magnesium bis(dipropan-2-ylazanide)

Toxicity to microorganisms

Administrative data

Endpoint:

activated sludge respiration inhibition testing

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2006

Report date:

2006

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

OECD Guideline 209 (Activated Sludge, Respiration Inhibition Test

Test guideline 2

Qualifier:

according to guideline

Guideline:

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

GLP compliance:

yes (incl. QA statement)

Test material

Reference

Name:

Unnamed

Type:

Constituent

Type:

Constituent

Sampling and analysis

Analytical monitoring:

no

Test organisms

Test organisms (species):

sewage, domestic

Study design

Limit test:

no

Total exposure duration:

3 h

Results and discussion

Effect concentrations

Duration:

3 h

Dose descriptor:

EC50

Effect conc.:

>= 420 - <= 420.01 mg/L

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Conclusions:

EC50 (IC50) at 3 hours is 420 mg MDA/L.

All validity criteria were met. In pre-test and main studies, the EC50 of the reference item lay within the recommended range of 5 to 30 mg/L.
The O2 consumption rates of all controls showed a maximum variation of 9.4 % in the pre-test, 10.0 % in the first main study and 13.8 % in the 2nd main study, which is below the recommended limit of 15%.
The values at the begin and at the end of the evaluated O2 measurements were within the recommended range of 6.5 to 2.0 mg/L.

Executive summary:

Three valid experiments were performed: one pre test and two main studies. In the pre-test, the test item was examined using four concentrations (ranging from 1052 to 1 mg/L). The duration of the pre-test was three hours. Inoculum was activated sludge from a domestic sewage treatment plant that was washed before usage (dry matter: 3.77 g suspended solids/L, giving a concentration of 1.51 g suspended solids/L). The inhibitions of the respiration of the activated sludge due to the test item MDA were determined as follows: 88 % inhibition at 1052 mg/L . All other concentrations showed inhibition values below 10%. The reference item "3,5-Dichlorophenole" was tested at five concentrations and an EC50 of 8.3 mg/L (95% confidence interval: 6.1 to 11 mg/L) was determined, which that met the validity criteria (range of 5 to 30 mg/L). The first main study was performed using five concentrations, ranging from 1025 to 102 mg/L. The dry matter of the activated sludge was determined as 3.66 g suspended solids/L, giving a concentration of 1.46 g suspended solids/L in the test. The EC50 of the reference item was determined as 6.4 mg/L (95% confidence interval: 5.0 to 7.9 mg/L), which lies within the range of 5 to 30 mg/L. The following results for the test item MDA were determined in the first main study: NOEC 3h= 181 mg/L 3h EC20 = 330 mg/L (95% confid. interv.: 270 - 380 mg/L) 3h EC50 = 420 mg/L (95% confid. interv.: 490 - 570 mg/L) Because the factor between concentrations had not been equal, the main study was repeated using five concentrations, ranging from 1018°mg/L to 102 mg/L. The dry matter of the activated sludge was determined as 3.91°g suspended solids/L, giving a concentration of 1.56°g suspended solids/L in the test. The EC50 of the reference item was determined as 15 mg/L (95% confidence interval: 10 - 23°mg/L), which lies within the range of 5°-30°mg/L. The following results for the test item MDA were determined in the second main study: NOEC 3h= 160 mg/L 3h EC20 = 270 mg/L (95% confid. interv.: 210 - 320 mg/L) 3h EC50 = 520 mg/L (95% confid. interv.: 440 - 650 mg/L) All measured inhibitions of the two main studies showed good correlation. For safety reasons, the lower values should be used for the assessment of the test item.