4-amino-5-methoxy-N,2-dimethylbenzenesulphonamide

Toxicity to microorganisms

Administrative data

Endpoint:

activated sludge respiration inhibition testing

Type of information:

experimental study

Adequacy of study:

key study

Study period:

1988 - 1989

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: well performed OECD study but without GLP

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1989

Report date:

1989

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 209 (Activated Sludge, Respiration Inhibition Test

Deviations:

not specified

GLP compliance:

no

Test material

Test material information

Constituent 1

Reference substance name:

4-amino-5-methoxy-N,2-dimethylbenzenesulphonamide

EC Number:

256-380-5

EC Name:

4-amino-5-methoxy-N,2-dimethylbenzenesulphonamide

Cas Number:

49564-57-0

Molecular formula:

C9H14N2O3S

IUPAC Name:

4-amino-5-methoxy-N,2-dimethylbenzene-1-sulfonamide

Sampling and analysis

Analytical monitoring:

no

Test solutions

Vehicle:

no

Test organisms

Test organisms (species):

activated sludge, domestic

Details on inoculum:

Origin: Sewage treatment plant at Frankfurt am Main-Sindlingen
Preparation of the suspension : sediment from activated sewage sludge was washed three times by centrifuging and resuspending in water with 0.9 % NaCl.
Content of suspended solids in the sewage sludge suspension: 2 g/L (dry matter)

Study design

Test type:

static

Limit test:

no

Total exposure duration:

3 h

Test conditions

Test temperature:

21 +- 1 °C

pH:

7.6 - 7.7

Nominal and measured concentrations:

500 mg/L and 1000 mg/L nominal

Details on test conditions:

Incubation vessels: Glasbottles with a diameter of 60 mm and a grounded neck (NS29), height 170 mm and a total volume of approx. 480 ml. The
bottles contained magnetic stirrer bars and were incubated in a water bath on magnetic stirrers.
Test volume: 200 ml each batch
Aeration rate/test vessel : 45 litres per hour, only during the incubation period.

Reference substance (positive control):

yes

Remarks:

3,5-Dichlorophenol

Results and discussion

Effect concentrations

Effect concentrations 1

Duration:

3 h

Dose descriptor:

EC10

Effect conc.:

491.7 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

inhibition of total respiration

Remarks:

respiration rate

Effect concentrations 2

Duration:

3 h

Dose descriptor:

EC50

Effect conc.:

962.1 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

inhibition of total respiration

Remarks:

respiration rate

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Conclusions:

The EC50 of Kresidinsulfmethylamid to activated sludge (domestic sewage treatment plant) is 962.1 mg/L.

Executive summary:

In the respiration inhibition test, the oxygen consumption rates of aliquots of activated domestic sewage sludge were simultaneously measured in the presence of various test substance concentrations. The decreasing oxygen concentrations were monitored by recorders. The slopes of the plotted curves were used as measure for the respiratory activities. The amounts of activity reduction were calculated as percentage in relation to the controls and assessed as respiration inhibition. If the inhibition values showed a clear dose-effect-relationship, the concentrations for 10%, 50% and 90% inhibition were determined as test result.

The sensitivity of the activated sludge was tested with a reference batch. Reference substance was 3,5-Dichlorophenol in the concentrations of 5 and 30 mg/L. As blank control an inoculated test culture without addition of the test substance was used. It was topped up to the standard batch volume with water.

The EC50 of Kresidinsulfmethylamid to activated sludge (domestic sewage treatment plant) is 962.1 mg/L.