Mercury Concentrations In Liver Research Articles

The Total Mercury Concentration in Organs of Eurasian Magpies (Pica pica) and Common Woodpigeons (Columba palumbus) from the Warsaw Municipal Area.

Mercury is a toxic element widely distributed in the natural environment, affecting animals' health. It is released into the environment from both natural and anthropogenic sources. The present study analyzed the mercury concentrations in liver, kidney, heart and muscle tissue in two species of birds from the Warsaw area, which were used as bioindicators of local environmental pollution with this metal. The mercury content in the examined samples was determined using atomic absorption spectrometry (AAS) utilizing automatic mercury analyzer type AMA 254. The highest mercury content was found in the body of Eurasian magpies, in which it was 0.025; 0.021; 0.006; 0.0037 and 0.029 mg kg-1 of tissue wet weight for kidney, liver, heart, thigh muscles and pectoral muscles, respectively. In the case of common woodpigeons, the content of this metal was significantly lower, amounting to 0.007; 0.005; 0.002; 0.001 and 0.001 mg∙kg-1 wet weight for kidney, liver, heart, thigh muscles and pectoral muscles, respectively. In light of data from the available literature, the values obtained should be considered low, not causing a risk to animal health. The results obtained indicate low environmental exposure to this element.

A review of inorganic contaminants in Australian marine mammals, birds and turtles

Environmental context Metal concentrations can build up to potentially harmful levels in marine mammals as they are at the top of the food chain. This review summarises the information available on metal concentrations in marine mammals, birds and turtles from around Australia. Despite large data gaps, the available data suggest that metal concentrations are similar to those encountered in other regions of the world. Abstract A comprehensive compilation of the published data for trace element concentrations (metals and metalloids) in Australian marine mammals, birds and turtles is presented. The majority of studies have relied on the utilisation of opportunistically collected samples, animal strandings and bycatch. This has resulted in large gaps in geographical, temporal and species coverage data. For instance, little or no data are available for cetaceans in New South Wales or the Northern Territory, and out of 14 endemic species of dolphins, data only exist for seven species. The aforementioned data gaps make it hard to identify statistically significant trends, a problem compounded by data being reported in the form of ranges without raw data. Trace element concentrations measured in various marine species and their tissue types are extremely variable, with ranges typically spanning several orders of magnitude, but are generally comparable with international data. Trends in contaminant concentrations with tissue type follow generally accepted patterns of behaviour for higher organisms, with the highest mercury concentrations in liver and cadmium in kidney tissues. Herbivores have lower contaminant loadings than carnivores, reflecting the importance of diet, and there are identifiable age-related trends for elements such as mercury. The lack of supporting pathology on dead and stranded animals and data on specimens from uncontaminated locations restrict conclusions on organism health impacts. There have been some attempts to use non-invasive sampling of indicator tissues such as fur, bristle and feathers. However, it is currently difficult to extrapolate these data to estimate contaminant concentrations in major organs. Recommendations for future investigations are made.

Insights sobre um encalhe em massa de falsas orcas (Pseudorca Crassidens Owen, 1846)

False killer whales (FKWs; Pseudorca crassidens) are found in deep waters of temperate and tropical oceans worldwide. This species is considered near threatened and global populations’ trends are unknown although there is evidence of decline of various populations. The mass stranding of cetaceans remains an intriguing event and often the cause(s) are unclear or poorly investigated. In Brazil, cetacean mass strandings have been recorded yet they have not been investigated. In this study, we aimed to report the epidemiologic features of a mass stranding event involving 30 live FKWs occurred in northeastern Brazil in 2013. Releasing attempts and posterior monitoring data indicated successful outcome for 24 of 30 FKWs. Postmortem pathologic investigations confirmed live-stranding stress response and intestinal (Bolbosoma sp.) and otic (Stenurus sp.) endoparasitism. Toxicologic analyzes detected high concentrations of total mercury in liver correlating with liver damage, as indicated by elevated transaminases. In this mass stranding, key factors were early notification, organizational and operational framework, trained and sufficient personnel, resources and equipment, government support, and strategy and decision making. These results underscore the benefits of a rapid marine mammal network response, the importance of integrative multidisciplinary investigations, and set baseline information for mass strandings of cetaceans in Brazil.

The protective effect of nano calcium produced from freshwater clam shells on the histopathological overview of the liver and kidneys of mice exposed to mercury toxins

Background and aimFreshwater clam shells nanoparticles powder is one of the uses of freshwater clams that can manufacture instant granular mineral supplements. This product can be used as a supplement to detoxify heavy metal toxins, such as Mercury. Mercury is an element that is detectable in all environmental media. Adults and children receive the most Mercury from food, air, and water intake. The majority of Mercury in the environment comes from the waste from mining activities and the metal industry. Mercury was found widely in the biosphere and is known as a dangerous hepatotoxicant. This study aimed to describe the hepatoprotective role of nano minerals (Ca, Mg, and Zn) produced from freshwater clam shells against mercury acetate poisoning in mice. Material and methodsThe mice were divided randomly into a control group (aqua bidest and mercury acetate) and an experimental group for this purpose. The experimental mice group was given orally nano Ca supplementation in three dose groups (9 mg, 18 mg, and 27 mg/200 g animal body weight) once a day for 21 consecutive days. The mice are then given mercury acetate (1300 µg/200 g animal body weight intraperitoneally) on the 21st day. One hour after giving the nano Ca supplement, the mice's blood was taken. Liver and kidney were autopsied two days later to check quantitative and qualitative changes caused by mercury concentrations in liver and kidney histopathologies. ResultsThe results demonstrated the importance of nano Ca supplementation before mercury acetate induction, which has been shown to reduce necrotic depletion and hepatocyte degeneration. ConclusionNano Ca supplementation has decreased the concentration of Hg in the blood of mice so that it can be used as a potential health supplement to detoxify mercury toxins.

Mercury Accumulation and Elimination in Different Tissues of Zebrafish (Danio rerio) Exposed to a Mercury-Supplemented Diet

In this study, we evaluated the bioaccumulation of mercury in zebrafish (Danio rerio) exposed to mercury-contaminated food for 21 days and the depuration of mercury for a subsequent post-exposure period of 28 days. Four tissues (muscle, liver, gills, and skin) were analyzed for mercury content. Overall, data indicated that Hg accumulation in the liver is faster than in other tissues. Furthermore, the liver is the tissue with the highest accumulation rate per day (0.021 µg Hg g−1 day−1), followed by muscle, skin, and gills. Conversely, the Hg depuration rates in different tissues showed the following order: gills > skin > muscle > liver. The bioaccumulation factor values of liver and muscle increased linearly during the uptake period. The ratios between mercury concentration in liver and muscle during the experiment also increased during the uptake period and remained higher than 1 during the elimination period, suggesting that Danio rerio needed more than 4 weeks of depuration. Finally, the distribution of Hg in the water column during the accumulation period is Hg particulate > Hg dissolved, and during the depuration period it is the opposite, mercury particulate < mercury dissolved. In conclusion, this study contributes to a better understanding of the differences in Hg dynamics during the accumulation and depuration stages in a model fish, also emphasizing the alterations on Hg available in the water column.

Mercury exposure and risk assessment for Eurasian otters (Lutra lutra) in Denmark

Mercury (Hg) exposure may cause a wide range of adverse effects in mammals. A piscivorous apex predator, as the Eurasian otters (Lutra lutra) may accumulate and biomagnify heavy metals and pollutants. Here we investigate the Hg burden in 117 otters from Denmark to evaluate Hg concentrations and risks of health effects. Mercury concentrations ranged between 0.02 and 10.1 μg/g wet weight (ww) in liver tissue and 0.30–40.0 μg/g dry weight in fur. Concentrations in liver and fur in individual otters were highly correlated (P < 0.001). Generalized linear modelling showed that mercury concentrations in both liver and fur increased with age (liver: P < 0.002; fur P < 0.05) and with distance to the marine coastline i.e. towards freshwater habitats (P = 0.0526), and δ13C in muscle tissues (P < 0.001). No differences were detected between males and females (P > 0.59) and no correlation were detected between Hg concentration and trophic level (δ15N) (liver: P = 0.35; fur: P = 0.54). Mercury concentrations in the liver exceeded the No Risk threshold in 15% of the otters, and 25% had levels above the lowest observed effect level of 3.4 μg/g ww that may be associated with adverse effects on the central nervous system. The proportion exceeding these thresholds should therefore be monitored to document possible temporal and spatial trends in Hg exposure and the potential risk to the conservation status of the otter population.

Total mercury level in tissues of commercial mammalian species (wild boar, moose) of the Russky Sever National Park (North-West of Russia)

Bioaccumulation of mercury in the food chain can pose a threat to human health. Therefore, in our article, we obtained data on the concentrations of mercury in the tissues of wild animals, which are a food resource for humans. We determined the mercury concentrations in liver, kidneys, muscles and hair of wild boar and moose, which are consumed by the population of the Russky Sever National Park. The average mercury concentrations in moose tissues ranged from 0.004 mg / kg wet weight in muscles to 0.079 mg / kg wet weight in kidneys. The average concentrations of mercury in boar tissues ranged from 0.136 mg / kg wet weight in wool to 0.711 mg / kg wet weight in kidneys. The main trends of mercury bioaccumulation in the tissues of moose and wild boar were determined.

БИОАККУМУЛЯЦИЯ РТУТИ И СЕЛЕНА В ОРГАНИЗМЕ РУССКОГО (ACIPENSERGUELDENSTAEDTII) И ПЕРСИДСКОГО (ACIPENSERPERSICUS) ОСЕТРОВ

The purpose of the research was to study accumulation of mercury and selenium in muscles and liver of Russian and Persian sturgeons caught in the Caspian Sea. Analysis of the data revealed preferential accumulation of mercury and selenium in liver compared to muscle tissues of both species. The article shows that the degree of mercury accumulation in the liver and muscles of the Persian sturgeon was higher than of the Russian. Correlation analysis of data showed that mercury content in the sturgeon liver and muscles statistically significantly depended on age, length and weight of the fish. In the course of these studies there has been identified a direct correlation between selenium content in muscle tissue and body weight of fish. The results of the analysis indicate that the accumulation of mercury and selenium in Persian and Russian sturgeon species is stipulated by their physiological characteristics and properties of the chemical elements. Mercury concentration in liver and muscles of the tested species is little, which corresponds to the standards adopted in Russia. The level of selenium in the liver increases with the concentration of mercury in it, which confirms the defensive function of selenium against heavy metals.

Total mercury concentrations in liver and muscle of European whitefish (Coregonus lavaretus (L.)) in a subarctic lake - Assessing the factors driving year-round variation

Subarctic lakes are characterised by extreme seasonal variation in light and temperature which influences growth, maturation, condition and resource use of fishes. However, our understanding of how seasonal changes affect mercury concentrations of fishes is limited. We conducted a year-round study (3 ice-covered months, 3 open-water months) with open-water inter-annual aspect (3 years: samples from August/September), focusing on total mercury (THg) concentrations and ecological characteristics of a common freshwater fish, European whitefish (Coregonus lavaretus (L.)) from a subarctic lake. We measured THg concentrations from tissues with fast (liver, n = 164) and moderate (muscle, n = 225) turnover rates, providing information on THg dynamics over different temporal scales. In both tissues, lipid-corrected THg concentrations were highest in winter (liver: 1.70 ± 0.88 μg/g, muscle: 0.24 ± 0.05 μg/g) and lowest in summer (liver: 0.87 ± 0.72 μg/g, muscle: 0.19 ± 0.04 μg/g). THg concentrations increased in winter following the summer-autumn dietary shift to pelagic zooplankton and starvation after spawning. Whitefish THg concentrations decreased towards summer, and were associated with consumption of benthic macroinvertebrates and subsequent growth dilution. Mercury bioaccumulated in both tissues with age, both showing the strongest regression slopes in winter and lowest in summer. THg concentrations in liver and muscle tissue were correlated throughout the year, however the correlation was lowest in summer, indicating high metabolism during somatic growing season in summer and growth dilution. Multiple linear regression models explained 50% and 55% of the THg variation in liver and muscle both models dominated by seasonally-variable factors i.e. sexual maturity, δ13C, and condition factor. Seasonally varying bioaccumulation slopes and the higher level of intra-annual variation (21%) in whitefish THg concentration in muscle than the inter-annual accumulation (8%) highlight the importance of including seasonal factors in future THg studies.

Dietary selenomethionine influences the accumulation and depuration of dietary methylmercury in zebrafish (Danio rerio)

Methylmercury (MeHg) is a toxicant of concern for aquatic food chains. In the present study, the assimilation and depuration of dietary MeHg and the influence of dietary selenium on MeHg toxicokinetics was characterised in zebrafish (Danio rerio).In a triplicate tank experimental design (n=3 tanks per treatment group), adult zebrafish were exposed to dietary MeHg (as methylmercury-cysteine) at 5 and 10μg/g and with or without selenium (as selenomethionine) supplemented to the diets at a concentration of 5μg/g for 8 weeks followed by a 4-week depuration period.Methylmercury accumulated in muscle, liver and brain of zebrafish; with higher mercury concentrations in liver and brain than in muscle following 8 weeks of exposure. In muscle, the mercury concentrations were 3.4±0.2 and 6.4±0.1μg/g ww (n=3) in zebrafish fed the 5 and 10μg Hg/g diets, respectively. During the depuration period, mercury concentrations were significantly reduced in muscle in both the 5 and 10μg Hg/g diet groups with a greater reduction in the high dose group. After depuration, the mercury concentrations were 2.4±0.1 and 4.0±0.3μg/g ww (n=3) for zebrafish fed the 5 and 10μg Hg/g diets, respectively.Data also indicated that supplemented dietary selenium reduced accumulation of MeHg and enhanced the elimination of MeHg. Lower levels of mercury were found in muscle of zebrafish fed MeHg and SeMet compared with fish fed only MeHg after 8 weeks exposure; the mercury concentrations in muscle were 5.8±0.2 and 6.4±0.1μg/g ww (n=3) for zebrafish fed the 10μg Hg/g+5μg Se/g diet and the 10μg Hg/g diet, respectively. Furthermore, the elimination of MeHg from muscle during the 4-week depuration period was significantly greater in the fish fed the diet containing SeMet compared to a control diet; the mercury concentrations were 3.3±0.1 and 4.0±0.3μg/g ww (n=3) for zebrafish fed the 5μg Se/g and the control diets, respectively. In summary, dietary SeMet reduces the accumulation and enhances the elimination of dietary MeHg in muscle of zebrafish.

Mercury in Pelecanus occidentalis of the Cispata bay, Colombia

ABSTRACTObjective. Assessment the total concentration of mercury in the liver and feathers of Pelecanus occidentalis of the Cispata bay, Colombia. Materials and methods. Mercury concentrations in liver and feather of Pelecanus occidentalis residents in the Cispata bay – Colombia were evaluated by digestion with an acidic mixture of H2SO4–HNO3 and KMnO4 to eliminate organic matter. The concentration of mercury was determined by the Atomic Absorption - Cold Vapor method (CVAAS). Results. Total mercury levels found in this study were higher in feathers (0.31-9.17 mgHg/kg) than in the liver (0.63–6.29 mgHg/kg), being higher than those reported in other seabirds studies. Conclusions. The high levels of total mercury in feathers and liver can be explained by the feeding habits of the organisms under study, showing the utility of feathers as a potential non-invasive tool for the monitoring of the ecosystem and thereby preventing the sacrifice of specimens

Distribution and accumulation of elements (As, Cu, Fe, Hg, Mn, and Zn) in tissues of fish species from different trophic levels in the Danube River at the confluence with the Sava River (Serbia)

Pikeperch (Sander lucioperca), European catfish (Silurus glanis), common carp (Cyprinus carpio), and gobies (Neogobius gymnotrachelus, Neogobius melanostomus) were collected from the Danube River (Belgrade section), and samples of liver, muscle, or whole-body composites (in the case of gobies) were analyzed for As, Cu, Fe, Hg, Mn, and Zn with inductively coupled plasma optical spectrometry to find out if there was a correlation between accumulation of these elements in predatory and prey species, as well as in pairs of species with overlapping diets. Concentrations of all analyzed elements were either higher (Cu, Fe, Mn, Zn) in liver than in muscle, or equal (As, Hg), except for Hg in carp, which was higher in muscle. Mercury concentration in liver and muscle of predators (catfish, pikeperch) was significantly (<10(-4)) higher than in prey fishes (carp and gobies). The results indicate that Hg concentration was biomagnified through the food chain. Concentrations of As, Fe, and Hg in carp liver and gobies whole-body composite were similar, but carp had significantly (<10(-4)) higher values of Zn and Cu in liver. The regression analysis and trendline equations indicate that the concentrations of all tested elements, except for As in liver, and Mn and Fe in muscle, were similar in predatory fish (pikeperch and catfish), on one hand, and in prey fish (carp and gobies), on the other hand. Distinctly high Zn concentration in carp is very common in this species due to its physiology. Concentrations of Hg and Zn were higher than the maximum acceptable concentration due to the high pollution level in this section of the Danube River, accordingly posing a risk for the human consumption of these fish species.

Two decades of biomonitoring polar bear health in Greenland: a review

SummaryWe present an overview of studies of anthropogenic pollutants in East Greenland polar bears over the period of 1999-2011. East Greenland polar bears are among the most polluted species, not just in the Arctic but globally, and represent an excellent biomonitoring species for levels and effects of global pollution in an apex predator. Therefore, an international multidisciplinary team joined to monitor and assess the patterns and concentrations of contaminants and their potential negative impact on polar bears. The review showed that East Greenland polar bears are exposed to a mix of chlorinated, brominated and fluorinated organic compounds as well as mercury which are all known to have endocrine, immune and organ-system toxic properties. For example, the concentrations of PCBs (polychlorinated biphenyls) in blubber ranged approximately 800-21,000 ng/g lw while mercury concentrations in liver and kidney ranged 0.1-50 μg/g ww. Regarding health endpoints, bone density seemed to decrease as a function of time and OHC (organohalogen compound) concentrations and further T-score for adult males indicated risk for osteoporosis. .The size of sexual organs decreased with increasing OHC concentrations. In the lower brain stem, mercury-associated decreases in NMDA-receptor levels and DNA-methylation was found The present review indicated that age was one of the major drivers for liver and renal lesions, although contaminants and infectious diseases may also play a role. Lesions in thyroid glands were most likely a result of infectious and genetic factors and probably, together with endocrine disrupting chemical (EDCs), the reason for disturbances/fluctuations in blood plasma thyroid hormone concentrations. Except for bone density reductions and neurological measures, all findings were supported by case-control studies of Greenland sledge dogs exposed long-term orally to similar combinations of contaminant concentrations. The studies of sledge dogs also indicated that the mixture of contaminants and fatty acids in the blubber of prey similar to that of polar bears induces cellular as well as humoral immune toxic changes. These controlled studies using model species for polar bears indicate that the correlative findings between health endpoint and contaminants in polar bears could be a cause-and-effect relationship. Physiologically based pharmacokinetic (PBPK) modelling showed that the risk quotients were ≥1 for ΣPCB, dieldrin and PFOS, which indicate an increased risk of prenatally reproductive pathology. In conclusion polar bears are susceptible to long-range transported chemicals that may have various adverse effects on multiple organ systems such as the reproductive and immune system.

Physiological responses to mercury in feral carp populations inhabiting the low Ebro River (NE Spain), a historically contaminated site

The low Ebro River course (Northeast Spain) is historically affected by mercury pollution due to a chlor-alkali plant operating at the town of Flix for more than a century. River sediments analysed during the last 10 years showed high mercury levels in the river section starting just downstream the factory and spanning some 90 km, down to the river delta. The possible environmental impact was studied by a combination of field and laboratory studies. Mercury concentrations in liver, kidney and muscle of feral carp ( Cyprinus carpio) sampled downstream Flix were one to two orders of magnitude higher than those from carps sampled upstream Flix. Elevated levels of mercury in these samples associated with significant increases on the concentration of reduced glutathione (GSH) in liver and on mRNA expression of two metallothionein genes, MT1 and MT2, in kidney and, partially, in scales, but not in liver. Conversely, no biochemical evidence for oxidative stress or DNA damage was found in these tissues. Non-contaminated carps subjected to intraperitoneal mercury injection resulted in a 20-fold increase of MT1 and MT2 mRNA levels in carp kidney, with minimal changes in liver levels. Our data suggests the coordinate increase of metallothionein mRNA in kidney and of GSH in liver constitutes an excellent marker of exposure to sub-toxic mercury levels in carps. This study also demonstrates that apparently healthy fish populations may exceed the mercury contamination acceptable for human consumption.

Trace Metal and Organochlorine Pesticide Concentrations in Cold-Stunned Juvenile Kemp's Ridley Turtles (Lepidochelys kempii) from Cape Cod, Massachusetts

Whole blood and keratin mercury concentrations, complete blood cell counts, and plasma biochemical health profiles were evaluated in 31 juvenile cold-stunned Kemp's ridley turtles (Lepidochelys kempii) from Cape Cod, Massachusetts. In addition, plasma copper, zinc, selenium, and cadmium concentrations were measured for 16 of these turtles. Liver mercury concentrations were measured for 6 turtles that were dead upon acquisition or died during rehabilitation. Concentrations of 18 organochlorine pesticides were measured in plasma of 18 live turtles, and liver, kidney, fat, and brain of 3 deceased turtles. Metal levels were generally similar to those previously published for sea turtles, with mean values (wet weight) of 24 ng/g for blood mercury, 67 ng/g for liver mercury, 389 ng/g for keratin mercury, 690 ng/g for plasma copper, 2290 ng/g for plasma zinc, and 490 ng/g for plasma selenium. Cadmium was not detected in any sample. Organochlorine levels were generally low in comparison to values published for cold-stunned juvenile Kemp's ridley turtles in the 1980s. Several significant correlations between metal levels, hematology, and plasma biochemical health parameters were detected; however, the cause of these correlations could not be determined. This study demonstrates that Kemp's ridley turtles may be exposed to contaminants at a young age. Further investigation of the sources and effects of contaminants in juvenile sea turtles is warranted.

Human accumulation of mercury in Greenland

In the Arctic, the traditional diet exposes its people to a high intake of mercury especially from marine mammals. To determine whether the mercury is accumulated in humans, we analyzed autopsy samples of liver, kidney and spleen from adult ethnic Greenlanders who died between 1990 and 1994 from a wide range of causes, natural and violent. Liver, kidney and spleen samples from between 33 and 71 case subjects were analyzed for total mercury and methylmercury, and liver samples also for selenium. Metal levels in men and women did not differ and were not related to age except in one case, i.e. for total mercury in liver, where a significant declining concentration with age was observed. The highest total mercury levels were found in kidney followed by liver and spleen. Methylmercury followed the same pattern, but levels were much lower, constituting only 19% of the total mercury concentration in liver and spleen and as little as 3% in kidney. In liver selenium was found in surplus to mercury on a molar basis. Mercury concentrations in the liver and kidneys of Greenlanders were elevated compared to levels in the general population in Japan, Korea and several European countries, except in the Faroe Islands where mercury levels were 2-3 times higher. This is in accordance with the expected exposure of mercury in the diet.

Role of Selenium in Mercury Intoxication in Mice

Studies were conducted to examine the effect of pre and post-treatment of selenium in mercury intoxication (20 micromole/ kg b.w. each given intraperitoneally) in mice in terms of lipid peroxidation (LPO), glutathione (GSH) content, activities of superoxide dismutase (SOD), glutathione peroxidase (GPx), catalase (CAT) and mercury concentration in liver, kidney and brain. No significant alteration was observed in all the organs examined after mercury or selenium treatment in LPO and GSH but administration of selenium (pre and post) resulted in an increase in the level of LPO and GSH. The activity of SOD was depleted in liver and kidney while that of GPx was lowered in liver of mercury exposed animals. Selenium administration resulted in restoration of the depletion of these enzymatic activities. The activity of CAT in liver and brain was enhanced both in mercury and selenium treated animals. Administration of selenium significantly arrested enhanced CAT activity. Kidney showed the highest mercury concentration among the organs examined. Administration of selenium resulted in further enhancement of mercury concentration in the tissues. An increase in selenium level in liver was observed after mercury treatment, which was also restored by mercury selenium co-administration. Our results indicate that the prooxidant effect of selenium was greater by its pretreatment.

Investigation of cadmium, mercury and arsenic accumulation in wild boar tissues from hunting areas in Serbia

The present survey aimed at the residues of risk elements (cadmium, mercury and arsenic) in different tissues of wild boars, from selected hunting areas in Serbia. Livers, kidneys and muscle tissues were obtained from wild boars, hunted at random during 2004. and 2005. This examination included altogether 64 wild boars (64 kidneys, 64 livers and 21 muscles). Occasion of this survey, 447 analyses carried out. Total number of analyzed tissue samples were 149. There was registered that the ratio between cadmium and mercury concentration in liver and in kidneys increases with the intensity of exposure. .

Tissue heavy metal concentrations of stranded California sea lions ( Zalophus californianus) in Southern California

Concentrations of nine heavy metals (As, Cd, Cu, Fe, Hg, Pb, Mn, Mo and Zn) were determined in the hepatic and renal tissues of 80 stranded California sea lions ( Zalophus californianus). Significant age-dependant increases were observed in liver and kidney concentrations of cadmium and mercury, and renal zinc concentrations. Hepatic iron concentrations were significantly higher in females than males. Animals with suspected domoic acid associated pathological findings had significantly higher concentrations of liver and kidney cadmium; and significantly higher liver mercury concentrations when compared to animals classified with infectious disease or traumatic mortality. Significantly higher hepatic burdens of molybdenum and zinc were found in animals that died from infectious diseases. This is the largest study of tissue heavy metal concentrations in California sea lions to date. These data demonstrate how passive monitoring of stranded animals can provide insight into environmental impacts on marine mammals.

Assessment of mercury concentrations in small mammals collected near Las Vegas, Nevada, USA

Mercury concentrations in liver and hair tissue were determined for five species of small mammals captured near Las Vegas, Nevada, USA. These data were then used to evaluate the suitability of using hair as a noninvasive technique for determining body burdens of mercury. A total of 104 small mammals were captured and analyzed; four main species were examined and included: Dipodomys merriami, Chaetodipus penicillatus, Peromyscus eremicus, and Neotoma lepida. Mean mercury concentrations were highest in N. lepida, followed by D. merriami, C. penicillatus, and P. eremicus respectively. Positive associations were found between hair and liver taken from D. merriami (r = 0.647) and C. penicillatus (r = 0.533) indicating that hair may be a suitable indicator of body burdens in these two species.