4,4'-Isopropylidenediphenol, polymer with 1-chloro-2,3-epoxypropane, propane-1,2-diol acrylate and succinic anhydride

Toxicity to microorganisms

Link to relevant study record(s)

Reference

Endpoint:

activated sludge respiration inhibition testing

Type of information:

read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

key study

Study period:

From 26 May, 2010 to 27 May, 2010

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study with acceptable restrictions

Remarks:

KL2 due to RA

Justification for type of information:

Refer to section 13 of IUCLID for details on the read-across justification. The study with the read across substance is considered sufficient to fulfil the information requirements as further explained in the read across justification.

Reason / purpose for cross-reference:

read-across source

Qualifier:

according to guideline

Guideline:

OECD Guideline 209 (Activated Sludge, Respiration Inhibition Test

Deviations:

no

Qualifier:

according to guideline

Guideline:

EPA OPPTS 850.6800 (Modified Activated Sludge, Respiration Inhibition Test for Sparingly Soluble Chemicals)

Deviations:

no

Qualifier:

according to guideline

Guideline:

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

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Analytical monitoring:

no

Details on sampling:

Incubation period: 3 h

Vehicle:

no

Details on test solutions:

Test concentrations: 10, 32, 100, 320 and 1000 mg test substance/L (nominal)
Two controls (tap water, synthetic sewage and inoculum, but without addition of the test substance) were tested in parallel.

Test organisms (species):

activated sludge

Details on inoculum:

Activated sludge, microorganisms from a domestic waste water treatment plant was supplied by the municipal sewage treatment plant Darmstadt, Germany.

Limit test:

no

Total exposure duration:

3 h

Hardness:

Controlled environment room

Test temperature:

20 - 22°C during dissolution phase (24 h)
19°C during pre-incubation (3 h)
19 - 20°C during evaluation period

Dissolved oxygen:

At least 7.8 mg O2/L

Nominal and measured concentrations:

Nominal concentrations: 10, 32, 100, 320 and 1000 mg test substance/L

Details on test conditions:

For the measurement of the respiration rate a well-mixed sample of each test medium was poured into a Karlsruher flask after exactly 3 h incubation time, and was not further aerated. The oxygen concentration was measured with an oxygen electrode, and was recorded for about 10 min. During measurement, the samples were continuously stirred on a magnetic stirrer. The oxygen consumption (in mg O2 L-1 min-1) was determined from the most linear part of the respiration curve in the range between approx 6.5 - 2.5 mg O2/L. In case of a low oxygen consumption the values over a period of 10 min were used.

Reference substance (positive control):

yes

Remarks:

3,5 Dichlorophenol

Key result

Duration:

3 h

Dose descriptor:

other: EC20

Effect conc.:

ca. 64.6 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

inhibition of total respiration

Remarks:

respiration rate

Key result

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:

In comparison to the inoculum controls the respiration rate of the activated sludge was slightly inhibited by 4.8% and 16.7% at the two lowest nominal concentrations of 10 and 32 mg/L, respectively. At the next higher nominal concentration of 100 mg/L, the respiration rate was moderately inhibited by 26.2%, respectively, and reached a plateau at 320 mg/L and the highest nominal test concentration of 1000 mg/L with an inhibition rate of 40.5%. Test substance concentrations exceeding 1000 mg/L were not tested. Based on measured inhibition rates, no 3-h EC50 could be quantified because up to the highest nominal test concentration of 1000 mg/L less than 50% inhibition was noted after 3 h incubation. Nevertheless, the 3 h EC50 is clearly higher than 1000 mg/L under the present test conditions. The 3 h EC20 was calculated by linear regression analysis using the inhibition rates of the 320, 100 and 32 mg/L test concentrations, and was calculated to be 64.6 mg/L nominal.

Results with reference substance (positive control):

The following nominal concentrations of the positive control 3,5-dichlorophenol were tested on the same activated sludge and under identical conditions as the test substance: 32, 10 and 3.2 mg/L. In comparison to the controls the respiration rate of the activated sludge was moderately inhibited by 35.7% at the lowest nominal concentration of 3.2 mg/L. At the nominal concentrations of 10 and 32 mg test substance/L, the respiration rate was inhibited by 42.9 and 81.0%, respectively. The 3 h EC50 of 3,5-Dichlorophenol was calculated to be 9.1 mg/L. Due to mathematical reasons, no 95 % confidence limits could be determined.

Validity criteria fulfilled:

yes

Remarks:

The respiration rates of the two controls did not differ by more than 15%. The coefficient of variation was 1.7%.

Conclusions:

Based on the results of the read across study, the 3 h EC20 and EC50 values of the test substance are considered to be 64.6 and >1,000 mg/L, respectively.

Executive summary:

A study was performed to assess the inhibitory effect of the read across substance BADGEDA, on the oxygen consumption rate of aerobic microorganisms (activated sludge) according to OECD Guideline 209, EU Method C.11 and EPA OPPTS 850.6800, in compliance with GLP. The read across substance is insoluble in water. Therefore, it was directly weighed into the test vessels and stirred for about 24 h before using in the experiment. In comparison to the inoculum controls, the respiration rate of the activated sludge was slightly inhibited by 4.8% at the lowest nominal test concentrations of 10 mg/L. At the next higher concentrations of nominal 32 mg/L and 100 mg/L, inhibition was 16.7 and 26.2%, respectively. At concentrations of 320 and 1,000 mg/L, respiration rate was moderately inhibited by 40.5% at a plateau. No dose related response was found. Concentrations exceeding 1,000 mg/L nominal were not tested. Under the conditions of the study, the 3 h EC20 was calculated to be 64.6 mg/L while the 3 h EC50 was considered to exceed the highest nominal test concentration of 1000 mg/L (Feil, 2010). Based on the results of the read across study, similar EC20 and EC50 values can be considered for the test substance.

Description of key information

Based on the results of the read across study with BADGEDA, the 3 h EC20 and EC50 values of the test substance are considered to be 64.6 and >1,000 mg/L (nominal) respectively. 

Key value for chemical safety assessment

EC50 for microorganisms:

1 000 mg/L

Additional information

A study was performed to assess the inhibitory effect of the read across substance '4,4’-Isopropylidenediphenol, oligomeric reaction products with 1-chloro-2,3-epoxypropane, esters with acrylic acid (BADGEDA)', on the oxygen consumption rate of aerobic microorganisms (activated sludge) according to OECD Guideline 209, EU Method C.11 and EPA OPPTS 850.6800, in compliance with GLP. The read across substance is insoluble in water. Therefore, it was directly weighed into the test vessels and stirred for about 24 h before using in the experiment. In comparison to the inoculum controls, the respiration rate of the activated sludge was slightly inhibited by 4.8% at the lowest nominal test concentrations of 10 mg/L. At the next higher concentrations of nominal 32 mg/L and 100 mg/L, inhibition was 16.7 and 26.2%, respectively. At concentrations of 320 and 1,000 mg/L, respiration rate was moderately inhibited by 40.5% at a plateau. No dose related response was found. Concentrations exceeding 1,000 mg/L nominal were not tested. Under the conditions of the study, the 3 h EC20 was calculated to be 64.6 mg/L while the 3 h EC50 was considered to exceed the highest nominal test concentration of 1000 mg/L (Feil, 2010). Based on the results of the read across study, similar EC20 and EC50 values can be considered for the test substance.