Pyridinium, 1,1'-[(6,13-dichloro-4,11-disulfo-3,10-triphenodioxazinediyl)bis[imino-2,1-ethanediylimino[6-[(2,5-disulfophenyl)amino]-1,3,5-triazine-4,2-diyl]]]bis[3-carboxy-, dihydroxide, bis(inner salt), hexasodium salt

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:

From October 19, 2016 to December 20, 2016

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 209 (Activated Sludge, Respiration Inhibition Test (Carbon and Ammonium Oxidation))

GLP compliance:

yes

Test organisms (species):

activated sludge

Details on inoculum:

- Source of inoculum/activated sludge: Dihua sewage treatment plant, Taiwan.

Total exposure duration:

3 h

Test temperature:

20 ± 2 °C

pH:

6.78-7.77

Nominal and measured concentrations:

10, 100 and 1000 mg/L

Details on test conditions:

- Aeration: The test mixture was incubated under conditions of forced aeration at 0.5-1.0 L/min with air removed dust and oil.
- No. of vessels per abiotic control (replicates): three
- Sludge concentration: 1.50 g/L
- Nitrification inhibitor used : N-allylthiourea

Reference substance (positive control):

yes

Remarks:

3,5-Dichlorophenol

Duration:

3 h

Dose descriptor:

EC50

Effect conc.:

> 1 000 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth inhibition

Table 1. Oxygen consumption rates for the preliminary test

Group (mg/L)	Oxygen consumption rate (mg/Lh)	Average	Coefficient of variation (%)
Blank control group	43.44	39.00	16.10
	34.56
Nitrification control group	28.68	─	─
Test group
10	28.08	─	─
100	37.56	─	─
1000	33.60	35.84	14.76
1000	32.04
1000	41.88
Reference control group
1	38.52	─	─
10	31.20	─	─
100	6.84	─	─
Abiotic control group	9.36	5.24	68.33
	2.88
	3.48

Table 2. Inhibition rates of total oxygen uptake and EC₅₀ for the preliminary test

Group (mg/L)	Inhibition rate of total oxygen uptake (%)	Average	EC50 (mg/L)
Test group
10	28.00	─	>1000.00
100	3.69	─
1000	13.85	8.11
1000	17.85
1000	-7.38
Reference control group
1	1.23	─	23.99
10	20.00	─
100	82.46	─

Validity criteria fulfilled:

yes

Conclusions:

According to OECD 209 test method, the EC50 of Everzol SB26 for oxygen consumption rate of sludge was greater than 1000 mg/L.

Executive summary:

This test using the procedures outlined in the SuperLab Study Plan for M62-151100136001EN which is based on the SOP for the OECD 209 (SOPE-508) and OECD 209 (OECD, 2010). The results of this OECD 209 test for Everzol SB26 show that all validity criteria were met. The EC50 of Everzol SB26 for oxygen consumption rate of sludge was greater than 1000 mg/L.

Description of key information

The EC₅₀ of Everzol SB26 for oxygen consumption rate of sludge was greater than 1000 mg/L (OECD TG 209).

Key value for chemical safety assessment

EC50 for microorganisms:

1 000 mg/L

Additional information

For blank control groups at the end of the test, the coefficient of variation of oxygen consumption rate were less than 30% and greater than 20.00 mg/h of per one gram of sludge, respectively. The EC50 of reference control group (3,5-Dichlorophenol) was lied in the range between 2.00 and 25.00 mg/L. All test validity criteria were met.The EC50 of Everzol SB26 for oxygen consumption rate of sludge was greater than 1000 mg/L.