Reaction product of 6H-dibenz[c,e][1,2]oxaphosphorin 6-oxide, itaconic acid and ethylene glycol

Toxicity to microorganisms

Link to relevant study record(s)

Reference

Endpoint:

activated sludge respiration inhibition testing

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2011-12-07 - 2012-01-30

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: The GLP study was conducted according to an internationally accepted guideline. All study parameters are given in detail.

Qualifier:

according to guideline

Guideline:

OECD Guideline 209 (Activated Sludge, Respiration Inhibition Test

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Analytical monitoring:

no

Details on sampling:

In the control vessels 16 mL nutrient solution were mixed with 234 mL water. The positive control and the treatments were prepared by putting the appropriate amount of positive control solution respectively test item into the test vessel, adding 16 mL nutrient solution and water to give 250 mL. Then, 250 mL inoculum was added in five minute intervals and the mixture was aerated.

After three hours, the content of the first vessel was poured in a 250 mL narrow-neck bottle and the respiration rate was determined by measurement of the 02-concentration over a period of five minutes1. The following vessels were measured likewise in five minute intervals.

Vehicle:

no

Details on test solutions:

Chemicals and Nutrient Solution

All chemicals used in the test were "analytical grade" or "for use in microbiology".

Composition of nutrient solution (synthetic sewage):

Peptone 16.0 g

Meat Extract 11.0 g

Urea 3.0 g

NaCI 0.7 g

CaCI2*2H20 0.4 g

MgS04*7H20 0.2 g

K2HP04 2.8 g

Deionised water ad 1000 mL

The measured pH of the solution was 7.1. Therefore no pH adjustment to pH 7.5 ± 0.5 was necessary.
The nutrient solution was freshly prepared; the inoculum was taken from its source, washed, aerated and the dry matter was determined. The stock solutions of the test item and the positive control were prepared.
Concentrations of test and positive control were calculated using the concentration of the respective stock solution and the dilution factor.
The test item was added to the test vessels directly.

Test organisms (species):

activated sludge, domestic

Details on inoculum:

The sludge was taken from the activation basin of the ESN (Stadtentsorgung Neustadt) sewage treatment plant D-67435 NW-Lachen-Speyerdorf and aerated during transport.

Upon arrival in the test facility, the sludge was filtrated, washed with tap water and re-suspended in tap water. The activated sludge was aerated until usage in the test and fed daily with 50 ml /L synthetic sewage feed.

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

3 h

Hardness:

1.08 mmol/l

Test temperature:

18.1-18.8 "C

pH:

7.9 - 8.1

Nominal and measured concentrations:

Nominal:
1008, 1068, 1036, 1086, 1040, 101.4, 11.2, 1 mg/l

Reference substance (positive control):

yes

Remarks:

3,5-Dichlorophenol

Key result

Duration:

3 h

Dose descriptor:

other: EC20

Remarks:

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

Key result

Duration:

3 h

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

Duration:

3 h

Dose descriptor:

NOEC

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:

see below

Results with reference substance (positive control):

see below

Vessel	Content	Concentration	02consump­	02consump­	Inhibition	pH
No.		in mg/L	tion in	tion in	in%
			mg/(L*min.)	mg/(L*h)
1	Control	0	0.4495	26.970		8.0
2	Control	0	0.4290	25.738	—	8.0
3	Positive Control	5	0.3011	18.063	34.5	8.1
4	Positive Control	10	0.1958	11.748	57.4	8.1
5	Positive Control	20	0.1201	7.205	73.9	8.1
6	Positive Control	40	0.0683	4.097	85.1	8.2
7	Control	0	0.4705	28.230	—	8.0
8	Control	0	0.4625	27.748		8.0
9	Test Item	1008	0.4706	28.235	-2.4	8.0
10	Test Item	1068	0.4832	28.991	-5.1	7.9
11	Test Item	1036	0.4849	29.095	-5.5	7.9
12	Test Item	1086	0.4732	28.394	-2.9	7.9
13	Test Item	1040	0.4872	29.231	-6.0	7.9
14	Test Item	101.4	0.4800	28.798	-4.4	7.9
15	Test Item	11.2	0.4662	27.973	-1.4	7.9
16	Test Item	1.0	0.4765	28.590	-3.6	8.0
17	Control	0	0.4738	28.431	—	8.0
18	Control	0	0.4733	28.400		8.0

Validity criteria fulfilled:

yes

Conclusions:

The following results for the test item Ukanol FR 70 were determined:

3h NOEC = 1000 mg/L
3h EC20 > 1000 mg/L
3h EC50 > 1000 mg/L

Executive summary:

The toxicity of Ukanol FR 70 towards microorganism was assessed according to OECD test method 209. One experiment was performed. As the EC50 was found as > 1000 mg/L and the highest test concentration of 1000 mg/l showed no significant inhibition, no further testing was done. All validity criteria were met. For the estimation of the EC50 of the positive control 3,5-dichlorophenole, the fit showed good statistical correspondence of the data with the dose-response-equation. The positive control gave an EC50 of 8.3 mg/L which is within the recommended range of 2 - 25 mg/L. The coefficient of variation of oxygen uptake rate in control replicates was below 30% at the end of the test. In the all treatments (range 1000 - 1 mg/L), no inhibition could be observed. The O2-consumption in all replicates of treatment 1000 mg/L was higher than the mean of the controls. Therefore 1000 mg/L can be stated as NOEC without an additional experiment for statistical determination.

Description of key information

The following results for the test item Ukanol FR 70 were determined:

3h NOEC = 1000 mg/L

3h EC20 > 1000 mg/L

3h EC50 > 1000 mg/L

Key value for chemical safety assessment

EC50 for microorganisms:

1 000 mg/L