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Chronic toxicity of unresolved complex mixtures (UCM) of hydrocarbons in marine sediments 总被引:1,自引:4,他引:1
Alan Scarlett Tamara S. Galloway Steven J. Rowland 《Journal of Soils and Sediments》2007,7(4):200-206
Background, Aim and Scope Unresolved complex mixtures (UCM) of hydrocarbons, containing many thousands of compounds which cannot be resolved by conventional
gas chromatography (GC), are common contaminants of sediments but little is known of their potential to affect sediment-dwelling
organisms. Evidence exists for reduced health status in mussels, arising from aqueous exposure to aromatic UCM components
acting through a narcotic mode of action. However, UCM contaminants in sediments may not be sufficiently bioavailable to elicit
toxic effects. The aim of our study was therefore to measure the sublethal effects of chronic exposure to model UCM-dominated
oils at environmentally realistic concentrations and compare this to effects produced by a UCM containing weathered crude
oil. A further aim was to determine which, if any, fractions of the oils were responsible for any observed toxicity.
Materials and Methods Whole oils were spiked into estuarine sediment to give nominal concentrations of 500 μg g−1 dry weight. Juveniles of the estuarine amphipod Corophium volutator were exposed to the contaminated sediment for 35 days and their survival, growth rate and reproductive success quantified.
Using an effect-directed fractionation approach, the oils were fractionated into aliphatic and two aromatic fractions by open
column chromatography and their toxicity assessed by further chronic exposures using juvenile C. volutator.
Results The growth rates of amphipods were reduced following exposure to the oils although this was only statistically significant
for the weathered oil; reproductive success was reduced by all oil exposures. Sediment spiked with UCM fractions also caused
reduced growth and reproduction but no particular fraction was found to be responsible for the observed toxicity. Survivorship
was not affected by any oil or fraction.
Discussion The study showed that chronic exposure to sediments contaminated by UCM-dominated oils could have population level effects
on amphipods. The observed effects could not be explained by hydrocarbons resolved by conventional GC and effects were similar
for both UCM-dominated and weathered oils. All of the fractions appeared to contribute to the observed effects; this is in
contrast to previous research which had shown that an aliphatic UCM did not cause adverse effects in mussels.
Conclusions To our knowledge, this is the first study to demonstrate population-level effects arising from exposure to sediments contaminated
by realistic environmental concentrations of UCM hydrocarbons. The results are consistent with many compounds, at very low
individual concentrations, contributing towards the overall observed toxicity.
Recommendations Risk assessments of contaminated sediments should take into account the contribution towards the potential for toxic effects
from UCM hydrocarbons. Studies into sediment contamination should report both aliphatic and aromatic UCM concentrations to
aid risk assessments.
ESS-Submission Editor: Henner Hollert (hollert@uni-heidelberg.de)
This paper has been developed from a presentation at SETAC Europe 16th Annual Meeting 2006 held at the The Hague, The Netherlands. 相似文献
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