Isobutyraldehyde

Toxicity to microorganisms

Link to relevant study record(s)

Reference

Endpoint:

toxicity to microorganisms, other

Remarks:

NOEC derived from a ready biodegradability test according to OECD TG 301C.

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

study well documented, meets generally accepted scientific principles, acceptable for assessment

Qualifier:

according to guideline

Guideline:

other: OECD Guideline 301C (Ready Biodegradability: Modified MITI Test (I))

Version / remarks:

From this study a NOEC may be derived as the substance is determined to be 'readily biodegradable'.

GLP compliance:

not specified

Remarks:

probably yes

Details on test solutions:

In the ready biodegradability study 100 mg/L test substance was inoculated with 30 mg/L activated sludge.

Test organisms (species):

activated sludge

Details on inoculum:

Although no specifics on used inoculum are reported, normally in Japanese studies a mixture of sewage, soil and natural water is used.

Test type:

static

Water media type:

freshwater

Total exposure duration:

14 d

Nominal and measured concentrations:

- Nominal concentration: 100 mg/L

Key result

Duration:

14 d

Dose descriptor:

NOEC

Effect conc.:

100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

other: ready biodegradability

Details on results:

After 14 days inoculation of 100 mg of the substance with activated sludge, 80-90% biodegradation was observed and the substance assessed as readily biodegradable.

Description of key information

The NOEC is set at 100 mg/L based on the substance being ready biodegradability at this concentration in a screening study according to OECD TG 301C.

Additional information

No activated sludge respiration inhibition test according to OECD TG 209 is available. However, in a biodegradation screening study according to OECD TG 301C, the substance was found to be readily biodegradable at a test substance concentration of 100 mg/L. According to REACH guidance R7.b, this concentration may be considered as a NOEC value for STP microorganisms.

The low toxicity is further supported by data available from a bacterial growth inhibition test according to DIN 38412. In this study Pseudomonas putida was exposed to nominal concentrations of 156.25, 312.5, 625, 1250, 2500, 5000, and 10000 mg/L mg/L for 17 hours under static conditions. The 17-h EC50 and EC10 values were determined at 468 mg/L and 337 mg/L, respectively.