Butan-2-ol

Short-term toxicity to fish

Description of key information

Reading across the result that methyl ethyl ketone was not acutely toxic to freshwater fish when tested according to OECD guideline 203 (Fish, Acute Toxicity Test), the substance is predicted to possess a 96-hour LC50 in freshwater fish of 2993 mg/L.

Key value for chemical safety assessment

Fresh water fish

Fresh water fish

Effect concentration:

2 993 mg/L

Additional information

Three studies addressing short-term toxicity to fish are presented in the dossier. The study selected as key was carried out on the read-across substance,methyl ethyl ketone (CAS No. 78-93-3). Metabolic data demonstrate that s-butanol is rapidly and extensively converted to methyl ethyl ketone via oxidation of the alcohol functional group by alcohol dehydrogenase in the liver. Thus, methyl ethyl ketone may be used as an appropriate surrogate for s-butanol and vice versa considering that exposure to either substance would essentially result in exposure to methyl ethyl ketone.

RA Short-term toxicity to fish.001- fathead minnow - 1998 - key: Acute toxicity of the read-across substance, methyl ethyl ketone (CAS No. 78-93-3), to the freshwater fish Pimephales promales (Fathead minnow) was assessed according to OECD guideline 203 (Fish, acute toxicity test) under GLP. Five concentrations at nominal values of 1296, 2160, 3600, 6000, and 10000 mg/L were utilized in this test with 20 fish per concentration under static conditions. Temperature was maintained at 22 ± 2°C and pH ranged between 8.2 and 8.6. The percentage of dead fish was recorded at 24, 48, and 96 hours, along with visible abnormalities. The following validity criteria were met: mortality in the control did not exceed 10% at the end of the test; dissolved oxygen concentrations remained above 60% of the air saturation value at the end of the test; and the pH of the control and of the test solution did not vary by more than one unit during the course of the test. The concentration of the test item was maintained within 80% of the initial value throughout the test for the 3 lowest doses (1296, 2160, and 3600); however, the 2 highest doses were not maintained within 80% of the initial value throughout the test. The measured concentrations at the end of the test were 1170, 1848, 2993, 3758, and 6090 mg/L, which were used to express the results of the test. The mortality in 1170, 1848, 2993, 3758, and 6090 groups were 0, 0, 50, 100 and 100% and one fish in the 1848 mg/L was observed to be lethargic. The 96 h LC50 was calculated to be 2993 mg/L with 95% confidence limits of 1848 and 3758 mg/L.

Short-term toxicity to fish.003 – Golden orf - 1978: Acute toxicity to the freshwater fish Leuciscus idus melanotus (Golden orf) was assessed according to Deutsche Einheitsverfahren zur Wasser-, Abwasser- und Schlammuntersuchung. L 15: Fischtest (Bestimmung der Wirkung von Wasserinhaltsstoffen auf Fische)not according GLP (pre-dates GLP). The fish were exposed to the substance under static conditions for 48 hours. The 48 – hour LC50 was determined to range between 3520 and 3540 mg/L. This lower toxicity over a shorter exposure period is in keeping with the result of the key study.

Short-term toxicity to fish.002 - Goldfish - 1973:Acute toxicity to the freshwater fish Carassius auratus (Goldfish) was assessed according to OECD guideline 203 (Fish, acute toxicity test) not according GLP (pre-dates GLP). The fish were exposed to the substance under static conditions for 24 hours.  The median tolerance limit (TLm: the concentration at which 50% animals survive) at 24 hours was reported to be 4300 mg/L. Detailed information was not provided in the report however, the results are in line with the key study.