2,2'-[(3,3'-dichloro[1,1'-biphenyl]-4,4'-diyl)bis(azo)]bis[3-oxo-N-phenylbutyramide]

Toxicity to microorganisms

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

activated sludge respiration inhibition testing

Type of information:

experimental study

Adequacy of study:

key study

Study period:

Year of publication: 1981

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study without detailed documentation

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 209 (Activated Sludge, Respiration Inhibition Test

GLP compliance:

no

Analytical monitoring:

not specified

Vehicle:

not specified

Test organisms (species):

activated sludge of a predominantly domestic sewage

Details on inoculum:

The sludge used by the different laboratories (5 laboratories) was domestic for 4 laboratories. One laboratory however used industrial sludge.
Preparation and amount of sludge used was as specified by OECD 209.

Test type:

static

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

3 h

Test temperature:

20 +- 2°C

pH:

pH: between 7 and 8

Nominal and measured concentrations:

Limit test: 100 mg/L nominal concentration

Details on test conditions:

Identical to OECD-guideline 209, as this publication was the basis for the development of the guideline.
For those chemicals whose respiration rate was at least 80% of the control, the IC50 (concentration for 50% inhibition of respiration rate) is recorded as >100 mg/L.

Reference substance (positive control):

yes

Remarks:

3,5-dichlorophenol

Key result

Duration:

3 h

Dose descriptor:

IC50

Effect conc.:

> 100 mg/L

Nominal / measured:

not specified

Conc. based on:

test mat.

Basis for effect:

inhibition of total respiration

Remarks:

respiration rate

Details on results:

The respiration rate for the submission substance at a concentration of 100 mg/L was >= 80% of the control samples without test item.

Results with reference substance (positive control):

Concentration of 3,5-dichlorophenol [mg/L] :: mean inhibition [%]:

100 :: 90%
50 :: 91%
25 :: 78%
10 :: 36%
1 :: 6%

Validity criteria fulfilled:

not specified

Remarks:

However, as validity criteria for guideline OECD 209 were specified, these criteria were probably fulfilled for the reported test results.

Conclusions:

In a publication regarding the development of a screening test for inhibitory effects of dye-stuffs on aerobic waste-water bacteria, later used as the methodical basis of the OECD 209 activated sludge respriation inhibition test, the toxicity of the submission substance to aerobic waste water bacteria had been tested. The EC50 (3 hours) had been determined as > 100 mg/L (defined as at least 80% respiration rate of the control) . This is probably a nominal concentration, however no specific indication is given. The sludge used by the different laboratories was predominantly domestic (4 laboratories used domestic, one of five laboratories however used industrial sludge). It is not clear, which type of sludge had been used with the submission substance. No information on substance purity is given.
However, as this interlaboratory study formed the basis for OECD guideline 209, the data are judged to be reliable (reliability category 2). From these data, the submission substance would be regarded as not harmful to aerobic microorganisms of sewage treatment plants.

Executive summary:

In a publication regarding the development of a screening test for inhibitory effects of dye-stuffs on aerobic waste-water bacteria, later used as the methodical basis of the OECD 209 activated sludge respriation inhibition test, the toxicity of the submission substance to aerobic waste water bacteria had been tested. The EC50 (3 hours) had been determined as > 100 mg/L (defined as at least 80% respiration rate of the control) . This is probably a nominal concentration, however no specific indication is given. The sludge used by the different laboratories was predominantly domestic (4 laboratories used domestic, one of five laboratories however used industrial sludge). It is not clear, which type of sludge had been used with the submission substance. No information on substance purity is given.

However, as this interlaboratory study formed the basis for OECD guideline 209, the data are judged to be reliable (reliability category 2). From these data, the submission substance would be regarded as not harmful to aerobic microorganisms of sewage treatment plants.

Reference 2

Endpoint:

activated sludge respiration inhibition testing

Type of information:

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

Adequacy of study:

key study

Reason / purpose for cross-reference:

read-across source

Key result

Duration:

3 h

Dose descriptor:

IC50

Effect conc.:

> 100 mg/L

Nominal / measured:

not specified

Conc. based on:

test mat.

Basis for effect:

inhibition of total respiration

Remarks:

respiration rate

Details on results:

The respiration rate for the submission substance at a concentration of 100 mg/L was >= 80% of the control samples without test item.

Results with reference substance (positive control):

Concentration of 3,5-dichlorophenol [mg/L] :: mean inhibition [%]:

100 :: 90%
50 :: 91%
25 :: 78%
10 :: 36%
1 :: 6%

Validity criteria fulfilled:

not specified

Remarks:

However, as validity criteria for guideline OECD 209 were specified, these criteria were probably fulfilled for the reported test results.

Conclusions:

In a publication regarding the development of a screening test for inhibitory effects of dye-stuffs on aerobic waste-water bacteria, later used as the methodical basis of the OECD 209 activated sludge respriation inhibition test, the toxicity of the submission substance to aerobic waste water bacteria had been tested. The EC50 (3 hours) had been determined as > 100 mg/L (defined as at least 80% respiration rate of the control) . This is probably a nominal concentration, however no specific indication is given. The sludge used by the different laboratories was predominantly domestic (4 laboratories used domestic, one of five laboratories however used industrial sludge). It is not clear, which type of sludge had been used with the submission substance. No information on substance purity is given.
However, as this interlaboratory study formed the basis for OECD guideline 209, the data are judged to be reliable (reliability category 2). From these data, the submission substance would be regarded as not harmful to aerobic microorganisms of sewage treatment plants.

Executive summary:

In a publication regarding the development of a screening test for inhibitory effects of dye-stuffs on aerobic waste-water bacteria, later used as the methodical basis of the OECD 209 activated sludge respriation inhibition test, the toxicity of the submission substance to aerobic waste water bacteria had been tested. The EC50 (3 hours) had been determined as > 100 mg/L (defined as at least 80% respiration rate of the control) . This is probably a nominal concentration, however no specific indication is given. The sludge used by the different laboratories was predominantly domestic (4 laboratories used domestic, one of five laboratories however used industrial sludge). It is not clear, which type of sludge had been used with the submission substance. No information on substance purity is given.

However, as this interlaboratory study formed the basis for OECD guideline 209, the data are judged to be reliable (reliability category 2). From these data, the submission substance would be regarded as not harmful to aerobic microorganisms of sewage treatment plants.

Description of key information

To assess the possible impact of the Diarylide Yellow Pigments on sewage treatment plant microbial activity, a reliable Activated Sludge Respiration Inhibition Test for Pigment Yellow 13 is available. At a pigment concentration far above the solubility limit, no respiration inhibition was observed (≥ 80% of the control). This is supported by a non-guideline study which focused on possible long term microbial degradation of Pigment Yellow 13. By light microscopy different microorganisms growing on the particle surface could be detected, arguing against microbial toxicity of the pigment. Judging from these experimental results, Diarylide Yellow Pigments are nontoxic to sewage treatment plant microorganisms.

Key value for chemical safety assessment

Additional information

To assess the possible impact of substances of the Pigment Yellow 12 and its strucutral analogues, the Diarylide Yellow Pigments, on sewage treatment plant microbial activity, a reliable Activated Sludge Respiration Inhibition Test for Pigment Yellow 13 is available (reliability category 2). At a pigment concentration far above the solubility limit, no respiration inhibition was observed (≥ 80% of the control). This is supported by a non-guideline study which focused on possible long term microbial degradation of Pigment Yellow 13. By light microscopy different microorganisms growing on the particle surface could be detected, arguing against microbial toxicity of the pigment.

Judging from these experimental results, Diarylide Yellow Pigments are nontoxic to sewage treatment plant microorganisms.