Teeth as biomonitors of selenium concentrations in tissues of beluga whales (Delphinapterus leucas)

Selenium (Se) is an essential element which has been shown to play an important role in protecting marine mammals against the toxic effects of mercury (Hg) and other metals. It has been suggested that metal concentration in marine mammal teeth can potentially be used as bioindicators for body burden. The objective of this study was to investigate the relationship between Se concentrations in beluga (Delphinapterus leucas) teeth and those previously measured in soft tissues (liver, kidney, muscle and muktuk). Tooth Hg concentrations are also measured, and the relationships between Se and Hg in teeth and soft tissues are examined. Se in the teeth of beluga was measured using hydride generation atomic fluorescence spectrometry (HG-AFS) and Hg in beluga teeth was measured by cold-vapour atomic absorption. Tooth Se concentrations ranged from 108 ng/g to 245 ng/g dry weight, and tooth Hg concentrations ranged from 10 to 189 ng/g dry weight. In the soft tissues, Se concentrations were highest in the liver, followed by kidney, muktuk, and muscle. There were significant correlations between tooth Se concentrations and animal age, tooth Se and liver and muscle Se, and between liver Se and animal age. The molar ratio of Hg:Se in the liver was found to be 0.70. This study is the first to measure Se in the teeth of a marine mammal species, and HG-AFS is found to be an effective technique for determining Se in beluga teeth. Tooth Se can be used as predictor for liver and muscle Se, although these relationships may be strongly influenced by the association of Se with Hg in marine mammal tissues. This study contributes to an increased understanding of the storage and metabolism of Se in marine mammals.     

Heavy metals in soft tissues of Tursiops truncatus and Delphinus delphis from west Atlantic Ocean by X-ray spectrometry

In this work, the concentration of heavy metals in muscle, liver, fat tissue and skin is studied in 15 Delphinus delphis and two Tursiops truncatus dolphins, stranded along the Portuguese coast of the Atlantic Ocean. Sample collection was performed post-mortem and the tissues were kept frozen until analysed. Sample preparation included lyophilising and grounding in a Teflon mill to avoid contamination by metals. The obtained powder was prepared as pellets for each sample and analysed directly by X-ray fluorescence spectrometry. The concentrations of K, Ca, Mn, Fe, Co, Ni, Cu, Zn, As, Se, Br, Rb, Sr, Hg and Pb were obtained. Significant differences between the muscle, the skin and the fat tissues were detected. Cobalt concentrations were similar in liver, skin and muscle. The levels of Ni, Rb and Sr are at the level of the detection limit and whenever measurable are rather constant in all the analysed tissues. The results show that the highest concentrations of Mn, Cu and Hg are always in liver tissues. Zinc and Se concentrations are higher in skin and Pb is present in very low concentrations in all the analysed tissues except in skin; Fe and As are enhanced in muscle and liver. In general, the two studied species did not seem to differ significantly in their heavy metals concentration in a given tissue.     

Arsenic and other elements in hair, nails, and skin-scales of arsenic victims in West Bengal, India

For the first time, biological tissues (hair, nails, and skin-scales) of arsenic victims from an arsenic affected area of West Bengal (WB), India were analyzed for trace elements. Analysis was carried out by inductively coupled plasma-mass spectrometry (ICP-MS) for 10 elements (As, Se, Hg, Zn, Pb, Ni, Cd, Mn, Cu, and Fe). A microwave digester was used for digestion of the tissue samples. To validate the method, certified reference materials--human hair (GBW 07601) and bovine muscle (CRM 8414)--were analyzed for all elements. The W test was used to study the normal/log normal distribution for each element in the tissue samples. For hair (n=44) and nails (n=33), all elements show log-normal distribution. For skin-scale samples (n=11), data are not sufficient to provide the information about the trend. Geometric mean, standard error, and range for each element were presented and compared with literature values for other populations. This study reveals the higher levels of toxic elements As, Mn, Pb, and Ni in the tissue samples compared with available values in the literature. The elevated levels of these toxic metals in the tissues may be due to exposure of these elements through drinking water and food. The correlations of Mn and Ni with other essential elements, e.g. Fe, Cu, Zn, suggest that Mn and Ni may substitute for those elements in hair, nails, and skin-scales. However, correlation represents the relation between two elements only and does not take into consideration of the presence of other elements. Principle component analysis was applied to explain the behavior among the elements present in hair and nails. This study reveals that in the arsenic-affected areas of WB, the concentrations of other toxic elements in drinking water and foodstuff should be monitored to evaluate the arsenic poisoning.     

Inverse relationships between selenium and mercury in tissues of young walleye (Stizosedion vitreum) from Canadian boreal lakes

The concentrations of total mercury (Hg), methylmercury (MeHg) and total selenium (Se) were determined in muscle, liver and brain tissues of young-of-the-year walleye (Stizosedion vitreum) specimens collected from 8 boreal lakes that are located within 107 km around the Sudbury smelters in Ontario, Canada. Dry weight basis concentrations of Hg were highest in muscle and lowest in brain (p < 0.05), those of MeHg were higher in muscle than in liver and brain but there was no significant difference between liver and brain (p < 0.05). The highest Se concentrations were found in liver and the lowest in brain (p < 0.05). Considering the biomass of the studied tissues, muscle was the part of the body where most of Hg, MeHg and Se were accumulated. In fish muscle, the percentage of MeHg over Hg was the highest and this percentage was the lowest in liver. The concentrations of Hg, MeHg and Se in the studied tissues were closely related to the concentrations of total dissolved Se in lake waters which vary with the distance of the lakes from the smelters. Thresholds of Se concentrations in tissues were revealed (6.2, 12.0 and 3.5 mg kg^− 1 dry wt., for muscle, liver and brain, respectively), above which a significant reduction of MeHg concentrations was observed in all studied tissues compared to lower Se levels in the same tissues. Based on the collected information and data analysis, possible mechanisms for the biological processes behind the observed inverse relationships between Se and Hg in fish tissues are discussed.     

Distribution and biokinetic analysis of Pb and Po in poultry due to ingestion of dicalcium phosphate

Dicalcium phosphate (DCP) is used as a calcium supplement for food producing animals (i.e., cattle, poultry and pig). When DCP is produced via wet acid digestion of the phosphate rock and depending on the acid used in the industrial process, the final product can result in enhanced ²¹⁰Pb and ²¹⁰Po specific activities (∼ 2000 Bq·kg⁻¹). Both ²¹⁰Pb and ²¹⁰Po are of great interest because their contribution to the dose received by ingestion is potentially large. The aims of this work are to examine the accumulation of ²¹⁰Pb and ²¹⁰Po in chicken tissues during the first 42 days of life and to build a suitable single-compartment biokinetic model to understand the behavior of both radionuclides within the entire animal using the experimental results. Three commercial corn-soybean-based diets containing different amounts and sources of DCP were fed to broilers during a period of 42 days. The results show that diets containing enhanced concentrations of ²¹⁰Pb and ²¹⁰Po lead to larger specific accumulation in broiler tissues compared to the blank diet. Radionuclides do not accumulate homogeneously within the animal body: ²¹⁰Pb follows the calcium pathways to some extent and accumulates largely in bones, while ²¹⁰Po accumulates to a large extent in liver and kidneys. However, the total amount of radionuclide accumulation in tissues is small compared to the amounts excreted in feces. The single-compartment non-linear biokinetic model proposed here for ²¹⁰Pb and ²¹⁰Po in the whole animal takes into account the size evolution and is self-consistent in that no fitting parameterization of intake and excretions rates is required.     

Influence of soil chemistry on metal and bioessential element concentrations in nymphal and adult periodical cicadas (Magicicada spp.)

Metal and bioessential element concentrations were measured in three species of 17-year periodical cicadas (Magicicada spp.) to determine how cicada tissue chemistry is affected by soil chemistry, measure the bioavailability of metals from both uncontaminated and lead-arsenate-pesticide contaminated soils, and assess the potential risks of observed metal contamination for wildlife. Periodical cicada nymphs feed on root xylem fluids for 13 or 17 years of underground development. The nymphs then emerge synchronously at high densities, before leaving their nymphal keratin exoskeleton and molting into their adult form. Cicadas are an important food source for birds and animals during emergence events, and influence nutrient cycles in woodland ecosystems. Nymphal exoskeletons and whole adult cicadas were sampled in Clarke and Frederick Counties, Virginia and Berkeley and Jefferson Counties, West Virginia during the Brood X emergence in May and June, 2004. Elements, such as Al, Fe, and Pb, are strongly enriched in the nymphal exoskeleton relative to the adult body; Cu and Zn are enriched in bodies. Concentrations of Fe and Pb, when normalized to relatively inert soil constituents such as Al and Ce, are similar in both the molt exoskeleton and their host soil, implying that passive assimilation through prolonged soil contact (adhesion or adsorption) might control these metal concentrations. Normalized concentrations of bioessential elements, such as S, P, K, Ca, Mn, Cu, Zn, and Mo, and chalcophile (sulfur-loving) elements, such as As, Se, and Au, indicate strong enrichment in cicada tissues relative to soil, implying selective absorption and retention by xylem fluids, the cicada nymphs themselves, or both. Element enrichment patterns in cicada tissues are similar to enrichment patterns observed in xylem fluids from tree roots. Chalcophile elements and heavy metals accumulate in keratin-rich tissues and may bind to sulfhydryl groups. Metal concentrations in the nymphal exoskeleton show a positive correlation with soil metal concentrations, with Au exhibiting particularly strong enrichment in the exoskeleton relative to soil concentrations. Metal concentrations in adult bodies do not correlate with soil chemistry. Bioessential elements S, Ca, Mn, Fe, and Zn differed by sex in adults, whereas Na, Mg, K, Ca, Mn, Fe, Zn, and As differed by species. Body concentrations of Ca differed by site conditions (orchard or reference setting). The high Pb contents of orchard soils contaminated by arsenical pesticide residues might inhibit Ca uptake by cicada nymphs. The adult cicadas contain concentrations of metals similar to, or less than, other invertebrates, such as earthworms. There does not appear to be a dietary threat to birds or other consumers of adult cicadas based on Maximum Tolerable Dietary Level (MTDL) Guidelines developed for agricultural animals.     

Uptake of 210Pb and 210Po by Brazilian Bunodosoma caissarum Corrêa, 1964 (cnidaria, actinidae)

Bunodosoma caissarum, a carnivorous marine species exclusive to the Brazilian southern coast, recognized as a sensitive bioindicator of artificial radioactive pollution, also shows a great capacity for concentrating natural alpha-emitters. The authors have measured the alpha-emitters 210Po and its precursor 210Pb in this animal. The average concentrations found are greater (by a factor of 4.6) for 210Po measured in samples gathered on Ponta Negra Beach (protected outer coast) than the values obtained in specimens collected on Boa Viagem Beach (closed bay) along the Rio de Janeiro coast, Brazil. The same was also found for 210Pb (a factor of 2.5).     

Study of selected trace elements in cancerous and non-cancerous human breast tissues from Sudanese subjects using instrumental neutron activation analysis

This study was performed to investigate the influence of cancer on selected trace elements among Sudanese patients with confirmed breast cancer. Instrumental neutron activation analysis was used to estimate contents of Se, Zn, Fe, Cr, Rb, Cs, Co and Sc in 40 subjects. Wilcoxon signed ranks test was used to examine if there was any difference in the concentrations of elements from normal and malignant tissues. It was found that Se, Zn and Cr elements from the malignant tissues are significantly elevated (P < 0.05) compared to the normal tissue. The results obtained have shown consistency with results obtained by some previous studies.     

Elemental characterization of tissues of Octopus vulgaris along the Portuguese coast

The concentrations of V, Mn, Fe, Ni, Cu, Zn, As, Se, Mo, and Pb were measured in digestive gland (DG), branchial hearts (BH), gill (G), and muscle (M) of Octopus vulgaris Cuvier, 1797 caught in three fishing areas of the Portuguese coast, Viana do Castelo, Cascais, and Santa Luzia, for 2 years. The elemental concentrations measured for the different tissues were in accordance with values reported in the literature. The digestive gland presented high concentration levels of Fe, Cu, and Zn, while the branchial hearts showed elevated levels of V, Ni, Mo, as well as Fe and Cu. Significant variations in As, V, Cu, Mo, and Pb tissue concentrations were observed for animals originated from different sampling sites. Pb and As determined in the digestive gland and branchial hearts of animals from Cascais and Santa Luzia, can reflect local environmental characteristics. The variability observed in the elemental concentrations may be useful to further assess the species susceptibility to environmental conditions.     

Lead-210 and polonium-210 concentrations in some species of marine molluscs.

Data are presented for 210Pb and 210Po concentrations in three species of molluscs collected in the intertidal region of the coast of Rio de Janeiro, Brazil. Lead-210 activity in the soft tissue of the edible mussel Perna perna was 20 times higher than that found in its shell. The visceral mass contained the largest activity for both radionuclides, which is attributed to the feeding habits of the molluscs. Animals collected from Ponta Negra beach (open sea) showed higher concentrations of isotopes than those collected from Boa Viagem beach (within Guanabara Bay).     

Distribution,cycling and mean residence time of 226Ra, 210Pb and 210Po in the Tagus estuary

Results for dissolved and particulate ²²⁶Ra, ²¹⁰Pb and ²¹⁰Po in the Tagus river, estuary and coastal sea system show different distribution and chemical behaviour patterns for these radionuclides in the three aquatic environments. ²²⁶Ra from riverborne particles dissolves in the estuary and contributes to increased concentrations of dissolved ²²⁶Ra in estuarine water. In the estuary, dissolved ²¹⁰Pb and ²¹⁰Po from river discharge and atmospheric deposition are scavenged by suspended matter, which in turn becomes enriched in these nuclides in comparison with riverborne particles. As a result of these processes, the estuarine water flowing into the coastal sea contains enhanced concentrations of dissolved ²²⁶Ra, but is depleted in dissolved ²¹⁰Pb and ²¹⁰Po. Under average river flow conditions, mass balance calculations for dissolved ²¹⁰Po and ²¹⁰Pb in the estuary allowed their mean residence times to be estimated as 18 and 30 days, respectively. Due to the rapid sorption of these radionuclides on to settling particles, bottom sediments in the estuary represent a sink for ²¹⁰Pb and ²¹⁰Po from both natural sources and industrial waste releases. Results also suggest that partial re-dissolution of these radionuclides from bottom sediments and intertidal mudflats is likely to occur in the mid- and low-estuary zones. Nevertheless, box-model computations indicate that the discharge of ²¹⁰Pb and ²¹⁰Po into the coastal sea takes place mainly with the transport of sediment, whereas the discharge in the dissolved fraction can only account for one third of the activities entering the estuary in the soluble phase. Implications of these results to the cycling of radionuclides in phosphate waste releases into estuarine environments are discussed.     

Assessment and biomonitoring of aquatic pollution by heavy metals (Cd,Cr, Cu,Pb and Zn) in Hammam Grouz Dam of Mila (Algeria)

Concentrations of Cd, Cr, Cu, Pb and Zn were determined in water, sediment and tissues of fish (Cyprinus carpio and Barbus setivimensis) from November 2014 to August 2015, in order to estimate the aquatic pollution in Hammam Grouz dam, by the technique of atomic absorption spectrophotometry. The concentrations of heavy metals in the water and sediment were higher than the WHO standards. The calculation of Bioconcentration factor showed that all fish species studied have accumulated heavy metals in their tissues (gill, liver, muscle and kidney). The concentrations of metals in B. setivimensis were higher than those in C. carpio. The highest concentration of heavy metals was recorded in the gill while the lowest was recorded in the muscle and kidney. Our study reveals that these fish species can be used as bioindicators in the biomonitoring of metallic pollution in aquatic ecosystem.     

Distribution of Pb and Po concentrations in wild berries and mushrooms in boreal forest ecosystems

The activity concentrations and distribution of ²¹⁰Pb and ²¹⁰Po in wild berries and edible mushrooms were investigated in Finnish forests. The main study areas were located in Scots pine (Pinus sylvestris L.) forests in southern and northern Finland. The activity concentrations of ²¹⁰Pb and ²¹⁰Po in blueberry (Vaccinium myrtillus L.) and lingonberry (Vaccinium vitis-idaea L.) samples decreased in the order: stems > leaves > berries (i.e. fruits). The activity ratios of ²¹⁰Po/²¹⁰Pb in the wild berry samples were mainly higher than one, indicating elevated activity concentrations of polonium in the samples. In mushrooms the activity concentrations of ²¹⁰Pb and especially ²¹⁰Po were higher than in fruits of the wild berries. The highest activity concentration of ²¹⁰Pb was detected in Cortinarius armillatus L. (16.2 Bq kg^− 1 d.w.) and the lowest in Leccinum vulpinum L. (1.38 Bq kg^− 1 d.w.). The ²¹⁰Po activity concentrations of the whole fruiting bodies ranged from 7.14 Bq kg^− 1 d.w. (Russula paludosa L.) to 1174 Bq kg^− 1 d.w. (L. vulpinum L.). In general, the highest activity concentrations of ²¹⁰Po were recorded in boletes. The caps of mushrooms of the Boletaceae family showed higher activity concentrations of ²¹⁰Po compared to the stipes. In most of the mushrooms analyzed, the activity concentrations of ²¹⁰Po were higher than those of ²¹⁰Pb. ²¹⁰Po and ²¹⁰Pb dominate the radiation doses received via ingestion of wild berries and mushrooms in northern Finland, while in southern Finland the ingested dose is dominated by ¹³⁷Cs from the Chernobyl fallout.     

Assessment of Committed Effective Dose due to consumption of Red Sea coral reef fishes collected from the local market (Sudan)

An assessment of Committed Effective Dose (CED) due to consumption of Red Sea fish containing (210)Po and (137)Cs was performed for 23 different marine fish samples collected from the local market at Port Sudan. The fish were classified according to their feeding habits into three categories: carnivores, herbivores, and omnivores. Measured activity concentrations of (210)Po were found in the ranges 0.25-6.42 (carnivores), 0.7-5 (omnivores) and 1.5-3.8 (herbivores) Bq/kg fresh weight. In the same study, activity concentrations of Cs-137 were determined to be in the ranges 0.1-0.46 (carnivores), 0.09-0.35 (omnivores) and 0.09-0.32 (herbivores) Bq/kg fresh weight, which were several times lower than those of (210)Po. Appropriate conversion factors were used to derive the CED, which was found to be 0.012, 0.01 and 0.01 (microSv/yr) in carnivores, omnivores and herbivores, respectively, for (137)Cs. This contributes about 0.4% of the total dose exclusively by ingestion of fish. For (210)Po, it was found to be 3.47, 4.81 and 4.14 (microSv/yr) in carnivores, omnivores and herbivores, respectively, which represents 99.6% of the total dose (exclusively by ingestion of fish). The results of CED calculations suggest that the dose received by the Sudanese population from the consumption of marine fish is rather small and that the contribution of (137)Cs is negligible compared to (210)Po.     

(210)Po and (210)Pb in the tissues of the deep-sea hydrothermal vent mussel Bathymodiolus azoricus from the Menez Gwen field (Mid-Atlantic Ridge)

The hydrothermal deep-sea vent fauna is naturally exposed to a highly specific environment enriched in potentially toxic species such as sulfides, metals and natural radionuclides due to the convective seawater circulation inside the oceanic crust and its interaction with basaltic or ultramafic host rocks. However, data on radionuclides in biota from such environment are very limited. An investigation was carried out on tissue partitioning of ²¹⁰Po and ²¹⁰Pb, two natural radionuclides within the ²³⁸U decay chain, in Bathymodiolus azoricus specimens from the Mid-Atlantic Ridge (Menez Gwen field). These two elements showed different distributions with high ²¹⁰Pb levels in gills and high ²¹⁰Po levels in both gills and especially in the remaining parts of the body tissue (including the digestive gland). Various factors that may explain such partitioning are discussed. However, ²¹⁰Po levels encountered in B. azoricus were not exceptionally high, leading to weighted internal dose rate in the range 3 to 4 μGy h^− 1. These levels are slightly higher than levels characterizing coastal mussels (~ 1 μGy h^− 1).     

Characterisation of bed sediments and suspension of the river Po (Italy) during normal and high flow conditions

Grain-size distribution, major elements, nutrients and trace metals were determined in bed sediments and suspension collected at 10 representative sites along the river Po under normal and high flow conditions. Grain-size distribution and major element composition of suspension highlighted the presence of two distinct particle populations in the upper-middle Po (coarser particles, lower carbonate content) and in the lower Po (finer particles, higher carbonate content). This change partly reflects the geological differences between the two parts of the basin, and also the presence of a hydroelectric power plant at Isola Serafini (Piacenza). With respect to environmental quality issues, bed sediments and suspension provide similar results. A moderate nutrient pollution is found in all but the uppermost parts of the river basin, while the most significant inputs of trace metals appear to originate from the urban areas of Turin and Milan. Calculation of sediment enrichment factors identifies Cd, Cu, Hg and Zn as the most impacted elements by human activities. On the other hand, the high levels of Ni and Cr throughout the river seem to derive mainly from the presence of basic rocks in the upper and middle parts of the basin. Both nutrient and trace metal particulate concentrations substantially decrease under high flow conditions possibly due to "flushing" of contaminated bed sediments and resuspension of coarser material. Under normal flow conditions, water hydrochemistry and concentrations of some elements (As, Ca, Cr, Cu, K, Mg, Mn, Na, Ni, and Pb) in the dissolved phase (<0.45 microm) were also determined. Calculation of trace metals partition coefficients shows that the relative importance of the particulate and water phases varies in response to water hydrochemistry and suspended solid content, but that most elements achieve a conditional equilibrium in the lower stretches of the river Po. These results are the first of this kind reported for the whole river course and highlight the factors and mechanisms controlling the origin, mobility and fate of nutrients and trace metals in the river Po.     

Trace metal accumulation in Clarias gariepinus (Teugels) exposed to sublethal levels of tannery effluent

The concentration and distribution of Cr, Cu, Pb and Zn among the tissues of a freshwater fish, Clarias gariepinus exposed to combined (composite) tannery effluent was investigated at two sublethal concentrations (2 and 6%) in static bioassay for 8 weeks. The distribution of the four metals in fish was of the order of Pb > Cr > Cu > Zn and the accumulation was found to be dose- and time-dependent. The metal levels in the liver were significantly higher (P > 0.05) than other tissues. This was followed by the gill and the gut. Relatively low accumulation of these metals was found in muscle tissue.     

Geographical differences of zinc, cadmium, mercury and selenium in polar bears (Ursus maritimus) from Greenland

Muscle, liver, and kidney tissues from 100 polar bears (Ursus maritimus), caught in the Avanersuaq area, north-west Greenland, and Ittoqqortoormiit area, central-east Greenland, were analysed for zinc, cadmium, mercury and selenium. The zinc concentrations in muscle and liver were higher than in kidney. Mean zinc concentrations ranged from 19.7 to 76.0 micrograms/g (all data are presented as geometric means on a wet wt. basis). The presented cadmium concentrations by area and age groups were all low in muscle and in many cases below the detection limit (range: < 0.015-0.048 microgram/g). Cadmium concentrations were intermediate in liver (range: 0.120-1.98 micrograms/g) and highest in kidney tissue (range: 2.16-28.9 micrograms/g). Mercury was likewise lowest in muscle tissue (range: 0.034-0.191 microgram/g). Mercury concentration ranged quite similarly in liver and kidney tissue (liver range: 2.13-22.0 micrograms/g; kidney range: 2.87-32.0 micrograms/g). The selenium concentration increased from muscle (range: < 0.2-0.452 microgram/g) over liver (range: 1.20-9.80 micrograms/g) to kidney (range: 2.34-13.9 micrograms/g). No age accumulation was found for zinc. A weak increase was found for selenium, whereas cadmium and mercury clearly accumulated with age. An exception was mercury concentrations in muscle tissue, where no clear pattern was observed. Polar bears had significantly lower cadmium concentrations than ringed seals from the same area in all three tissues. Likewise mercury was significantly lower in the muscle tissue of polar bears than in ringed seals, whereas liver and kidney concentrations were higher. Biomagnification factors are provided for different tissues and age groups. Tissue ratios are given for different age groups and metals to enable a rough extrapolation from one tissue to another. Tissue ratios for cadmium, selenium and for mercury vary up to a factor of 6 with age. No significant differences could be detected between the elements analysed in bears from two management zones in north-west Greenland. This finding is in agreement with the genetic pattern in the two areas. In central-east Greenland, however, cadmium, selenium, and some of the mercury concentrations in polar bears from the southern area were higher than from the northern area, indicating that the east Greenland area represents two different ecological regions with different polar bear populations. Geographical differences between polar bears from north-west and east Greenland were only found for mercury and cadmium in liver tissue, where the concentrations were highest in bears from north-west Greenland. The geographical trend of increasing cadmium concentrations in polar bear liver tissue from west to east, which has been found previously in Canada, could be extended to cover north-west Greenland as well. East of this region a decrease was found. Mercury concentrations in polar bear liver tissue showed an increase from Svalbard over east and north-west Greenland, peaking in bears from south-west Melville Island. A marked decrease was found west of Melville Island, and the lowest concentrations were found in the Chukchi Sea.     

Concentrations of some trace elements in hair, liver and kidney from autopsy subjects--relationship between hair and internal organs

Autopsy samples of hair, liver and kidney cortex from 30 Swedish subjects (Caucasian) were analysed for Ag, Co, Cr, Hg, Sb, Se and Zn by neutron activation analysis (NAA). The following elements were observed to have higher concentrations in hair than in liver and kidney cortex: Ag, (Co), Cr and Hg (on a dry weight basis). Selenium was highly concentrated in kidney cortex, and Fe in liver. The observed concentrations of most of the elements were very variable for each tissue. In particular, Co values for hair showed more than a 5000-fold difference. However, Se values for hair were relatively constant. A highly significant positive correlation was observed between Hg concentrations in hair and kidney cortex. Somewhat weaker correlations were found between Hg in kidney cortex and liver and Se in hair and kidney cortex. The concentration of Co in liver correlated with that in kidney cortex. It was concluded that, with the exception of mercury, and to a lesser degree selenium, hair analysis did not provide a useful measure of the trace element status of the subjects included in this study.     

Geographical variation and partition of metals in tissues of Octopus vulgaris along the Portuguese coast

Zinc, Cu, Cd, Pb and Hg were determined in mantle, arm and digestive gland of 59 individuals of Octopus vulgaris captured at six sites along the Portuguese coast. Metal concentrations in tissues did not vary significantly (P<0.05) with size/weight, sex or sexual stage. The abundance of metals in each analysed tissue was: Zn>Cu>Cd>Pb>Hg. Concentrations in the digestive gland reached one (Pb, Hg) and two (Zn, Cu, Cd) orders of magnitude higher than those found in arm and mantle, which indicates that the digestive gland contains the major storage sites for these elements, acting as a detoxification organ. However, concentrations in the digestive gland showed contrasting geographic patterns: Zn, Pb, Cu and Hg were higher in the Southern stations, while Cd levels increased drastically in Northern stations. This increase is in line with the contrasting Cd distribution in coastal waters. The lack of relations between metal concentration in tissues and biological parameters facilitates the recognition of those spatial patterns. The geographical contrast of Cd is extended to the accumulation in mantle and arm. A possible explanation for these enhanced values is that threshold level for Cd accumulation in digestive gland was attained and detoxification processes eventually modified.