Pyrazino[2,1-a]isochinolin-4-on, 4H-, 1,2,3,6,7,11b-hexahydr o-, Diphosphat

Toxicity to microorganisms

Administrative data

Endpoint:

activated sludge respiration inhibition testing

Type of information:

experimental study

Adequacy of study:

key study

Study period:

Sep 26 - Nov 25, 2002

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: GLP study performed according to OECD TG 209.

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2002

Report date:

2002

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 209 (Activated Sludge, Respiration Inhibition Test

Principles of method if other than guideline:

none

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Reference substance name:

Automatically generated during migration to IUCLID 6, no data available

IUPAC Name:

Automatically generated during migration to IUCLID 6, no data available

Test material form:

other: solid

Sampling and analysis

Analytical monitoring:

no

Test organisms

Test organisms (species):

activated sludge, domestic

Details on inoculum:

Species: activated sludge, micro organisms from a domestic waste water treatment plant.
Origin: supplied by the sewage plant Groß Zimmern, Germany

Study design

Test type:

other: aerobic

Water media type:

freshwater

Limit test:

no

Total exposure duration:

3 h

Test conditions

Hardness:

250 mg/L

Test temperature:

19 - 21 °C

pH:

saturated (7-8 mg/L)

Dissolved oxygen:

7 - 8 mg/L

Nominal and measured concentrations:

0, 32, 100, 320, 1000 mg/L nominal

Details on test conditions:

Measurement of Respiration Rate:

For the measurement of the respiration rate a well-mixed sample of each test medium was poured into a Karlsruher flask after exactly 3 hours incubation time, and was not further aerated. The oxygen concentration was measured with an oxygen electrode, and was recorded for about ten minutes. During measurement, the samples were continuously stirred on a magnetic stirrer.
The oxygen consumption (in mg 02 per L per minute) was determined from the most linear part of the respiration curve.

Reference substance (positive control):

yes

Remarks:

DCP

Results and discussion

Effect concentrations

Duration:

3 h

Dose descriptor:

EC50

Effect conc.:

> 1 000 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

inhibition of total respiration

Remarks:

respiration rate

Details on results:

-- Incolulum control:
The respiration rates of the two controls did not differ by more than 15 %.

-- Reference Item
The 3-hour EC 50 of the reference item 3,5-Dichlorophenol was determined to be 5.0 mg/L and is thus in the range of 5 to 30 mg/L for the used activated sludge batch.

-- Dissolved Oxygen
The concentration of dissolved oxygen did not drop below 2.5 mg 02/L during the incubation period, and just before the measurements of the respiration rates the oxygen concentrations were at least 6.9 mg 02/L.

--Determination of the Inhibitory Effects:
The 3-hour EC 50 of the reference item was calculated by Probit analysis. The 3-hour EC 20 and EC 50 of the test item could not be calculated due to the low toxicity of the test item to micro organisms under the tested conditions.

Results with reference substance (positive control):

The 3-hour EC 50 of the reference item 3,5-Dichlorophenol was determined to be 5.1 mg/L and is thus in the range of 5 to 30 mg/L for the used activated sludge batch.

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Conclusions:

The 3-hour EC50 of the test material was higher than 1000 mg/L under the present test conditions.

Executive summary:

Study design

The influence of the test item on the activity of activated sludge was evaluated by measuring the respiration rate under defined conditions. The respiration rate (oxygen consumption) of an aerobic activated sludge fed with a standard amount of synthetic sewage was measured in the presence of various concentrations (10, 32, 100, 320 and 1000 mg/L) of the test item after an incubation period of 3 hours. This study was conducted according to Good Laboratory Practice (GLP) and the method applied followed the OECD Guideline for Testing of Chemicals, Section 2, No.209: "Activated Sludge, Respiration Inhibition Test", adopted April 04, 1984.

Results

In comparison to the inoculum controls, the respiration rate of the activated sludge was inhibited by 2.3% and 8.4% at the two lowest nominal concentrations of 10 and 32 mg/L, respectively. At the three highest nominal concentrations of 100, 320 and 1000 mg/L, the respiration rates were inhibited by 24.6 %, 19.3 % and 49.7 %, respectively. Test item concentrations exceeding 1000 mg/L were not tested. Based on measured inhibition rates, the 3 hour EC20 was calculated to be 139.6 mg/L and the 3 -hour EC50 was higher than 1000 mg/L.

Conclusion

The 3 -hour EC50 of the test material was higher than 1000 mg/L under the present test conditions.