Arch Environ Contam Toxicol DOI 10.1007/s00244-014-0039-1
Assessment of Lead Exposure in Waterfowl Species, Korea Jungsoo Kim • Jong-Min Oh
Received: 17 February 2014 / Accepted: 16 April 2014 Ó Springer Science+Business Media New York 2014
Abstract Lead concentrations were analyzed in whitefronted geese (Anser albifrons, n = 15), mallards (Anas platyrhynchos, n = 4), and spot-billed ducks (A. poecilorhyncha, n = 13) found dead near Gimpo, Korea, to determine tissue- and species-specific lead concentration differences and to assess the effect of embedded lead shot. In livers, kidneys, and bones (tarsus), mallards and spotbilled ducks with embedded shot had greater lead concentrations than white-fronted geese and spot-billed ducks without lead shot. Lead concentrations in spot-billed ducks were greater in bones than in livers and kidneys suggesting chronic exposure to lead. Lead concentrations in 8 of 32 livers, 5 of 32 kidneys, and 9 of 32 bones exceeded the threshold level of abnormal exposure for wild birds ([5 lg/g dw in lives,[6 lg/g dw in kidney, and[6.75 lg/ g dw in bone). Increased lead concentrations in soft tissues and bones might be attributed to increased lead shot ingestion and embedded shot. Lead concentrations were correlated between livers and kidneys, between livers and bones, and between kidneys and bones. These results suggest that a relationship between acute exposure in livers and kidneys and chronic exposure in bones.
Lead is a widespread environmental contaminant and a highly toxic heavy metal that is a potential hazard to wildlife, including birds. It is toxic in most of its chemical
J. Kim J.-M. Oh (&) Department of Environmental Science and Engineering, Kyung Hee University, 1 Seocheon-dong, Giheung-gu, Yongin 446-701, Gyeonggi-do, Republic of Korea e-mail: [email protected] J. Kim e-mail: [email protected]
forms, and human activities such as mining and smelting have increased the amount of bioavailable lead in the environment (Eisler 1988). Because of its long residence time in the soil (Klaminder et al. 2006), lead poses a threat to the environment decades after it has been released (Berglund et al. 2009). The diffusion into the environment of lead produced by human activities might historically be shown to affect wildlife (Eens et al. 1999). In addition, acute poisoning by exposure to a high concentration of lead during a short time period can cause mortality, and chronic exposure by prolonged exposure to lead at lower concentrations can lead to sublethal effects on reproductive success, behavior, immune response, and physiology and may cause population declines in sensitive or vulnerable species (Burger and Gochfeld 2000; Fair and Ricklefs 2002; Snoeijs et al. 2004). Gimpo (Han River estuary) in Korea provides important habitat for many species of waterbirds, including various waterfowl, gull species, and white-naped cranes (Grus vipio) in the winter season. In Korea, white-fronted geese (Anser albifrons) and mallards (Anas platyrhynchos) are winter residents, and spot-billed ducks (A. poecilorhyncha) are permanent residents. Lead poisoning from residual lead shot used in hunting has long been a significant cause of mortality for a range of waterbird species in a wetland, and lead poisoning has been well-documented in waterfowl species (Bianchi et al. 2011; Taggart et al. 2009). In this study, we examined the levels and distributions of lead in livers, kidneys, and bones of three waterfowl species. Liver and bone were used to evaluate both acute (short-term) and chronic (long-term) exposure. Our primary objectives were to (1) determine contaminant levels in the liver, kidney and bone tissues and compare among the three waterfowl species; and (2) determine effects of embedded lead shot in waterfowl.
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Materials and Methods Study Site and Sampling Fifteen carcasses of white-fronted geese (11 adults and 4 immature), 4 mallards, and 13 spot-billed ducks (10 adults and 3 immature) from Gimpo (36°630 N, 126°720 E), Gyeonggi-do, Korea, in February, 2012, were found. We found lead shot in 8 spot-billed ducks and all 4 mallards, so these birds might have died by shot injuries. The other causes of death were unknown. Livers, kidneys, and bones (tarsus) were removed from the carcasses and carefully prepared to avoid external contamination, stored in chemically clean plastic bags, and kept at -20 °C until they were dissected and analyzed. When later thawed, all livers, kidneys, and bones were carefully removed from the body and weighed (±0.1 g). Every tissue of each species were dried in an oven for 24 hours at 105 °C until no further weight decrease occurred and were homogenized in a glass Teflon homogenizer. Lead concentrations (lg/g) in all tissues were estimated on dry-weight (dw) basis. Lead Levels We categorized the toxicity of lead concentrations based on selected reports. Values of hepatic lead concentration [5.0 lg/g dw are considered the threshold level of abnormal exposure to lead in livers of waterfowl (Guitart et al. 1994); 5.0–24.0 lg/g dw are considered threshold levels; and levels[24.0 lg/g dw are compatible with death of birds (Franson 1996; Clark and Scheuhammer 2003). Lead concentrations in kidney [6.0–18.0 lg/g dw were considered toxic, and levels[18.0 lg/g dw was compatible with death. Scheuhammer and Dickson (1996) identified that bone lead concentrations [10 lg/g dw in juvenile waterfowl might prove to be a toxic exposure to lead. In addition, Mateo et al. (2003) suggested that lead bone concentrations [10 lg/g dw represent increased and potentially toxic, long-term exposure to lead over the lifetime of the bird. In addition, Clark and Scheuhammer (2003) considered lead levels of 6.75–10 lg/g dw in the bone to indicate exposure greater than background levels. In bone, levels \6.75 lg/g dw can be considered normal background accumulation of lead and are expected to have no toxic repercussions (Martin et al. 2008). Lead Analysis Approximately 3 g of each sample was digested in the presence of a mixture of concentrated nitric, perchloric, and/or sulfuric acids in Kjeldahl flasks. Lead concentrations in the digested solutions were extracted with sodium N,
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N-diethyldithio-carbamate trihydrate ((C2H5)2NCS2Na 3H2O) and methyl isobutyl ketone (CH3CH2CH(CH3)2) and determined by flame atomic absorption (AA) spectrophotometry (Hitachi Z-6100) (Kim and Oh 2013). Seven or eight spikes and blanks were included in the analysis (approximately 20 % of the total number of samples). A spike, a blank, a standard, and a sample were run in triplicate in each analytical run. Spikes recoveries ranged from 94 to 106 %. Recovered concentrations of the samples were within 5 % of the SE. Detection limits were 0.1 lg/g for lead. Statistical Analysis We statistically tested for differences of lead concentration between white-fronted geese and spot-billed ducks using Student t test and among the three tissues using one-way analysis of variance (ANOVA). Bonferroni mean separation test was used to separate species means after a significant ANOVA. Data were log-transformed to obtain a normal distribution that satisfied the homogeneity-of-variance assumptions of ANOVA (Kim and Oh 2013). We present geometric means, 95 % confidence intervals (CIs), arithmetic mean, and SD in tables and text. Correlations of lead concentrations between tissues were assessed using Pearson correlation (r). Statistical analyses were performed using SPSS 12.0 version (SPSS, Chicago, IL).
Results Lead Concentrations and Distribution Mean concentrations of lead in three tissues were considerably greater in livers (geometric mean 4.13 lg/g dw), kidneys (geometric mean 4.70 lg/g dw), and bones (geometric mean 8.63 lg/g dw) of spot-billed ducks and mallards (respectively, geometric mean 4.27, 4.10, and 7.16 lg/g dw) than in white-fronted geese (respectively, geometric mean 0.43, 0.51, and 0.48 lg/g dw) (Student t test, p \ 0.001) (Table 1). In bone, spot-billed ducks with embedded lead shot (geometric mean 10.4 lg/g dw) had greater lead concentrations than spot-billed ducks without lead shot (geometric mean 5.49 lg/g dw) (Student t test, p \ 0.001), but lead levels were not different in livers and kidneys (Fig. 1). Lead concentrations were significantly different among tissues in spot-billed ducks and mallards (ANOVA, p \ 0.001), but they were not different in white-fronted geese. In spot-billed ducks and mallards, lead concentrations were significantly greater in bones (geometric mean 8.63, 7.16 lg/g dw) than in livers (geometric mean 4.13, 4.27 lg/g dw) and kidneys (geometric mean 4.70, 4.10 lg/g dw) (Table 1).
Arch Environ Contam Toxicol Table 1 Lead concentrations (geometric mean, 95 % CIs) and mean ± SD (lg/g dw) in various tissues of three waterfowl species from Gimpo, Korea, in 2012 Species
Liver
Kidney
Bone
p1
NS
White-fronted geese (n = 15) Geometric mean
0.43B2
0.51B
0.48B
CIs
0.08–1.75
0.07–3.42
0.10–1.10
Mean ± SD
1.32 ± 2.61
3.08 ± 5.75
0.93 ± 1.22
Geometric mean
4.27A,b3
4.10A,b
7.16A,a
CIs Mean ± SD
0.22–8.32 4.74 ± 2.92
3.94–4.26 4.10 ± 0.12
2.77–18.5 10.6 ± 11.1
Mallards (n = 4) \0.01
Spot-billed ducks (n = 13) Geometric mean
4.13A,b
4.70A,b
8.63A,a
CIs
2.39–5.87
3.23–6.17
3.83–13.4
Mean ± SD p4
4.61 ± 2.51
5.14 ± 2.12
10.3 ± 6.94
\0.001
\0.001
\0.001
\0.01
NS not significant 1
p value for ANOVA comparing among tissues for each species
2
Means sharing the same upper-case letter were not significantly different among species
3
Means sharing the same lower-case letter were not significantly different among tissues
4
p value for ANOVA comparing among species
Lead Levels
Discussion
Lead concentrations in livers in 1 of 15 (6.67 %) whitefronted geese (9.72 lg/g dw), 2 of 4 (50.0 %) mallards (5.45–6.08 lg/g dw), and 5 of 13 (38.5 %) spot-billed ducks (5.23–9.66 lg/g dw) exceeded the threshold level of abnormal exposure in livers for waterfowl ([5 lg/g dw). In kidneys, 5 of 13 (38.5 %) spot-billed ducks (6.38–7.68 lg/ g dw) exceeded the threshold level of abnormal exposure to lead in kidney for wild birds ([6 lg/g dw). In bones, 1 of 4 mallards (25.0 %) and 4 of 13 (30.8 %) spot-billed ducks were within the 6.75–10.0 lg/g dw (8.78 and 7.05–9.98 lg/g dw, respectively) range of elevated lead exposure. In addition, 1 of 4 mallards (25.0 %) and 3 of 13 spot-billed ducks (23.1 %) exceeded the toxic lead bone threshold of 10.0 lg/g dw (18.5 and 13.1–23.4 lg/g dw, respectively).
Tissue-Specific Comparison
Correlation Between Tissues In geese and ducks combined (n = 32), lead concentrations in livers were significantly correlated with lead concentrations in kidneys (r = 0.664, p \0.001) and bones (r = 0.818, p \ 0.001). There was a significant correlation between lead concentrations in kidneys and bones (r = 0.827, p \ 0.001) (Fig. 2).
In duck species, lead concentrations were significantly different among tissues with mean concentrations of lead being greater in bones than in livers and kidneys of spotbilled ducks and mallards but not geese. This tissue-specific accumulation has been found in other waterfowl species such as canada geese (Branta canadensis) (Tsipoura et al. 2011), marbled teals (Marmaronetta angustirostris), and white-headed ducks (Oxyura leucocephala) (Mateo et al. 2001) as well as some other waterfowl species (Guitart et al. 1994). In the present study, mean lead concentrations in bones of mallards and spot-billed ducks (with or without embedded shot) were greater than those observed in livers or kidneys, which might suggest chronic exposure to the metal. In contrast, one immature whitefronted goose had an increased lead concentration (9.72 lg/g dw) in the liver, whereas the bone concentration was the background lead level (4.33 lg/g dw) suggesting acute exposure in this one goose. Lead Levels in Relation to Toxicity In the present study, 8 of 32 (25.0 %) birds had increased levels of lead consistent with subclinical or acute effects in at
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Arch Environ Contam Toxicol 20
24
10
16
Bone (
/g dw) Kidney (
10
/g dw)
t-test, p < 0.001
/g dw Lead
15
5
8
0 Embedded shot
No shot
Livers
Embedded shot
No shot
Kidneys
Embedded shot
No shot
Bones
0
0 0
Correlations Between Tissues In soft tissues, such as the liver and kidney, elevated lead concentrations reflect recent and acute exposure to
123
0
/g dw)
5
Liver (
10
/g dw)
30
/g dw)
least one tissue. In the current study, 8 specimens had lead levels of 5.23–9.72 lg/g dw in the liver, and the percentage was relatively greater in mallards (50.0 %) and spot-billed ducks (62.5 %) with embedded shot than in white-fronted geese with embedded shot (6.67 %). These percentage were greater than those found in Spain, 25.6 % of mallards (Guitart et al. 1994), 23.3 % of 5 waterfowl species (Mateo et al. 1998), 31.6 % of 2 duck species (Mateo et al. 2001), 2.42 % of several waterfowl species (Taggart et al. 2006), 2.80 % of marbled teals, and 91.7 % of white-headed ducks (Taggart et al. 2009). Five spot-billed ducks with embedded shot (15.6 %) had [6 lg/g dw in the kidneys (considered threshold lead level). This was less than 34.5 % of shorebirds (Kim and Koo 2010). In this study, 5 of 32 (15.6 %) specimens had elevated lead levels in bone (6.75–10 lg/g dw [Clark and Scheuhammer 2003; Martin et al. 2008]). Four ducks (13.3 %) had lead concentrations in their bones suggestive of subclinical toxicity ([10 lg/g dw [Pain 1996]),and all of them had embedded shot. This was similar to Spain where 12.9 % of waterbirds—including waterfowl (Taggart et al. 2006), 8.24 % of 2 duck species (Mateo et al. 2001), 12.9 % of marbled teals (11 of 85) but less than 91.4 % (32 of 35) white-headed ducks (Taggart et al. 2009). Spot-billed ducks in this study had lead concentrations in livers and kidneys that were not different between the ducks with and without embedded shot, but the concentrations in bones were different. Based on these results, elevated lead concentrations in spot-billed ducks with embedded shot were associated with long-term exposure but not recent exposure by acute contamination.
Liver (
10
Bone (
Fig. 1 Lead concentrations (geometric mean, 95 % CIs) in livers, kidneys, and bones of spot-billed ducks from Gimpo, Korea, in 2012 with (n = 8) and without (n = 5) embedded shot
5
20
10
0
0
5
Kidney (
10
15
/g dw)
Fig. 2 Lead concentrations in various tissues in white-fronted geese (black circles no shot), mallards (black diamonds embedded shot), and spot-billed ducks (black squares no shot, black triangle embedded shot) from Gimpo, Korea, in 2012
environmental lead; however, lead tends to accumulate with age, and high lead concentrations in the bone represent long-term lead exposure because uptake of lead by bone is rapid and loss of lead slow (Scheuhammer 1987; Garcı´a-Ferna´ndez et al. 1997). In this study, lead concentrations of white-fronted geese were not different among tissues. Bone concentration of mallards and spot-billed ducks were greater than those in liver or kidney suggesting elevated chronic exposure to lead. We suggest that the chronic exposure is typical of environmental exposure to low lead levels over an extended period of time. In addition, this finding has been reported in many birds including waterfowl (Garcı´a-Ferna´ndez et al. 1997; Mateo et al. 2001; Taggart et al. 2006; Kim and Oh 2013). As a result of rapid deposition of lead into primarily liver and kidney after lead exposure (Pain 1996), lead concentrations in these two tissues are often correlated. We found strong correlations between lead concentrations in liver and those in kidney. Significant correlation between in
Arch Environ Contam Toxicol
these two tissues has been documented in various wild birds including waterfowl (Garcı´a-Ferna´ndez et al. 1997; Wayland et al. 1999; Mateo et al. 2001; Martin et al. 2008). Effect of Embedded Shot Acute lead poisoning may quickly cause death; therefore, elevated lead concentrations would only be detected in soft tissues, and bone lead concentration would not be elevated because lead deposition has no time to occur (Pain et al. 2005). In contrast, chronic and repeated non-lethal acute exposures in birds may lead to the high lead accumulation in bone over time in the absence of acute toxicity (Gangoso et al. 2009). Therefore, lead concentrations of mallards and spot-billed ducks in the present study probably came from chronic exposure rather than acute exposure although their concentrations were relatively greater than found in whitefronted geese. This study might be the first report on embedded lead shot in waterfowl in Korea.
Conclusion Lead concentrations in three species of waterfowl found dead had species- and tissue-specific accumulations. Many of them exceeded the background level in the liver (25.0 %), kidney (15.6 %), and bone (28.1 %) for wild birds. In mallards and spot-billed ducks, mean lead concentrations in bones probably reflected chronic exposure to lead. Chronic exposure in both species might represent exposure to high lead contamination in their migratory route as well a in their breeding and wintering habitats. We found strong and significant correlations between liver or kidney and bone. Mallards and spot-billed ducks with embedded lead shot had significant high lead concentrations compared with white-fronted geese and spot-billed ducks without lead shot. This problem will continue because of illegal hunting using lead shot. Acknowledgement We are grateful to Thomas W. Custer (United States Geological Survey) for critical reading of and comments on the manuscript.
References Berglund AMM, Klaminder J, Nyholm NEI (2009) Effects of reduced lead deposition on pied flycatcher (Ficedula hypoleuca) nestlings: tracing exposure routes using stable lead isotopes. Environ Sci Technol 43:208–213 Bianchi N, Fottino S, Leonzio C, Ancora S (2011) Ecotoxicological study on lead shot from hunting in the Padule di Fucecchio marsh. Chem Ecol 27:153–166
Burger J, Gochfeld M (2000) Effects of lead on birds (Laridae): a review of laboratory and field studies. J Toxicol Environ Health 3:59–78 Clark AJ, Scheuhammer AM (2003) Lead poisoning in up-landforaging birds of prey in Canada. Ecotoxicology 12:23–30 Eens M, Pinxten R, Verheyen RF, Blust R, Bervoets L (1999) Great and blue tits as indicators of heavy metal contamination in terrestrial ecosystems. Ecotoxicol Environ Safety 44:81–85 Eisler R (1988) Lead hazards to fish wildlife, and invertebrates: a synoptic review. Biological Report 85(1.14), Contaminant Hazard Reviews. United States Fish and Wildlife Service, Patuxent Wildlife Research Center, Laurel Fair JM, Ricklefs RE (2002) Physiological, growth, and immune responses of Japanese quail chicks to the multiple stressors of immunological challenge and lead shot. Arch Environ Contam Toxicol 42:77–87 Franson JC (1996) Interpretation of tissue lead residues in birds other than waterfowl. In: Beyer WN, Heinz GH, Redmon-Norwood AW (eds) Environmental contaminants in wildlife: interpreting tissue concentrations. CRC, Boca Raton, pp 265–279 ´ lvarez-Lloret P, Rodrı´guez-Navarro AAB, Mateo R, Gangoso L, A Hiraldo F, Dona´zar JA (2009) Long-term effects of lead poisoning on bone mineralization in vultures exposed to ammunition sources. Environ Pollut 157:569–574 Garcı´a-Ferna´ndez AJ, Motas-Guzman M, Nava I, Marı´a-Mo´jica A, Luna A, Sa´nchez-Garcı´a JA (1997) Environmental exposure and distribution of lead in four species of raptors in Southeastern Spain. Arch Environ Contam Toxicol 33:76–82 Guitart R, To-Figueras J, Mateo R, Bertolero A, Cerradelo S, Martı´nez-Vilalta A (1994) Lead poisoning in waterfowl from the Ebro Delta, Spain: calculations of lead exposure thresholds for mallards. Arch Environ Contam Toxicol 27:289–293 Kim J, Koo T-H (2010) Acute and/or chronic contaminations of heavy metals in shorebirds from Korea. J Environ Monit 12:1613–1618 Kim J, Oh J-M (2013) Tissue distribution of metals in white-fronted geese and spot-billed ducks from Korea. Bull Environ Contam Toxicol 91:18–22 Klaminder J, Bindler R, Emteryd O, Appleby P, Grip H (2006) Estimating the mean residence time of lead in the organic horizon of boreal forest soils using 210-lead, stable lead and a soil chronosequence. Biogeochemistry 78:31–49 Martin PA, Campbell D, Hughes K, McDaniel T (2008) Lead in the tissues of terrestrial raptors in southern Ontario, Canada, 1995–2001. Sci Total Environ 391:96–103 Mateo R, Belliure J, Dolz JC, Aguilar Serrano JM, Guitart R (1998) High prevalences of lead poisoning in wintering waterfowl in Spain. Arch Environ Contam Toxicol 35:342–347 Mateo R, Green AJ, Jeske CW, Urios V, Gerique C (2001) Lead poisoning in the globally threatened marbled teal and white headed duck in Spain. Environ Toxicol Chem 20:2860–2868 Mateo R, Taggart M, Meharg AA (2003) Lead and arsenic in bones of birds of prey from Spain. Environ Pollut 126:107–114 Pain DJ (1996) Lead in waterfowl. In: Beyer NW, Heinz GH, Redman-Norwood SW (eds) Environmental contaminants in wildlife: interpreting tissue concentrations. Lewis, Boca Raton, pp 251–264 Pain DJ, Meharg AA, Ferrer M, Taggart M, Penteriani V (2005) Lead concentrations in bones and feathers of the globally threatened Spanish imperial eagle. Biol Conserv 121:603–610 Scheuhammer AM (1987) The chronic toxicity aluminium, cadmium, mercury and lead in birds: a review. Environ Pollut 46:263–295 Scheuhammer AM, Dickson KM (1996) Patterns of environmental lead exposure in waterfowl in Eastern Canada. Ambio 25:14–20 Snoeijs T, Dauwe T, Pinxten R, Vandesande F, Eens M (2004) Heavy metal exposure affects the humoral immune response in a
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Arch Environ Contam Toxicol free-living small songbird, the great tit (Parus major). Arch Environ Contam Toxicol 46:399–404 Taggart MA, Figuerola J, Green AJ, Mateo R, Deacon C, Osborn D et al (2006) After the Aznalco´llar mine spill: Arsenic, zinc, selenium, lead and copper levels in the livers and bones of five waterfowl species. Environ Pollut 100:349–361 Taggart MA, Green AJ, Mateo R, Svanberg F, Hillstro¨m L, Meharg AA (2009) Metal levels in the bones and livers of globally threatened marbled teal and white-headed duck from El Hondo, Spain. Ecotoxicol Environ Safe 72:1–9
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Tsipoura N, Burger J, Newhouse M, Jeitner C, Gochfeld M, Mizrahi D (2011) Lead, mercury, cadmium, chromium, and arsenic levels in eggs, feathers, and tissues of Canada geese of the New Jersey Meadowlands. Environ Res 111:775–784 Wayland M, Neugebauer E, Bollinger T (1999) Concentrations of lead in liver, kidney, and bone of bald and golden eagles. Arch Environ Contam Toxicol 37:267–272
Assessment of Lead Exposure in Waterfowl Species, Korea Jungsoo Kim • Jong-Min Oh
Received: 17 February 2014 / Accepted: 16 April 2014 Ó Springer Science+Business Media New York 2014
Abstract Lead concentrations were analyzed in whitefronted geese (Anser albifrons, n = 15), mallards (Anas platyrhynchos, n = 4), and spot-billed ducks (A. poecilorhyncha, n = 13) found dead near Gimpo, Korea, to determine tissue- and species-specific lead concentration differences and to assess the effect of embedded lead shot. In livers, kidneys, and bones (tarsus), mallards and spotbilled ducks with embedded shot had greater lead concentrations than white-fronted geese and spot-billed ducks without lead shot. Lead concentrations in spot-billed ducks were greater in bones than in livers and kidneys suggesting chronic exposure to lead. Lead concentrations in 8 of 32 livers, 5 of 32 kidneys, and 9 of 32 bones exceeded the threshold level of abnormal exposure for wild birds ([5 lg/g dw in lives,[6 lg/g dw in kidney, and[6.75 lg/ g dw in bone). Increased lead concentrations in soft tissues and bones might be attributed to increased lead shot ingestion and embedded shot. Lead concentrations were correlated between livers and kidneys, between livers and bones, and between kidneys and bones. These results suggest that a relationship between acute exposure in livers and kidneys and chronic exposure in bones.
Lead is a widespread environmental contaminant and a highly toxic heavy metal that is a potential hazard to wildlife, including birds. It is toxic in most of its chemical
J. Kim J.-M. Oh (&) Department of Environmental Science and Engineering, Kyung Hee University, 1 Seocheon-dong, Giheung-gu, Yongin 446-701, Gyeonggi-do, Republic of Korea e-mail: [email protected] J. Kim e-mail: [email protected]
forms, and human activities such as mining and smelting have increased the amount of bioavailable lead in the environment (Eisler 1988). Because of its long residence time in the soil (Klaminder et al. 2006), lead poses a threat to the environment decades after it has been released (Berglund et al. 2009). The diffusion into the environment of lead produced by human activities might historically be shown to affect wildlife (Eens et al. 1999). In addition, acute poisoning by exposure to a high concentration of lead during a short time period can cause mortality, and chronic exposure by prolonged exposure to lead at lower concentrations can lead to sublethal effects on reproductive success, behavior, immune response, and physiology and may cause population declines in sensitive or vulnerable species (Burger and Gochfeld 2000; Fair and Ricklefs 2002; Snoeijs et al. 2004). Gimpo (Han River estuary) in Korea provides important habitat for many species of waterbirds, including various waterfowl, gull species, and white-naped cranes (Grus vipio) in the winter season. In Korea, white-fronted geese (Anser albifrons) and mallards (Anas platyrhynchos) are winter residents, and spot-billed ducks (A. poecilorhyncha) are permanent residents. Lead poisoning from residual lead shot used in hunting has long been a significant cause of mortality for a range of waterbird species in a wetland, and lead poisoning has been well-documented in waterfowl species (Bianchi et al. 2011; Taggart et al. 2009). In this study, we examined the levels and distributions of lead in livers, kidneys, and bones of three waterfowl species. Liver and bone were used to evaluate both acute (short-term) and chronic (long-term) exposure. Our primary objectives were to (1) determine contaminant levels in the liver, kidney and bone tissues and compare among the three waterfowl species; and (2) determine effects of embedded lead shot in waterfowl.
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Arch Environ Contam Toxicol
Materials and Methods Study Site and Sampling Fifteen carcasses of white-fronted geese (11 adults and 4 immature), 4 mallards, and 13 spot-billed ducks (10 adults and 3 immature) from Gimpo (36°630 N, 126°720 E), Gyeonggi-do, Korea, in February, 2012, were found. We found lead shot in 8 spot-billed ducks and all 4 mallards, so these birds might have died by shot injuries. The other causes of death were unknown. Livers, kidneys, and bones (tarsus) were removed from the carcasses and carefully prepared to avoid external contamination, stored in chemically clean plastic bags, and kept at -20 °C until they were dissected and analyzed. When later thawed, all livers, kidneys, and bones were carefully removed from the body and weighed (±0.1 g). Every tissue of each species were dried in an oven for 24 hours at 105 °C until no further weight decrease occurred and were homogenized in a glass Teflon homogenizer. Lead concentrations (lg/g) in all tissues were estimated on dry-weight (dw) basis. Lead Levels We categorized the toxicity of lead concentrations based on selected reports. Values of hepatic lead concentration [5.0 lg/g dw are considered the threshold level of abnormal exposure to lead in livers of waterfowl (Guitart et al. 1994); 5.0–24.0 lg/g dw are considered threshold levels; and levels[24.0 lg/g dw are compatible with death of birds (Franson 1996; Clark and Scheuhammer 2003). Lead concentrations in kidney [6.0–18.0 lg/g dw were considered toxic, and levels[18.0 lg/g dw was compatible with death. Scheuhammer and Dickson (1996) identified that bone lead concentrations [10 lg/g dw in juvenile waterfowl might prove to be a toxic exposure to lead. In addition, Mateo et al. (2003) suggested that lead bone concentrations [10 lg/g dw represent increased and potentially toxic, long-term exposure to lead over the lifetime of the bird. In addition, Clark and Scheuhammer (2003) considered lead levels of 6.75–10 lg/g dw in the bone to indicate exposure greater than background levels. In bone, levels \6.75 lg/g dw can be considered normal background accumulation of lead and are expected to have no toxic repercussions (Martin et al. 2008). Lead Analysis Approximately 3 g of each sample was digested in the presence of a mixture of concentrated nitric, perchloric, and/or sulfuric acids in Kjeldahl flasks. Lead concentrations in the digested solutions were extracted with sodium N,
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N-diethyldithio-carbamate trihydrate ((C2H5)2NCS2Na 3H2O) and methyl isobutyl ketone (CH3CH2CH(CH3)2) and determined by flame atomic absorption (AA) spectrophotometry (Hitachi Z-6100) (Kim and Oh 2013). Seven or eight spikes and blanks were included in the analysis (approximately 20 % of the total number of samples). A spike, a blank, a standard, and a sample were run in triplicate in each analytical run. Spikes recoveries ranged from 94 to 106 %. Recovered concentrations of the samples were within 5 % of the SE. Detection limits were 0.1 lg/g for lead. Statistical Analysis We statistically tested for differences of lead concentration between white-fronted geese and spot-billed ducks using Student t test and among the three tissues using one-way analysis of variance (ANOVA). Bonferroni mean separation test was used to separate species means after a significant ANOVA. Data were log-transformed to obtain a normal distribution that satisfied the homogeneity-of-variance assumptions of ANOVA (Kim and Oh 2013). We present geometric means, 95 % confidence intervals (CIs), arithmetic mean, and SD in tables and text. Correlations of lead concentrations between tissues were assessed using Pearson correlation (r). Statistical analyses were performed using SPSS 12.0 version (SPSS, Chicago, IL).
Results Lead Concentrations and Distribution Mean concentrations of lead in three tissues were considerably greater in livers (geometric mean 4.13 lg/g dw), kidneys (geometric mean 4.70 lg/g dw), and bones (geometric mean 8.63 lg/g dw) of spot-billed ducks and mallards (respectively, geometric mean 4.27, 4.10, and 7.16 lg/g dw) than in white-fronted geese (respectively, geometric mean 0.43, 0.51, and 0.48 lg/g dw) (Student t test, p \ 0.001) (Table 1). In bone, spot-billed ducks with embedded lead shot (geometric mean 10.4 lg/g dw) had greater lead concentrations than spot-billed ducks without lead shot (geometric mean 5.49 lg/g dw) (Student t test, p \ 0.001), but lead levels were not different in livers and kidneys (Fig. 1). Lead concentrations were significantly different among tissues in spot-billed ducks and mallards (ANOVA, p \ 0.001), but they were not different in white-fronted geese. In spot-billed ducks and mallards, lead concentrations were significantly greater in bones (geometric mean 8.63, 7.16 lg/g dw) than in livers (geometric mean 4.13, 4.27 lg/g dw) and kidneys (geometric mean 4.70, 4.10 lg/g dw) (Table 1).
Arch Environ Contam Toxicol Table 1 Lead concentrations (geometric mean, 95 % CIs) and mean ± SD (lg/g dw) in various tissues of three waterfowl species from Gimpo, Korea, in 2012 Species
Liver
Kidney
Bone
p1
NS
White-fronted geese (n = 15) Geometric mean
0.43B2
0.51B
0.48B
CIs
0.08–1.75
0.07–3.42
0.10–1.10
Mean ± SD
1.32 ± 2.61
3.08 ± 5.75
0.93 ± 1.22
Geometric mean
4.27A,b3
4.10A,b
7.16A,a
CIs Mean ± SD
0.22–8.32 4.74 ± 2.92
3.94–4.26 4.10 ± 0.12
2.77–18.5 10.6 ± 11.1
Mallards (n = 4) \0.01
Spot-billed ducks (n = 13) Geometric mean
4.13A,b
4.70A,b
8.63A,a
CIs
2.39–5.87
3.23–6.17
3.83–13.4
Mean ± SD p4
4.61 ± 2.51
5.14 ± 2.12
10.3 ± 6.94
\0.001
\0.001
\0.001
\0.01
NS not significant 1
p value for ANOVA comparing among tissues for each species
2
Means sharing the same upper-case letter were not significantly different among species
3
Means sharing the same lower-case letter were not significantly different among tissues
4
p value for ANOVA comparing among species
Lead Levels
Discussion
Lead concentrations in livers in 1 of 15 (6.67 %) whitefronted geese (9.72 lg/g dw), 2 of 4 (50.0 %) mallards (5.45–6.08 lg/g dw), and 5 of 13 (38.5 %) spot-billed ducks (5.23–9.66 lg/g dw) exceeded the threshold level of abnormal exposure in livers for waterfowl ([5 lg/g dw). In kidneys, 5 of 13 (38.5 %) spot-billed ducks (6.38–7.68 lg/ g dw) exceeded the threshold level of abnormal exposure to lead in kidney for wild birds ([6 lg/g dw). In bones, 1 of 4 mallards (25.0 %) and 4 of 13 (30.8 %) spot-billed ducks were within the 6.75–10.0 lg/g dw (8.78 and 7.05–9.98 lg/g dw, respectively) range of elevated lead exposure. In addition, 1 of 4 mallards (25.0 %) and 3 of 13 spot-billed ducks (23.1 %) exceeded the toxic lead bone threshold of 10.0 lg/g dw (18.5 and 13.1–23.4 lg/g dw, respectively).
Tissue-Specific Comparison
Correlation Between Tissues In geese and ducks combined (n = 32), lead concentrations in livers were significantly correlated with lead concentrations in kidneys (r = 0.664, p \0.001) and bones (r = 0.818, p \ 0.001). There was a significant correlation between lead concentrations in kidneys and bones (r = 0.827, p \ 0.001) (Fig. 2).
In duck species, lead concentrations were significantly different among tissues with mean concentrations of lead being greater in bones than in livers and kidneys of spotbilled ducks and mallards but not geese. This tissue-specific accumulation has been found in other waterfowl species such as canada geese (Branta canadensis) (Tsipoura et al. 2011), marbled teals (Marmaronetta angustirostris), and white-headed ducks (Oxyura leucocephala) (Mateo et al. 2001) as well as some other waterfowl species (Guitart et al. 1994). In the present study, mean lead concentrations in bones of mallards and spot-billed ducks (with or without embedded shot) were greater than those observed in livers or kidneys, which might suggest chronic exposure to the metal. In contrast, one immature whitefronted goose had an increased lead concentration (9.72 lg/g dw) in the liver, whereas the bone concentration was the background lead level (4.33 lg/g dw) suggesting acute exposure in this one goose. Lead Levels in Relation to Toxicity In the present study, 8 of 32 (25.0 %) birds had increased levels of lead consistent with subclinical or acute effects in at
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Arch Environ Contam Toxicol 20
24
10
16
Bone (
/g dw) Kidney (
10
/g dw)
t-test, p < 0.001
/g dw Lead
15
5
8
0 Embedded shot
No shot
Livers
Embedded shot
No shot
Kidneys
Embedded shot
No shot
Bones
0
0 0
Correlations Between Tissues In soft tissues, such as the liver and kidney, elevated lead concentrations reflect recent and acute exposure to
123
0
/g dw)
5
Liver (
10
/g dw)
30
/g dw)
least one tissue. In the current study, 8 specimens had lead levels of 5.23–9.72 lg/g dw in the liver, and the percentage was relatively greater in mallards (50.0 %) and spot-billed ducks (62.5 %) with embedded shot than in white-fronted geese with embedded shot (6.67 %). These percentage were greater than those found in Spain, 25.6 % of mallards (Guitart et al. 1994), 23.3 % of 5 waterfowl species (Mateo et al. 1998), 31.6 % of 2 duck species (Mateo et al. 2001), 2.42 % of several waterfowl species (Taggart et al. 2006), 2.80 % of marbled teals, and 91.7 % of white-headed ducks (Taggart et al. 2009). Five spot-billed ducks with embedded shot (15.6 %) had [6 lg/g dw in the kidneys (considered threshold lead level). This was less than 34.5 % of shorebirds (Kim and Koo 2010). In this study, 5 of 32 (15.6 %) specimens had elevated lead levels in bone (6.75–10 lg/g dw [Clark and Scheuhammer 2003; Martin et al. 2008]). Four ducks (13.3 %) had lead concentrations in their bones suggestive of subclinical toxicity ([10 lg/g dw [Pain 1996]),and all of them had embedded shot. This was similar to Spain where 12.9 % of waterbirds—including waterfowl (Taggart et al. 2006), 8.24 % of 2 duck species (Mateo et al. 2001), 12.9 % of marbled teals (11 of 85) but less than 91.4 % (32 of 35) white-headed ducks (Taggart et al. 2009). Spot-billed ducks in this study had lead concentrations in livers and kidneys that were not different between the ducks with and without embedded shot, but the concentrations in bones were different. Based on these results, elevated lead concentrations in spot-billed ducks with embedded shot were associated with long-term exposure but not recent exposure by acute contamination.
Liver (
10
Bone (
Fig. 1 Lead concentrations (geometric mean, 95 % CIs) in livers, kidneys, and bones of spot-billed ducks from Gimpo, Korea, in 2012 with (n = 8) and without (n = 5) embedded shot
5
20
10
0
0
5
Kidney (
10
15
/g dw)
Fig. 2 Lead concentrations in various tissues in white-fronted geese (black circles no shot), mallards (black diamonds embedded shot), and spot-billed ducks (black squares no shot, black triangle embedded shot) from Gimpo, Korea, in 2012
environmental lead; however, lead tends to accumulate with age, and high lead concentrations in the bone represent long-term lead exposure because uptake of lead by bone is rapid and loss of lead slow (Scheuhammer 1987; Garcı´a-Ferna´ndez et al. 1997). In this study, lead concentrations of white-fronted geese were not different among tissues. Bone concentration of mallards and spot-billed ducks were greater than those in liver or kidney suggesting elevated chronic exposure to lead. We suggest that the chronic exposure is typical of environmental exposure to low lead levels over an extended period of time. In addition, this finding has been reported in many birds including waterfowl (Garcı´a-Ferna´ndez et al. 1997; Mateo et al. 2001; Taggart et al. 2006; Kim and Oh 2013). As a result of rapid deposition of lead into primarily liver and kidney after lead exposure (Pain 1996), lead concentrations in these two tissues are often correlated. We found strong correlations between lead concentrations in liver and those in kidney. Significant correlation between in
Arch Environ Contam Toxicol
these two tissues has been documented in various wild birds including waterfowl (Garcı´a-Ferna´ndez et al. 1997; Wayland et al. 1999; Mateo et al. 2001; Martin et al. 2008). Effect of Embedded Shot Acute lead poisoning may quickly cause death; therefore, elevated lead concentrations would only be detected in soft tissues, and bone lead concentration would not be elevated because lead deposition has no time to occur (Pain et al. 2005). In contrast, chronic and repeated non-lethal acute exposures in birds may lead to the high lead accumulation in bone over time in the absence of acute toxicity (Gangoso et al. 2009). Therefore, lead concentrations of mallards and spot-billed ducks in the present study probably came from chronic exposure rather than acute exposure although their concentrations were relatively greater than found in whitefronted geese. This study might be the first report on embedded lead shot in waterfowl in Korea.
Conclusion Lead concentrations in three species of waterfowl found dead had species- and tissue-specific accumulations. Many of them exceeded the background level in the liver (25.0 %), kidney (15.6 %), and bone (28.1 %) for wild birds. In mallards and spot-billed ducks, mean lead concentrations in bones probably reflected chronic exposure to lead. Chronic exposure in both species might represent exposure to high lead contamination in their migratory route as well a in their breeding and wintering habitats. We found strong and significant correlations between liver or kidney and bone. Mallards and spot-billed ducks with embedded lead shot had significant high lead concentrations compared with white-fronted geese and spot-billed ducks without lead shot. This problem will continue because of illegal hunting using lead shot. Acknowledgement We are grateful to Thomas W. Custer (United States Geological Survey) for critical reading of and comments on the manuscript.
References Berglund AMM, Klaminder J, Nyholm NEI (2009) Effects of reduced lead deposition on pied flycatcher (Ficedula hypoleuca) nestlings: tracing exposure routes using stable lead isotopes. Environ Sci Technol 43:208–213 Bianchi N, Fottino S, Leonzio C, Ancora S (2011) Ecotoxicological study on lead shot from hunting in the Padule di Fucecchio marsh. Chem Ecol 27:153–166
Burger J, Gochfeld M (2000) Effects of lead on birds (Laridae): a review of laboratory and field studies. J Toxicol Environ Health 3:59–78 Clark AJ, Scheuhammer AM (2003) Lead poisoning in up-landforaging birds of prey in Canada. Ecotoxicology 12:23–30 Eens M, Pinxten R, Verheyen RF, Blust R, Bervoets L (1999) Great and blue tits as indicators of heavy metal contamination in terrestrial ecosystems. Ecotoxicol Environ Safety 44:81–85 Eisler R (1988) Lead hazards to fish wildlife, and invertebrates: a synoptic review. Biological Report 85(1.14), Contaminant Hazard Reviews. United States Fish and Wildlife Service, Patuxent Wildlife Research Center, Laurel Fair JM, Ricklefs RE (2002) Physiological, growth, and immune responses of Japanese quail chicks to the multiple stressors of immunological challenge and lead shot. Arch Environ Contam Toxicol 42:77–87 Franson JC (1996) Interpretation of tissue lead residues in birds other than waterfowl. In: Beyer WN, Heinz GH, Redmon-Norwood AW (eds) Environmental contaminants in wildlife: interpreting tissue concentrations. CRC, Boca Raton, pp 265–279 ´ lvarez-Lloret P, Rodrı´guez-Navarro AAB, Mateo R, Gangoso L, A Hiraldo F, Dona´zar JA (2009) Long-term effects of lead poisoning on bone mineralization in vultures exposed to ammunition sources. Environ Pollut 157:569–574 Garcı´a-Ferna´ndez AJ, Motas-Guzman M, Nava I, Marı´a-Mo´jica A, Luna A, Sa´nchez-Garcı´a JA (1997) Environmental exposure and distribution of lead in four species of raptors in Southeastern Spain. Arch Environ Contam Toxicol 33:76–82 Guitart R, To-Figueras J, Mateo R, Bertolero A, Cerradelo S, Martı´nez-Vilalta A (1994) Lead poisoning in waterfowl from the Ebro Delta, Spain: calculations of lead exposure thresholds for mallards. Arch Environ Contam Toxicol 27:289–293 Kim J, Koo T-H (2010) Acute and/or chronic contaminations of heavy metals in shorebirds from Korea. J Environ Monit 12:1613–1618 Kim J, Oh J-M (2013) Tissue distribution of metals in white-fronted geese and spot-billed ducks from Korea. Bull Environ Contam Toxicol 91:18–22 Klaminder J, Bindler R, Emteryd O, Appleby P, Grip H (2006) Estimating the mean residence time of lead in the organic horizon of boreal forest soils using 210-lead, stable lead and a soil chronosequence. Biogeochemistry 78:31–49 Martin PA, Campbell D, Hughes K, McDaniel T (2008) Lead in the tissues of terrestrial raptors in southern Ontario, Canada, 1995–2001. Sci Total Environ 391:96–103 Mateo R, Belliure J, Dolz JC, Aguilar Serrano JM, Guitart R (1998) High prevalences of lead poisoning in wintering waterfowl in Spain. Arch Environ Contam Toxicol 35:342–347 Mateo R, Green AJ, Jeske CW, Urios V, Gerique C (2001) Lead poisoning in the globally threatened marbled teal and white headed duck in Spain. Environ Toxicol Chem 20:2860–2868 Mateo R, Taggart M, Meharg AA (2003) Lead and arsenic in bones of birds of prey from Spain. Environ Pollut 126:107–114 Pain DJ (1996) Lead in waterfowl. In: Beyer NW, Heinz GH, Redman-Norwood SW (eds) Environmental contaminants in wildlife: interpreting tissue concentrations. Lewis, Boca Raton, pp 251–264 Pain DJ, Meharg AA, Ferrer M, Taggart M, Penteriani V (2005) Lead concentrations in bones and feathers of the globally threatened Spanish imperial eagle. Biol Conserv 121:603–610 Scheuhammer AM (1987) The chronic toxicity aluminium, cadmium, mercury and lead in birds: a review. Environ Pollut 46:263–295 Scheuhammer AM, Dickson KM (1996) Patterns of environmental lead exposure in waterfowl in Eastern Canada. Ambio 25:14–20 Snoeijs T, Dauwe T, Pinxten R, Vandesande F, Eens M (2004) Heavy metal exposure affects the humoral immune response in a
123
Arch Environ Contam Toxicol free-living small songbird, the great tit (Parus major). Arch Environ Contam Toxicol 46:399–404 Taggart MA, Figuerola J, Green AJ, Mateo R, Deacon C, Osborn D et al (2006) After the Aznalco´llar mine spill: Arsenic, zinc, selenium, lead and copper levels in the livers and bones of five waterfowl species. Environ Pollut 100:349–361 Taggart MA, Green AJ, Mateo R, Svanberg F, Hillstro¨m L, Meharg AA (2009) Metal levels in the bones and livers of globally threatened marbled teal and white-headed duck from El Hondo, Spain. Ecotoxicol Environ Safe 72:1–9
123
Tsipoura N, Burger J, Newhouse M, Jeitner C, Gochfeld M, Mizrahi D (2011) Lead, mercury, cadmium, chromium, and arsenic levels in eggs, feathers, and tissues of Canada geese of the New Jersey Meadowlands. Environ Res 111:775–784 Wayland M, Neugebauer E, Bollinger T (1999) Concentrations of lead in liver, kidney, and bone of bald and golden eagles. Arch Environ Contam Toxicol 37:267–272
