3-hydroxypropiononitrile

Toxicity to microorganisms

Administrative data

Endpoint:

activated sludge respiration inhibition testing

Type of information:

experimental study

Adequacy of study:

key study

Study period:

30-0kt-1989 - 02-Nov-1989

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: Guideline study, GLP

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1989

Report date:

1989

Materials and methods

Test guideline

Test guideline 1

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

Test guideline 2

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 209 (Activated Sludge, Respiration Inhibition Test

GLP compliance:

yes

Test material

Test material information

Constituent 1

Reference substance name:

3-hydroxypropiononitrile

EC Number:

203-704-8

EC Name:

3-hydroxypropiononitrile

Cas Number:

109-78-4

Molecular formula:

C3H5NO

IUPAC Name:

3-hydroxypropanenitrile

Details on test material:

- Name of test material (as cited in study report): 2-Cyanoethanol
- Analytic purity: 99.08%
- Storage conditions: cool, dark

Sampling and analysis

Analytical monitoring:

no

Details on sampling:

- Sampling method: samples of activated sludge were withdrawn from a sewage plant mainly fed with domestic sewage
- Activated sludge was aerated during transportation to the laboratory
- Concentration(suspended solids): adjusted to 3g/l
- Temp: 20 ±2 °C
- pH: 6-8 (adjustment was not necessary)
- Sample storage conditions before analysis: test vessels are placed in a temp controlled room (20 ±2°C)

Test solutions

Details on test solutions:

- Concentrations: 1, 10, 100, 10000 mg/l (test substance)
- Controls one blanc control with inoculum but without test material, one physico-chemical control (with test - respectively reference- substance,
but without activated sludge, to determine the chemical oxygen consumption)

Test organisms

Test organisms (species):

activated sludge of a predominantly domestic sewage

Study design

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

180 min

Remarks on exposure duration:

Determination of the EC50 after 30 min exposure.

Test conditions

Test temperature:

20 ±2°C

pH:

6.0 - 8.0

Nominal and measured concentrations:

Nominal: 1, 10, 100, 1000 and 10000 mg/L

Details on test conditions:

- Test vessel: each prepared with 16 ml synthetic sewage, dilution water to obtain a volume of 500ml and different amounts of test
material - Renewal rate of test solution (frequency/flow rate): no flowrate, vessels were stirred and aerated with an aeration rate of 1l/min.

Reference substance (positive control):

yes

Remarks:

3,5-Dichlorophenol

Results and discussion

Effect concentrations

Duration:

30 min

Dose descriptor:

EC50

Effect conc.:

> 10 000 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

inhibition of total respiration

Remarks:

respiration rate

Results with reference substance (positive control):

- Results with reference substance valid?: Yes. 50% effect concentration(EC) for 180 min contact time lays between 5-10 mg/l, in case of 30 min
contact time 50% EC is reached at a substance level between 10-30 mg/l .
- Relevant effect levels: for the test substance, effect level for 50% inhibition was not obtained for 30 min contact time , therefore extrapolated EC 50: > 10000mg/l

Any other information on results incl. tables

The oxygen consumption (mg/l x h) was calculated from the linear part of the curves of the oxygen concentration versus time.

The percentage inhibition was calculated at each concentration as follows:

I(%) =[1- (Rs - Rpc)/ Rc)]x100

I = percentage  inhibition of oxygen consumption

Rs = oxygene consumption rate by the test mixture

Rc =  oxygen consumption rate by the blanc control

Rpc= oxygen uptake rate by the physico-chemical control  

Table 2: Oxygen uptake and inhibition (%) of the test substance 2-Cyanoethanol after a contact time of 30 min

 

	O2 uptake (mg/l*h)	Inhibition (%)
Control C	61.60
1 mg/l	62.60	-2
10 mg/l	63.20	-3
100 mg/l	60.20	2
1000 mg/l	61.80	0
10000 mg/l	58.20	6
phsico-chemical control	0.00

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Remarks:

The EC50 of 3,5-Dichlorphenol was in the accepted range of 5 to 30 mg/L.

Executive summary:

Even the highest concentration (10 g/l) of the test substance, ethylencyanhydrin, caused no significant raise of the inhibition rate.  The O2-uptake of the activated sludge was reduced at a contact time about 30 min for only ~ 6%. Therefore, to obtain 50% inhibition of respiration as measurable effect, substance concentration must be >10 g/l. That means, EC50 (ethylencyanhydrin) is > 10 g/l,as it is shown by extrapolating the curve of function  (inhibition of respiration vs concentration of ethylencyanhydrin) to higher values.