Trisodium 7-[[4-chloro-6-[ethyl[3-[[2-(sulphonatooxy)ethyl]sulphonyl]phenyl]amino]-1,3,5-triazin-2-yl]amino]-4-hydroxy-3-[(4-methoxy-2-sulphonatophenyl)azo]naphthalene-2-sulphonate

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:

From March 15, 1999 to March 18, 1999

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

comparable to guideline study with acceptable restrictions

Remarks:

RA study

Reason / purpose for cross-reference:

read-across: supporting information

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 209 (Activated Sludge, Respiration Inhibition Test

Qualifier:

according to guideline

Guideline:

other: Commission Directive 88/302/EEC; Official Journal of the EC L 133, Part C: Biodegradability: Test for inhibition of oxygen consumption

GLP compliance:

yes

Analytical monitoring:

no

Vehicle:

no

Remarks:

direct weighing

Details on test solutions:

Test concentrations: 0, 100, 1000 and 10000 mg/L
The test substance has been added to about 130 mL deionized water and stirred overnight before testing (equilbrium phase)

Test organisms (species):

activated sludge

Details on inoculum:

Origin: aeration tank of a waste water plant treating predominantly domestic sewage (Wupper area water authority)
Pretreatment: none
Test concentration of the activated sludge: 560 mg/L
pH of the suspension before application: 6.8

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

3 h

Test temperature:

20 +/- 2°C

pH:

7.1 - 8.2

Nominal and measured concentrations:

0, 100, 1000 and 10000 mg/L (nominal)

Reference substance (positive control):

yes

Remarks:

3,5-dichlorophenol (purity: 97%; stock solution: 500 mg/L) at concentrations of 5, 10 and 20 mg/L

Key result

Duration:

3 h

Dose descriptor:

EC50

Effect conc.:

> 10 000 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

inhibition of total respiration

Key result

Duration:

3 h

Dose descriptor:

EC10

Effect conc.:

> 10 000 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

inhibition of total respiration

Details on results:

There was no physico-chemical oxygen consumption at the highest test substance concentration, therefore no physico-chemical oxygen consumption has been determined at the lower concentrations.

Table 1. Results for the test substance

Test concentration (mg/L)	Respiratory rate test substance (mg/L*h)	Phys. chem. O2 -consumption (mg/L*h)	Respiratory rate - phys. chem. O2 - consumption (mg/L*h)	Inhibition (%)
100	27.8	0.0	27.8	1.1
1000	28.3	0.0	28.3	0.0
10000	24.8	0.0	24.8	11.7

Control mean: 28.1 mg/L*h (respiratory rate)

Table 2. Results for the reference substance

Test concentration (mg/L)	Respiratory rate (mg/L*h)	Inhibition (%)
5	22.3	20.6
10	15.0	46.6
20	6.8	75.8

Validity criteria fulfilled:

yes

Conclusions:

Under the study conditions, the nominal 3 h EC50 of the substance in activated sludge was determined to be greater than 10000 mg/L.

Executive summary:

A study was conducted to determine the toxicity of the read-across substance to the respiration of activated sludge microorganisms according to a method equivalent to OECD Guideline 209. Activated sludge (at 560 mg/L suspended solids level) was exposed to the test substance at nominal concentrations of 0, 100, 1000 and 10000 mg/L for 3 h. The reference substance3,5 -dichlorophenol was run in parallel at 5, 10 and 20 mg/L. Temperature and pH were recorded at test end. Under the study conditions, the nominal 3 h EC50 of the substance in activated sludge was determined to be greater than 10000 mg/L (Müller, 1999).

Key value for chemical safety assessment

EC50 for microorganisms:

10 000 mg/L

EC10 or NOEC for microorganisms:

10 000 mg/L

Additional information

A study was conducted to determine the toxicity of the read-across substance to the respiration of activated sludge microorganisms according to a method equivalent to OECD Guideline 209. Activated sludge (at 560 mg/L suspended solids level) was exposed to the test substance at nominal concentrations of 0, 100, 1000 and 10000 mg/L for 3 h. The reference substance 3,5 -dichlorophenol was run in parallel at 5, 10 and 20 mg/L. Temperature and pH were recorded at test end. Under the study conditions, the nominal 3 h EC50 of the substance in activated sludge was determined to be greater than 10000 mg/L (Müller, 1999).