A 1500-year record of lead, copper, arsenic, cadmium, zinc level
in Antarctic seal hairs and sediments
Xuebin Yina,b, Xiaodong Liua, Liguang Suna,c,⁎, Renbin Zhua,
Zhouqing Xiea, Yuhong Wanga,d
aInstitute of Polar Environment, University of Science and Technology of China, Hefei, Anhui 230026, P.R. China
bState Key Lab. of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing, Jiangsu 210008, P.R. China
cCAS Key Laboratory of Crust–Mantle Materials and Environments, School of Earth and Space Sciences,
University of Science and Technology of China, Hefei, Anhui 230026, China
dNational Institutes of Health, Bethesda, MD 20892, USA
Received 25 April 2006; received in revised form 13 July 2006; accepted 13 July 2006
Available online 22 August 2006
To reconstruct the profiles of heavy metal levels in the South Ocean ecosystem of Antarctica, the concentrations of lead (Pb),
copper (Cu), arsenic (As), cadmium (Cd), and zinc (Zn) in seal hairs and lake sediments spanning the past 1500 years from Fildes
Peninsula of King George Island and in weathering lake sediments from Nelson Island of West Antarctica were determined. The lead
contents in the seal hairs and the weathering sediments show a sharp increase since the late 1800s, very likely due to anthropogenic
contamination from modern industries. After the 1980s, the Pb content in seal hairs dropped by one-third, apparently due to the
substantially affected by climatic conditions. The concentrations of Cd, As, and Zn do not show any clear temporal trends.
© 2006 Published by Elsevier B.V.
Keywords: Antarctica; Seal hair; Excrement; Heavy metal; Anthropogenic source; Natural source
The Antarctic Continent, thanks to its remarkable
distance from thickly populated areas and its poor
for research on the global changes caused by man in the
environment. The sources of modern atmospheric
contaminants on the remote continent can be well tracked
by their characteristic component of aerosol (Rahn, 1982;
Rahn et al., 1989; Dick, 1991; Slemr and Langer, 1992).
The ice cores in the Antarctic and Greenland (Vandal et
al., 1993; Hong et al., 1994; Wolff and Suttie, 1994;
Wolff etal.,1999; Candeloneetal.,1995; Planchonetal.,
2002), and lake sediments (Muir et al., 1995, 1996; Blais
et al., 1998; Jackson et al., 2004) have been analyzed to
investigate long-term depositional flux and emission of
heavy metals from natural and anthropogenic sources
(Fitzgerald et al., 1998). The researches on the ice cores
indicate that anthropogenic activities have become the
most important source of Pb in Antarctic and Greenland
(Planchon et al., 2002), and the record of Pb in the lake
sediments there can even be used as a chronological
marker for Europe (Renberg et al., 2001). The level of Pb
Science of the Total Environment 371 (2006) 252–257
⁎Corresponding author. Institute of Polar Environment, University
of Science and Technology of China, Hefei, Anhui 230026, P.R.
E-mail address: firstname.lastname@example.org (L. Sun).
0048-9697/$ - see front matter © 2006 Published by Elsevier B.V.
in the Greenland ice cores has increased over 100 times
from the early to the middle 20th century (Candelone et
al., 1995), then there has been a decline since ca. 1970s
(Boutron et al., 1991); anthropogenic Cu and Zn levels in
Antarctic snowhaveincreasedremarkablydue tomodern
industrial emissions (Wolff et al., 1999; Planchon et al.,
Besides geological materials, marine animals' excre-
ments (or hair) have been applied to study the past
contamination in their living environment (Sun and
Xie, 2001; Sun et al., 2004, 2006, in press). A 3000-
year record of Pb concentrations in penguin droppings
suggested that the marked anthropogenic Pb contam-
ination on King George Island, a sub-Antarctic island,
began at least 200 years ago (Sun and Xie, 2001). The
mercury profiles in Antarctic seal hairs on King George
Island showed that the seal hairs have been signifi-
cantly affected by human activities for the past
2000 years (Sun et al., 2006). These studies provided
a direct perspective on the historical loadings of
contaminants in the marine animals and helped in
understanding the relationship between environmental
changes and heavy metal contamination of marine
animals. However, the temporal changes of the levels
of Pb and other heavy metals (such as, Cu, Zn, Cd, As)
in seals on King George Island and whether their
changes are caused by anthropogenic contaminations
In this study, in order to investigate the historical
changes in Pb, Cu, As, Cd, Zn levels in Antarctic seals,
seal hair series, the lake sediments amended by seal
excrement from Antarctica spanning about 1500 years,
and the weathering sediments in the same area. We will
also discuss the relationship between the temporal pro-
files of these heavy metals, anthropogenic contaminants,
and climatic changes.
2. Experiment section
2.1. Study site
King George Island (63°23′S, 57°00′W), 80 km long
and 30 km wide, has an area of 1160 km2and a moist
marine climate in the Southern Ocean (Sun et al., 2004).
The average annual temperature is −2.5 °C. The annual
precipitation is modelled to be 600 mm. About one-
tenth of the area is free of snow and ice during austral
summer. The whole studied area consists mainly of
Tertiary andesitic and basaltic lavas and tuffs (Sun and
Xie, 2001). In the field, the site of a copper mine with an
area of about 1 km2was found on Barton Peninsula. The
detailed map can be found in our previous paper (Sun
et al., 2004).
2.2. Sample collection
The seal excrement sediment core (named as HF4),
42.5 cm in length, was collected from a catchment
(62°11′57″S,59°58′48″W)on thesecond marine terrace
at the King George Island in February 2002 (Sun et al.,
2004). During sampling, a PVC plastic gravity pipe of
12 cm in diameter was vertically pushed down to the
bedrock and then quickly extracted. For comparison, we
collected a weathered sediment core (named as N1) with
a little organic matter from a catchment close to modern
Nelson Ice Cap in March 2000 (Liu et al., 2004).
For collecting seal hairs, the HF4 core was sectioned
at 0.5 cm intervals for the upper 18 cm with many seal
hairs and 1.0 cm intervals for the next 3 cm with fewer
hairs and the rest 21.5 cm without hairs. Seal hair was
identified with reference to elephant seal hairs from
Fildes Peninsula on the King George Island (Sun et al.,
2004). These seal hairs without any visible inter-slice
of unique species of seal. We picked out about 0.1–0.5 g
ofsealhairs (thousands innumber)from eachsubsample
of the upper 21 cm except 19–20 cm (36 in upper 18 cm,
2 in 18–19 cm and 20–21 cm, n=38). Since the time
Comparison between the determined concentrations of elements in the
certified reference materials (CRMs, supplied by National Research
Center for CRMs of China, Beijing) and the reference values
Elements Methods CRMs no.Measured valuesReference
ND: not determined. Content of elements is in μg g−1.
GF-AAS GBW 07402 22±1, n=2
GF-AAS GBW 07403 ND
GF-AAS GBW 07405 545, n=1
GF-AAS GBW 07407 12, n=1
FAAS GBW 07402 18.0±1.4, n=2
FAAS GBW 07403 12.5, n=1
FAAS GBW 07405 145, n=1
FAAS GBW 07407 92, n=1
AFS GBW 07402 14.2±0.1, n=2
AFS GBW 07403 4.2, n=1
AFS GBW 07405 ND
AFSGBW 07407 4.3, n=1
GF-AAS GBW 07402 0.065±0.007, n=2 0.071±0.014
GF-AAS GBW 07403 0.040, n=1
GF-AAS GBW 07405 0.44, n=1
GF-AAS GBW 07407 0.08, n=1
FAASGBW 07402 38±3, n=2
FAAS GBW 07403 35, n=1
FAAS GBW 07405 515, n=1
FAAS GBW 07407 143, n=1
253 X. Yin et al. / Science of the Total Environment 371 (2006) 252–257
span of every slice is in decades, the seasonal variations
in the seal hairs are expected to be averaged out.
The upper 16 cm sediments of the HF4 core were
sampled at 0.5 cm intervals (n=32) after picking out
seal hairs. N1 core was uniformly sectioned at 1.0 cm
intervals. All subsamples were air-dried in a clean room.
2.3. Element analysis
lotionand hot de-ionizedwater three times toremoveany
adsorbedand externalcontaminants; theywerethendried
temperature of the hot de-ionized water was about 60 °C.
The cleaned and dried samples were dissolved in high
purity grade nitric acid, hydrochloric acid, and perchloric
acid(Dickman etal.,1999).The HF4 sediments were air-
dried first, sieved with standard 100 mesh dm−2, pow-
dered and then dissolved. The total As concentrations of
all samples were determined using atomic fluorescence
spectrometry (AFS-2202a, Beijing Vital Co., China) with
instrument (Perkin-Elmer, PE1100B) with air-acetylene
flame. Graphite furnace atomic absorption spectroscopy
(GF-AAS; Perkin-Elmer, PE1100B) was used to deter-
mine the low contents of Pb and Cd. For quality control
purposes, certified reference materials (CRMs, supplied
batch of samples in 10% proportion. Table 1 lists the
determined contents of the certified reference material
Concentrations (μg g−1) of lead, copper, cadmium, zinc and arsenic in HF4 sediments (left) and in seal hairs (right) against depth
Lead CopperCadmium ArsenicZinc
SedimentsHairs SedimentsHairs SedimentsHairs SedimentsHairs Sediments Hairs
ND: not determined.
254X. Yin et al. / Science of the Total Environment 371 (2006) 252–257
results generally agree well with the certified values.
The chronological control of HF4 and N1 core was
based on conventional14C dating and was reported in
our previous publications (Liu et al., 2004; Sun et al.,
2004). Briefly, to reduce or eliminate the marine reser-
voir effect on14C dating, four HF4 subsamples with
very few seal hairs and six N1 subsamples were deter-
mined. The bottom ages of HF4 and N1 cores were
determined to be 1980 years before the present (yr BP,
the present as 2000 A.D.) and 3500 yr BP, respectively.
3. Results and discussion
The Pb concentrations are given in Table 2 and
show a clear upward increase in the seal hairs and the
N1 core, but not in the sediments of HF4. The lack of
a noticeable trend in the sediments of HF4 may be due
to the large grain sizes of the upper lake sediments; Pb
is more likely adsorbed by clay minerals, which con-
stitute a very small proportion of the beach sand sedi-
ments of HF4.
The Pb contents in the seal hairs and the weathering
sediments of N1 are plotted in Fig. 1 versus time and
show a sharp increment from the late 1800s. These
profiles are similar to these in penguin droppings (Sun
and Xie, 2001); and as in the penguin droppings, the
major source of Pb in the seal hairs could be the anthro-
pogenic Pb emissions since the industrial revolutions ca.
1840. The recent decrease of Pb deposition is consistent
with that observed in Antarctic snow (Wolff and Suttie,
1994), very likely owing to the ban on leaded gasoline
usage in the Southern Hemisphere. The decrease of Pb is
not observed in the surface sediments of N1 core,
probably due to the low-resolution of the data (Fig. 1).
As listed inTable 2,the concentrations of Cuinthe seal
hairs and the sediments of HF4 show a gradual decrease
from bottom to top. The Cu contents in the seal hairs and
the sediments of HF4 were 582 μg g−1and 147 μg g−1,
respectively, at 15–16 cm; they decreased to 213 μg g−1
and 104 μg g−1near the surface. The Cu content in the
weathering sediments of N1 core decreased from
126 μg g−1at 28–29 cm to 89.6 μg g−1on the surface.
The Cu content was almost constant during the last
was far lower than that (400–600 μg g−1) from 1000 A.D.
to 500 A.D.
An increasing emission of anthropogenic Cu was
reported in the Antarctic snow core since the mid-20th
century (Wolff et al., 1999; Planchon et al., 2002). If the
influence of human activities on the seal's living envi-
ronment is significant, the Cu content in seal hairs and
excrements would be expected to have a rising trend
similar to that in snow layers. However, the Cu content
is almost constant during the last 500 years. These
results suggest that the impact of human activities on the
Cu level of the studied seal hairs is insignificant. Addi-
tionally, we examined the 4100-year record of explosive
volcanism in the Southern Hemisphere (Cole-Dai et al.,
2000) and found no remarkable correlation between the
intensity of volcanic eruptions and the Cu contents in
the seal hairs. Therefore, the impact of volcanic erup-
tions appears immaterial.
As shown in Fig. 2a, however, there exists a notice-
able association between the Cu contents in all three
profiles (seal hairs, HF4 sediments, N1 sediments) and
the Fe2O3/FeO ratios; and statistical analysis (SPSS,
11.5 for Windows) gave a slightly positive correlation
(r=0.234, n=35, 2-tailed, p=0.186) between the levels
of Cu and Fe2O3/FeO in the N1 sediments (Fig. 2b). For
example, the Cu level significantly decreased between
1500 and 750 yr BP; similarly, the ratio of Fe2O3/FeO in
N1 decreased to 2.36 from 3.58. Both the Cu levels and
the Fe2O3/FeO ratios show peaks in the time periods of
3000–2500 yr BP and 1700–1400 yr BP and troughs in
the time periods of 2500–2000 yr BP and 3500 yr. BP,
respectively (Fig. 2b). A high ratio of Fe2O3/FeO indi-
cates warm/oxidation conditions. One possible explana-
tion for this association is that the warmer climate could
enlarge the ice-free area, enhance the weathering
Fig. 1. Concentrations of lead in the seal hairs and sediments of HF4
core on Fildes Peninsula and in weathering soil sediments of N1 core
on Nelson Island since 500 A.D.
255X. Yin et al. / Science of the Total Environment 371 (2006) 252–257
process, and bring more Cu-rich sand mass into the
marine environments; and the copper in seawater is
taken up by lives marine organisms and accumulated,
via bioaccumulation effect, in seal hairs.
The background level of Cu on King George Islands
and the Cu concentration in fresh animal droppings
from this region and East Antarctica are given in
Table 3. The Cu content in Gentoo penguin droppings
from Fildes Peninsula is 11.7 times that in Adelie pen-
guin droppings from Zhongshan Station in East Antarc-
tica, very likely due to the high background Cu level on
King George Islands. The Cu content in the surface soil
of King George Islands is about 2–3 times the Clarke
value, the average Cu content in earth crust. Natural
weathering processes, which are directly related to cli-
mate, could release Cu from Cu-rich rock in the envi-
3.3. Arsenic, cadmium, zinc
Pronounced enhancements of As, Cd and Zn were
observed during recent decades in Antarctic snow/ice,
and they were attributed to the emissions of heavy
metals into the atmosphere from human activities in
Southern America, Southern Africa and Australia,
Fig. 2. (a) Concentrations of copper in the seal hairs and sediments of
HF4 core on Fildes Peninsula and in the weathering soil sediments of
N1 core on Nelson Island since 500 A.D. (b) Temporal changes of
copper concentrations and climate proxy of Fe2O3/FeO in N1 core.
Comparison of the copper contents (μg g−1) in the droppings and
background soils from King George Island and Zhongshan Station,
Materials King George Island
Barton copper mined site
Clarke value of earth crust 31
Fig. 3. Concentrations of arsenic (a), cadmium (b), and zinc (c) in the
seal hairs and sediments of HF4 core and in weathering sediments of
N1 core since 500 A.D.
256 X. Yin et al. / Science of the Total Environment 371 (2006) 252–257
especially from non-ferrous metal mining and smelting
(Wolff et al., 1999; Planchon et al., 2002).
Similar trend does not exist in the seal hairs and in the
HF4 sediments, except for the abrupt increase of zinc at
the surface (Table 2). For the past 1500 years, the con-
centrations of As, Cd and Zn in the seal hairs and the
sediments of HF4 were very stable (Fig. 3). The in-
creasing Zn concentration near the surface is likely from
anthropogenic contamination, consistent with the report
that the aerosol in Antarctica is contaminated by the Zn
of modern industries (Dick, 1991).
The Pb concentration in the studied seal hairs and
weathering sediments sharply increased after the late
1800s, very likely the result of modern industrial activi-
ties; but it has fell by one third since the 1980s thanks to
the reduced use of leaded gasoline in the Southern
Hemisphere. The fluctuations of the Cu level seem to be
associated with climatic conditions. The contents of
As, Cd and Zn do not exhibit any remarkable temporal
Authors wish to thank Kenneth A. Rahn (University
of Rhode Island) for valuable advices and discussions.
The present study was financially supported by the
National Natural Science Foundation of China (Grant
Nos. 40476001 and 40231002).
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