β-methyl-3-(1-methylethyl)benzenepropanal

Toxicity to microorganisms

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

activated sludge respiration inhibition testing

Type of information:

experimental study

Adequacy of study:

supporting study

Study period:

18 December, 1990 - 19 December, 1990

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

comparable to guideline study with acceptable restrictions

Justification for type of information:

Non-GLP study.

Qualifier:

according to guideline

Guideline:

OECD Guideline 209 (Activated Sludge, Respiration Inhibition Test

Deviations:

no

Qualifier:

according to guideline

Guideline:

ISO 8192 (Water quality - Test for inhibition of oxygen consumption by activated sludge for carbonaceous and ammonium oxidation)

Deviations:

no

GLP compliance:

no

Specific details on test material used for the study:

Lot No. 183831;
Purity : 97.3%.

Analytical monitoring:

no

Remarks:

Non-substance specific analytics. Oxygen electrode to follow respiration of sludge.

Vehicle:

yes

Remarks:

Test substance solutions prepared in ethanol.

Details on test solutions:

Four test item concentrations were tested, in duplicate incubates :
30 mg/L
90 mg/L
270 mg/L
484 mg/L
Duplicate Controls were also employed

Test organisms (species):

activated sludge of a predominantly domestic sewage

Details on inoculum:

Activated sludge obtained from the biological waste treatment plant at Aire, City of Geneva. The sludge was prepared and used on the same day of collection.

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

3 h

Test temperature:

20 °C

Reference substance (positive control):

yes

Remarks:

3,5-dichlorophenol

Duration:

3 h

Dose descriptor:

EC50

Effect conc.:

> 100 - < 200 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

inhibition of total respiration

Remarks:

respiration rate

Remarks on result:

other: Average inhibition of respiration rate at Nominal exposure concentration of 90 mg/L was 39%

Details on results:

The average inhibition of respiration observed :
30 mg/L 5.5%
90 mg/L 39.0%
270 mg/L 86.5%
484 mg/L 91.5%

Results with reference substance (positive control):

One test concentration of 3,5-dichlorophenol was tested : 40 mg/L. This concentration level demonstrated 78% inhibition of respiration.

Validity criteria fulfilled:

not specified

Conclusions:

The 3 hour EC50 of Florhydral reported in the report is 100 to 200 mg/L.

The average inhibition of respiration observed :
30 mg/L 5.5%
90 mg/L 39.0%
270 mg/L 86.5%
484 mg/L 91.5%

Reference 2

Endpoint:

activated sludge respiration inhibition testing

Type of information:

experimental study

Adequacy of study:

key study

Study period:

13 May, 1993 - 14 May, 1993

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study with acceptable restrictions

Qualifier:

according to guideline

Guideline:

OECD Guideline 209 (Activated Sludge, Respiration Inhibition Test

Deviations:

no

GLP compliance:

yes

Specific details on test material used for the study:

Lot No. 213739;
Purity 97.6%.

Analytical monitoring:

no

Remarks:

Non-substance specific analytics. Dissolved oxygen was measured in a flat bottom (BOD) flask using an O2 electrode.

Vehicle:

yes

Remarks:

Test item solutions prepared in Ethanol.

Details on test solutions:

Five concentration levels were tested of Nominal concentration 10, 32, 100, 320 and 1000 mg/L.

Test organisms (species):

activated sludge of a predominantly domestic sewage

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

3 h

Test temperature:

22 °C

pH:

pH in the Controls and Nominal exposure concentrations of 10, 32 and 100 mg/L were 7.0. In the 320 and 1000 mg/L exposure solutions was a pH of 7.5.

Reference substance (positive control):

yes

Remarks:

3,5 - dichlorophenol

Duration:

3 h

Dose descriptor:

EC50

Effect conc.:

> 50 - < 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

inhibition of total respiration

Remarks:

respiration rate

Remarks on result:

other: 3 hour EC50 reported to be between 50 and 100 mg/L, but probably closer to 100 mg/L. An inhibition of 53% was observed for the 100 mg/L incubates. No respiration inhibition effects were observed at the 32 mg/L test concentration.

Key result

Duration:

3 h

Dose descriptor:

EC0

Effect conc.:

32 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

inhibition of total respiration

Remarks on result:

other: The 3-hour inhibition rate observed for the 32 mg/L incubate was -6%.

Results with reference substance (positive control):

The 3 hour EC50 for 3,5-dichlorophenol should be within the range of 5 to 30 mg/L.

The reference substance was tested at both 5 mg/L and 30 mg/L Nominal. The % inhibition of respiration observed were :
3% at 5 mg/L
68 % at 30 mg/L.

Results :

Validity criteria fulfilled:

yes

Conclusions:

The 3-hour EC50 for inhibition of sewage sludge respiration is reported as between 50 and 100 mg/L. The result for the 100 mg/L incubate demonstrates an inhibition rate of 53%, suggesting that the 3-hour EC50 is closer to 100 mg/L rather than 50 mg/L.

In addition, the EC0 for the test is 32 mg/L.

Description of key information

The 3-hour EC50 for inhibition of sewage sludge respiration is reported as between 50 and 100 mg/L. The result for the 100 mg/L incubate demonstrates an inhibition rate of 53%, suggesting that the 3-hour EC50 is closer to 100 mg/L rather than 50 mg/L.

The EC0 for the test is 32 mg/L and is used as the relevant end-point for the assessment.

Key value for chemical safety assessment

EC10 or NOEC for microorganisms:

32 mg/L

Additional information

The 3-hour EC50 for inhibition of sewage sludge respiration is reported as between 50 and 100 mg/L. The result for the 100 mg/L incubate demonstrates an inhibition rate of 53%, suggesting that the 3-hour EC50 is closer to 100 mg/L rather than 50 mg/L.

The EC0 for the test is 32 mg/L and is used as the relevant end-point for the assessment.

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