2,2-bis(hydroxymethyl)propionic acid

Toxicity to microorganisms

Administrative data

Endpoint:

activated sludge respiration inhibition testing

Type of information:

experimental study

Adequacy of study:

key study

Study period:

13 August 1999

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: GLP and guideline compliant study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1999

Report Date:

1999

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to

Guideline:

OECD Guideline 209 (Activated Sludge, Respiration Inhibition Test

Deviations:

no

Test guideline 2

Qualifier:

according to

Guideline:

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

Deviations:

no

GLP compliance:

yes

Test material

Reference

Name:

Unnamed

Type:

Constituent

Type:

Constituent

Details on test material:

- Name of test material (as cited in study report): Dimethylolpropionsaure (Bis-MPA)
- Physical state: white solid
- Analytical purity: 99.4%
- Lot/batch No.: SE 8069

Specific details on test material used for the study:

Details on properties of test surrogate or analogue material (migrated information):
Not applicable

Sampling and analysis

Analytical monitoring:

not required

Details on sampling:

Not applicable

Test solutions

Vehicle:

no

Test organisms

Test organisms (species):

activated sludge

Details on inoculum:

Activated sludge was taken from laboratory wastewater plants treating municipal sewage.

The inoculum was washed, brought to a concentration of 5 g/I 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/I dry substance in the test.

Study design

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

30 min

Post exposure observation period:

Not applicable

Test conditions

Hardness:

Not applicable

Test temperature:

20 ± 2 °C

pH:

See results tables

Dissolved oxygen:

See results tables

Salinity:

Not applicable

Nominal and measured concentrations:

Nominal concentration of dimethylolpropionsaure used: 1000 mg/L

Reference substance (positive control):

yes

Remarks:

3,5-dichlorophenol

Results and discussion

Effect concentrations

Effect concentrations 1

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

Effect concentrations 2

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

Effect concentrations 3

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

Details on results:

Not applicable

Results with reference substance (positive control):

Reference substance after 30 min incubation time:
 
EC20(mg/L) - 1.5
EC50(mg/L) - 5.5
EC80(mg/L) - 45

 
 

Reported statistics and error estimates:

Not aplicable

Any other information on results incl. tables

pH values during the study

Vessel number	BC1	BC2	BC3	TS1
pH value before adding the inoculum: before correction: after correction:	6.7 7.2	6.7 7.2	6.7 7.4	6.8 7.2
pH value after 30 minute incubation	-	-	-	7.5

 

Results of the definitive test after 30 min incubation period with 1000 mg/L dimethylolpropionsaure

Vessel no.	mv BC	TS1	RS1	RS2	RS3
Oxygen concentration start (mg O2/L)	-	7.8	7.4	8.2	8.7
Oxygen concentration after 6 min (mg O2/L)	-	5.8	5.7	7.5	8.5
Oxygen consumption rate (mg O2/L x 6 min)	1.9	2.0	1.7	0.7	0.2
Oxygen consumption rate (mg O2/L x h)	19	20	17	7	2
Specific oxygen consumption rate (mg O2/g x h)	19	20	17	7	2
Change in oxygen consumption rate compared with the blank control (%)	-	-5	11	63	89

mv BC = mean value of blank control

TS = test substance

RS = reference number

 

Reference substance after 30 min incubation time

	EC20(mg/L)	EC50(mg/L)	EC80(mg/L)	EC20(mg/L)
Reference substance	ca. 1.5	ca. 5.5	ca. 45	100

 

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Remarks:

The EC50 for the reference inhibitor, 3,5-dichlorophenol was in the range of 5 - 30 mg/L.

Conclusions:

Activated sludge obtained from laboratory wastewater plants treating municipal sewage was exposed in a 30 -minute inhibition of oxygen consumption test to 1000 mg dimethylolpropionsaure/L. The test design followed OECD 209 guidelines. The 30 -minute EC50 based on respiration inhibition was >1000 mg/L (the highest nominal exposure concentration tested).

Executive summary:

Activated sludge obtained from laboratory wastewater plants treating municipal sewage was exposed in a 30 -minute inhibition of oxygen consumption test to 1000 mg dimethylolpropionsaure/L. The test design followed OECD 209 guidelines. The 30 -minute EC50 based on respiration inhibition was >1000 mg/L (the highest nominal exposure concentration tested).