p-aminobenzamide

Toxicity to microorganisms

Administrative data

Endpoint:

activated sludge respiration inhibition testing

Type of information:

experimental study

Adequacy of study:

key study

Study period:

1988

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: The respiration inhibition test with sewage sludge was performed to national standards (DIN 8192:2007-005)

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1988

Report date:

1988

Materials and methods

Test guideline

Test guideline 1

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 209 (Activated Sludge, Respiration Inhibition Test

Deviations:

yes

Remarks:

In the today's methods no industrial but municipal wastewater sludge is used

Test guideline 2

Qualifier:

equivalent or similar to guideline

Guideline:

EU Method C.11 (Biodegradation: Activated Sludge Respiration Inhibition Test)

Deviations:

yes

Remarks:

In the today's methods no industrial but municipal wastewater sludge is used

GLP compliance:

not specified

Test material

Test material information

Constituent 1

Reference substance name:

p-aminobenzamide

EC Number:

220-612-3

EC Name:

p-aminobenzamide

Cas Number:

2835-68-9

Molecular formula:

C7H8N2O

IUPAC Name:

4-aminobenzamide

Sampling and analysis

Analytical monitoring:

no

Test solutions

Details on test solutions:

Due to the low solubility no stock solution was used. The test item was weighed out directly into the test vessels.

Test organisms

Test organisms (species):

activated sludge, industrial

Details on inoculum:

- Origin: sewage treatment of Hoechst AG, site Kelsterbach (industrial activated sludge)
- Pretreatment: corresponding to the cited test guideline
- Content of suspended solids in the sewage sludge suspension: 1 g/L (dry matter)

Study design

Test type:

static

Water media type:

freshwater

Total exposure duration:

3 h

Test conditions

Test temperature:

23.3 °C at all times

pH:

not recorded

Nominal and measured concentrations:

Nominal concentrations: 31, 63, 125 and 250 mg/L

Details on test conditions:

TEST SYSTEM
- Test vessel: Glasbottles with a diameter of 60 mm and a grounded neck (NS 29), height 170 mm, total volume appr. 480 ml. The bottles contained magnetic stirrer bars and were incubated in a water bath on magnetic stirrers.
- Test volume: 200 ml each batch

Results and discussion

Effect concentrations

Effect concentrations 1

Duration:

3 h

Dose descriptor:

EC0

Effect conc.:

> 250 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.:

> 250 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

inhibition of total respiration

Remarks:

respiration rate

Details on results:

The highest concentration in the test, 250 mg/L showed no inhibition. The activity was enhanced in the test batches towards the blank control.

Any other information on results incl. tables

Table 1: Concentrations and results

Controls and test batches	Activity [mg O2/L x h]	Respiration inhibition [%]
Control 1 + 2	62.4	-
250 mg/L	64.8	103
125 mg/L	64.8	103
63 mg/L	84	134
31 mg/L	84	134

Applicant's summary and conclusion

Conclusions:

The test item is not toxic at concentration < 250 mg/L to activated sludge of a industrial sewage treatment plant.

Executive summary:

A Respiration Inhibition Test according to OECD Guideline No. 209 was performed with the test item at Hoechst AG, Abteilung Umweltschutz, Frankfurt. The respiration rate of test item was measured after a contact time of three hours. The EC0 is > 250 mg/L to industrial activated sludge.

An increase of activity was observed at low concentration levels.