2-Propenoic acid, 2-isocyanatoethyl ester

Toxicity to microorganisms

Administrative data

Endpoint:

activated sludge respiration inhibition testing

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: GLP Guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2007

Report date:

2007

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

OECD Guideline 209 (Activated Sludge, Respiration Inhibition Test

Deviations:

yes

Remarks:

The test substance was considered reactive when added to water with potential gaseous products generated. Therefore, an alternative aeration strategy, to maximise exposure of the test substance to sludge, was considered appropriate.

Test guideline 2

Qualifier:

according to guideline

Guideline:

other: EC Directive 88/302, ‘Biodegradation - Activated Sludge Respiration Inhibition Test

Principles of method if other than guideline:

The test substance was considered reactive when added to water with potential gaseous products generated. Therefore, an alternative aeration strategy, to maximise exposure of the test substance to sludge, was considered appropriate, which involved vigorous shaking rather than air sparging.

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Reference substance name:

-

EC Number:

482-140-6

EC Name:

-

Cas Number:

13641-96-8

Molecular formula:

Hill formula: C6 H7 N O3 CAS formula: C6 H7 N O3

IUPAC Name:

2-isocyanatoethyl prop-2-enoate

Sampling and analysis

Analytical monitoring:

no

Test solutions

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION
- Method: Information supplied by the Sponsor indicated that the test substance was a liquid that reacted with water. Therefore, in order to maximise test substance contact with the inoculum, the tests were conducted using two litre Erlenmeyer flasks and the contents aerated on an orbital
shaker for 3 hours at a constant speed of ca. 200 rpm. Test concentrations, based on the specific gravity of AOI (1.132), were established by the
addition of appropriate volumes of the test substance using an automatic pipette to flasks containing 284 mL RO water immediately before test set up. Additions of synthetic sewage and the inoculum were then made at fifteen minute intervals to give a final volume of 500 mL.

Test organisms

Test organisms (species):

activated sludge of a predominantly domestic sewage

Details on inoculum:

- Laboratory culture: No, A sample of activated sludge was obtained from Worlingworth Sewage Treatment Works, which treats predominantly domestic waste.
- Pretreatment: In the laboratory, the samples were maintained under aerobic conditions until required. Synthetic sewage (50 mL/L) was added to each stock of activated sludge and these were aerated overnight.

Study design

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

3 h

Test conditions

Test temperature:

19.9 - 20.9

pH:

7.6 - 8.0

Nominal and measured concentrations:

Nominal concentrations: 6.25, 12.5, 25, 50, 100 mg/L

Details on test conditions:

TEST SYSTEM
- Test vessel:
- Material, size: two litre Erlenmeyer flasks
- Aeration: yes
- No. of vessels per concentration (replicates): 1
- No. of vessels per control (replicates): 2


TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: Reverse Osmosis (RO) water
- other: Synthetic sewage feed for activated sludge was prepared by dissolving the following in one litre of RO water:
peptone - 16.0 g
meat extract - 11.0 g
urea - 3.0 g
sodium chloride - 0.7 g
calcium chloride dihydrate - 0.4 g
magnesium sulphate heptahydrate - 0.2 g
di-potassium hydrogen phosphate - 2.8 g


OTHER TEST CONDITIONS
- Adjustment of pH: No

Reference substance (positive control):

yes

Remarks:

3,5-Dichlorophenol (3,5-DCP)

Results and discussion

Effect concentrations

Effect concentrations 1

Duration:

3 h

Dose descriptor:

EC50

Effect conc.:

12.9 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

inhibition of total respiration

Remarks:

respiration rate

Effect concentrations 2

Duration:

3 h

Dose descriptor:

other: EC20

Effect conc.:

3.9 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
- Relevant effect levels: EC50 for 3,5-DCP : 6.6 mg/L in the preliminary test and 7.3 mg/L in the definitive test.

Any other information on results incl. tables

Test substance:

Concentration-related inhibition of respiration rates occurred at each AOI concentration in the definitive test. The highest tested concentration of AOI in the definitive test (100 mg/l) caused 91% inhibition.

The EC50 of the test substance was calculated from the results of the definitive test to be 12.9 mg/l (95% confidence limits, 10.0 - 16.5 mg/l). The EC20 and EC80 values were calculated to be 3.9 and 43.3 mg/l (95% confidence limits, 2.2 – 5.9 and 31.5 – 63.5 mg/l).

Reference substance

The three-hour EC50 for 3,5-DCP (6.6 mg/l in the preliminary test and 7.3 mg/l in the definitive test) fulfilled the validity criterion relating to sensitivity to inhibition (acceptable EC50 range 5 to 30 mg/l), and that relating to the respiration rates in the control (variation not greater than 15%) was also satisfied.