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Title: Effect of temperature on the toxicity of the water-soluble fractions of Diesel Fuel No. 2 and H-Coal crude oil to Daphnia magna

Technical Report ·
OSTI ID:5293869

The purpose of this study was to evaluate the effects of the interactions between temperature and the water soluble fractions (WSFs) of H-coal crude oil and No. 2 diesel fuel oil on the survival, respiration, and food assimilation of Daphnia magna. Results of acute toxicity tests with both oils showed that mortality was directly related to temperature and that H-coal was more toxic than diesel fuel oil to D. magna. The 48-h LC50s for diesel oil at 10, 20, and 25/sup 0/C were 87%, 32%, and 9.7% WSF, respectively. The values for H-coal were 0.70% at 10/sup 0/C, 0.44% at 20/sup 0/C, and 0.18% at 25/sup 0/C. Respiration rates of animals exposed to sublethal concentrations of the two oils at 10, 20, and 25/sup 0/C were dependent on the concentration of the oil and temperature. Low concentrations of diesel oil stimulated respiration rates at each temperature, but higher concentrations depressed them. At all temperatures, oxygen consumption rates of animals exposed to H-coal oil decreased with increased concentration. The exposure to sublethal concentrations of both oils affected food assimilation of the animals in a manner similar to that observed when respiration was the criterion of toxic effect. At 20 and 25/sup 0/C, low concentrations of diesel oil stimulated assimilation rates, whereas low concentrations of H-coal depressed them. Generally, higher concentrations of both oils depressed assimilation rates below controls. Assimilation rates of animals at 10/sup 0/C decreased sharply with low concentrations of both oils as compared with controls, but with increased concentrations the respective decreases were much less. The use of short-term physiological tests as predictors of long-term effects is briefly discussed.

Research Organization:
Oak Ridge National Lab., TN (USA)
DOE Contract Number:
W-7405-ENG-26
OSTI ID:
5293869
Report Number(s):
ORNL/TM-7823; ON: DE82014724
Country of Publication:
United States
Language:
English