E93D0420.HTM

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[D-4.2 The estimation of toxic effects of water-soluble fractions of crude oil on marine organisms]


[Contact Person]


Ryosuke Kuroshima
Environment Conservation Division
National Research Institute of Fisheries Science, Fisheries Agency
6-31-1 Nagai, Yokosuka, Kanagawa 238-03 Japan
Phone +81-468-56-2887, 2888, Fax +81-468-57-3075


[Total Budget for FY1991-1993]


3,166,000 Yen (FY1993 3,130,000 Yen)


[Abstract]


The increase in oil contamination of marine and estuarine environments has led to concern about the effects of oil pollution on marine organisms. The most immediate toxic and subtoxic fractions of oils are those soluble in water. The water-soluble fraction of crude oil may produce sublethal effects, such as physiological and biochemical changes, morphological deformations, tissue damage, and abnormal behavior. We examined toxicity of the water-soluble fraction of crude oil and its components. Results are given as under.
1. Main components in water-soluble fraction of Kuwait crude oil were analyzed. Highly volatile compounds like butanes, propanes, pentanes and hexanes were easily lost from seawater. Naphthalenes remained for a longer period. Water-soluble fractions had severe toxic effects on saltwater fish and prawn.
2. 24-h lethal concentrations to red sea bream were 7.8l/l(benzene), 12.7l/l(toluene), 0.75mg/l(naphthalene). The values of these chemicals to prawn were 9.7l/l, 12.6l/l, and 3.98mg/l, respectively.
3. Dibenzothiophene, which is one of organic sulfur compounds contained in crude oil, was found to remain in seawater for a long time. The lethal concentrations of this component to red sea bream were 0.39(24h), 0.28(48h), 0.17(72h), and 0.15mg/l(96h) and those to prawn 0.47mg/l(24-96h). The bioconcentration factors of dibenzothiophene were 900 in red sea bream and 180 in prawn after exposure for 6 weeks.


[Key Words]


Water-Soluble Fraction, Marine Organisms, Volatile Compounds, Organic Sulfur Compounds, Bioconcentration