 > 118 in liver samples. These congeners, which accounted for the majority of total PCB concentrations, are normally found as the dominant PCB congeners in marine mammals (Kannan et al., 1993; Fillmann et al., 2007; Ylitalo et al., 2008). The presence of some high chlorinated congeners (the most persistent and widespread type) may also be associated with local sources (waste burning and dumping sites) (Montone et al., 2003). The mean PCB and DDT concentrations in liver did not show statistical difference from those in muscle (p > 0.05). 1,1-Dichloro-2,2bis (p-chlorophenyl)-ethylene (p,p0 -DDE), which is the major breakdown/metabolic product of DDT, accounted for 64% and 59% of total DDT concentrations in liver and muscle respectively. p,p0 -DDE values were one order of magnitude higher than those reported by Miranda-Filho et al. (2007) in blubber of southern elephant seal pups, but of the same order as those reported for adult southern elephant seals. Since the present samples were from seal pups, higher pesticide concentrations in adult southern fur seals may be presumed. p,p0 -DDE seems to be easily transferred through the placenta than the various DDT forms (Borrell et al., 1995), which may explain our finding of high concentrations of p,p0 -DDE also in stillborn seal pups. HCB concentrations were one or two orders of magnitude lower P than those of PCBs and DDT, both in seal pups and penguin eggs (Table 1). HCB accounted for 1% of the total POP residues. The concentrations of HCB observed in fur seals in this study were similar to those detected in other Antarctic pinnipeds (Vetter et al., 2001; Miranda-Filho et al., 2007).
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b
Blubber
Liver
206
205
194
207
195
189
201
196
170
199
180
172
177
156+202+171
174
185
128
183
Muscle
178
138
137
176
141
105
153
146
134
118+149
151
144+135
99
110
101
95
60+56
70+76
%
16 14 12 10 8 6 4 2 0
158
Liver
a 18
187
266
M uscle
60 50 40
%
30 20 10 1234678 9-OCDF
1234678HpCDF
123789HxCDF
234678HxCDF
123678HxCDF
123478HxCDF
23478PeCDF
12378PeCDF
2378TCDF
1234678 9-OCDD
1234678HpCDD
123789HxCDD
123678HxCDD
123478HxCDD
12378PeCDD
2378TCDD
0
Fig. 1. Percentage contribution of each congener to the total PCB residue (a) and PCDDs and PCDFs (b) in different tissues of seal pups.
Contaminant toxicity and risk in pinnipeds are little understood. Kannan et al. (2000) recommended a safe upper PCB threshold concentration of 8700 ng/g lw for marine mammals’ blood or liver and a threshold of 17 000 ng/g lw for PCBs in the blubber due to adverse effects on immune function, based on several studies that measured a range of toxicological endpoints (e.g. natural killer cell activity, thyroid hormone concentrations) and levels of PCBs. PCB burdens in the pups in this study were found to be much lower. These observations suggest that the population is not currently at risk for adverse health effects due to PCBs, but there is a clear need for further monitoring and research to assess the average levels and the future trend of a broad range of organochlorines (OCs) and other halogenated compounds in Antarctic seals. Moreover, these contaminant threshold values were derived for species other than Antarctic fur seals, and fur seals may be more or less sensitive to the effects of these compounds. 3.2. Levels of PCDDs and PCDFs in seal tissues Several PCDDs and PCDFs were not detected in the tissues of fur seal pups at a detection limit of 0.1–0.15 pg/g ww. Residue concentrations of planar halogenated aromatic hydrocarbons occurred in the order PCDFs > PCDDs in all seal pup tissues (Table 1). A similar pattern was found by Senthil Kumar et al. (2002) in Weddell seal
liver, fish, Adélie penguin and skua egg samples from Terra Nova Bay, by Corsolini et al. (2002) in Weddell seal blubber and skua liver from the Ross Sea; and by Jimènez et al. (1999) in the subcutaneous fat of sea lions from Punta Bermeja (Argentina). On the other hand, samples from the northern hemisphere have generally shown a different trend, with PCDDs > PCDFs (Addison et al., 2005; Kajiwara et al., 2008). This suggests that the two hemispheres are affected by different sources of contamination. The frequency of occurrence of PCDD and PCDF residues was too sporadic in samples to show any clear statistical correlation between the tissues. Our results were one to three orders of magnitude greater than those found in previous studies on Antarctic seals (Table 2). Relatively higher values obtained in this study may also be due to local sources. Livingston Island, where our seal samples were collected, is the second largest island of the South Shetlands, and hosts three permanent scientific bases, while there are nine research stations on nearby King George Island. Research bases in Antarctica may contribute to PCDD/F contamination through incineration activities (Miller et al., 1999), although atmospheric transport from other continents is recognized as a major pathway for their dispersal and is thought to be the primary source (UNEP, 2003). 2,3,4,7,8-PeCDF and 1,2,3,7,8-PeCDD were the congeners exhibiting the highest levels both in the tissues of fur seal pups (Fig. 1b).
Table 1 Mean (± standard deviation) organochlorine concentrations (ng/g wet weight) and PCDD/Fs (pg/g wet weight) in the tissues of Antarctic fur seal pups collected from Livingstone Island (Antarctic Peninsula) and in the eggs of Pygoscelis penguins collected from King George Island (Antarctic Peninsula). Tissues
n
RPCBs
RDDTse (p,p0 -DDE)
HCB
RPCDD (TEQ PCDD)
RPCDF (TEQ PCDF)
PCDD/Fs (TEQ)
Antarctic Fur seal blubber Antarctic Fur seal liver Antarctic Fur seal muscle Adélie penguin egg Chinstrap penguin egg Gentoo penguin egg
5 20 20 9 9 9
na 59 ± 43d 33 ± 22d 12 ± 4c 6 ± 4c 5 ± 3c
na 191 ± 106 (123 ± 52) 103 ± 55 (60 ± 26) 23 ± 10 (18 ± 10) 17a ± 15 (15 ± 12.2) 15b ± 9 (12.5 ± 10.4)
na 2.2 ± 0.88 1.37 ± 0.69 7.63 ± 1.8 3.8 ± 3.7 3.7 ± 3.5
54 ± 55.6 (17) 10.6 ± 17.6 (4.2) 3.5 ± 8.8 (0.4) na na na
96.4 ± 114.7 (13.3) 153.7 ± 211 (22.6) 85 ± 76.6 (8.2) na na na
150 (30.6) 164 (26.8) 88.5 (8.6) na na na
na: not analyzed. a n = 7. b n = 6. c Sum of 23 congeners (Aroclor 1254). d Sum of 44 congeners (Aroclor 1260). e RDDTs: sum of o,p0 -p,p0 -DDE, o,p0 -p,p0 -DDT and o,p0 -p,p0 -DDD.
267
A. Schiavone et al. / Chemosphere 76 (2009) 264–269 Table 2 Planar halogenated aromatic hydrocarbons, PCDD/Fs, (pg/g lw; ng/g ww) in tissues of Pinnipeds from Antarctica. Tissue
Date of collection
Species
Age/Sex class
n
Location
PCDDs
Blubber
1986
Lobodon carcinophagus (Crabeater seal) Arctocephalus gazella (Antarctic fur seal) Leptonychotes weddelli (Weddell seal) Arctocephalus gazella (Antarctic fur seal)
m+f
17
Antarctic Ocean
nd
f
11
Adult
1
Pup m + f
5
Bird Island (South Gorgia) Terra Nova Bay (Ross sea) Livingston Island
f
1
Pup m + f
19
Adult
1
Pup m + f
20
lw
96.4
30.6
This study
0.65
Terra Nova Bay (Ross sea)
31
12
18
Corsolini et al. (2002)
Livingston Island
3.5
8.5
8.6
This study
0.11
3.8
0.12
23
due to the different lactation period between age groups. The frequency of occurrence of PCDD residues was too sporadic in the samples for a correct correlation analysis and scatterplots showed a negative linear regression in muscle samples and no significant correlation (p > 0.05) in liver samples. Iwata et al. (2004) found an increasing trend of PCDD/Fs with age in the liver of male Baikal seals. Moreover, in our samples the PeCDF congeners showed a significant increase with age (p < 0.05) in liver and muscle, indicating lower metabolic capability for this compound, as also found by Iwata et al. (2004) in Baikal seals. In the case of highly chlorinated congeners, no increasing trend was observed in either type of fur seal tissue. Interestingly, Iwata et al. (2004) reported a declining tendency with age of some PCDD/F congeners in the liver of adult female seals, suggesting the maternal transfer of PCDD/Fs to pups through lactation. This author also found a significant regression with negative slope values for a limited number of congeners, including 2,3,4,7,8-PeCDF, which showed a significant increase with age in the liver of our seal pup samples. 3.4. Levels of PCBs and chlorinated pesticides in penguin eggs
Chinstrap
Gentoo
138
Adélie penguin eggs had significantly higher mean PCB concentrations (p < 0.05) than eggs of other two penguin species, but there was no difference in DDT levels (p > 0.05). No statistically different (p > 0.05) concentrations were found between Gentoo and Chinstrap eggs for any compounds. Chinstrap and Gentoo penguin eggs showed the same PCBs patterns (Fig. 2), with hexachlorobiphenyls as the major homologues, followed by hepta- > penta> tetra-CBs, while Adélie penguin eggs showed different patterns, with pentachlorobiphenyls as the major homologues, followed by hepta- > tri- > hexa-CBs. The differences observed between Adélie penguins and the other Pygoscelis penguins, which inhabit the same area, may be related to diet, reproductive status, ecological niches, and migration.
118
123
105
114
101
66
44
52
53.6
26.8
Adèlie
28
Corsolini et al. (2002)
153.7
No difference was found in OC and PCDD/F concentrations between male and female seal pups (p > 0.05), probably due to their immature state, while levels of PCBs, DDTs and PCDFs in both liver and muscle increased significantly with the age of pups (p < 0.05). In contrast, HCB did not differ between age groups (p > 0.05). The same results were found in a study of exposure to organohalogens during the lactation period in harbor seal pups (Neale et al., 2005). In the initial stage of a seal’s life the higher levels detected are only
18
17
10.6
3.3. Correlations between different seal groups
8
17
Senthil Kumar et al. (2002) This study
The main sources of 2,3,4,7,8-PeCDF in the environment are technical PCB mixtures and combustion processes (Rappe et al., 1989). Significant concentrations of 1,2,3,7,8-PeCDD have been attributed to chlorophenol related sources from waste incineration (Senthil Kumar et al., 2002). Moreover, our samples came from seal pups and limited pharmacokinetic information is available on transfer of dioxin and furan congeners other than TCDD to fetus, placenta, and pups. The TEQ concentrations (Table 1) were in the following decreasing order: blubber > liver > muscle. TEQ values in fur seal blubber in our study were one order of magnitude lower than those considered to elicit immune dysfunction in adult harbor seals (209 pg TEQ/g lw) (Iwata et al., 2004). The threshold concentration for TEQs to elicit physiological effects in the liver of aquatic mammals has been estimated to range from 160 to 1400 (mean: 520) pg/g lw (Kannan et al., 2000). Our values were one order of magnitude lower. This estimate does not include the safety factors that are generally applied for inter-specific comparison, and it should be borne in mind that our values came from seal pups, and higher TEQ values are expected for adult Antarctic fur seals. In fact, it has been estimated that mean total PCDD concentrations in pup blubber samples are usually about 60% of those of their mothers (Addison et al., 1999).
16 14 12 10 % 8 6 4 2 0
3.7
Fig. 2. Percentage contribution of each congener to the total PCB residue in the three species of penguin eggs.
206
Arctocephalus gazella (Antarctic fur seal)
Oehme et al. (1995)
195
2004
2
189
Muscle
Bignert et al. (1989)
7
170
1996
5.1
ww
15.7
180
2004
Terra Nova Bay (Ross sea) Livingston Island
lw
References
1–3
157
Leptonychotes weddelli (Weddell seal) Arctocephalus gazella (Antarctic fur seal) Leptonychotes weddelli (Weddell seal)
ww
3.7–6.1
156
1995–1996
TEQs
lw
167
Liver
ww
128
2004
187
1996
153
1987
PCDFs
268
A. Schiavone et al. / Chemosphere 76 (2009) 264–269
Table 3 Organochlorine concentrations (ng/g lw; ng/g ww) in eggs of Penguins from Antarctica. Matrix Date of collection
Species
Egg
Pygoscelis Pygoscelis Pygoscelis Pygoscelis Pygoscelis Pygoscelis Pygoscelis Pygoscelis Pygoscelis
1995 1981 1978 2004
1988-1990 1995/6 1981 1983 1978
a
adéliae (Adélie penguin) adéliae (Adélie penguin) adéliae (Adélie penguin) papua (Gentoo penguin) adéliae (Adélie penguin) antarctica (Chinstrap penguin) papua (Gentoo penguin) adéliae (Adélie penguin) adéliae (Adélie penguin)
Pygoscelis adéliae (Adélie penguin) Aptenodytes forsteri (Emperor penguin) Pygoscelis papua (Gentoo penguin) Eudyptes chrysocome (Rockhopper penguin) Eudyptes schlegeli (Royal penguin)
n
Location
5 1
Terranova Bay (Ross sea) Syowa Station Falkland Island
9 9 9 27 6
King Gorge Island (South Shetland)
PCBs
DDTs
HCB
lw ww
lw ww
lw ww
20 Prydz Bay 11 5 Macquarie Island 6
<100 <100 <100 <100
<0.1a 98.2a 197.5a 130a 23 17 15 (7.1) 6.3a 23 (20.7a) 5a 10a 40a 20a
10
<100
40a
Cape Bird (Ross Island) Edmonson Point (Ross sea)
2.8 19.6 110 <10 12 6 5 8.8
References
<0.1 Corsolini et al. (2002) Tanabe et al. (1986) nd Ballschmiter et al. 30 (1981) 7.63 This study 3.8 3.7 5.6 Court et al. (1997) 18.7 Corsolini et al. (2006)
10
10 20 10 20
Luke et al. (1989)
Only p,p0 -DDE.
Comparing our results to previous works on egg samples, a clear tendency of increasing levels of PCBs in Antarctic penguin eggs was lacking (Table 3). Total DDTs and p,p0 -DDE values were higher than those reported in previous works in Adèlie eggs (Luke et al., 1989; Court et al., 1997) while they were similar to those reported by Corsolini et al. (2006) in Adélie eggs from the Wood Bay area (Ross Sea). A same increasing trend was reported by Weber and Goerke (2003), who investigated p,p0 -DDE concentrations in Antarctic fish species and found a significant increase in p,p0 -DDE between 1987 and 1996. p,p0 -DDE is the most persistent metabolite of p,p0 -DDT, which has been used extensively in the southern hemisphere (Connell et al., 1999) and is still employed in significant amounts for vector control against malaria in the lower latitudes. It is known that the avian egg has proved to be an advantageous tool for monitoring contaminant exposure in a multitude of species as its composition directly reflects that of maternal tissues (Drouillard and Norstrom, 2001; Verreault et al., 2006). The are many risks associated with an increased pollutant burden in birds – even subtle changes in behaviour have been seen and associated with pollution. As far as we know, only one recent study has been carried P out on Antarctic birds (Bustnes et al., 2007). HCB and PCB concentrations found in penguin eggs in this study were similar to those found by Bustnes et al. (2007) in blood of female south polar skuas during breeding (6.17 ng/g ww for HCB, and 6.94 ng/g ww P for PCB), while p,p0 -DDE concentrations were one order of magnitude higher in penguin eggs than in skua blood (4.87 ng/g ww in female blood). Bustnes et al. (2007) found associations between these OC concentrations and fitness components in skuas for the first time. The timing of reproduction and the hatching mass of chicks were both adversely related to the mothers’ blood residues of OCs. Bustnes et al. (2007) concluded that such changes may affect the population parameters in long-lived birds. In our three penguin species, pollutant burdens in reproductive specimens were greater than those found in the skua population. Moreover, the three penguin species share the same environment and have adopted a fine ecological segregation to reduce niche overlap and competition. For this reason penguins may be more sensitive to the adverse effects of OCs. In fact, while all the Pygoscelis species are very synchronous in nesting, the breeding cycles of the three species are quite asynchronous (Trivelpiece et al., 1987). Chicks hatched at approximately 2 week intervals, with Adélie p. being the earliest and Chinstrap p. the latest to hatch annually. Asynchronous breeding cycles greatly reduce competition for food between Adélie penguins and their congeners during chick rearing, so, a
subtle change in the timing of reproduction can also noticeably affect reproduction success. 4. Conclusions Our data contribute to the limited literature on concentrations of persistent organic contaminants in marine mammals and birds from the Antarctic region. DDE is the main pollutant, followed by PCBs; other organochlorine compounds such as HCB and PCDD/Fs are usually found only in minor quantities. Seal liver did not show a significantly different degree of contamination from muscle. The eggs study indicated that Adélie penguins were more susceptible to accumulation of contaminants from their environment than Gentoo and Chinstrap penguins. The concentrations of organochlorines in penguin eggs and seal tissues reported here may be toxicologically insignificant, but more studies are needed to assess the real health risks associated with these levels of pollutants. Seals and penguins are particularly sensitive to contaminants, since the natural stress on wildlife in extreme environments, such as the Antarctic, is often more severe than in temperate regions, rendering such species more vulnerable to the effects of pollutants. Acknowledgments This research was funded by the Italian National Program of Research in Antarctica (PNRA). The National Science Foundation supported S. Corsolini’s stay and travel to and from King George Is. We are very grateful to Daniel Torres and Daniel Torres jr (Instituto Antarctico Chileno, Santiago, Chile) for collecting the fur seal samples during the 2003/04 expedition, and to Wayne Trivelpiece, and Susan Trivelpiece for collecting the penguin egg samples. We thank Roger Hewitt, Agunsa (Punta Arenas, Chile) and Raytheon (USA) for their friendly logistic support. References Addison, R.F., Ikonomou, M.G., Stobo, W.T., 1999. Polychlorinated dibenzo-p-dioxins and non-ortho- and mono-ortho-chlorine substituted polychlorinated biphenyls in grey seals (Halichoerus grypus) from Sable Island, Nova Scotia, in 1995. Mar. Environ. Res. 47, 225–240. Addison, R.F., Ikonomou, M.G., Fernandez, M.P., Smith, T.G., 2005. PCDD/F and PCB concentrations in Artic ringed seals (Phoca hispida) have not change between 1981 and 2000. Sci. Total Environ., 301–311. AMAP Workshop on Persistent Organic Pollutants (POPs) in the Arctic: Human Health and Environmental Concerns, Artic Monitoring and Assessment Programme Report 2000, 1,
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