G9 Mercury exposure in wildlife

Thursday, 28 July, 2011

RG9-P1 — 11:00-12:00 and 17:30-18:30
Authors: ALDERSHOFF, Jennifer1, MURPHY, Jule W. 1, DEMENT, Samuel H.2, GUENTZEL, Jane L.1
(1) Coastal Carolina University, jlalders@coastal.edu; (2) Visiting Scientist Coastal Carolina University;

The increased anthropogenic usage and mobilization of mercury in the environment poses a toxicological risk to fish and wildlife. Many studies concerning the fate and transport of mercury in the environment have focused on aquatic species and seabirds, but there is growing interest in mercury cycling and bioaccumulation in terrestrial ecosystems. Loggerhead Shrikes are predatory songbirds that breed in grasslands and shrub-steppe areas. These birds feed on grasshoppers, small lizards, snakes, rodents, and other small birds. Loggerhead shrike populations have experienced significant declines throughout their North American breeding range and are listed as a U.S. Fish and Wildlife Service migratory bird of conservation concern in the northeast. A previous study by deMent et al., 2008 reports that Loggerhead Shrikes in South Carolina are non-migratory residents. Outer rectrices were collected from 29 Loggerhead Shrikes throughout 5 counties in South Carolina from 2005-2010 (U.S. Dept of Interior banding permit #22771). The counties are located in the Piedmont Ecoregion (Abbeville), Southeastern Plain Ecoregion (Calhoun, Clarendon, Lexington) and Middle Atlantic Coastal Plain Ecoregion (Williamsburg). A recent aquatic ecosystem study by Glover et al., 2010 reported that the highest freshwater fish tissue Hg concentrations have been found in the Southeastern Plain and the Middle Atlantic Coastal Plain Ecoregions, with lower fish Hg concentrations found in the Piedmont Ecoregion. The objective of this study is to determine levels of total Hg in outer rectrices from these birds and to examine how the mercury levels in these non-migratory terrestrial birds may vary with ecoregion.

RG9-P2 — 11:00-12:00 and 17:30-18:30
Authors: JIANWEN, Bai1, NING, Wang1, GANG, Zhang1
(1)Northeast Normal University, baijw248@nenu.edu.cn

Being of neurological toxicity, Methylmercury can be passed along food chains and accumulated in organisms by bioconcentration and biomagnification, which is a fact that has been proved many times. In the thesis laws of methylmercury enriched from organisms’ habitat environment have been researched. Indoor microcosm device has been built to simulate river-land amphibian biotope and hibernation habitat of the Rana chensinensis. Based on the methylmercury exposure experiments of the Rana chensinensis, accumulation response and biomagnification response of methylmercury have been discussed. In contrast, the hibernant Rana chensinensis from the native biotope in the area of Huadian gold mine of Jilin Province in China have been collected.

Two concentration gradients: 0.01ug/L and 0.03ug/L have been used in the experiments. Adding a certain amount of methylmercury everyday into the microcosm device in which Rana chensinensis have been bred and sampling the Rana chensinensis on schedule, then the concentration of methylmercury in the 4 parts of Rana chensinensis (skin, muscle, organs and brain) have been determined. So do the concentration of methylmercury in water and sediments. Furthermore, the bioaccumulation factors of methylmercury in organisms and their environment have been calculated.The results show that: the methylmercury concentration increases gradually with time, and after reaching the peak value it drops rapidly. During the latter period of the experiments, the concentration appears uplift slowly, which shows Rana chensinensis’ emergency response and detoxicate reaction for methylmercury and the cumulative effects of methylmercury. The main source of methylmercury on Ranas chensinensis’ bodies is from the experimental water.

In contrast, every 10-11 pieces Rana chensinensis in three different places around the Huadian gold mine have been collected. The samples’ bodies have been divided into four parts(skin, muscle, organs and brain). Each part of the samples bodies, water and sediments have been measured. The results show: the Rana chensinensis contaminated from gold mining have the same accumulative trends of methylmercury. The methylmercury from the ambient sediments and water can enter into Rana chensinensis’ bodies via the skins of the organisms.

RG9-P3 — 11:00-12:00 and 17:30-18:30
Authors: YAFEN, Li1, NING, Wang2, GANG, Zhang2
(1) Northeast Normal University,China, liyf990@nenu.edu.cn; (2) Northeast Normal University;

In the 1960s, severe mercury contamination of Songhua River caused by chemical pollution in Northeastern China had raised worldwide concern. Although the pollution has greatly reduced in recent years, it is still prominent ascribed to the upstream gold mining of the Songhua River. In this paper, the Jiapigou gold mine in Huadian City is selected as the studied area in Jilin Province. The Rana chensinensis samples as the representative amphibian of the native river-forest-wetland system have been captured, and the water and sediment of the river as the representative environmental factors have been collected. In contrast, samples of the same types have been collected in Jinchuan of Huinan town which is located in the Jilin Longwan National Forest Park. The methylmercury (MeHg) concentrations and the amount of MeHg of these samples have been determined with the methods of gas chromatography (GC). Brains, viscera except livers, livers alone, frogspawns, muscles and skins have been determined respectively to reveal the regularities of vivo MeHg distribution in the Rana chensinensis. The results show: 1.The higher MeHg concentration in the brains and livers have been detected; the body weight and snout-vent length (SVL) are both negatively correlate to the concentration of MeHg, which indicate the pollutant in organism is diluted as the frog growing in its life history. 2. The Rana chensinensis in researched area gets a 3.38times higher of MeHg than the comparison. 3. The contents of MeHg concentration in the water and sediment of the river in researched area are higher than the comparison, and the MeHg concentration is positively correlates to the distance from the pollutant source. Furthermore, the highest concentration is in Wudaogou area which is the furthest to the source. 4. The positively correlation of the concentration of MeHg between the environmental factors and organisms of Rana chensinensis suggest the close connection of each other and the pollutant source of the internal MeHg of Rana chensinensis.

RG9-P4 — 11:00-12:00 and 17:30-18:30
Authors: FALKOWSKA, Lucyna1, SZUMI?O, Emiia1, SZUBSKA, Marta1, FILA, Grzegorz1, BELDOWSKA, Magdalena1, MEISNER, W?odzimierz2, BZOMA, Szymon3
(1) Institute of Oceanography, University of Gdansk; (2) Dept. of Vertebrate Ecology and Zoology, University of Gdansk; (3) Sea Fisheries Institute, Gdynia.

Organisms discharge a part of accumulate toxic compounds – including mercury. Phytoplankton exudes mercury via cellular membranes complexed to dissolved organic matter or reduces it to the gaseous form, while fish discharges metals with feces and roe. Birds expel mercury in several ways: through guano, accumulation in feathers and claws, or include it in eggs. Because of that, toxic substances are partially removed from birds in feeding grounds, and transported together with migrations over long distances, and deposited in breeding and wintering grounds.

In the Gulf of Gdansk area (Southern Baltic) three large municipal dumps create a basic feeding ground for several thousand seagulls. They can then transport toxins indulged there to other areas. Especially vulnerable are bird colonies in the coastal zone (birds reserves, breakwaters, harbors etc.). Mercury in birds feces occurs in labile forms, hence it can readily enter the foodchain.

Samples of guano, unfertilized eggs, claws and feathers of dead Larus argentatus and Larus marinus were collected in the coastal zone of the Gulf of Gdansk between December 2009 and February 2011. Claws and feathers were cleaned with 50% acetone and placed for 30 minutes in ultrasonic bath prior to analysis. Unfertilized eggs were freeze dried and homogenized, while guano samples were analyzed as a whole after freeze drying.

Mercury concentration was measured using AMA 254 mercury analyzer. Precision and accuracy control was handled by the analysis of certified reference material (Quality control has been carried out by the measurement of certified reference materials, with RSD equal to 5% of the mean. Total mercury concentration (HgT) was expressed in µg g-1 dry weight. Average concentration for sample was calculated for three analyses.

Mercury concentration in guano was most variable among analyzed materials - it varied from 5 pg·g-1 d.w. to 2 µg·g-1 d.w. In claws and feathers concentration span was smaller - 0.4 µg·g-1 d.w. to several µg·g-1 d.w. The highest concentrations were observed in contour feathers and claws – it amounted to 10 µg·g-1 d.w.

RG9-P5 — 11:00-12:00 and 17:30-18:30
Authors: SZUMI?O, Emilia1, FALKOWSKA, Lucyna1, FILA, Grzegorz1, SZUBSKA, Marta1, BELDOWSKA, Magdalena1, KWA?NIAK, Justyna1, MEISSNER, W?odzimierz2, KRAUZE, Izabela3
(1)Institute of Oceanography, University of Gdansk; (2) Dept. of Vertebrate Ecology and Zoology, University of Gdansk ; (3) Municipal Zoological Garden, Gda?sk.

Mercury is able to biomagnify, resulting in the increase of mercury concentrations in higher levels of the food web. The highest concentrations are observed in tissues of top predators: polar bears, seals or seabirds. Mercury levels in the tissues of the predator depend mostly on the food mercury concentrations and increases together with the marine fish share of their diet. This is one of the reasons for seabirds, located in high levels of the trophic pyramid, being recognized bioindicators of the marine environment pollution.

This study includes results for two bird species wintering in the Gulf of Gdansk area: herring gull (Larus argentatus) and great black-backed gull (Larus marinus). The first feeds mostly on fish, marine invertebrates, carrion and municipal waste from the waste dumps, while the latter consumes mostly food of marine origin – fish and mussles. Another specimens included in this study are african penguins (Spheniscus demersus), bred in captivity in the Gdansk Zoo. Their diet consist mostly of fish (herrings from the Gulf of Gdansk).

Analyzed tissues were obtained from the dead birds found in colonies at the Southern Baltic coast (Wladyslawowo, Poland) in winter, in the years 2009-2011 and from the Zoo. Mussel and liver samples were homogenized and freeze dried. Mercury concentration was measured using AMA 254 mercury analyzer. Precision and accuracy control was handled by the analysis of certified reference material (Quality control has been carried out by the measurement of certified reference materials, with RSD equal to 5% of the mean. Total The highest mercury concentrations were recorded in liver, which is probably the effect of its detoxifying functions. Hg(T) levels in marine feeding Larus marinus were comparable to those of Spheniscus demersus, restricted mostly to herring – the average concentration in liver equaled 3.13 µg·g-1 (seagulls) and 3.92 µg·g-1 (penguin), while mean muscle concentration was 1.17 µg·g-1 (seagulls) and 1.96 µg·g-1 (penguin). Mercury concentration in Larus argentatus, with diet balance heavily shifted towards terrestrial food, were an order of magnitude lower – 0.59 µg·g-1 in liver and 0.32 µg·g-1 in muscles.

RG9-P6 — 11:00-12:00 and 17:30-18:30
Authors: IGNACIO, Aurea1, OLIVEIRA, Robson Flores1, SANTOS FILHO, Manoel1, DÍEZ, Sergi2, MALM, Olaf3, KEHRIG, Helena Amaral3
(1)UNEMAT, aurea@unemat.br; (2) CSIC; (3) UFRJ;

Most mercury found in the environment comes from human activity, mainly gold mining, where mercury is used to form gold-mercury amalgam. Mercury is a toxic metal the causes various harms to human health due to the concentration and bioaccumulation of this metal in the organism. Pantantal’s caiman (Caiman yacare) is a carnivore at the top of the food chain in aquatic environments, and, for this reason, it has a high potential of mercury bioaccumulation when exposed to this contaminant. In this study, we assessed mercury concentration in the scales of caimans’ tails and nails in Paraguay River, Cáceres, MT (area 1), and Bento Gomes River, Poconé, MT (area 2). Animals were trapped using a torch and Lutz’ lasso at night, when they were immobilised for sample collection. Samples were separately conditioned and processed to assess THg concentrations. After weighing - 0.5g wet weight for tail scales, and 0.05g dry weight for nails – samples were treated with acid digestion over night. THg concentrations were assessed using atomic absorption spectrometry with Flow Injection Mercury System (FIMS) and FIAS 400 (Perkin Elmer, USA), with detection limit of 0.01 ppb. Assessments were done with duplicate samples. THg average concentrations (µg/kg) found in animals of Paraguay River during rainy season: in nails (average ± SD) was 1.153 ± 0.2853 µ/g (N=6) and in tail scales 0.03843 ± 0.01409 µ/g (N=7). During the dry season: in nails was 0.6308 ± 0.1447 µ/g (N=10) and 0.1367 ± 0.02482 µ/g (N=10) in tail scales. Animals trapped in Bento Gomes River had average concentrations during the rainy season of: 2.175 ± 0.7938 µ/g (N=9) in nails, and 0.3796 ± 0.06486 µ/g (N=9) in tails scales; during the dry season: 1.579 ± 0.6723 µ/g (N=13) in nails, and 0.1782 ± 0.02945 µ/g (N=13) in tail scales. Thus, we showed that the highest concentrations of THg were in the nails of trapped animals in Bento Gomes River, followed by nails of trapped animals in Paraguay River. Tail scales collected in Bento Gomes River also showed high concentrations of THg compared to tails scales of animals trapped in Paraguay River. These results indicated that nails are better bioindicators of mercury contamination than tail scales, and animals from Bento Gomes River have higher concentration of mercury compared to those from Paraguay River.

RG9-P7 — 11:00-12:00 and 17:30-18:30
(1) Universidad de Castilla-La Mancha, rosacarmen.rodriguez@uclm.es; (2) CSIC-UCLM;

Most studies have devoted to the aquatic environments and little attention has been paid to mercury in terrestrial ecosystems. However, there are several reasons why the study of mercury in terrestrial animals is of great interest. Firstly, major differences exist compared to the aquatic ecosystem and there are probably different mechanisms of mercury accumulation and transfer. Additionally, human is exposed to mercury pollution through the consumption of different terrestrial animal tissues. And, finally, very important information about negative impact of metal pollution, in terms of lethal and/or sublethal effects, and protection/detoxification mechanism can be obtained from these animals and extrapolated to human beings.

We focus on the study of total mercury and selenium concentration in red deer (n=168) and wild boar (n=58) from the Almadén mining district (Spain). The selected tissues were liver, kidney, bones (metacarpus), testis and muscle. The objectives of the present study were as follows: 1. To know the environmental impact of mercury pollution in wildlife and species of interest for hunting; 2. To assess the route of mercury and its transfer into terrestrial organisms tissues; 3. To identify adverse effect of metal pollution on oxidative stress biomarkers and possible defence mechanisms (selenium interaction).

Highest Hg concentrations were found in kidney (0.092 and 0.103 µg/g d.w. for red deer and wild boar, respectively) followed by the levels in liver (0.013 and 0.023 µg/g d.w. for red deer and wild boar, respectively). A significative correlation (r=-0.609, p=0.007) was found between mercury concentrations and distance to the Almadén mercury district. Highest selenium concentrations correspond to kidney (2.60 and 6.08 µg/g in red deer and wild boar, respectively) and testis (2.20 µg/g in red deer). Differences between red deer and wild boar were statistically significant (p>0.05) in all tissues for selenium, being higher in wild boar than in red deer. A very strong significant correlation was found between Hg and Se in kidney (r=0.386, p>0.001 for red deer and r=0.567, p=0.005 for wild boar). Oxidative stress biomarkers in red deer liver and testis have been used to identify adverse effects of metal pollution.

RG9-P8 — 11:00-12:00 and 17:30-18:30
Authors: DORNBOS, Peter1, STROM, Sean2, BASU, Niladri 1
(1) University of Michigan School of Public Health, pdornbos@umich.edu; (2) Wisconsin Department of Natural Resources ;

River otters (Lontra canadensis), along with other fish-eating wildlife, have been found to bioaccumulate high levels of the neurotoxicant mercury (Hg). While the deposition of Hg within the body and whole brain has been documented in several organisms, few have characterized distribution in specific brain regions. Such information may be important in resolving mechanisms underlying Hg neurotoxicity. Here, river otter carcasses (N=9) were collected from trappers within the state of Wisconsin and dissected into 9 brain regions including frontal cortex (Fx), temporal cortex (Tx), parietal cortex (Px), occipital cortex (Ox), cerebellum (Cb), thalamus (Th), basal ganglia (Bg), brain stem (Bs), and the pituitary gland (Pit). Total Hg was measured with a Direct Mercury Analyzer (DMA) in each brain region, as well as fur, liver, and muscle. Hg concentrations across brain regions spanned a wide range. Highest concentrations were measured in the Fx (1.3±2.0 ppm) and lowest within the Bs (0.6±0.5 ppm), and rank order of other regions (highest-lowest) was Tx (1.2±1.9), Px (1.0±1.4), Ox (1.0±1.3), Bg (1.0±1.4), Cb (0.9±1.3), and Th (0.7±0.6). There were no statistically significant differences in Hg across brain regions, but additional samples will be analyzed to increase the statistical power of this study. Mercury levels in fur (6.7±4.6 ppm) and liver (5.7±9.4 ppm) were significantly greater than muscle (1.7±2.0 ppm) and most brain regions. Mercury levels across several brain regions (e.g., Fx, Tx, Th, Px, Bg, Ox) significantly correlated (p≤0.002, R ≥0.92) though regions, such as the Cb and Bs, had no significant correlations. In general, Hg levels in brain regions significantly correlated with other tissues (fur, liver, muscle), but Th and Bs did not. These results provide important insight into target sites of Hg in the brain, which may lead to increased understanding of possible ecological implications associated with Hg neurotoxicity in river otters and other mammalian wildlife.

RG9-P9 — 11:00-12:00 and 17:30-18:30
Authors: HALL, Britt D.1, BATES, Lara M.1, DOUCETTE, Jennifer 2, NIYOGI, Som3, SOMERS, Christopher M.1
(1) University of Regina, britt.hall@uregina.ca; (2) Unversity of Regina; (3) University of Saskatchewan;

Total Hg (THg; all forms of Hg) concentrations were measured from a small piece of breast and liver tissue sampled from Double Crested Cormorants (DCCO; Phalacrocorax auritus) nesting on five lakes in Saskatchewan, Canada. Total Hg was also measured in the cisco, yellow perch and salamanders, the major dietary prey items for these populations. We observed a wide range of concentrations in both types of DCCO tissue (range = 100–2770 and 258-25111 ng g-1, in breast and liver, respectively). Across all lakes, THg concentrations in breast was correlated with concentrations in liver (r2=0.44). Concentrations of THg in both breast and liver varied significantly among different populations, with the lowest concentrations observed in birds nesting on lakes in the Boreal transition zone (Egg, Canoe, and Dore lakes; average for breast = 191±29, 501±79, 446±51.3 ng g-1, respectively, average for livers = 498±127, 1798±363, 3039±1019 ng g-1, respectively) and the highest concentrations in birds nesting on a saline lake (Reed Lake; breast and liver average = 2700 ± 188 and 16054±2222 ng g-1, respectively) in the south-west region of the province.

With the exception of the population on Reed Lake, the main diet items for DCCO were yellow perch and cisco. The main diet of birds nesting on saline Reed Lake was salamanders, which had significantly higher THg concentrations compared to concentrations in the prey of birds nesting on other lakes. In three of the five lakes (Reed, Egg, and Last Mountain lakes) THg concentrations in breast tissues of birds were explained by THg concentrations in main prey items. However, in Canoe and Dore lakes, THg concentrations in the breast tissue of DCCO were independent from those in the prey items. Although THg concentrations in DCCO in Canoe and Dore lakes were similar, concentrations in cisco and yellow perch from Dore Lake were four and five times higher, respectively, than those same prey items from Canoe Lake. Preliminary analysis of food web structure indicates that differences cannot be attributed to trophic position or pelagic vs. littoral feeding behaviours. Selenium concentrations in liver tissues, as well as bioenergenic modelling are currently being explored as possible explanations for the disconnect between THg concentrations in prey items with breast concentrations in the DCCO.

RG9-P10 — 11:00-12:00 and 17:30-18:30
Authors: LÁZARO, Wilkinson L.1, FRANCH, Marc2, FERNÁNDEZ-GÓMEZ, Cristal3, SANPERA, Carola2, JOVER, Lluís2, LLORENTE, Gustavo2, DÍEZ, Sergi3
(1) Biodiversity and Ethnobiology Research Center, CELBE-UNEMAT, wilkinsonlopes@hotmail.com; (2) University of Barcelona, UB; (3) Institute of Environmental Assessment and Water Research, IDAEA-CSIC;

Turtles are excellent environmental indicators that have been shown to be effective biomonitors of mercury contamination. Because of their long lives, feeding in aquatic ecosystems and relatively high tropic position in the food web, they have the potential to bioaccumulate significant levels of mercury.

Total Hg (THg) concentrations in blood were determined for freshwater turtle Mauremys leprosa from three different areas in Spain: a long-term Hg-contaminated reservoir in the Ebro river (FR), a river basin impacted by industrial and urban activities (AB) and a pristine site (OR). Additionally, THg concentrations also were determined in samples of claws collected from the hot spot. We also determined whether body size, weight, sex and sexual maturity significantly affect THg levels in blood by regressing log-transformed THg against different variables.

Significant differences in THg levels (median ± SD in µg/g dw) in blood were found among sites, FR 1.4±0.21 >> AB (0.82±0.32) > OR (0.72±0.32), suggesting that blood can be used as a bioindicator of Hg exposure in turtles. In addition, values in claws were very high (2.54±2.16) ranged from 0.70 to 9.05 µg/g.

Because the feeding ecology of this species differs drastically depending of the area, stable isotope signatures of carbon and nitrogen were employed to fulfil the relationship between relative trophic position, feeding habits and THg. Interestingly, positive correlations were obtained between body size and both stable isotopes in the hot spot. This highlights that there are quite marked changes in feeding habits during stage development of turtles, both in the trophic level and in the foraging habitat they seek in different depths of the reservoir.

In sum, our results suggest that blood and claws provide valid means for estimating Hg burdens in freshwater turtle, and that these nonlethal monitoring tools may also prove valuable for establishing turtles as sentinel species for aquatic environments.

RG9-P11 — 11:00-12:00 and 17:30-18:30
Authors: RIEHL, Kimberly N1, ROSS, Peter S2, WANG, John Y3, YANG, Shih-Chu3, STERN, Gary A4, HICKIE, Brendan E1
(1) Trent University, kimberlyriehl2@trentu.ca; (2) Institute of Ocean Science (DFO); (3) FormosaCetus Research and Conservation Group; (4) Freshwater Institute/Fisheries and Oceans Canada;

The eastern Taiwan Strait (ETS) Indo-Pacific humpback dolphins, Sousa chinensis, is a critically endangered population (numbering <100) existing off the highly industrialized and populated west coast of Taiwan. This population inhabits a small/narrow coastal habitat where threats are abundant, including noise pollution, net entanglement, habitat loss, and municipal and industrial pollution such as persistent organic pollutants and mercury. The presence of anthropogenically-released mercury in the environment has long been a health concern for cetaceans as it is persistent and can biomagnify to potentially dangerous concentrations in long-lived, high trophic level species. Mercury is known to have deleterious effects on the reproductive, immune, and nervous systems. Because their conservation status prevents us from acquiring tissues samples via biopsies, our evaluation of the risk associated with mercury exposure was based on estimating tissue concentrations using measured concentrations from two potential food baskets and tissue-specific biomagnification factors (BMFs) derived from data-rich odontocetes. Fish samples believed to be important prey of ETS humpback dolphins were collected and were pooled into two food baskets, based on our understanding of their feeding preferences. Total mercury in these food baskets ranged from 0.06 to 0.09 mg/kg wet weight (ww). A literature review of BMFs in odontocetes revealed that the most robust data set was from Canadian Arctic beluga whales (Delphinapterus leucas), where BMFs for liver were exponentially related to age (BMF=55.62e0.0921*age, r2=0.70) and ranged from ~60 for young animals up to ~2200 for older individuals. Estimated total mercury liver concentrations in ETS humpback dolphins ranged from ~3-190 mg/kg ww, suggesting that older individuals (>28 years) would exceed the effects threshold for liver damage of 60 mg/kg ww. This assessment highlights a number of research needs that could improve risk assessments for mercury in cetaceans, including: the need for effects thresholds for neurotoxicity, the need for effects thresholds that are sensitive to mercury speciation in tissues, and extrapolation between species.

RG9-P12 — 11:00-12:00 and 17:30-18:30
Authors: KAUMEYER, Morgan1, CASTRO, Mark1
(1)University of Maryland Center for Environmental Science, mkaumeyer@umces.edu

The purpose of this project was to determine if total mercury concentrations ([THg]) in stream salamanders were influenced by species of salamander and water quality characteristics between streams. We measured the [THg] in five species of stream salamanders from Garrett County, Maryland collected during spring, summer, and fall 2010. These were the northern two-lined salamander (NTL, Eurycea bislineata), northern dusky salamander (ND, Desmognathus fuscus), eastern red-spotted newt, (RSN, Notophthalmus viridescens), Allegheny mountain dusky salamander (MD, Desmognathus ocraphaeus), and seal salamander (S, Desmognathus monticola). These were chosen because they occupy similar stream habitats, have distinct niches within the stream ecosystem, and have different life histories. Salamanders were collected from nine streams, selected by historic pH and Acid Neutralizing Capacity (ANC), either low (pH<5 with ANC < 50ueq L-1), medium, or high (pH>6 with ANC>150ueq L-1). Seasonal sampling of the salamanders showed variations among sites and variations between different species. In the spring at Mud Lick (historically high pH and ANC), NTL had a mean [THg] of 32.75ng g-1, which was significantly higher than RSN (20.21ng g-1). During summer mean [THg] in NTL (38.99ng g-1) and RSN (33.91ng g-1) were significantly higher than ND (21.34ng g-1). In the fall, [THg] was significantly higher in NTL (59.40ng g-1) than ND (34.40ng g-1) and RSN (37.56ng g-1). In the spring at Monroe Run (historically high pH and ANC), NTL had a mean [THg] of 38.11ng g-1, which was significantly higher than ND (15.68ng g-1). In the summer mean [THg] in MD (24.23ng g-1) were significantly higher than ND (17.74ng g-1) and S (11.48ng g -1). NTL (24.54ng g-1) were also significantly higher than S. In the fall ND (34.40ng g-1), MD (44.20ng g-1) and NTL (59.40ng g-1) from Mud Lick were significantly higher than the same species from Monroe Run (22.48ng g-1, 15.36ng g-1, and 20.88ng g-1 respectively). We will further discuss the relationships between salamander species and the mean [THg] at all stream sites as well as relationships between stream water chemistry, including total and methyl mercury concentrations and major ion concentrations, and variations in mean [THg] in salamanders between stream sites.

RG9-P13 — 11:00-12:00 and 17:30-18:30
Author: RIVERA CÓRDOVA, Sandra Jahel1
(1)Wildlife Conservation Society, sandyrbo@gmail.com

Mercury and melilmercury contamination in the Beni basin is an important issue for the indigenous communities that live along the river. Takana, one of such communities, feed mostly on fish and alligators. During the years 2007 and 2009 muscle tissue samples were collected from eight wildlife species (seven fish and one alligator). Total mercury was extracted with acid digestion and measured with atomic absorption spectrometer Perkin Elmer model 3110. Non carnivorous fish species (Prochilodus nigricans and Piaractus brachypomus) have lower concentrations (0.099 ± 0.027 and 0.041 ± 0.019 µg/g respectively) than carnivorous fish (Pygocentrus nattereri, Pseudoplatystoma tigrinum, Zungaro zungaro, Plagioscion squamosissimus and Leiarius marmuratus), which on average have total Hg concentrations above 0.353 µg/g and up to 1.266 µg/g. In the alligator (Caiman yacare) the average concentrations of total Hg was 0.210 ± 0.217 µg/g (n = 66), which is lower than expected, considering that alligators have at least the same trophic level as carnivorous fish and relatively long life-spans. This may be because concentrations in caiman muscle may not reflect the concentrations in the whole organism; It is possible that mercury in caimans is accumulated in other organs, distinct from the ones sampled in this study, but it is also possible that physiological mechanisms are involved that help caimans get rid of ingested mercury. However, our data allow us to recommend caiman muscle consumption despite their apparent trophic position, size and life span.

RG9-P14 — 11:00-12:00 and 17:30-18:30
Authors: BUSHEY, Joseph1, BRADY, Steven P2, ARAGON-JOSE, Alejandra T1, SKELLY, David2
(1) University of Connecticut, joseph.bushey@uconn.edu; (2) Yale University;

As ubiquitous elements of land development, roads are distributed pervasively throughout much of North America. Runoff from impervious surfaces, an indirect effect of roads, contributes contaminants, including mercury (Hg), to roadside wetlands and waterways. However, the impact of salinization of waterways on biogeochemical cycles, particularly organic carbon cycling, and Hg speciation is lacking. DOC and Hg-Cl complexes impact potential bioavailability, particularly at sub-lethal levels. Many investigations focus on lethal doses of single chemical exposure. However, our burgeoning understanding of the influence of rapid evolution on ecological patterns suggests that sub-lethal geochemical processes and demographic processes may interact, resulting in outcomes that vary among local populations. Understanding the impact that these interactions may have on Hg fate is critical as our society moves forward with evaluating sustainable development approaches.

We examined the potential influence of road proximity and development on the chemical characteristics of five forest and five roadside temporary wetlands located in northeastern Connecticut. In roadside wetlands, specific conductance—a close proxy for road salt—was approximately 25 times that of forest pools, demonstrating the influence of impervious road surfaces. Hg species along with base cation, anion and DOC content were analyzed from water samples collected in April, May and early July 2009. To investigate biological outcomes, we used a reciprocal transplant experimental design in which spotted salamanders embryos were grown out in field enclosures in each of the ten wetlands to parse the influence of the environment and the population on bioaccumulation. Total Hg values in late-stage larvae in roadside ponds increased 25% relative to forested ponds. Average larval content was 0.10 ppm with surprisingly lower levels for roadside ponds relative to forested ponds, possibly reflecting the decrease in dissolved organic carbon. Additionally, we examined the potential impact of maternal transfer on the reproductive success of amphibians. We collected adult woodfrogs in Spring 2010 returning to select roadside and forested vernal pools in the Yale Experimental Forest, CT. Pairs of amphibians were bred in captivity with mating adults and a subsection of the fertilized eggs analyzed for Hg content. Reproductive success was documented by hatchling success. Adult females contained higher Hg concentrations (176 ng/g) relative to males (130 ng/g), with slightly higher content in forest specimens. While egg content increased with female parent Hg content for both roadway and forest specimens, maternal transfer of Hg was only significantly related (a=0.05) for the forested samples.

RG9-P16 — 11:00-12:00 and 17:30-18:30
Authors: YATES, David E1, KUNZ, Thomas H2, EVERS, David C1, DIVOLL, Tim1
(1) BRI, dave.yates@briloon.org; (2) Boston University;

Mercury and other aquatic-based persistent bioaccumulative contaminants are prevalent in freshwater environments. Mercury availability to fish and wildlife varies inter-regionally because its availability is strongly influenced by biogeochemistry and hydrology. The atmospheric deposition of sulphur (S) and mercury (Hg) has the potential to have negative landscape-level impacts on bat and bird populations. Sulphur deposition or acid rain has negatively impacted parts of northeastern North America for many decades. Hg methylation by sulfate-reducing anaerobic bacteria that convert non-toxic inorganic mercury (Hg) into toxic organic methlymercury (MeHg) is enhanced in acidic environments. Insectivorous bats in acidified areas of mountains and potentially bog habitats are thus particularly susceptible to the combined impacts of air pollutants because they occur at high trophic levels (e.g., susceptible to biomagnification of Hg). Bats were captured and sampled for Hg accumulation. During 2008 fur samples were collected in 6 (Costa Rica, Belize, Malaysia, China, Sweden, Germany) countries at 13 individual sites. A total of 210 fur samples were analyzed for Hg concentrations. Germany had the highest concentrations followed by Malaysia and Sweden. Forty five of the samples acquired were above the level of concern (10.8 ppm (fw)) found for wild mice. Since there is a lack of bat Hg data other mammal fur Hg are used for assessment purposes. Anthropogenic inputs of mercury (Hg) in surface water across the world have potential to created hotspots which may have long-term impacts on ecological and human health.

RG9-P17 — 11:00-12:00 and 17:30-18:30
Authors: ADAMS, Evan1, EVERS, David C1, BUCK, David G1, WILLIAMS, Kathryn1, OSBORNE, Carrie1, DIVOLL, Tim1, YATES, Dave1, KUNZ, Tom H2, MARTINEZ, Wilber3, TZUL, David3, CAL, Reynold4, GARCIA, William5, ELIZONDO, Pablo6
(1) BioDiversity Research Institute, evan.adams@briloon.org; (2) Boston University; (3) Birds Without Borders; (4) Birds Without Borders; (5) Belize Foundation for Research and Environmental Education; (6) Partners in Flight - Costa Rica.

The TERRA (Terrestrial Ecosystem ReseaRch and Assessment) Mercury Network focuses on using songbirds and bats to determine the potential negative impact of pollutants on terrestrial ecosystems. Mercury (Hg), a toxin long thought to affect only aquatic systems, also has the ability to move into terrestrial systems and bioaccumulate in upper trophic level terrestrial organisms. TERRA examines mercury exposure in multiple aspects of ecosystems, including soil, atmospheric deposition, litterfall, several invertebrate compartments, songbirds, and bats. This breadth of information allows us to examine how inorganic mercury moves into ecosystems, becomes bioavailable to organisms, accumulates in invertebrates, and then biomagnifies up the food chain.

Goals for TERRA are to 1) Understand and describe a previously undocumented terrestrial pathway linking atmospheric deposition of mercury with the bioaccumulation of converted methylmercury into the blood of insect-eating birds and bats; 2) Evaluate the exposure of biota in locations and ecosystems thought to be most sensitive to long-distance mercury transport; and 3) Evaluate the exposure of upper trophic level biota that are thought to be most vulnerable to mercury contamination.

The TERRA network currently includes 221 locations across the globe, with a focus on expanding in the Neotropics. Preliminary results from TERRA sites in Belize and Costa Rica indicate that (1) some bird species, including neotropical migrants such as the Hooded Warbler and Northern Waterthrush, have body burdens of mercury that exceed adverse effect levels to reproductive success, (2) some bat species exceed adverse effect levels to biochemical processes in the brain and (3) high methylmercury availability is linked to lowland tropical habitats that experience a regular wetting and drying process.

RG9-P18 — 11:00-12:00 and 17:30-18:30
Authors: BOCZULAK, Stacy1, HALL, Britt D.1
(1) University of Regina, stacyboczulak@hotmail.com

The long-range transport of Hg through the atmosphere and hydrological systems of landscapes can cause elevated levels of Hg accumulation in remote areas such as the wetlands of the prairie pothole region in the Great Plains of North America. These systems offer ideal conditions for the production of neurotoxic methylmercury (MeHg), the bioaccumulation of which is a major health concern for wildlife and humans that consume aquatic organisms. In amphibians, increased concentrations of MeHg have led to decreased growth, lower survival, and developmental instability, and since amphibians can be an important prey item for higher trophic levels, this may lead to similar effects in predators such as birds and fish. Furthermore, amphibian populations are experiencing a recent global decline, which may be attributed to heavy-metal pollution of this susceptible class of animals. We measured total Hg (THg) concentrations in two tadpole species (boreal chorus-Pseudacris maculata, and wood- Rana sylvatica) residing in wetlands surrounded by four different land-use types: wildlife areas, minimum tillage farms (heavy pesticide use and tilling 0-1 times a year), organic farms (no inorganic pesticide use), and conventional farms (pesticide use and tilling 3 times a year). Total Hg concentrations and body burdens were lower in boreal chorus frog tadpoles (mean ±standard error: 597 ±132ng/g, and 33 ±17ng/frog) than wood frog tadpoles (1688 ±336ng/g, and 329 ±76ng/frog), which was expected, as boreal chorus tadpoles are herbivorous while wood tadpoles exhibit omnivorous tendencies. We observed differences in tadpole THg concentrations from ponds with different land uses. The lowest concentrations were found in tadpoles from wildlife areas (chorus: 152 ±16ng/g, wood: 463 ±248ng/g), followed by those from minimum tillage farms (chorus: 392 ±142ng/g, wood: 716 ±341ng/g), and organic farms (chorus: 1228 ±485ng/g, wood: 1082 ±680ng/g), respectively. Tadpoles sampled from conventional farms contained the highest THg concentrations (chorus: 913 ±272ng/g, wood: 3348 ±847ng/g) of all land-use types. However we did not observe significant differences in body burdens. Our results suggest that both trophic level and factors associated with land use may influence tadpole THg levels. The observed concentrations in tadpoles were higher than gastropods sampled in similar systems, which occupy a similar trophic level (range =11.7 - 161.2, 25.9-2736.4, and 41.2-7889.3 ng/g for gastropods, chorus tadpoles and wood tadpoles, respectively). Thus, tadpoles may be accelerating the bioaccumulation process in these Saskatchewan wetlands.

Thursday, 28 July, 2011