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Long-term toxicity to fish

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Description of key information

Long-term toxicity to was examined in a pre-guideline study investigating the effect of (1-methylethyl)-1,1'-biphenyl on spawning, hatching, and fry survival of flagfish.

Key value for chemical safety assessment

EC10, LC10 or NOEC for freshwater fish:
0.43 mg/L

Additional information

In a pre-OECD guideline study (Ozburn et al 1980), effects of (1-methylethyl)-1,1'-biphenyl on spawning of adult flagfish, hatching of exposed eggs (21 d exposure period each), and survival of fry (10 d exposure) at five graduate concentrations was examined. Effect thresholds were > 0.42 mg/L for spawning and hatching impairment and 0.43 mg/L for survival of fry.

Data are partly in contrast to results of short-term toxicity tests with flagfish. For fry, a 96 h LC50 of 0.28 mg/L was observed. It is not easy to explain that an even not exactly defined threshold value (0.43 mg/L), corresponding to a long-term LC10 or NOEC, is higher than the short-term LC50. Together with the spawning and hatching data, results of the long-term experiment can be taken as evidence that an extended exposure period (21 or 10 d respectively) does not severely enhance the adverse effects of isopropylbiphenyl to flagfish.

The lowest value observed (0.43 mg/L) is taken with due caution as key value to characterise the long-term toxicity of (1-methylethyl)-1,1'-biphenal to fish.