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1.
During August-September 1993, a joint Russian-United States expedition to the Bering and Chukchi Seas took place. Surface water samples were collected from 21 sites and separated into dissolved (duplicates) and suspended solids; 19 sediment and 6 air samples were also collected. These samples were analysed for 19 organochlorine pesticides, 11 chlorobenzenes and 113 PCB congeners. The report provides data on selected compounds which occured in > or = 75% of the water samples. Highest water concentrations were observed for HCH in open waters north and south of the Bering Strait, both regions being similar (alpha-HCH; 2.2 ng/L and lindane: 0.35 ng/L). Air levels observed were also constant (alpha-HCH; 0.041 ng/m3, lindane: 0.0093 ng/m3). Suspended solids and air particulares contributed little to the concentrations in their respective media, an observation common to all analytes except for the PCBs and the DDT residues. The sum of PCB concentrations in water were higher in the Bering Sea area compared to the Chukchi Sea (1.0 vrs 0.67 ng/L) and lower for air (0.46 vrs 0.23 ng/m3). Sum of DDT in water was higher in the Bering Sea than in the Chukchi Sea (0.23 vrs 0.15 ng/L) while in sediments and air, the Bering Sea concentrations were lower (0.95 vrs 1.6 ng/g and 36 vrs 56 pg/m3, respectively). Other organochlorine compounds for which data are presented include: pp'-DDE, pp'-DDT, dieldrin, HCB, 3 chlorobenzenes and 3 PCB congeners. Fluxes of all these chemicals through the Berin Strait are estimated; they ranged from 57 t/a (alpha-HCH) through 26 t/a (for sum of PCBs) to 0.2 t/a (pp'-DDE, dieldrin and 1,2,3-trichlorobenzene). Fugacity ratios for the HCHs and PCBs indicate the alpha-HCH is degassing in both the Bering and Chukchi Seas and that the gamma-isomer is degassing in the Bering Sea and is close to equilibrium (weakly absorbing) in the Chuchi Sea; the sum of PCBs are strongly absorbing in both areas.  相似文献   

2.
The Greenland shark (Somniosus microcephalus) is a high-trophic fish species present in Arctic waters. The present study aimed to determine concentrations of polychlorinated dibenzo-p-dioxins and furans (PCDDs/Fs), dioxin-like (DL) PCBs and six non-dioxin-like (NDL) PCBs in muscle and liver from 10 female Greenland sharks collected between 2001 and 2003 from Icelandic waters. The mean total concentrations of PCDDs/Fs were 13 and 530pg/g fat for muscle and liver, respectively, and show enrichment in the liver. Concentrations of DL-non-ortho PCBs were also higher in liver compared to muscle with mean concentrations of 7.8 and 0.36ng/g fat, respectively. No enrichment in the liver was found for DL-mono-ortho- and NDL-PCBs. No correlation was found between the size range studied and total concentrations of the compounds analyzed. Total WHO-TEQs (PCDDs/Fs and DL-PCBs) ranged between 7.1-70 and 54-1500pg/g fat in muscle and liver, respectively.  相似文献   

3.
Natural background levels of trace metals in marine organisms from a West Greenland inlet were studied during the summer of 1972 and 1973. Dry weight arsenic levels ranged from 11.1 to 307 ppm in fish fillets and from 7.6 to 512 ppm in fish livers. Prawns had arsenic levels ranging up to 80.2 ppm, contrasting with 6.0 ppm in planktonic copepods. The results suggest that in certain marine organisms organo-arsenics predominate and are less toxic than inorganic arsenic compounds.  相似文献   

4.
Rabbitfish (Siganus oramin, also known as Siganus canaliculatus) samples were collected from different coastal sites in the Victoria Harbour and Tolo Harbour in the summer of 1997 for the analyses of metal (cadmium, copper, lead, and zinc) concentrations in liver, gills, and muscle. The overall metal concentrations in rabbitfish tissues were below regulatory levels implemented through the government of Hong Kong. For cadmium and lead, the metal concentrations detected were place concentrations here. Generally speaking, the metal concentrations in liver samples were higher than that of gills and muscle. However, the mean values of lead concentrations of rabbitfish from the Tolo Harbour and Victoria Harbour are higher in the gills than in the livers.  相似文献   

5.
The lead, cadmium and mercury content of soft tissues and bone were determined for the common seal (Phoca vitulina) collected from off the coast of East Anglia and the West of Scotland. Lead levels were low in all tissues, cadmium accumulated with age in the kidney of West Scotland seals and mercury accumulated to high levels in the liver of seals from both areas. Comparison of our results with those of other workers, suggests that the rate of mercury accumulation in the liver of seals increases in the order: Canadian Arctic and Atlantic coast < West Scotland < East Anglia < Netherlands coast. Accumulation of mercury in the kidney and spleen of older seals, lends tentative support to the hypothesis that a protective demethylation and retention process in the liver may begin to leak mercury to other tissues at the high concentrations which have been recorded in the liver of older seals, and at the high dose rates which have been used in toxicological experiments.  相似文献   

6.
Contamination of persistent organochlorines (OCs) such as PCBs (polychlorinated biphenyls), DDT and its metabolites (DDTs), HCH (hexachlorocyclohexane) isomers (HCHs), chlordane compounds (CHLs), and HCB (hexachlorobenzene) were examined in mussels collected from coastal waters of Asian countries such as Cambodia, China, Hong Kong, India, Indonesia, Japan, Korea, Malaysia, Philippines, Far East Russia, Singapore, and Vietnam in 1994, 1997, 1998, 1999, and 2001 to elucidate the contamination status, distribution and possible pollution sources and to assess the risks on aquatic organisms and human. OCs were detected in all mussels collected from all the sampling sites investigated. Considerable residue levels of p,p(')-DDT and alpha-HCH were found in mussels and the concentrations of DDTs and HCHs found in mussels from Asian developing countries were higher than those in developed nations suggesting present usage of DDTs and HCHs along the coastal waters of Asian developing countries. On the other hand, lower concentrations of PCBs detected in mussels from Asian developing countries than those in developed countries indicate that PCBs contamination in mussels is strongly related to industrial and activities. To our knowledge, this is a first comprehensive report on monitoring OCs pollution in the Asia-Pacific region.  相似文献   

7.
Paleomagnetic measurements have been carried out on six samples of Early Triassic age and five samples of Middle Triassic age from East Greenland. The mean stable remanent magnetization directions obtained after alternating-field demagnetization tests give the virtual geomagnetic pole positions as: (1) 49°N, 158°E for the Middle Triassic and (2) 34° 30′N, 176°W for the Early Triassic. The Greenland Triassic paleomagnetic results have been compared with those for Europe and North America. It is inferred from this comparison that these preliminary results for Greenland do not conform with the requirements of a reconstruction based on a geometrical fit of the three landmasses.  相似文献   

8.
The concentrations of copper, zinc, cadmium, selenium and mercury were determined in eggs, muscle, liver, kidney and stomach content of nestilings and adults of the Antarctic petrel, Thalassoica antarctica, and its predator, the south polar skua, Chataracta maccormicki, from Svarthamaren, Dronning Maud Land, Antarctica. The dominant food of the petrels is krill, Euphausia superba. The results show relatively high levels of cadmium in krill, which is assumed to be the main reason for the high levels of cadmium in petrels and skuas. Cadmium is almost absent in eggs, but accumulates very rapidly with age in nestlings. The copper concentrations in livers of nestling petrels reach very high levels during growth. This may be seen in connection with physiological development processes. Mercury seems to be accumulated with age and between trophic levels. Among the nestlings, the mercury levels decrease with increasing age, which may be accomplished by the excretion of mercury through the growth of feathers and as a dilution effect during growth. Selenium and mercury are inversely correlated in nestlings. The levels of zinc were similar for different nestling stages and between nestlings and adults in skuas and petrels.  相似文献   

9.
Persistent organochlorines such as polychlorinated biphenyls including coplanar congeners, DDT compounds and HCB were measured in different tissues (muscle, liver and eggs) of two Mediterranean shark species: namely Centrophorus granulosus and Squalus blainvillei. The concentrations of organochlorines in the tissues and organs of both species were in the order DDTs>PCBs>HCB. The highest values of DDTs, PCBs and HCB were found in liver followed by eggs and muscle. Among DDTs the compound found in greatest concentration was p,p′-DDE. The PCB profiles were dominated by congeners 138, 153, and 180. The isomers with higher TEQs values were non- and mono-ortho congeners than di-ortho ones in muscle, liver and eggs of both species. Among the non-ortho, PCB 126 was the major contributing individual to the total TEQs in both species.  相似文献   

10.
Using the single zircon technique, two areas which give some of the oldest ages on earth have been investigated, namely the Minnesota River Valley and West Greenland.The results on single zircons from the Minnesota River Valley and from the Amîtsoq gneisses (West Greenland) do not differ significantly from the results of Farhat (1975) and Baadsgaard (1973) at about 3.3 and 3.65 b.y., respectively.The U-Pb analyses of single zircons from acid boulders from the conglomerate unit at Isua (West Greenland) yield the oldest age so far reported for a terrestrial rock, namely 3.824?0.009+0.012 b.y.  相似文献   

11.
Ion probe UPb age determinations on zircons from two samples of metasediment belonging to the Malene supracrustals of southern West Greenland closely constrain the age of sedimentation, between the youngest age obtained from detrital material and the age of metamorphic overgrowth. For both samples, older and younger limits of ca. 2900 Ma and ca. 2650 Ma, respectively, are indicated. Some of the detrital zircons are best interpreted as derived from their source rock after the regional high-grade metamorphism at ca. 2800 Ma: if so, the older limit of the age of sedimentation is younger than 2800 Ma. The hypothesis that all Malene supracrustal rocks pre-date the middle to late Archaean Nuˆk gneisses is no longer valid. This has major implications for interpretations of the late Archaean crustal evolution of western Greenland: the period between 2800 and 2500 Ma was characterised by major tectonic activity and metamorphism.  相似文献   

12.
Changes of mean annual net accumulation at the surface on the grounded ice sheets of East Antarctica, West Antarctica and Greenland in response to variations in sea ice extent are estimated using grid-point values 100 km apart. The data bases are assembled principally by bilinear interpolation of remotely sensed brightness temperature (Nimbus-5 ESMR, Nimbus-7 SMMR), surface temperature (Nimbus-7 THIR), and surface elevation (ERS-1 radar altimeter). These data, complemented by field data where remotely sensed data are not available, are used in multivariate analyses in which mean annual accumulation (derived from firn emissivity) is the dependent variable; the independent variables are latitude, surface elevation, mean annual surface temperature, and mean annual distance to open ocean (as a source of energy and moisture). The last is the shortest distance measured between a grid point and the mean annual position of the 10% sea ice concentration boundary, and is used as an index of changes in sea ice extent as well as of mean concentration. Stepwise correlation analyses indicate that variations in sea ice extent of ± 50 km would lead to changes in accumulation inversely of ± 4% on East Antarctica, ± 10% on West Antarctica, and ±4% on Greenland. These results are compared with those obtained in a previous study using visually interpolated values from contoured compilations of field data; they substantiate the findings for the Antarctic ice sheets (±4% on East Antarctica, ±9% in West Antarctica), and suggest a reduction by one half of the probable change of accumulation on Greenland (from ±8%). The results also suggest a reduction of the combined contribution to sea level variability to ±0.19 mm a-1 (from ±0.22 mm a-1).  相似文献   

13.
Paleocene volcanic rocks in West Greenland and Baffin Island were among the first products of the Iceland mantle plume, forming part of a larger igneous province that is now submerged beneath the northern Labrador Sea. A 40Ar/39Ar dating study shows that volcanism commenced in West Greenland between 60.9 and 61.3 Ma and that 80% of the Paleocene lava pile was erupted in 1 million years or less (weighted mean age of 60.5±0.4 Ma). Minimum estimates of magma production rates (1.3×10−4 km3 year−1 km−1) are similar to the present Iceland rift, except for the uppermost part of the Paleocene volcanic succession where the rate decreases to <0.7×10−4 km3 year−1 km−1 (rift). The timing of onset of volcanism in West Greenland coincides with the opening of the northern Labrador Sea and is also strikingly similar to the age of the oldest Tertiary volcanic rocks from offshore SE Greenland and the British–Irish province. This is interpreted as manifesting the impact and rapid (>1 m/year) lateral spreading of the Iceland plume head at the base of the Greenland lithosphere at 62 Ma. We suggest that the arrival, or at least a major increase in the flux, of the Iceland mantle plume beneath Greenland was a contributing factor in the initiation of seafloor spreading in the northern Labrador Sea. Our study has also revealed a previously unrecognised Early Eocene volcanic episode in West Greenland. This magmatism may be related to movement on the transform Ungava Fault System which transferred drifting from the Labrador Sea to Baffin Bay. A regional change in plate kinematics at 55 Ma, associated with the opening of the North Atlantic, would have caused net extension along parts of this fault. This would have resulted in decompression and partial melting of the underlying asthenosphere. The source of the melts for the Eocene magmatism may have been remnants of still anomalously hot Iceland plume mantle which were left stranded beneath the West Greenland lithosphere in the Early Paleocene.  相似文献   

14.
Perfluorinated alkyl compounds (PFCs) including perfluorooctane sulphonate (PFOS) and perfluorooctanoate (PFOA) were measured in environmental samples collected from around Homebush Bay, an urban/industrial area in the upper reaches of Sydney Harbour and Parramatta River estuary. Water, surface sediment, Sea Mullet (Mugil cephalus), Sydney Rock Oyster (Saccostrea commercialis) and eggs of two bird species; White Ibis (Threskiornis molucca), and Silver Gull (Larus novaehollandiae) were analysed. In most samples PFOS was the dominant PFC. Geometric mean PFOS concentrations were 33 ng/g ww (wet weight) in gull eggs, 34 ng/g ww in ibis eggs, and 1.8 ng/g ww and 66 ng/g ww in Sea Mullet muscle and liver, respectively. In sediment the PFOS geometric mean was 1.5 ng/g, in water average PFOS and PFOA concentrations ranged from 7.5 to 21 ng/L and 4.2 to 6.4 ng/L, respectively. In oysters perfluorododecanoic acid was most abundant, with a geometric mean of 2.5 ng/g ww.  相似文献   

15.
In order to collect baseline information on the environmental occurrence of volatile organic compounds (VOCs) in groundwater in East China, shallow groundwater samples were collected from five alluvial plains in East China in 2008 to 2009. All samples were analyzed for 54 VOCs representing a wide variety of uses and origins. Sampling sites were mainly selected in the areas to be susceptible to contamination from human activities in terms of previous hydrogeological survey. The data of all samples showed a variety of different hydrogeological systems with potential sources of VOCs, with 36 of the 54 VOCs being found. The most frequently detected compounds include naphthalene (56.9%), chloroform (16.9%), 1,2‐dichloroethane (16.2%), 1,2‐dichloropropane (13.1%), and 1,2,3‐trichlorobenzene (12.3%). The concentrations of methylene chloride, 1,2‐dichloroethane, carbon tetrachloride, trichloroethene, 1,2‐dichloropropane, and tetrachloroethene exceeded the relating drinking water standards. Future work will be needed to identify those factors that are most important in determining the occurrence and concentrations of VOCs in groundwater in China.  相似文献   

16.
The majority of freshwater input from Greenland to the global ocean stems from the Greenland Ice Sheet. Currently, almost a quarter of the freshwater flowing from Greenland is derived from catchments that are disconnected from the Greenland Ice Sheet. Despite their importance to the total freshwater flux and influence on fjord geochemistry, there is relatively little monitoring data available for those catchments and therefore the drivers of regional differences in export are largely unknown. We present a dataset of 12 years of discharge of four catchments less than 15 km apart, that are different in size (between 7 and 32 km2), local glacier coverage (4%–11%) and lake cover (0%–5%). They all drain into Kobbefjord, a well-studied fjord in West Greenland, near Greenland's capital Nuuk. Between catchments, the magnitude of discharge varies at annual, seasonal and sub-daily timescales, due to differences in physical catchment properties as well as local climate variability. We find that annual specific discharges vary greatly (between 1.2 and 1.9 m/year on a 12-year average) due to a longitudinal precipitation gradient from West to East caused by different amount of orographic precipitation shading. The seasonal cycle of discharge (amplitude, timing and minimum flow) differs among the sites mainly due to different exposure to solar radiation as a driver for major snowmelt; the small ice coverage in the catchments plays only a minor role in discharge variability. Dry years generally increase the relative differences in annual specific discharge and no significant temporal trends have been found in the studied catchments. On a sub-daily timescale, the difference in timing of maximum discharge during fair-weather days (>80% maximum solar radiation and no precipitation) ranged between 7 and 12 h, which is attributed to differences between the presence and elevation of lakes among the catchments. The response of discharge to major precipitation events is discussed, where a delay of between 5 and 7 h is found for the catchments that do not contain lakes near the gauge.  相似文献   

17.
This paper summarizes results obtained for Greenland??s mass balance observed with NASA??s GRACE mission. We estimate a Greenland ice sheet mass loss at ?201 ± 19 Gt/year including a discernible acceleration of ?8 ± 7 Gt/year2 between March 2003 and February 2010. The mass loss of glacier systems on the South East of Greenland has slowed down while the mass loss increases toward the North along the West side of Greenland. The mass balance can be compared with results obtained by a regional climate model of the Greenland system and ice sheet altimeter data obtained from NASA??s ICEsat mission. Our GRACE-only results differ to within 15% from these independently calculated values; we will comment on the possible causes and the quality of the glacial isostatic adjustment model which is used to correct geodetic datasets.  相似文献   

18.
《Marine pollution bulletin》2013,71(1-2):204-209
The potential toxicity of sediments from various ports was assessed by means of two different liquid-phase toxicity bioassays (acute and chronic) with embryos and eggs of sea urchin Paracentrotus lividus. Performances of embryos and eggs of P. lividus in these bioassays were compared for their interchangeable applicability in integrated sediment quality assessment. The obtained endpoints (percentages of normally developed plutei and fertilized eggs) were linked to physical and chemical properties of sediments and demonstrated dependence on sediment contamination. The endpoints in the two bioassays were strongly correlated and generally exhibited similar tendency throughout the samples. Therein, embryos demonstrated higher sensitivity to elutriate exposure, compared to eggs. It was concluded that these tests could be used interchangeably for testing toxicity of marine sediments. Preferential use of any of the bioassays can be determined by the discriminatory capacity of the test or vulnerability consideration of the test subject to the surrounding conditions.  相似文献   

19.
The paleomagnetic data sets from the British Tertiary Igneous Province (BTIP) have recently been criticized as being unreliable and discordant with data from elsewhere in the North Atlantic Igneous Province (NAIP) [Riisager et al. Earth Planet. Sci. Lett. 201 (2002) 261–276; Riisager et al. Earth Planet. Sci. Lett. 214 (2003) 409–425]. We offer new paleomagnetic data for the extensive lava flow sequence on the Isle of Mull, Scotland, and can confirm the paleomagnetic pole positions emanating from important earlier studies. Our new north paleomagnetic pole position for Eurasia at 59 ± 0.2 Ma has latitude 73.3°N, longitude 166.2°E (dp/dm = 5.2/7.0).A re-evaluation and an inter-comparison of the paleomagnetic database emanating from the NAIP were carried out to test for sub-province consistency. We find a general agreement between the Eurasian part of NAIP (BTIP and Faeroes) and East Greenland data. However a compilation of West Greenland data displays a large and unexplained dispersion. We speculate on if this is related to different sense of block rotation of the Tertiary West Greenland constituents. Combining all data from the NAIP constituents, give a pole position at 75.0°N, 169.9°E (N = 25, K = 84.3, A95 = 3.2) in Eurasian reference frame.  相似文献   

20.
Concentrations of total arsenic and individual arsenic compounds were determined in livers of cetaceans (Dall's porpoise and short-finned pilot whale), pinnipeds (harp and ringed seals), sirenian (dugong), and sea turtles (green and loggerhead turtles) to characterize arsenic accumulation profiles in higher trophic marine animals. Hepatic arsenic concentrations in sea turtles were highest among the species examined. Chemical speciation of arsenic revealed that arsenobetaine was the major arsenic compound in almost all the species. In contrast, arsenobetaine was a minor constituent in dugong. Dimethylarsinic acid, methylarsonic acid, arsenocholine, tetramethylarsonium ion, arsenite, and an unidentified arsenic compound were also detected as minor constituents. However, the composition of arsenic compounds was different among these species. These results might reflect the differences in the metabolism of arsenic and/or the compositions of arsenic compounds in their preys. To our knowledge, this is the first report on the large variation in the composition of arsenic species in liver of marine mammals and sea turtles.  相似文献   

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