Concentration and subcellular distribution of trace elements in liver of small cetaceans incidentally caught along the Brazilian coast

Concentrations of trace elements (V, Cr, Mn, Fe, Co, Cu, Zn, Ga, As, Se, Rb, Sr, Mo, Ag, Cd, Sb, Cs, Ba, T-Hg, Org-Hg, Tl and Pb) were determined in liver samples of estuarine dolphin (Sotalia guianensis; n = 20), Franciscana dolphin (Pontoporia blainvillei; n = 23), Atlantic spotted dolphin (Stenella frontalis; n = 2), common dolphin (Delphinus capensis; n = 1) and striped dolphin (Stenella coeruleoalba; n = 1) incidentally caught along the coast of Sao Paulo State and Parana State, Brazil, from 1997 to 1999. The hepatic concentrations of trace elements in the Brazilian cetaceans were comparable to the data available in literature on marine mammals from Northern Hemisphere. Concentrations of V, Se, Mo, Cd, T-Hg and Org-Hg increased with increasing age in liver of both estuarine and Franciscana dolphins. Very high concentrations of Cu (range, 262-1970 microg/g dry wt.) and Zn (range, 242-369 microg/g dry wt.) were observed in liver of sucklings of estuarine dolphin. Hepatic concentrations of V, Se, T-Hg, Org-Hg and Pb were significantly higher in estuarine dolphin, whereas Franciscana dolphin showed higher concentrations of Mn, Co, As and Rb. Ratio of Org-Hg to T-Hg in liver was significantly higher in Franciscana dolphin than estuarine dolphin, suggesting that demethylation ability of methyl Hg might be lower in liver of Franciscana than estuarine dolphins. High hepatic concentrations of Ag were found in some specimens of Franciscana dolphin (maximum, 20 microg/g dry wt.), and 17% of Franciscana showed higher concentrations of Ag than Hg. These samples with high Ag concentration also exhibited elevated hepatic Se concentration, implying that Ag might be detoxified by Se in the liver. Higher correlation coefficient between (Hg+0.5 Ag) and Se than between Hg and Se and the large distribution of Ag in non-soluble fraction in nuclear and mitochondrial fraction of the liver also suggests that Ag might be detoxified by Se via formation of Ag2Se in the liver of Franciscana dolphin.     

Interelement relationships and age-related variation of trace element concentrations in liver of striped dolphins (Stenella coeruleoalba) from Japanese coastal waters

Concentrations of 19 trace elements (V, Cr, Mn, Fe, Co, Cu, Zn, Se, Rb, Sr, Mo, Ag, Cd, Sb, Cs, Ba, Tl, Hg, and Pb) were determined in the liver of the striped dolphins (Stenella coeruleoalba) collected around Japan during 1977-1982 to examine the sex difference, age dependence, and interrelationships among trace elements. Tissue distribution of trace elements was also investigated in one adult and one fetus specimens. Generally, concentrations of Se, Sr, Ag, Cd, Cs, Ba, Hg, and Pb were higher in the tissues of adult than those of fetus, whereas the opposite trend was observed for Cr and Tl. There were no significant sex differences in the trace element levels in the liver. Significant positive correlations between age (0-26.5 years) and hepatic concentrations were found for Ag, Se, Hg, V, Fe, Pb, and Sr, suggesting their age-dependent accumulation in the liver. In contrast, hepatic concentrations of Mn and Zn decreased with age. Significant positive relationships were observed between Se, and Hg, Ag, V, Fe, and Sr in the liver.     

Interelement relationships and age-related variation of trace element concentrations in liver of striped dolphins (Stenella coeruleoalba) from Japanese coastal waters

Concentrations of 19 trace elements (V, Cr, Mn, Fe, Co, Cu, Zn, Se, Rb, Sr, Mo, Ag, Cd, Sb, Cs, Ba, Tl, Hg, and Pb) were determined in the liver of the striped dolphins (Stenella coeruleoalba) collected around Japan during 1977–1982 to examine the sex difference, age dependence, and interrelationships among trace elements. Tissue distribution of trace elements was also investigated in one adult and one fetus specimens. Generally, concentrations of Se, Sr, Ag, Cd, Cs, Ba, Hg, and Pb were higher in the tissues of adult than those of fetus, whereas the opposite trend was observed for Cr and Tl. There were no significant sex differences in the trace element levels in the liver. Significant positive correlations between age (0–26.5 years) and hepatic concentrations were found for Ag, Se, Hg, V, Fe, Pb, and Sr, suggesting their age-dependent accumulation in the liver. In contrast, hepatic concentrations of Mn and Zn decreased with age. Significant positive relationships were observed between Se, and Hg, Ag, V, Fe, and Sr in the liver.     

Interelement relationships and age-related variation of trace element concentrations in liver of striped dolphins (Stenella coeruleoalba) from Japanese coastal waters

Concentrations of 19 trace elements (V, Cr, Mn, Fe, Co, Cu, Zn, Se, Rb, Sr, Mo, Ag, Cd, Sb, Cs, Ba, Tl, Hg, and Pb) were determined in the liver of the striped dolphins (Stenella coeruleoalba) collected around Japan during 1977–1982 to examine the sex difference, age dependence, and interrelationships among trace elements. Tissue distribution of trace elements was also investigated in one adult and one fetus specimens. Generally, concentrations of Se, Sr, Ag, Cd, Cs, Ba, Hg, and Pb were higher in the tissues of adult than those of fetus, whereas the opposite trend was observed for Cr and Tl. There were no significant sex differences in the trace element levels in the liver. Significant positive correlations between age (0–26.5 years) and hepatic concentrations were found for Ag, Se, Hg, V, Fe, Pb, and Sr, suggesting their age-dependent accumulation in the liver. In contrast, hepatic concentrations of Mn and Zn decreased with age. Significant positive relationships were observed between Se, and Hg, Ag, V, Fe, and Sr in the liver.     

Trace element accumulation in fishes collected from coastal waters of the Caspian Sea

Concentrations of 13 trace elements (V, Mn, Cr, Co, Cu, Zn, Se, Mo, Ag, Cd, Hg, Tl and Pb) were determined in muscle of bony fishes collected from coastal areas of the Caspian Sea (Kazakhstan, Azerbaijan, Turkmenistan and Iran). In all the fishes, Zn concentration was highest, followed by Cu, Se, Mn and Co, while levels of toxic elements (Ag, Cd, Cd, Tl and Pb) were relatively low. Concentrations of several elements were significantly varied between the species in each sampling area. For most of the trace elements examined, the concentrations decreased significantly with body weight of fishes. In contrast, a positive correlation with body weight was found for Co, Se and Pb concentrations in one fish species, and Hg in 2 fish species. Geographical difference in the concentrations of trace elements was examined using the Caspian roach collected from five stations of Iranian coastal waters. The concentrations of Co, Mo, Ag, Cd and Tl were higher in fishes from western stations than those from eastern stations, whereas the opposite trend was observed for Hg, indicating that local sources of trace metal pollution may be present in the Iranian coastal areas of the Caspian Sea. Levels of trace elements in Caspian fishes were relatively low in comparison to those of other regions, but Zn and Hg levels in some specimens exceeded the guideline values for food.     

Subcellular distribution of trace elements in the liver of sea turtles

Subcellular distribution of Cu, Zn, Se, Rb, Mo, Ag, Cd and Pb was determined in the liver of green turtles (Chelonia mydas) and hawksbill turtles (Eretmochelys imbricata) from Yaeyama Islands, Japan. Also, hepatic cytosol from sea turtles was applied on a Sephadex G-75 column and elution profiles of trace elements were examined. Copper, Zn, Se, Rb, Ag and Cd were largely present in cytosol in the liver of both species, indicating that cytosol was the significant site for the accumulation of these elements in sea turtles. In contrast, Mo and Pb were accumulated specifically in nuclear and mitochondrial fraction and microsomal fraction, respectively. Gel filtration analysis showed that Cu, Zn, Ag and Cd were bound to metallothionein (MT) in the cytosol of sea turtles. To our knowledge, this is the first report on the association of trace elements with MT in sea turtles.     

Concentrations of trace elements in marine fish and its risk assessment in Malaysia

Concentrations of trace elements (V, Cr, Mn, Co, Cu, Zn, Ga, Se, Rb, Sr, Mo, Ag, Cd, Sn, Sb, Cs, Ba, Hg, Tl, Pb and Bi) were determined in muscle and liver of 12 species of marine fish collected from coastal areas in Malaysia. Levels of V, Cr, Mn, Co, Cu, Zn, Ga, Sr, Mo, Ag, Cd, Sn, Ba and Pb in liver were higher than those in muscle, whereas Rb and Cs concentrations showed the opposite trend. Positive correlations between concentrations in liver and muscle were observed for all the trace elements except Cu and Sn. Copper, Zn, Se, Ag, Cd, Cs and Hg concentrations in bigeye scads from the east coast of the Peninsular Malaysia were higher than those from the west, whereas V showed the opposite trend. The high concentration of V in the west coast might indicate oil contamination in the Strait of Malacca. To evaluate the health risk to Malaysian population through consumption of fish, intake rates of trace elements were estimated on the basis of the concentrations of trace elements in muscle of fish and daily fish consumption. Some specimens of the marine fish had Hg levels higher than the guideline value by US Environmental Protection Agency (EPA), indicating that consumption of these fish at the present rate may be hazardous to Malaysian people. To our knowledge, this is the first study on multielemental accumulation in marine fish from the Malaysian coast.     

Total and subcellular distribution of trace elements in the liver of a mother-fetus pair of Dall's porpoises (Phocoenoides dalli)

Total and subcellular hepatic Zn, Cu, Se, Mn, V, Hg, Cd, and Ag were determined in a mother-fetus pair of Dall's porpoises (Phocoenoides dalli). Except for higher fetal Cu concentration, all maternal elements were higher. Elements existed mostly in the cytosol of both animals except in the case of maternal Ag in the microsome and fetal Cu and Ag in the nuclei and mitochondria. In the maternal cytosol, Zn, Mn, Hg, and Ag were present in the high-molecular-weight substances (HMW); Se and V were present in the low-molecular-weight substances (LMW); Cu and Cd were mostly sequestered by metallothionein (MT). In the fetal cytosol, Zn, Se, Mn, Hg, Cd, and Ag were present in the HMW and V in the LMW, while Cu and Ag were mostly associated with MT. MT isoforms were characterized using the HPLC/ICP-MS. Two and four obvious peaks appeared in the maternal and fetal MT fractions, respectively. The highest elemental ion intensities were at a retention time of 7.8 min for the mother, and for the fetus the peak elemental ion intensities occurred at a retention time of 4.3 min, suggesting that different MT isoforms may be involved in elemental accumulation in maternal and fetal hepatocytosols.     

Selenium and mercury concentrations in harbor seals (Phoca vitulina) from central California: Health implications in an urbanized estuary

We measured total selenium and total mercury concentrations ([TSe] and [THg]) in hair (n = 138) and blood (n = 73) of harbor seals (Phoca vitulina) from California to assess variation by geography and sex, and inferred feeding relationships based on carbon, nitrogen, and sulfur stable isotopes. Harbor seals from Hg-contaminated sites had significantly greater [THg], and lesser [TSe] and TSe:THg molar ratios than seals from a relatively uncontaminated site. Males had significantly greater [THg] than females at all locations. Sulfur stable isotope values explained approximately 25% of the variability in [THg], indicating increased Hg exposure for seals with a greater use of estuarine prey species. Decreased [TSe] in harbor seals from Hg-contaminated regions may indicate a relative Se deficiency to mitigate the toxic effects of Hg. Further investigation into the Se status and the potential negative impact of Hg on harbor seals from Hg-contaminated sites is warranted.     

Distribution of trace elements in subcellular fractions of three aquatic birds

This study investigated the subcellular distribution of Cu, Zn, Cd and Ag in liver of mallard (Anas platyrhynchos), spot-billed duck (A. poecilorhyncha) and great cormorant (Phalacrocorax carbo) to better understand metal fractionation and dynamics in avian liver. Most of the total Cu, Zn, Cd and Ag were present in hepatocytosol, and their concentrations increased with total hepatic levels in all the three avian species. Copper, Zn and Cd in hepatocytosol were present mostly in metallothionein fractions (MTs), and Cu and Cd contents in this fraction were positively correlated with hepatocytosol levels in all the species. Silver was observed mostly in both high-molecular weight and MT fractions in hepatocytosol in mallard and great cormorant, whereas it was present in both low-molecular weight and MT fractions in spot-billed duck, suggesting that distribution of Ag in the hepatocytosol was species-specific. The elution profile of metals in MT fractions revealed six metallic peaks in mallard and spot-billed duck, and three peaks in great cormorant, implying the presence of multiple MT isoforms in the liver of these avian species. The present study demonstrated that MTs are closely associated with metal regulation, especially Cu and Cd, in these three aquatic birds.     

Trace elements in tissues of cetacean species rarely stranded along the Israeli Mediterranean coast

In this paper we present the concentrations of Hg, Cd, Se, Pb, Cu, Mn, Zn and Fe in organs of 6 non-common specimens of cetaceans that were stranded along the Israeli Mediterranean coast (IMC), during 2002–2010: two fin whales, one minke whale, one Cuvier’s beaked whale, one rough-toothed dolphin, and one Risso’s dolphin. Most of the specimens were calves stranded by accident. Concentrations of Hg and Cd were low in tissues of the baleen whales and higher in the toothed whales, with maximum concentrations of 1067 mg kg⁻¹ Hg in the liver of the Risso’s dolphin and 29 mg kg⁻¹ Cd in the kidney of the Cuvier’s beaked whale. As far as we are aware, this is the first report of trace elements in baleen whales in the Eastern Mediterranean, and the first report of trace elements in minke whale and rough-toothed dolphin in the Mediterranean.     

Accumulation features of trace elements in mass-stranded harbor seals (Phoca vitulina) in the North Sea coast in 2002: the body distribution and association with growth and nutrition status

Body distribution and growth- and nutritional status-dependent accumulation of 21 trace elements were investigated in harbor seals (Phoca vitulina) stranded in the North Sea coast in 2002. Higher concentrations and burdens of Mn, Se, Mo, Ag, Sn, Hg, and Bi in the liver, Cd in the kidney, As in the blubber, and Co, Sr, and Ba in the bone were observed. Significant positive correlations of hepatic Se, Mo, Ag, Cd, Sn, Hg, Tl, and Bi with standard body length were found, while significant negative relationships were detected for Mn, As, Rb, Sr, and Sb in the liver. Concentrations of Co, Se, Sr, Sn, Hg, and Bi in the liver, V, Sr, Ag, Sn, and Hg in the kidney, V, Mn, Co, Rb, Sr, Sn, Ba, and Pb in the blubber increased with decreasing blubber thickness of harbor seals, indicating enrichment of these elements in the target tissue by emaciation.     

Organohalogen and organotin compounds in killer whales mass-stranded in the Shiretoko Peninsula, Hokkaido, Japan

Blubber and liver samples were obtained for analysis of wide ranges of contaminants from killer whales (Orcinus orca) which were locked away in drifting sea ice on the coast of Rausu, the Shiretoko Peninsula in Eastern Hokkaido, Japan in February 2005. Among the organohalogen compounds analyzed, DDTs were the predominant contaminants with concentrations ranging from 28 to 220 microg/g on a lipid-weight basis followed by PCBs and other organochlorine pesticides. PBDEs levels were two or three orders of magnitude lower than those of PCBs and DDTs. 2,3,7,8-Tetrachlorodibenzo-p-dioxin toxic equivalents (TEQs) derived by WHO mammal-TEF in killer whales were in the range of 110-440 pgTEQ/g. Mono-ortho coplanar PCBs contributed to 75-98% of total TEQs, indicating coplanar PCBs are significant contaminants for risk assessment in this species. The fact that hepatic residue levels of butyltins (from 13 to 770 ng/g wet weight) were much higher than those of phenyltins may be reflecting extensive use of tributyltin as antifouling paint.     

Non-destructive monitoring of trace element levels in short-tailed albatrosses (Phoebastria albatrus) and black-footed albatrosses (Phoebastria nigripes) from Torishima Island, Japan using eggs and blood

Concentrations of 18 trace elements (V, Cr, Mn, Co, Cu, Zn, Se, Rb, Sr, Mo, Ag, Cd, Sb, Cs, Ba, Hg, Tl and Pb) were determined in abandoned eggs of short-tailed albatrosses and abandoned eggs and blood of black-footed albatrosses from Torishima Island, Japan in 2002. Mercury concentration was highest among the toxic elements in egg content of both the two species. In some egg contents of black-footed albatrosses, Hg concentrations were higher than the threshold level that may cause decreased hatchability and aberrant nesting behavior in some avian species. Concentrations of Cd in egg content and Ba in egg content and shell increased with an increase in egg breadth/length ratio, whereas Hg in egg content showed an opposite trend in black-footed albatrosses. Since egg breadth/length ratio is known to increase with the age of mother bird, this result may imply that concentrations of these elements in eggs vary with age of mother bird. In blood of black-footed albatross chicks, concentration of Hg was highest among the toxic elements and the Hg concentration showed an increase in the later growth stages. In contrast, concentration of Sr in blood decreased with growth stage. Since the behaviour of Sr is similar to that of Ca in animals, it is conceivable that Sr was used along with Ca for the formation of bone.     

Non-destructive monitoring of trace element levels in short-tailed albatrosses (Phoebastria albatrus) and black-footed albatrosses (Phoebastria nigripes) from Torishima Island, Japan using eggs and blood

Concentrations of 18 trace elements (V, Cr, Mn, Co, Cu, Zn, Se, Rb, Sr, Mo, Ag, Cd, Sb, Cs, Ba, Hg, Tl and Pb) were determined in abandoned eggs of short-tailed albatrosses and abandoned eggs and blood of black-footed albatrosses from Torishima Island, Japan in 2002. Mercury concentration was highest among the toxic elements in egg content of both the two species. In some egg contents of black-footed albatrosses, Hg concentrations were higher than the threshold level that may cause decreased hatchability and aberrant nesting behavior in some avian species. Concentrations of Cd in egg content and Ba in egg content and shell increased with an increase in egg breadth/length ratio, whereas Hg in egg content showed an opposite trend in black-footed albatrosses. Since egg breadth/length ratio is known to increase with the age of mother bird, this result may imply that concentrations of these elements in eggs vary with age of mother bird. In blood of black-footed albatross chicks, concentration of Hg was highest among the toxic elements and the Hg concentration showed an increase in the later growth stages. In contrast, concentration of Sr in blood decreased with growth stage. Since the behaviour of Sr is similar to that of Ca in animals, it is conceivable that Sr was used along with Ca for the formation of bone.     

Spatial variability in selenium and mercury interactions in a key recreational fish species: Implications for human health and environmental monitoring

Selenium’s (Se) protective effects against mercury (Hg) toxicity have been demonstrated; however, this is seldom considered in health assessments, where dietary exposure is still evaluated by Hg concentration alone. Se:Hg ratios and selenium health benefit values (Se HBVs) offer a more comprehensive seafood safety model. Here we describe total mercury (THg), methylmercury (MeHg) and Se concentrations in fish from a Hg-polluted estuary. Spatial variation in THg, MeHg and Se was evident, though all regions maintained Se:Hg ratio values >1. Se HBV varied between regions and in one region mean negative values (−5.17) were evident. This study provides the first evidence that quoting a single all-encompassing Se HBV is not appropriate when species demonstrate strong site fidelity. It highlights the need for research into Se–Hg relationships in environments with established Hg pollution and reinforces the assertion that Se concentration be considered in assessments of human health risk to Hg exposure.     

Trace metals in tissues of gray whale (Eschrichtius robustus) carcasses from the Northern Pacific Mexican Coast

Samples of liver, lung, heart, muscle, and blubber tissue from the carcasses of juvenile gray whales (Eschrichtius robustus) found stranded on the coast off the Sea of Cortez, México were analyzed for a range of trace metals (Cu, Fe, Zn, Mn, Ni, Pb, and Cd). The highest concentrations of copper, iron, zinc, and manganese were found in liver; nickel and lead in heart, and cadmium in kidney. In all tissues analyzed, iron, zinc and copper were present in the highest concentrations; however, some whales also showed high levels of cadmium in the kidney which could be related to their diet. Elevated concentrations of copper were found only in the liver of one whale. In general, where low levels of iron were found in the liver, they were associated with poor nutrition. Lead, nickel, manganese and zinc levels in liver were within the normal range, indicating that these whales had not been exposed to high levels of these metals.     

First experiments on the maternal transfer of metals in the cuttlefish Sepia officinalis

The aim of this study was to provide a first insight on the incorporation of eight metals in the eggs of the cuttlefish Sepia officinalis via maternal transfer, using radiotracer techniques ((110m)Ag, (241)Am, (109)Cd, (60)Co, (134)Cs, (54)Mn, (75)Se and (65)Zn). The cuttlefish was fed daily with radiolabelled crabs for two weeks; it then started to spawn every three days. Among the eight tracers, only (110m)Ag, (75)Se and (65)Zn were significantly transferred to the eggs. The radiotracer distribution among the egg compartments showed that (75)Se and (65)Zn were accumulated mainly in the vitellus whereas (110m)Ag was found in similar proportion in the vitellus and the eggshell. During the embryonic development, (75)Se and (65)Zn contained in the vitellus were progressively transferred to the embryo, likely to supply its metabolic needs in these essential elements. Although it has no known biological functions, Ag contained in both vitellus and eggshell was also transferred to the embryo. Overall, our results showed that transfer of Ag, Se, and Zn does actually occur from a female cuttlefish to its eggs, at least during the last two weeks before spawning.     

Sponges as sentinels: patterns of spatial and intra-individual variation in trace metal concentration

If sponges are to be effective biomonitors we require a better understanding of the spatial scales over which metals vary in these organisms. We determined how concentration of Cd, Zn, Cu, Pb, Hg and Se varied over four spatial scales for two common estuarine sponge species in the Sydney region. We examined variability with a fully nested sampling design; between coastal lakes, within coastal lakes, between sponges and within sponges. Calculation of variance components confirmed that 'within-sponge' variation in Cd, Zn, Cu, Pb and Se concentrations were low (1-14%) relative to the two largest spatial scales (49-98%) examined. In contrast, Hg concentrations exhibited marked variability 'between-sponges' and were below detection at one location. There was little evidence that sponge size was a good predictor of metal concentration. Taken together, these outcomes confirm that fragments of these sponges could be successfully transplanted and therefore show promise as biomonitors of metal contamination.     

Perfluorinated compounds in minke whales (Balaenoptera acutorostrata) and long-beaked common dolphins (Delphinus capensis) from Korean coastal waters

This is the first study to report the concentrations and accumulation profiles of PFCs in marine mammals from Korea. The concentrations and profiles of 10 PFCs in the liver of minke whales and common dolphins from Korean coastal waters were recorded in this study. The mean concentrations of PFOS and PFUnDA were 3-20 times higher than that found for other PFCs analyzed. The concentrations of PFOS in cetaceans from Korea were relatively lower than those reported in other countries. Inter-species differences in the concentrations of PFOS, PFOSA and PFNA were found between two cetacean species, while no difference was observed in the concentrations of PFDA, PFUnDA and PFDoDA between the species. The dominant PFC compounds found in cetaceans were PFUnDA and PFOS, accounting for 70-80% of the PFCs. The accumulation profiles and correlation analysis indicated that two cetacean species have different exposure routes and metabolic capacity for PFCs.