5-[(4-chloro-2-nitrophenyl)azo]-1-ethyl-1,2-dihydro-6-hydroxy-4-methyl-2-oxonicotinonitrile

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:

Study completion date: 24 September 1987

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

comparable to guideline study with acceptable restrictions

Qualifier:

according to guideline

Guideline:

OECD Guideline 209 (Activated Sludge, Respiration Inhibition Test

Deviations:

not specified

GLP compliance:

no

Specific details on test material used for the study:

- Identification: FAT 36091/E
- Purity: 16.1 %

Analytical monitoring:

no

Vehicle:

not specified

Test organisms (species):

other: sludge

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

3 h

Nominal and measured concentrations:

- Nominal concentrations: 10, 32 and 100 mg/L

Reference substance (positive control):

yes

Remarks:

3,5-Dichlorophenol

Duration:

3 h

Dose descriptor:

IC50

Effect conc.:

> 400 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth inhibition

Results with reference substance (positive control):

IC 50 (3 hours) = 16 mg/L

Results test item:

	3 hours
Test item in mg/L	O2 -consumption (mg/Liter/min)	Inhibition (%)
100	1.31	6.4
32	1.41	0.0
10	1.56	0.0
Control 1	1.38
Control 2	1.42

Results reference substance:

	3 hours
3,5 -Dichlorophenol (mg/L)	O2 -consumption (mg/Liter/min)	Inhibition (%)
100	0.08	94.3
32	0.11	92.1
10	1.15	17.9

Validity criteria fulfilled:

not specified

Conclusions:

IC50 (3 hours) of the test item is found to be greater than 400 mg/L.

Executive summary:

A study was performed to assess the effect of FAT 36091/E on the respiration of activated sewage sludge. The method followed was designed to be compatible with the OECD Guidelines for Testing of Chemicals (2010) No. 209 "Activated Sludge, Respiration Inhibition Test (Carbon and Ammonium Oxidation)". Activated sewage sludge was exposed to an aqueous solution of the test item at concentrations of 10, 32 and 100 mg/L for a period of 3 hours. The rate of respiration was determined after 3 hours contact time and compared to data for the control and a reference item, 3,5-dichlorophenol.

Results: The effect of the test item on the respiration of activated sewage sludge gave a 3‑hour EC₅₀value of greater than 400 mg/L. The reference item gave a 3 -hour EC₅₀value of 16 mg/L.

Description of key information

A study was performed to test the toxicity of FAT 36091/E on micro-organisms. The IC50 (3 hours) of the test item was found to be greater than 400 mg/L. Severals studies, (supporting studies), were also performed on the differents batches to test the toxicity on micro-organisms. BST (toxicity to activated sludge) was found to be greater then 300 mg/L on batch A, B and D. For the batch F, IC50 was found to be greater than 400 mg/L.

Key value for chemical safety assessment

EC50 for microorganisms:

400 mg/L