Reaction mass of N-butylphthalimide and N-sec-butylphthalimide and N-propylphthalimide

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:

31 July - 1 August 1990

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

comparable to guideline study with acceptable restrictions

Remarks:

The study generally follows test guideline OECD209. The test report is without detailed documentation. The test parameters documented do not totally comply with the specific testing guideline, but are sufficient to accept the data.

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 209 (Activated Sludge, Respiration Inhibition Test

Version / remarks:

Guideline followed not mentioned on the study report

GLP compliance:

not specified

Specific details on test material used for the study:

Dark straw coloured liquid
Storage: in original container at room temperature

Vehicle:

no

Details on test solutions:

Method of prepartion: Direct dispersion in water

Test organisms (species):

activated sludge

Details on inoculum:

A mixed population of activated sewage sludge microorganisms.
Source: The aeration Stage of Severn Trent PLC Sewage Treatment Plant, Belper, Derbyshire, UK

Test type:

not specified

Water media type:

not specified

Limit test:

yes

Total exposure duration:

3 h

Test temperature:

21 °C

pH:

7.0

Nominal and measured concentrations:

100 mg/l nominal

Details on test conditions:

TEST SYSTEM
- Aeration: continous
- No. of vessels per concentration (replicates): 3
- No. of vessels per control (replicates): 2
- Sludge concentration (weight of dry solids per volume): 3.9 g/l

OTHER TEST CONDITIONS
- Adjustment of pH: addition of sodium hydroxide solution

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) :
O2 consumption mgO2/l/min

TEST CONCENTRATIONS
- Range finding study:
- Test concentrations: 0.1, 10, 100, 1000 mg/l
- Results used to determine the conditions for the definitive study: % inhibition 100mg/l: 6%, %inhibition 1000 mg/l: 92%

Reference substance (positive control):

yes

Remarks:

3,5-dichlorophenol, concentrations: 3.2 and 32 mg/l

Key result

Duration:

3 h

Dose descriptor:

EC50

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

not specified

Basis for effect:

inhibition of total respiration

Remarks:

measured O2 consumption rates mgO2/l/min

Results with reference substance (positive control):

Concentration 3.2 mg/l: 15% inhibition
Concentration 32 mg/l: 87% inhibition
Variation between controls: +/- 2%

Concentration (mg/l)		O2 consumption rates mgO2/l/min ^3 hour contact time	% inhibition
Control R1 R2		0.44 0.45	- -
Test 100 R1 100 R2   100 R3		0.44 0.42 0.40	1 6 10
Reference 3.2 Reference 32		0.38 0.06	15 87

Conclusions:

The EC50 (3 hour contact time) of the test material is >100 mg/l.

Description of key information

The EC50 (3 hour contact time) of the test material is >100 mg/l.