Benzyldimethyl(octadecyl)ammonium chloride

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 November 24, 2003 to December 04, 2003

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study

Remarks:

KL2 due to RA

Justification for type of information:

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

Reason / purpose for cross-reference:

read-across source

Qualifier:

according to guideline

Guideline:

OECD Guideline 209 (Activated Sludge, Respiration Inhibition Test

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Analytical monitoring:

no

Test organisms (species):

activated sludge of a predominantly domestic sewage

Details on inoculum:

- Nature: secondary activated sludge
- Source: Nieuwgraaf in Duiven, The Netherlands, a sewage treatment plant treating predominantly domestic sewage
- Sampling site: Sewage treatment plant
- Laboratory culture: No, the activated sludge was directly used after getting it from the sewage treatment plant.
- Preparation of inoculum for exposure: Prior to use it was homogenised with a syringe
- Pretreatment: No
- Initial cell concentration: The dry weight of the activated sludge in the incubation vessel was 1.5 g/L

Test type:

other: biodegradation

Water media type:

freshwater

Total exposure duration:

28 d

Test temperature:

20°C

pH:

7.1 - 7.3

Nominal and measured concentrations:

Not specified

Details on test conditions:

- Organic substrate: The soil was amended with powdered alfalfa meal (Medicago sativa), 5 g of alfalfa meal per kg of soil (dry weight).
- Aeration of dilution water: No
- Suspended solids concentration: The dry weight of the activated sludge in the incubation vessels was 1.5 g/L
- Method of soil incubation: individual subsamples
- Aeration: No

Reference substance (positive control):

no

Key result

Duration:

30 min

Dose descriptor:

EC50

Effect conc.:

11 mg/L

Conc. based on:

act. ingr.

Basis for effect:

inhibition of total respiration

Remarks:

respiration rate

Remarks on result:

other: calculated

Duration:

30 min

Dose descriptor:

other: EC20

Effect conc.:

5 mg/L

Conc. based on:

act. ingr.

Basis for effect:

inhibition of total respiration

Remarks:

respiration rate

Remarks on result:

other: calculated

Duration:

30 min

Dose descriptor:

other: EC80

Effect conc.:

24 mg/L

Conc. based on:

act. ingr.

Basis for effect:

inhibition of total respiration

Remarks:

respiration rate

Remarks on result:

other: calculated

Duration:

30 min

Dose descriptor:

EC10

Effect conc.:

4 mg/L

Conc. based on:

act. ingr.

Basis for effect:

inhibition of total respiration

Remarks:

respiration rate

Details on results:

The EC50 of the test substance for activated sludge was 11 mg a.i./L with 95% confidence limits of 3 and 27 mg a.i./L. The EC10, EC20 and EC80 were 4, 5 and 24 mg a.i./L, respectively.

Results with reference substance (positive control):

The EC50 of the reference compound 3,5-dichlorophenol (5.2 mg/L) was within the prescribed range of 5 to 30 mg/L.

Reported statistics and error estimates:

The EC values were computed from the best fitted line (least square method) through the points given by the probit of the percentage inhibition and the logarithm of the concentration of the test substance. The EC10, 25, 50 values were computed from the best fitted line (least-squares method) through the points given by the probit of the percentage inhibition and the logarithm of the concentration of the test substance. Confidence limits were computed on the basis of Fieller's theorem. All computations were performed using the TOXCALC version 5.0 program.

Validity criteria fulfilled:

yes

Conclusions:

Under the study conditions, the 30 mins EC50 of the test substance for activated sludge was 11 mg a.i./L (with 95% confidence limits of 3 and 27 mg a.i./L). The EC10, EC20 and EC80 were 4, 5 and 24 mg a.i./L, respectively. The test substance was therefore considered harmful to activated sludge.

Executive summary:

A study was conducted to determine the toxicity to microorganisms of the read across substance, C12-16 ADBAC (active: 49.9%), according to OECD Guideline 209, in compliance with GLP. The respiration inhibition test was performed on activated sludge fed with a standard amount of synthetic sewage. The respiration rate of the same activated sludge in the presence of various concentrations of the test substance under identical conditions was also measured. The inhibitory effect of the test substance at a particular concentration was expressed as a percentage of the mean respiration rates of the controls. The validity of the test was shown by two criteria. First, the control respiration rates were within 15% of each other and secondly, the EC50 of the reference compound 3, 5-dichlorophenol (5.2 mg/L) was within the prescribed range of 5 to 30 mg/L. No analytical dose determination was performed. Under the study conditions, the 30 mins EC50 of the test substance for activated sludge was 11 mg a.i./L (with 95% confidence limits of 3 and 27 mg a.i./L). The 30 mins EC10, EC20 and EC80 were 4, 5 and 24 mg a.i./L, respectively (Geerts, 2004). Based on the results of the read across study, similar the 30 mins EC50 value can also be considered for the test substance, C18 ADBAC, for toxicity to microorganisms.

Description of key information

Based on the results of the read across study, the 30 mins EC50 and EC10 for the test substance, C18 ADBAC, for toxicity to microorganisms is considered to be 11 mg a.i./L and 4 mg a.i./L (nominal) respectively.

Key value for chemical safety assessment

EC50 for microorganisms:

11 mg/L

EC10 or NOEC for microorganisms:

4 mg/L

Additional information

A study was conducted to determine the toxicity to microorganisms of the read across substance, C12-16 ADBAC (active: 49.9%), according to OECD Guideline 209, in compliance with GLP. The respiration inhibition test was performed on activated sludge fed with a standard amount of synthetic sewage. The respiration rate of the same activated sludge in the presence of various concentrations of the test substance under identical conditions was also measured. The inhibitory effect of the test substance at a particular concentration was expressed as a percentage of the mean respiration rates of the controls. The validity of the test was shown by two criteria. First, the control respiration rates were within 15% of each other and secondly, the EC50 of the reference compound 3, 5-dichlorophenol (5.2 mg/L) was within the prescribed range of 5 to 30 mg/L. No analytical dose determination was performed. Under the study conditions, the 30 mins EC50 of the test substance for activated sludge was 11 mg a.i./L (with 95% confidence limits of 3 and 27 mg a.i./L). The 30 mins EC10, EC20 and EC80 were 4, 5 and 24 mg a.i./L, respectively (Geerts, 2004). Based on the results of the read across study, similar the 30 mins EC50 value can also be considered for the test substance, C18 ADBAC, for toxicity to microorganisms.