Registration Dossier
Registration Dossier
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EC number: 205-498-5 | CAS number: 141-75-3
Toxicity to aquatic algae and cyanobacteria
Administrative data
Link to relevant study record(s)
Description of key information
Parent compound butyryl chloride: No data available.
Hydrolysis product butyric acid: No data available, therefore the risk
assessment is based on read-across to the structurally similar substance
isobutyric acid.
Isobutyric acid: Acutely harmful to aquatic algae and cyanobacteria.
Key value for chemical safety assessment
- EC50 for freshwater algae:
- 53.9 mg/L
- EC10 or NOEC for freshwater algae:
- 33.7 mg/L
Additional information
In aquatic systems, butyryl chloride (CAS 141-75-3) hydrolyses quickly and forms HCl (CAS 7647-01-0) and butyric acid (CAS 107-92-6) (for details see section 5.1.2).
Parent compound butyryl chloride and hydrolysis product butyric acid:
No data are available for butyryl chloride (CAS 141-75-3) and butyric acid (CAS 107-92-6). Therefore, the short-term toxicity to aquatic algae is assessed via read across to the structurally similar substance isobutyric acid (CAS 79-31-2).
Isobutyric acid (CAS 79-31-2): Isobutyric acid was tested on Desmodesmus subspicatus in a study following the German Industrial Standard DIN 38412, part 9 (similar to OECD 201). The 72 -h ErC10 and ErC50 were 33.7 and 53.9 mg/L, respectively (BASF, 1990, 2/0244/89).
The test concentrations were not analytically monitored. However, it is assumed that the test item remained stable over the exposure period based on a high water solubility (618 g/L, OECD 105, OXEA, 2009), a low vapour pressure (2 hPa at 20 °C, OXEA, 2009) a low Henry's Law constant (0.098 Pa*m³/mol, HENRYWIN v3.20, BASF SE, 2022) and a low adsorption potential (log Kow = 1.1, OXEA, 2009; log Koc = 1.66 according to Franco&Trapp, BASF SE, 2022).
Based on the available data on isobutyric acid the parent compound and its hydrolysis product are assessed to be acutely harmful to aquatic algae and cyanobacteria.
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