Hexasodium 2,2'-[vinylenebis[(3-sulphonato-4,1-phenylene)imino[6-[(2-cyanoethyl)[2-(2-hydroxyethoxy)ethyl]amino]-1,3,5-triazine-4,2-diyl]imino]]bis[benzene-1,4-disulphonate]

Toxicity to microorganisms

Link to relevant study record(s)

Reference

Endpoint:

activated sludge respiration inhibition testing

Type of information:

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

Adequacy of study:

key study

Study period:

May the 16th,1989

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

test procedure in accordance with generally accepted scientific standards and described in sufficient detail

Justification for type of information:

Justification for read across is detailed in section 13.

Reason / purpose for cross-reference:

read-across source

Qualifier:

according to guideline

Guideline:

OECD Guideline 209 (Activated Sludge, Respiration Inhibition Test

Version / remarks:

adopted on 4 April, 1989

GLP compliance:

yes

Details on test solutions:

The test item was dissolved in bidistilled water at a concentration of 500 mg/l.

Test organisms (species):

activated sludge of a predominantly domestic sewage

Details on inoculum:

PRETREATMENT
- Name and location of sewage treatment plant where inoculum was collected: ARA, Sissach/Switzerland.
- Incubation: 22 °C; under areation.
- pH (final): 7.8
- rRe-treatment: the sludge was coarsely sieved, centrifuged, the supernatant liquid phase decanted, the solid material resuspended in tap water and again centrifuged. The procedure was repeated a further two times. An aliquot of the final sludge suspension was weighed, dried and the ratio of wet sludge (ml) to its dry weight (g) determined.
- Preparation of the inoculum: a volume of washed sludge suspension corresponding to 4.0 g dry material were made up with Soerensen buffer (pH= 7) to 1 litre. To that mixture, 50 ml OECD recommended synthetic sewage feed were added.

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

3 h

Test temperature:

22 °C

Nominal and measured concentrations:

3.2, 10, 32, 50 and 100 mg/l (nominal)

Details on test conditions:

TEST SYSTEM
- Test vessel: glass flasks (> 500 ml)
- Aeration: 0.2 l/minute.
- Amount of sludge: 200 ml

MEASUREMENTS
After 180 minutes first sample was taken for oxygen measurement over a period of 10 minutes. Thereafter, in 15 minutes intervals, the rest of the samples were submitted to measurement of oxygen concentration. During measurement the sample was not areated but continuosly stirred. pH was measured along with oxygen measurements.
- Apparatus: WTW OXI-meter and WTW pH-meter

Reference substance (positive control):

yes

Remarks:

3,5-dichlorophenol sodium salt

Duration:

3 h

Dose descriptor:

IC50

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

inhibition of total respiration

Details on results:

Respiration rate of the sludge was inhibited by 0.7 % at the maximum tested concentration (100 mg/l). Therefore, the test item IC50 is higher than 100 mg/l.

Results with reference substance (positive control):

At a concentration of the standard of 10 mg/l the respiration rate was inhibited to 51.7 %. The IC50 determined by linear regression was found to be 7.2 mg/l. Almost complete inhibition (97.2 %) was observed at 50 mg/l.

Influence of test item and reference substance on oxygen consumption

Flask	Chemical	Concentration [mg/l]	Oxygen consumption [mg O2/l min]	Inhibition [%]	Starting pH
1	control	-	0.73	-	7.6
12	control	-	0.72	-	7.6
7	test article	100	0.72	0.7	7.6
8	test article	50	0.73	-0.7	7.6
9	test article	32	0.77	-6.2	7.6
10	test article	10	0.73	-0.7	7.6
11	test article	3.2	0.75	-3.4	7.6
2	positive control	50	0.02	97.2	7.6
3	positive control	32	0.03	95.9	7.6
4	positive control	10	0.35	51.7	7.6
5	positive control	3.2	0.56	22.8	7.6
6	positive control	1	0.67	7.6	7.6

Validity criteria fulfilled:

yes

Remarks:

Variation coefficient of oxygen uptake of controls <30 %; inhibitory effects of reference substance within the the 5-30 mg/l IC50 range.

Conclusions:

IC50 (3h) > 100 mg/l (nominal)
IC10 (3h) > 100 mg/l (nominal)

Executive summary:

Test article was investigated for inhibitory effects on aerobic waste-water bacteria, according to OECD 209. The test is considered valid since it met all the requirement of the followed guideline.

Up to the maximum tested nominal concentration of 100 mg/l, no adverse effect on microorganisms was observed (only 0.7 % of inhibition), therefore IC50 (3 h) was esteblished to be higher than 100 mg/l.

Conclusion

IC50 (3h) > 100 mg/l (nominal)

IC10 (3h) > 100 mg/l (nominal)

Description of key information

Non toxic to microorganisms

Key value for chemical safety assessment

EC10 or NOEC for microorganisms:

100 mg/L

Additional information

The substance was tested for toxicity potential to microorganisms (activated sludge) following the ETAD recommended method 103. The IC50 was indicted to be higher than 100 mg/l. Unfortunately, a complete test report is not available and only a sheet of test results can currently be retrieved; in addition, the lot tested was characterized by a limited content of Optical Brightener 380. Therefore, a reliability cannot be assigned and the test has been included just for completeness sake.

In order to confirm the toxicity potential to microorganisms of Optical Brightener 380, the available data on the structural analogous Similar Substance 01 have been taken into consideration. The read across approach can be considered reliable and appropriate to investigate the property (details for the approach are included into the IUCLID section 13).

Similar Substance 01 was investigated for inhibitory effects on aerobic waste-water bacteria, according to OECD 209. The test is considered valid since it met all the requirement of the followed guideline. Up to the maximum tested nominal concentration of 100 mg/l, no adverse effect on microorganisms was observed (only 0.7 % of inhibition).