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  • 1
    ISSN: 1432-0703
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering , Medicine
    Notes: Abstract. The golden-brown algae Isochrysis galbana, a primary producer, was used to determine the influence of the chemical dispersing agent, Corexit 9527®, on the bioavailability of naphthalene. Cells were exposed to laboratory preparations of either the water-accommodated fraction (WAF) of Prudhoe Bay crude oil (PBCO) or a dispersed oil (DO) mixture of PBCO and Corexit 9527 spiked with [U-14C]naphthalene. Uptake was determined by the amount of algae-associated [14C]. High-pressure liquid chromatography (HPLC) co-chromatography was used to fractionate and identify metabolic products. A 24-h bioaccumulation factor (BAF) was calculated in the absence of steady state. The presence of Corexit 9527, had significant influence (p = 0.001) on the uptake of naphthalene, but no significant effect on the 24-h BAF (BAF: 168 and 180 from WAF and DO, respectively), or metabolic fate of naphthalene in I. galbana. Results of this research indicate that dispersants have the potential to increase organismal exposure to certain petroleum hydrocarbons without increasing their aqueous concentration.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1432-0703
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering , Medicine
    Notes: Abstract. Comparative studies were done to determine the influence of a dispersant on the bioavailability of naphthalene from crude oil to the unicellular golden-brown algae, Isochrysis galbana, under changing temperature and salinity conditions. Conditions were selected to represent a range (two temperatures, 12 and 20°C, and two salinities, 22 and 34‰) encountered in Pacific waters, where extensive crude oil transport and refining occurs. Cells were exposed to laboratory preparations of either the water-accommodated fraction (WAF) of Prudhoe Bay crude oil (PBCO) or a dispersed oil (DO) mixture of PBCO and Corexit 9527® spiked with [U-14C]naphthalene. Uptake increased by as much as 50% in DO, 20°C exposures run at 22‰ (0.24 μmol naphthalene/g algae in WAF, 0.37 μmol naphthalene/g algae in DO) compared with comparable exposures at 34‰ (0.23 μmol naphthalene/g algae in WAF, 0.37 μmol naphthalene/g algae in DO). A 24-h bioaccumulation factor (BAF) calculated in the absence of steady state indicated increasing bioaccumulation with decreasing temperature. No significant variation in relative metabolite composition occurred under the different experimental conditions. Results of these experiments showed that the use of dispersants enhanced the uptake of naphthalene by microalgae under a variety of temperature and salinity conditions, independent of aqueous concentration.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Springer
    Archives of environmental contamination and toxicology 36 (1999), S. 281-287 
    ISSN: 1432-0703
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering , Medicine
    Notes: Abstract. Hsp60 induction was selected as a sublethal endpoint of toxicity for Brachionus plicatilis exposed to a water accommodated fraction (WAF) of Prudhoe Bay crude oil (PBCO), a PBCO/dispersant (Corexit 9527®) fraction and Corexit 9527® alone. To examine the effect of multiple stressors, exposures modeled San Francisco Bay, where copper levels are approximately 5 μg/L, salinity is 22‰, significant oil transport and refining occurs, and petroleum releases have occurred historically. Rotifers were exposed to copper at 5 μg/L for 24 h, followed by one of the oil/dispersant preparations for 24 h. Batch-cultured rotifers were used in this study to model wild populations instead of cysts. SDS-PAGE with Western Blotting using hsp60-specific antibodies and chemiluminescent detection were used to isolate, identify, and measure induced hsp60 as a percentage of control values. Both PBCO/dispersant and dispersant alone preparations induced significant levels of hsp60. However, hsp60 expression was reduced to that of controls at high WAF concentrations, suggesting interference with protein synthesis. Rotifers that had been preexposed to copper maintained elevated levels of hsp60 upon treatment with WAF at all concentrations. Results suggest that induction of hsp60 by chronic low-level exposure may serve as a protective mechanism against subsequent or multiple stressors and that hsp60 levels are not additive for the toxicants tested in this study, giving no dose-response relationship. The methods employed in this study could be useful for quantifying hsp60 levels in wild rotifer populations.
    Type of Medium: Electronic Resource
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