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  • 1
    Electronic Resource
    Electronic Resource
    s.l. : American Chemical Society
    Environmental science & technology 28 (1994), S. 1-15 
    ISSN: 1520-5851
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology , Energy, Environment Protection, Nuclear Power Engineering
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1432-0495
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences
    Notes: Abstract For a typical offshore petroleum well, 500–1000 t (dry weight excluding cuttings) of drilling fluid solids are discharged into the sea. In this study, concentrations of selected trace elements present in drilling fluids (Ba, Cd, Cr, Cu, Fe, Pb, Ni, V), were determined in surface sediments and macroepifauna around a Gulf of Mexico exploratory drilling site before, during, and after drilling operations. Observed significant increases in the levels of Fe in organisms and Ba and Cr in sediments were attributable to drilling discharges. Shrimp, which constitute the largest commercial fishery in the region, were intensively studied. Shrimp collected during the last few days of drilling had abdominal muscle Fe concentrations more than twice those in shrimp sampled before or after drilling. Enhanced Fe solubility (bioavailability) in sea-water, caused by soluble organic chelating agents in the drilling fluids, is the most likely explanation for the observed increases. Significant increases in sediment Ba were observed at all sampling radii but large increases (up to 7.5 fold) were only observed within a few hundred meters of the drilling site. An accurate mass balance of total discharged (excess) Ba present in sediments within 1000 m of the drilling site was determined. Only 9.3% of the total Ba used, and presumably other similar drilling mud components traced by Ba, was present within 1000 m at the conclusion of drilling. After 2.6 mo, only 6.6% was present. Significant sediment resuspension and transport occurring in the high current nearshore study site (24 m water depth) was responsible for the low retention and rapid loss of discharged Ba in the sediment. The largest mean increase in sediment Cr (26%) occurred at the 1000 m sampling radii.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Springer
    Environmental geology 30 (1997), S. 224-230 
    ISSN: 1432-0495
    Keywords: Key words Sediment ; Washington ; DC ; Pollution ; phosphorus ; nutrients
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences
    Notes: Abstract  Sediments in the rivers and basins around Washington, DC, have high concentrations of phosphorus, which, based on geographic distributions, is largely derived from urban runoff and municipal sewage. Dissolved-particulate phosphate exchange reactions and biological uptake of dissolved phosphorus from the water column may be an added source of phosphorus to the sediments. Concentrations of total sedimentary phosphorus ranged from 24 to 56 μm P/g-dw, and were highest in areas near combined sewer outfalls. As a part of this study, sedimentary phosphorus was fractionated into Fe-P, Ca-P, Al-P, and organic phases using a selective-sequential leaching procedure. The distribution of the phases in all sediments analyzed follow the order , Fe-P〉Ca-P〉Al-P. Spatial variations in the amounts of phosphorus in the different phases is related to the sources of phosphorus to the area. The proportions of occluded Al-P and organic P are 10–20% of the total P, respectively. This suggests that phosphorus from natural sources is small compared to anthropogenic inputs in this area. The high leachable Fe-P and Ca-P in these sediments might contribute a substantial amount of P to the water column under conditions of remobilization.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Springer
    Environmental geology 39 (2000), S. 1216-1226 
    ISSN: 1432-0495
    Keywords: Key words Bioaccumulation ; Heavy metals ; Oyster ; Sediment
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences
    Notes: Abstract Oysters and sediment have been collected from most major US Gulf of Mexico bays and estuaries each year since 1986. Selected samples of oyster soft tissue, shell and sediments were analyzed for Cd, Cr, Cu, Fe, Mn, Pb, and Zn for this study. Concentrations varied considerably from place to place but ratios of metals remained relatively constant. Cu and Zn are greatly enriched in oyster tissues, which is related to their physiological function. Cd is enriched in oyster shell because of the easy substitution between Cd and Ca. The concentrations of Pb and Cr in oysters are significantly lower than that in sediment, suggesting a good discrimination against these metals by oysters. Metal variations are a result of both nature and human activity.
    Type of Medium: Electronic Resource
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  • 5
    ISSN: 1432-1793
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Acute toxicity bioassays conducted at various salinities demonstrated that mercury (as mercuric chloride) at low concentrations was lethal to Petrolisthes armatus. Ninety-six hour LC50 values varied from 50 to 64 parts per billion (ppb) of mercury, depending on test salinities. Lower salinities. decreased the time to death of mercuryexposed crabs. Differences in survival after 96 h due to salinity were not statistically significant. Blood chloride concentrations were regulated hyperchloride to the medium at low salinities and hypochloride at high salinities by acclimated crabs. The salinity isochloride to blood was 20‰ S. Transfer of crabs from 15‰ S to salinities ranging from 7 to 35‰ S resulted in new steadystate chloride levels within 12 h. Exposure to 50 ppb mercury did not alter chloride ion regulation of either acclimated crabs or crabs adjusting to new salinities.
    Type of Medium: Electronic Resource
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  • 6
    ISSN: 1432-1793
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The results of toxicity experiments have shown that a level of 17 ppb ionic mercury is acutely toxic (96-h LC50) to postlarval white shrimp (Penaeus setiferus). In addition, the size of the shrimp, within the range tested (7 to 35 mm) did not significantly alter the toxicity values of mercury to this species. Fifty-seven days pre-exposure to low levels of mercury (0.5 and 1.0 ppb) had no effect on the acute toxicity (96-h LC50) of mercury to the shrimp. The effect of chronic exposure to low levels of mercury on the respiratory rate, growth, and molting rate of postlarval P. setiferus was studied, and the results showed that 60 days exposure to 0.5 and 1.0 ppb mercury did not significantly affect any of these parameters for the postlarvae.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    [s.l.] : Nature Publishing Group
    Nature 312 (1984), S. 260-262 
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] Most of the samples used in this study were collected by Trefry8 who determined their major and minor inorganic constituents. Bottom sediment was collected on the shelf, slope and abyssal plain of the Gulf of Mexico by a conventional 7-cm diameter gravity core equipped with a polybutyrate liner. ...
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    Springer
    Bulletin of environmental contamination and toxicology 16 (1976), S. 520-527 
    ISSN: 1432-0800
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering , Medicine
    Notes: Conclusions Organisms from San Antonio Bay have been shown to have low heavy metal concentrations. This is most likely the result of low natural metal levels in the area and minimal man-introduced contamination due to the bay's location far from any dense industrial or population centers. In addition, vigorous shell dredging activity in the bay for more than 50 years has not in any obvious way increased the concentrations of heavy metals in the organisms found there. Analyses have shown that metal concentrations in sediments from depths up to 2 meters (representing several centuries) are both low and uniform (Trefry, 1974). This indicates that the sediments do not represent any unusual metal reservoir for dredging to disturb, and shows that no recent increase in metal input to the bay has occurred. In general, organisms from San Antonio Bay were lower in almost every metal than organisms from other areas where dredging and pollution are thought to be minimal. Molluscs were observed to concentrate metals more than the other organisms studied, but the levels observed are very much lower than those thought to be lethal or toxic (Bowen, 1966). Except for a few large fish, metal concentrations did not correlate significantly with the size or growth stage of the individual. In the fish, certain organs, such as the liver, were found to concentrate metals, in agreement with previous reports.
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    Springer
    Archives of environmental contamination and toxicology 5 (1977), S. 241-255 
    ISSN: 1432-0703
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering , Medicine
    Notes: Abstract A variety of marine biota, including zooplankton, sargassum, surface plankton, squid, shrimp, and fish collected along the south Texas Outer Continental Shelf, were analyzed for Cu, Zn, Cd, Pb, Cr, Ni, Fe, and Mn. Although there is a great deal of variation in the chemical content of the various samples, both within species and between species, the variations all fall within the range of values published for similar organisms collected elsewhere. An increase in Pb concentration from north to south, and an increase in Cd concentration from nearshore to further offshore in the zooplankton mirrors the sediment patterns. Statistical analysis of the chemical and biological data for these samples indicates that relatively small percentages of the biological makeup of the sample can markedly affect the concentrations of Pb, Cd, Ni, and Zn. This is particularly true for the larvacea, ostracoda, and mollusca. Chemical analyses of the exoskeletons of shrimp and the skin of both squid and fish indicate that they generally contain higher metal levels in comparison with the flesh from the same organism. This is probably the result of either adsorption from seawater and/or an internal detoxification procedure employed by the organism. The analysis of a composite sample of squid ‘pens’ indicates that they contain enriched Cu, Cd, Zn, Pb, and Fe levels in comparison with the skin and flesh. These elevated levels are probably the result of an internal detoxification procedure and/or may represent a means of storing necessary metabolites, at least in the case of Cu and Zn, but can not be attributed to adsorption as the chitinous ‘pen’ is imbedded in tissue and is not directly exposed to seawater.
    Type of Medium: Electronic Resource
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  • 10
    ISSN: 1438-3888
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract As part of NOAA's Status and Trends Program, oysters were sampled from 43 sites throughout the Gulf of Mexico from Brownsville, Texas, to the Florida Everglades from 1986 to 1989. Oysters were analysed for body burden of a suite of metals and petroleum aromatic hydrocarbons (PAHs), the prevalence and intensity of the oyster pathogen,Perkinsus marinus, and condition index. The contaminants fell into two groups based on the spatial distribution of body burden throughout the Gulf. Arsenic, selenium, mercury and cadmium were characterized by clinal reduction in similarity with distance reminiscent of that followed by mean monthly temperature and precipitation. Zinc, copper, PAHs and silver showed no consistent geographic trend. Within local regions, industrial and agricultural and use andP. marinus prevalence and infection intensity frequently correlated with body burden. Contaminants and biological attributes followed one of three temporal trends. Zinc, copper and PAHs showed concordant shifts over 4 years throughout the eastern and southern Gulf. Mercury and cadmium showed concordant shifts in the northwestern Gulf. Selenium, arsenic, length, condition index andP. marinus prevalence and infection intensity showed concordant shifts throughout most of the entire Gulf. Concordant shifts suggest that climatic factors, the El Niño/Southern Oscillation being one example, exert a strong influence on biological attributes and contaminant body burdens in the Gulf. Correlative factors are those that probably affect or indicate the rate of tissue turnover and the frequency of reproduction; namely, temperature, disease intensity, condition index and length.
    Type of Medium: Electronic Resource
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