Cd In Liver Research Articles

Liver, gills, and skin histopathology and heavy metal content of the Danube sterlet (Acipenser ruthenus Linnaeus, 1758)

The sterlet (Acipenser ruthenus L.) is a bottom-feeding fish species with a direct exposure to contaminants from water and sediments. Although heavy metal pollution is believed to be one of the main threats to the sterlet population in the Danube River basin, there is a lack of knowledge of the exact impact of heavy metals on their survival. In the present study, effects of heavy metal pollution on sterlet in the Danube basin were assessed as well as the utility of different sterlet organs and tissues as indicators of heavy metal contamination. The sterlet were sampled at three different sites in the Danube basin, in Hungary and Serbia, isolated from each other by dams. Heavy metal analysis included measurement of Cd, As, Pb, Cr, Hg, Cu, Ni, Fe, Mn, and Zn concentrations in sterlet gills, muscle, liver, and intestine, and histopathological analyses comprised assessment and scoring of the extent and intensity of alterations in skin, gills, and liver tissue. Analysis revealed a significant presence of sublethal histopathological changes that were most pronounced in the liver and skin and increased accumulation of heavy metals, with the highest concentrations in the liver. Canonical discriminant analysis showed significant differentiation among the three studied localities, suggesting that the heavy metal concentrations in sterlet populations were site specific. The present study concludes that the accumulation of heavy metals is a response to the presence of these pollutants in the environment, and, together with other pollutants, it affects the vital organs of natural sterlet populations.

Concentration of heavy metals in tissues of green turtles (Chelonia mydas) sampled in the Cananéia estuary, Brazil

Thirty specimens (15 adults and 15 juveniles) of Chelonia mydas found in the Cananéia estuary in the state of São Paulo on the southeastern Brazilian coast between January 2005 and September 2006, were analyzed The concentrations of Cd, Cu, Pb, Mn and Ni in liver and kidney samples of adult and juvenile green turtles were determined by Flame Atomic Absorption Spectrophotometry.The average Cd concentration found in adult livers (0.57µg.g-1) was significantly higher than that in juveniles (0.279µg.g-1). Cu concentrations were significantly higher in the liver than in the kidney, and significantly higher in adults (39.9µg.g-1) than in juveniles (20.7µg.g-1) Average Mn concentrations in liver and kidney did not differ between adults (4.32 and 4.17µg.g-1) and juveniles (4.81 and 3.82µg.g-1), whereas Ni concentrations in adults (0.28 and 0.19µg.g-1, respectively) were significantly higher than in juveniles (0.13 and 0.089µg.g-1, respectively). Pb concentrations in liver were significantly higher in adults (0.37µg.g-1) than in juveniles (0.06µg.g-1). The concentrations of essential trace elements in Chelonia mydas were generally comparable to values reported in other, similar studies. With respect to non-essential metals (Cd, Pb and Ni), Chelonia mydas presented lower values than those reported for their northern Atlantic counterparts.

Estimation of the Combined Effect of Eleutherococcus senticosus Extract and Cadmium on Liver Cells

Cadmium (Cd) is an important industrial pollutant, even though its mechanism of toxicity has not been completely clarified. Cd(2+) is toxic to a wide range of organs and tissues. Liver and kidneys are the primary target organs of cadmium toxicity. Cd(2+) induces apoptosis and causes necrotic cell death in certain pathophysiological situations. Eleutherococcus senticosus (Rupr. et Maxim.) Maxim. has many beneficial features. It supports the organism's stress response, immune system, and endocrine system, including the adrenal glands, spleen, and thymus gland. The aim of our study was to investigate the effects of the Eleutherococcus senticosus (ES) liquid extract on the accumulation of Cd(2+) in liver and on the mitotic and apoptotic activity of liver cells after chronic intoxication by Cd(2+). Experiments were carried out on white laboratory mice. Laboratory mice were given to drink solutions of different Cd(2+) and ES concentrations for 8 weeks. Cd(2+) concentration in mouse liver was detected using atomic absorption spectroscopy. Mitotic and apoptotic activity of liver cells was expressed as an estimated number of mitotic and apoptotic cells in randomly selected reference areas in a histological slide. ES combined with CdCl(2) leads to a significant decrease of cadmium concentration in the blood and liver of experimental mice. ES decreased the cadmium-induced mitotic and apoptotic activity of liver cells.

Distribution of Heavy Metals in Bones, Gills, Livers and Muscles of (Tilapia) Oreochromis niloticus from Henshaw Town Beach Market in Calabar Nigeria

Two sets of samples of commercially important fish species Oreochromis niloticus of size 29 cm and 20 cm respectively were purchased from the Henshaw town beach market in Calabar, Calabar South Local Government Area of Cross River State, Nigeria in October 2007. The concentrations of five heavy metals (Pb, Zn, Cd, As and Hg) in their bones, gills, livers and muscles were determined using flame atomic absorption spectrophotometer. The result showed the heavy metal concentrations in the 29 cm size samples to be Pb (0.069 ppm) Cd (0.019 ppm) and Zn (0.103 ppm) in the bones. Pb (0.173 ppm) Cd (0.049 ppm) and Zn (0.257 ppm) in the livers. Pb (0.053 ppm) Cd (0.015 ppm) Zn (0.079 ppm) in the muscles Pb (0.133 ppm), Cd (0.038 ppm) and Zn (0.198 ppm) in gills. While the 20 cm size samples had Pb (0.067 ppm) Cd (0.019 ppm) and Zn (0.100 ppm) in bones. Pb (0.067 ppm) Cd (0.019 ppm) and Zn (0.099 ppm) in livers. Pb (0.062 ppm) Cd (0.017 ppm) and Zn (0.095 ppm) in muscles and Pb (0.153 ppm) Cd (0.044 ppm) and Zn (0.227 ppm) in gills. Arsenic and mercury were not detected in any of the samples. The result revealed the distribution of the heavy metal in both 29 cm and 20 cm size samples to follow the order Zn> Pb> Cd while the distribution of the heavy metals in the investigated parts (organs) is shown to follow the order livers > gills > bones > muscles for the 29 cm size samples. And Gills > Livers = bones > muscles in the 20 cm size samples. The result also revealed that the 29 cm size samples had higher concentrations of the heavy metals than the 20 cm size samples. The result also showed that the muscle of Tilapia is safer to consumed than the other parts investigated as it has been shown to contain the least concentrations of the heavy metals determined. This reveals the adverse health effect the people in the study area could be exposed to by the consumption of liver, gills and bones of Tilapia which have high levels of these heavy metals.

Heavy metal concentrations in the selected tissues of the Persian sturgeon, Acipencer persicus, from the southern coast of the Caspian Sea

Bioaccumulation of heavy metals including Cd, Pb, Cu and Zn in muscle, gill, liver, kidney and stomach in Acipencer persicus was studied. Fish were collected from the ‘Iranian fishery zone 1’ located between Astara and Kiyahshahr. Samples (n=25) were collected from five stations in the study area during the autumn catch season in 2001. Samples were analyzed by wet digestion with hydrogen peroxide and nitric acid. Analyses were testified using spike method. A sample of bovine liver (CRM 185R) was tested to ascertain reliability of analyses. Digested samples were analyzed using Flame Atomic Absorption Spectrophotometer. The bioaccumulation pattern for Zn in different tissues studied was stomach>liver> kidney> gills>muscle tissue. The mean concentration of Zn in the stomach was 136.6±10.70mg g-1 dry weight. Cu with the maximum concentration of 39.71±8.85mg g-1 dry weight in liver showed a bioaccumulation pattern of liver>kidney>stomach>gills>muscle tissue. The bioaccumulation pattern for Pb was determined as gills>liver> kidney>stomach>muscle tissue. Maximum mean concentrations of Pb 6.87±2.25mg g-1 dry weight belonged to gills. Bioaccumulation pattern for Cd in the different organs studied in A. persicus was kidney>liver>gills>stomach> muscle tissue. Maximum mean concentration of 5.1±0.97mg g-1 dry weight belonged to kidneys and the minimum mean concentration of 0.05±0.007mg g-1 dry weight belonged to muscle tissue. Concentration of the metals in the muscles samples were below the most guidelines for human consumption. Concentrations for heavy metals were lower than the guidelines in some organs and were higher than that in the other organs studied. The observed concentrations do not pose health problems as these organs are not used for human consumption.

Food chain transfer of cadmium and lead to cattle in a lead–zinc smelter in Guizhou, China

Cadmium (Cd) and Lead (Pb) are environmental pollutants. Environmental samples and bovine tissues were collected from the areas around a lead–zinc smelter in Guizhou, China for Cd, Pb, zinc (Zn) and copper (Cu) analysis. Cd in soil (10 mg/kg) and feed (6.6 mg/kg) from the polluted areas was 10 times higher than the Chinese Standards, resulting in higher Cd in bovine kidney (38 mg/kg) and liver (2.5 mg/kg). Pb in feed (132 mg/kg) from the polluted area was much higher than unpolluted areas, causing higher Pb levels in bovine tissues. Environmental Zn was elevated, but bovine tissue Zn was normal. Cu in bovine liver decreased with increased Cd and Pb. Metals in drinking water and in bovine muscle were within the Standard range. Thus, in the areas of this lead–zinc smelter, the environment has been contaminated with Cd and Pb, which has been transferred to cattle through the food chain.

Ascorbic acid, garlic extract and taurine alleviate cadmium-induced oxidative stress in freshwater catfish ( Clarias batrachus)

An experiment was conducted to investigate bioaccumulation potential of cadmium (Cd) and changes in oxidative stress indices in liver and kidney tissues from Cd-exposed catfish ( Clarias batrachus) with or without simultaneous treatment of water with ascorbic acid, garlic extract or taurine. C. batrachus ( n = 324) with average length of 20 ± 4 cm and weight of 86 ± 5 g were used for the present investigation. Fishes were divided into nine groups (I to IX) each comprising 36 fishes. The fishes of groups II, III, IV and V were challenged with 5 ppm of cadmium chloride monohydrate (CdCl 2.H 2O), whereas groups VI, VII, VIII and IX were exposed to 10 ppm CdCl 2.H 2O solution for a period of 45 days. Group I was kept as negative control and the fishes of this group were maintained in water containing no added Cadmium. Group II and VI were maintained as Cd exposed non treated control to serve as positive controls. Fishes of III and VII, IV and VIII, V and IX received ascorbic acid (5 ppm), extract of dried garlic (5 ppm) or taurine (5 ppm), respectively during the entire experiment period. The concentrations of Cd in liver and kidney increased significantly following exposure to Cd and the level continued to rise with the increase in exposure duration. Treatment of tank water with ascorbic acid, garlic or taurine significantly reduced the Cd concentrations in tissues compared to the positive control group, but the level in Cd exposed groups was greater than the negative control group. Fishes exposed to Cd and treated with ascorbic acid, garlic or taurine had reduced oxidative stress as evidenced from lower concentration of lipid peroxides and higher activities of superoxide dismutase and catalase in liver, kidney and erythrocytes compared to fishes exposed to Cd. The reduction in Cd induced oxidative stress was highest in ascorbic acid treated group followed by garlic and taurine treatment. The results suggest that ascorbic acid, garlic and taurine have potential to reduce tissue accumulation of Cd and associated oxidative stress in freshwater catfish.

Vapor Generation Atomic Absorption Spectrometric Determination of Cadmium in Environmental Samples with In-Line Anion Exchange Separation

A novel in-line anion exchange separation method is described for the removal of Mn(2+), Fe(3+), Ni(2+), Co(2+), Cu(2+), Zn(2+), and Pb(2+) from Cd(2+) and for its subsequent determination by vapor generation atomic absorption spectrometry. High Cd(2+) retention efficiency and maximum exclusion of other metal ions were achieved by using Cl(-), Br(-), or I(-) loaded strong base anion exchange resin and fiber in chloride medium. SO(4)(2-) and NO(3)(-) affected the retention of Cd(2+) on Cl(-) or Br(-) loaded exchangers but were beneficial for elution from I(-) loaded exchangers. Fast and efficient elution from the exchangers was achieved by using ethylenediamine solution. The removal of Zn(2+) was unnecessary as it prevents a decline in the sensitivity of cadmium response when ethylenediamine and high acid concentration were used. Under optimum conditions, the achievable detection limits (3sigma) with sample loadings of 0.48 and 9.6 mL were 40 ng L(-1) and 3 ng L(-1), respectively. Interference of residual organic matrix, in sample digests, with the separation and retention of cadmium were eliminated by use of microwave assisted digestion. The method was successfully applied to the determination of Cd in river sediment, fish liver, and water samples.

Accumulation of trace metals in the muscle and liver tissues of five fish species from the Persian Gulf

In this study, concentrations of 16 elements were quantified in muscles and livers of 141 fishes belonging to five commercially species. It was also our intention to evaluate potential risks to human health associated with seafood consumption. The grunt, flathead, greasy grouper, tiger-tooth croaker and silver pomfret fish species were obtained from Abadan, Deylam, Bushehr-Nirogah, Dayyer port, Lengeh port and Abbas port in Hormozgan, Bushehr and Khozesran provinces at the Iranian waters of the Persian Gulf. The contents of Al, As, Be, Cd, Cr, Co, Cu, Fe, Pb, Mn, Mo, Ni, Sb, Tl, V and Zn in fish muscles and livers were determined by Inductively Coupled Plasma Mass Spectrometry (ICP MS), after digestion in a CEM (Mars 5) microwave oven using nitric acid and hydrogen peroxide. Our results indicated that almost all metals were more accumulated in younger flathead, greasy grouper and tiger-tooth fishes. Contrary to the other fish species, grunt seems to stronger accumulating elements in the older fishes. Strong and positive correlations were observed in three or more of the fish species between V, Al, Fe, Tl, Co and Pb. The results confirmed that fish muscle and liver tissues appeared to be good bio-indicators for identification of coastal areas exposed to metallic contaminants. The results also showed that the element levels in the muscles of all fishes in our study were lower than the maximum allowable concentrations and pose no threat to public health, except for arsenic.

Biochemical and histopathological endpoints of in vivo cadmium toxicity in Sparus aurata

Cadmium (Cd) is a non-essential metal common in water bodies subjected to anthropogenic pollution. Its proven toxicity to aquatic and terrestrial organisms (including humans) has made this metal a subject of particular interest in toxicological studies, especially concerning common coastal fish species that are important marine resources, such as Sparus aurata. In order to establish laboratory tests and biomarker techniques to assess in vivo Cd toxicity in a multilevel (from histological to biochemical) approach, a short-term (48 h) assay was performed using juvenile S. aurata injected intraperitoneally with individual Cd dosages (0–8.1 µg Cd g–1 fish w.w.). The results showed that Cd causes a fast and pronounced histopathological degeneration of liver tissue and an exponential induction in liver metallothionein-like proteins (MTs) strongly correlated to the injected Cd dosage (Spearman R = 0.97, P < 0.01) but not to Cd bioaccumulation or survival time. The relationships between Cd dosage, liver Cd, and liver MT suggested the existence of an absorbed Cd threshold after which the animals were no longer able to regulate and bioaccumulate the metal. This threshold was not dependent on survival time but rather on Cd dosage. The findings also confirmed the suitability of S. aurata as a test organism regarding toxicity caused by Cd. Complimentarily, a histological technique using a fluorochrome (acridine orange) to enhance tissue detail is described, as well as a method suitable for the detection of MTs in SDS-PAGE gels with a colloidal Coomassie blue stain.

Towards a safe standard for heavy metals in reclaimed water used for fish aquaculture

The objective of the present study is to provide a basis for the development of a standard on the concentration of heavy metals in reclaimed water used for edible fish aquaculture, focusing on the four heavy metals addressed by the Israel standard for food quality (arsenic, cadmium, lead and mercury). A series of experiments were carried out on three commercial fish species of differing feeding habits and complementary measurements were made in fish growing in a reservoir with secondary treated effluent. In a field experiment the fish were raised on natural food and on pelleted feed, in reclaimed wastewater and in freshwater. In laboratory experiments, the fish were raised in aquaria while exposing them to heavy metals supplied in the pelleted feed or dissolved in the water. In the field experiment with fish growing in tertiary treated reclaimed water during five months, no detectable levels of the four tested heavy metals were found in fish flesh (no analyses in internal organs performed). In fish reared during two years in secondary treated reclaimed water, no detectable levels of heavy metals were found in fish flesh, but the concentrations of Cd and Pb in liver and bones of some fish were above the food standard. Laboratory experiments on rearing fish while exposing them to water and pelleted feed with increasing levels of heavy metals, revealed detectable levels of these heavy metals in fish flesh, bone and mainly in liver. The standards on reclaimed water for unrestricted irrigation are a good basis for the development of a water quality standard for growing fish in reclaimed water, because fish can be grown in the reservoirs used to storage the reclaimed water and/or this is the reclaimed water that can be used to fill fish ponds. Except for Hg, the proposed Israel requirements for heavy metals in reclaimed water used for unrestricted irrigation (As = 0.1 mg/l, Cd = 0.01 mg/l, Pb = 0.1 mg/l, Hg = 0.002 mg/l) are safe regarding the consumption of flesh from fish reared in reclaimed water, even if the growing season is long (up to two years). These requirements are not equally safe regarding the consumption of liver (and probably other viscera).

Analysis of Cd, Cu, Pb, Zn, Hg and Mn in kidneys and liver from human cadavers – A case study in South Western Nigeria

In this study, autopsy tissue samples from human liver and kidneys were analysed for Cd, Cu, Pb, Zn, Hg and Mn in 25 subjects (16 males and 9 females) ranging in age from 2 to 70 years. Tissue samples that were pathologically normal were obtained at postmortem and concentrations of metals were determined. In both kidneys and liver, the concentrations of metals followed the order Cd > Hg > Pb > Zn > Mn > Cu irrespective of gender and age group, except in female kidneys where the order was Cd > Pb > Hg > Zn > Mn > Cu. Generally, males had higher concentrations of metals in both the kidneys and liver. Significant correlations of the metals were found in kidney and liver tissues.

Levels of As, Cd, Pb, Cu, Se and Zn in bovine kidneys and livers in Jamaica

Paired liver and kidney samples from 100 free-range cattle in different parts of Jamaica were analyzed for essential and non-essential trace elements. We found significant enrichment of elements in the kidney (K) compared to the liver (L) with the K/L concentration ratios being 5.2 for Cd, 4.1 for Pb, 3.5 for Se and 2.1 for As, but the Cu contents of the kidney were significantly higher with the K/L ratio of 0.45. A large number of kidney and liver samples showed Cu concentrations in the ranges that were associated with deficiency effects in mammals. About 15% of the hepatic samples had Zn concentrations below 20 μg/g, suggesting that there might be zinc insufficiency in some of the animals. Positive associations were found between the metals in both the kidney and liver. On average, the intake of Cd from consumption of both bovine kidney and liver from the island was estimated to be 5.2 μg/day, equivalent to about 7% of the provisional tolerable daily intake (PTDI), although anyone who habitually consumed the few kidneys or livers with >40 μg/g cadmium may be at some risk of exceeding the PTDI. The consumption of offal from local animals did not appear to be an important dietary source of any of the essential microelements.

Heavy metal and mineral concentrations and their relationship to histopathological findings in the bowhead whale ( Balaena mysticetus)

The bowhead whale ( Balaena mysticetus) is a species endangered over much of its range that is of great cultural significance and subsistence value to the Inuit of Northern Alaska. This species occupies subarctic and arctic regions presently undergoing significant ecological change and hydrocarbon development. Thus, understanding the health status of the Bering–Chukchi–Beaufort Sea (BCBS) stock of bowhead whales is of importance. In this study, we evaluated the concentrations of six essential and non-essential elements (Zn, tHg, Ag, Se, Cu and Cd) in liver and kidney of bowhead whales ( n = 64). These tissues were collected from the Inuit subsistence hunt in Barrow, Wainwright and Kaktovik, Alaska between 1983 and 2001. Reference ranges of these elements (including previously reported data from 1983–1997) were developed for this species as part of a health assessment effort, and interpreted using improved aging techniques (aspartic acid racemization and baleen isotopic 13C methods) to evaluate trends over time with increased statistical power. Interactions between element concentrations and age, sex and harvest season were assessed. Age was found to be of highest significance. Sex and harvest season did not effect the concentrations of these elements, with the exception of renal Se levels, which were significantly higher in fall seasons. In addition, histological evaluation of tissues from whales collected between 1998–2001 was performed. Associations between concentrations of Cd in kidney and liver and scored histopathological changes were evaluated. Liver Cd concentration was strongly associated with the degree of lung fibromuscular hyperplasia ( P = 0.001) and moderately associated with the degree of renal fibrosis ( P = 0.03). Renal Cd concentration influenced the degree of lung fibromuscular hyperplasia and renal fibrosis ( P = 0.01). A significant age effect was found for both pulmonary fibromuscular hyperplasia and renal fibrosis, indicating age may be a causative factor. Improvements in aging techniques and the addition of histological indices help clarify the relationships between elements and the influence of life history parameters on concentrations of these elements and potential impacts on health. These data provide essential baseline input useful for monitoring the effects of arctic ecosystem change as it relates to global climate change and industrial development, as well as help inform epidemiological studies examining the public health implications of heavy metals in subsistence foods.

Direct and Indirect (Foodweb Mediated) Effects of Metal Exposure on the Growth of Yellow Perch (Perca flavescens): Implications for Ecological Risk Assessment

ABSTRACT Yellow perch (YP) are metal tolerant fish that form large populations in many metal-impacted regions across Canada. While they are able to survive and reproduce successfully in environments with water and sediment metal concentrations that are toxic to many invertebrates, perch experience a suite of direct and indirect impacts. YP were studied in a series of Canadian Precambrian Shield lakes near Sudbury, Ontario, along a gradient of metal exposure downwind from metal smelters. In lakes at the high end of our exposure gradient, concentrations of metals (Cu, Ni, and Cd) in YP liver and kidney were well above levels seen in fish from reference lakes. Direct effects linked to metal-exposure were observed, ranging from effects at the cellular level, to effects in organs and tissues, individuals, and populations. In addition to direct or physiological effects, we also documented indirect, foodweb-mediated effects of metals on YP in the most contaminated lakes resulting from the elimination of metal-sensitive large benthic invertebrates and their replacement by small metal-tolerant taxa. The most common indication of such indirect effects on YP is severely stunted growth coupled with a high degree of zooplankton dependence throughout their life. Such indirect effects have important implications for ecological risk assessment (ERA) because they indicate that higher trophic levels may be functionally altered even though the functional groups that they depend on are present and abundant. Although the functional groups important to yellow perch can be abundant in metal-impacted lakes, their benthic communities are impoverished and this is strongly reflected in their size structure upon which energy transfer to higher trophic levels depends. Thus indirect (foodweb-mediated) effects can be important in situations where invertebrate size structure is impacted in such a way as to reduce the efficiency of energy transfer to higher trophic levels, and therefore measures should be taken to protect and/or restore large sensitive benthic species.

Metallothionein induction by Cu, Cd and Hg in Dicentrarchus labrax liver: Assessment by RP-HPLC with fluorescence detection and spectrophotometry

Metallothionein was quantified in sea bass Dicentrarchus labrax intraperitoneally (i.p.) injected with different Cu, Cd and Hg doses (50-250 microg kg(-1) wet wt) after 48 h exposure. A distinct peak with 16.8 min retention time was obtained by reversed-phase high performance liquid chromatography coupled to fluorescence detection (RP-HPLC-FD) with the three metals. Total metallothionein levels assayed in unheated liver extracts by RP-HPLC-FD were significantly higher (1.3-1.95-fold) than those obtained by the well-established spectrophotometric method. In the RP-HPLC-FD method, metallothionein increased linearly with Cu and Hg doses, being saturated beyond 100 mug kg(-1) Cd. Maximum induction was obtained at 100 microg kg(-1) Cd (5.3-fold), and 250 microg kg(-1) Cu or Hg (8- and 5.1-fold, respectively). At low doses no metallothionein induction was shown by the less sensitive spectrophotometric assay.

Determination of some heavy metal levels and oxidative status in Carassius carassius L., 1758 from Eber Lake

In this study, the levels of some heavy metals (Al, Cd, Co, Cr, Cu, Fe, Li, Mn, Ni, Pb and Zn) in muscle, gill, and liver of Carassius carassius and in the water samples from Eber Lake (Afyonkarahisar, Turkey) have been investigated. Additionally, one of the lipid peroxidation markers, malondialdehide (MDA) and glutathion (GSH) levels were investigated. All the metal analysis was performed by using ICP-AES. According to results obtained, it was observed that heavy metals were accummulated in liver in the highest degree and lowest one in the muscle tissues. MDA and GSH levels varied in the seasons but their winter levels were found to be statistically meaningful when compared with other seasons. The obtained data of metals from the study were compared with the acceptable levels of Turkish governmental regulation and they were found not to be harmful for human health. On the other hand, it was suggested that oxidative stress markers should be checked regularly in order to get important data for continuous life of aquatic organisms.

Metal distribution and metallothionein in loggerhead (Caretta caretta) and green (Chelonia mydas) sea turtles

The first aim of our study was to determine the concentrations of selected trace elements (Zn, Cu, Fe, Mn, Cd and Pb) in tissues of green turtles from Tortuguero National Park on the North Caribbean coast of Costa Rica and of loggerheads from the Mediterranean Sea. Zn, Cu, Fe, Mn and Cd were present at detectable concentrations in all samples and showed clear organotropism, whereas Pb was not always over the detection limit and did not show any particular tissue distribution. The two species presented significant differences: Cu and Cd in liver and kidney of Chelonia mydas were significantly higher with respect to the concentrations found in Caretta caretta.The second and major goal of our study was to evaluate hepatic and renal metallothionein (MT) as a biomarker of environmental metal exposure. The present paper is the first to describe and quantify MT in kidney and liver of loggerhead turtles and in kidney of green turtles. MT concentrations were higher in green than in loggerhead turtles. In addition, positive correlations were found between Cu and Cd concentrations and Cu–MT and Cd–MT in liver and kidney in both species, suggesting a pivotal role of MT in metal storage and detoxification. The quantification of metals and MT in liver and kidney may be a valid biomarker of metal exposure in the aquatic environment to assess the health of marine sea turtles as long as accurate analytical methods are adopted.

Metals and selenium in the liver and bone of three dolphin species from South Australia, 1988–2004

Metal and selenium concentrations (wet weight) were determined in the liver (Cd, Hg, Pb, Zn, Cu and Se) and bone (Pb and Cd) of common dolphins (Delphinus delphis, N=71) and bottlenose dolphins (Tursiops truncatus, N=12, and Tursiops aduncus, N=71) stranded or by-caught in South Australia from 1988 to 2004. Differences in metal burdens existed between species, stranding location, and relative age. T. aduncus had the greatest mean tissue burdens of liver Pb (0.45 mg/kg), Cd (6.45 mg/kg), Hg (475.78 mg/kg), Se (178.85 mg/kg) and Zn (93.88 mg/kg) and bone Pb (2.78 mg/kg), probably reflecting their coastal habitat and benthic prey. Mean Cu was highest in T. truncatus (21.18 mg/kg). Bone Cd was measured only in T. aduncus and averaged 0.05 mg/kg. Stranding location impacted metal burdens. Dolphins from Spencer Gulf had higher mean levels of liver Pb (0.39 mg/kg) while Gulf St Vincent dolphins had greater liver Hg (444.64 mg/kg), liver Se (163.12 mg/kg), and bone Pb (2.85 mg/kg). This may be due to high anthropogenic inputs of Pb and Hg into Spencer Gulf and Gulf St Vincent respectively. Liver Cd, Hg, Se and Pb increased with age in all species while Cu decreased with age, in keeping with previous studies. Se and Hg were positively correlated. The possibility that metallothioneins are driving observed correlations between Zn, Cd, Hg and Cu are discussed. Future research must investigate the toxicological consequences of the metal concentrations reported.

Normal cadmium uptake in microcytic anemia mk/mk mice suggests that DMT1 is not the only cadmium transporter in vivo

Divalent metal transporter 1 (DMT1) is a mammalian iron (Fe) transporter and also transports Cadmium (Cd) in vitro. This study compared Cd absorption in DMT1-dysfunctional MK/Rej- mk / mk mice ( mk/mk mice) and in DMT1-functional, Fe-deficient wild-type (WT) mice, to clarify the role of DMT1 in intestinal Cd absorption in vivo. Mice were given 1 ppm CdCl 2 aq in drinking water for 2 weeks, and the concentrations of Cd and Fe in liver, kidney, and intestinal epithelium were subsequently determined. The Fe concentration in intestinal epithelia of WT mice was decreased in proportion to the level of dietary Fe limitation, while Cd accumulation under the same conditions was increased. DMT1 mRNA expression in the small intestine of Fe-deficient WT mice was clearly increased compared to that in Fe-sufficient WT mice. Iron deficiency resulted in up-regulation of Cd uptake in the intestine of Fe-deficient WT mice. The mk/mk mice have a mutation in DMT1 and loss of its function led to decreased intestinal Fe concentration. However, intestinal Cd accumulation was the same as in WT mice and it was also increased in Fe-deficient situation. There is the possibility that an unknown Cd pathway has taken a role on Cd intestinal absorption in vivo and that this pathway is regulated by food Fe concentrations. Therefore, DMT1 is not the sole transporter of intestinal cadmium absorption in vivo.