(2R,3S)-butane-2,3-diol

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:

key study

Study period:

20 July 1999

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study with acceptable restrictions

Remarks:

guideline version from 1993

Qualifier:

according to guideline

Guideline:

OECD Guideline 209 (Activated Sludge, Respiration Inhibition Test

Version / remarks:

1993

Deviations:

no

GLP compliance:

yes

Specific details on test material used for the study:

Batch no. 34-2127
Date of production: December 1998
Colour: colourless/yellowish

Analytical monitoring:

no

Vehicle:

no

Test organisms (species):

activated sludge, domestic

Details on inoculum:

- Preparation of inoculum for exposure: The inoculum was washed, brought to a concentration of 5 g/l dry substance and aerated for about 24 hours. 50 ml were added to a total volume of 250 ml to obtain a concentration of 1 g/l dry substance in the test.
- Inoculum: concentration of dry substance: 1 g/l
- Pretreatment: none

Test type:

static

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

30 min

Test temperature:

20±2 °C

pH:

7.4 (start) - 7.7 (end)

Dissolved oxygen:

7.9 (start) - 6.5 (after 6 min) mg/L O2/L

Nominal and measured concentrations:

Nominal test concentration: 1000 mg/L

Details on test conditions:

TEST SYSTEM
- Test vessel: Erlenmeyer-vessel (nominal volume 250 ml)
- Type (delete if not applicable): closed
- Aeration: none
- No. of vessels per concentration (replicates): 1
- No. of vessels per control (replicates): 3

Reference substance (positive control):

yes

Remarks:

3,5-dichlorophenol

Duration:

30 min

Dose descriptor:

other: EC20

Effect conc.:

> 1 000 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

inhibition of total respiration

Remarks:

respiration rate

Duration:

30 min

Dose descriptor:

other: EC80

Effect conc.:

> 1 000 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

inhibition of total respiration

Remarks:

respiration rate

Key result

Duration:

30 min

Dose descriptor:

EC50

Effect conc.:

> 1 000 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

inhibition of total respiration

Remarks:

respiration rate

Details on results:

No respiration inhibition observed.

Results with reference substance (positive control):

EC50 ca. 23 mg/L (3,5-dichiorophenol)

MEASURED DATA blank control (BC) and test substance (TS) after 30 minutes incubation time

Vessel no.:	BC1	BC2	BC3	my BC	TS1
Concentration of test substance (mg/1)	-	-	-	-	1000
Added volume of stock solution(mVvessel)	-	-	-	-	-
Direct addition (mg/vessel)	-	-	-	-	250.0
Oxygen concentration start (mg 02/I)	8.3	8.3	8.4	-	7.9
Oxygen concentration after 6 min (mg 02/l)	7.0	7.0	7.2	-	6.5
Oxygen consumption rate (mg02/I*6 min)	1.3	1.3	1.2	1.3	1.4
Oxygen consumption rate (mg02/1*h)	13	13	12	13	14
Specific oxygen consumption rate (mg02/g*h)	13	13	12	13	14
Change in oxygen consumption ratecompared with the blank control (%)	-	-	-	-	-8

my BC = mean value of blank control

pH-VALUES  blank control (BC) and test substance (TS) after 30 minutes incubation time

Vessel no.:	BC1	BC2	BC3		TS1
pH-value before adding the inoculum before correction:	6.7	6.7	6.7		6.7
after correction:	7.5	7.2	7.4		7.4
pH-value after an incubation time of 30 min	-	-	-		7.7

Validity criteria fulfilled:

yes

Remarks:

according to OECD 209 adopted 1993

Conclusions:

The test substance did not inhibit respiration of activated sludge microorganisms at 1000 mg/L. The derived 30min - EC50 (sludge microorganisms, respiration inhibition) > 1000 mg/L (nominal).

Executive summary:

The study investigated respiration inhibition of activated sludge microorganisms according to OECD guideline 209 (adopted 1993). Domestic activated sludge was used as inoculum. No inhibition of respiration was observed under static test conditions. The effect concentrations EC20 and EC50 (respiration inhibition) were derived at > 1000 mg/L after 30 minutes of exposure. In conclusion, the test substance was considered to not inhibit respiration of activated sludge microorganisms. The validity criteria of the test guideline (adopted 1993) were fulfilled. Despite of some deficiencies with respect to the updated guideline, the study was considered adequate and reliable for environmental hazard assessment.

Reference 2

Endpoint:

activated sludge respiration inhibition testing

Type of information:

read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

key study

Justification for type of information:

Please find endpoint specific justification in the read-across assessment report.

Reason / purpose for cross-reference:

read-across source

Reason / purpose for cross-reference:

assessment report

Key result

Duration:

30 min

Dose descriptor:

EC50

Effect conc.:

> 1 000 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

inhibition of total respiration

Remarks on result:

other: Effect conc. are identical for the submission substance, because target and source substance have the same MW.

Validity criteria fulfilled:

yes

Remarks:

according to OECD 209, adopted 1993

Conclusions:

The test substance did not inhibit respiration of activated sludge microorganisms at 1000 mg/L. The derived 30min - EC50 (sludge microorganisms, respiration inhibition) > 1000 mg/L (nominal).

Executive summary:

The study used as source investigated repiration inhibition of actived sludge microorganisms. The study results of the source compound were considered applicable to the target compound. Justification and applicability of the read-across approach (structural analogue) is outlined in the read-across report in section 13.

Description of key information

EC50 (sludge microorganisms, respiration) > 1000 mg/L (experimental, OECD 209)

Additional information

No toxicity data concerning respiration inhibition of activated sludge is available for the submission substance. However, adequate and reliable data are reported here for a structural analogue (source substance 2,3 -butanediol). Please also refer to the read-across justification document.

In the reliable key study respiration inhibition of activated sludge microorganisms was investigated according to OECD guideline 209 (adopted 1993). Domestic activated sludge was used as inoculum. No inhibition of respiration was observed under static test conditions. The effect concentrations EC20 and EC50 (respiration inhibition) were derived at > 1000 mg/L after 30 minutes of exposure. In conclusion, the test substance was considered to not inhibit respiration of activated sludge microorganisms. The validity criteria of the test guideline (adopted 1993) were fulfilled. Despite of some deficiencies with respect to the updated guideline, the study was considered adequate and reliable for environmental hazard assessment.