Carbamic acid, N-[(1R)-2-hydroxy-1-phenylethyl]-, 1,1-dimethylethyl ester

Toxicity to microorganisms

Administrative data

Endpoint:

activated sludge respiration inhibition testing

Type of information:

experimental study

Adequacy of study:

key study

Study period:

31st May 2018 - 1st June 2018

Reliability:

1 (reliable without restriction)

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2018

Report date:

2018

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

other: MEP, P.R. China, the Guidelines for the Testing of Chemicals, Effects on Biotic Systems (the Second Edition), No. 209 "Activated Sludge, Respiration Inhibition Test". (2013.8).

Version / remarks:

Second Edition

Test guideline 2

Qualifier:

according to guideline

Guideline:

OECD Guideline 209 (Activated Sludge, Respiration Inhibition Test (Carbon and Ammonium Oxidation))

Version / remarks:

Adopted 2010

GLP compliance:

yes (incl. QA statement)

Remarks:

SEPA, P.R. China, the Guidelines of Chemical Testing Good Laboratory Practices (HJ/T 155-2004).

Test material

Test material information

Constituent 1

Reference substance name:

Carbamic acid, N-[(1R)-2-hydroxy-1-phenylethyl]-, 1,1-dimethylethyl ester

EC Number:

600-273-1

Cas Number:

102089-74-7

Molecular formula:

C13H19NO3

IUPAC Name:

Carbamic acid, N-[(1R)-2-hydroxy-1-phenylethyl]-, 1,1-dimethylethyl ester

Test material form:

solid: particulate/powder

Specific details on test material used for the study:

Lot Number: US17600768
Appearance: white powder containing lumps
Purity: 99.7%
Storage: Room temperature 15 - 25 C

Sampling and analysis

Details on sampling:

DOC for total respiration was measured in 10 minutes internals after 3 hours contact time until 6 h.

Test solutions

Vehicle:

no

Details on test solutions:

To prepare test item mixtures, the test item was directly weighed into the test vessel and distilled water was added.

Test organisms

Details on inoculum:

The activated sludge was derived from a treatment plant receiving predominantly domestic sewage. A fresh sample of activated sludge was collected from the aeration tank of Shenyang North Sewage Treatment Plant 1 day before the test was started and feed the sludge daily with synthetic sewage feed.

Study design

Test type:

static

Water media type:

freshwater

Total exposure duration:

3 h

Test conditions

Test temperature:

20±2 °C

Nominal and measured concentrations:

The definitive test was conducted with 4 concentrations of 10, 100, 300 and 1000 mg/L. 10, 100, 300 mg/L were tested with 1 replicate, 1000 mg/L was tested with triplicate and an abiotic control at concentration of 1000 mg/L was performed.

Details on test conditions:

Test water: distilled water
Air for aeration: clean oil-free air, flow rate 0.5 ~ 1 L/min

Reference substance (positive control):

yes

Remarks:

Chemical name: 3,5-dichlorophenol (3,5-DCP) Lot number: C10066558 Purity: 98%

Results and discussion

Effect concentrations

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

Details on results:

Based on the results of test item test, the EC50 mg/L of test item for total respiration resulted in a total of >1000. Validity criteria were met throughout test.

Results with reference substance (positive control):

3,5-dichlorophenol was used as a reference item in order to check the sensitivity of the activated sludge used as microbial inoculum on the day of exposure. The reference item was tested at 0.5, 1.3, 3.5, 9.4 and 25 mg/L with 1 replicate. Based on the results of the reference item test, the EC50 ( 3 hours) of the reference substance for three different respiration's were as follows: EC50 (mg/L)= 3.5 mg/L with a 95% confidence limit of 2.2 ~ 5.6 mg/L.

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Conclusions:

Based on the results of test item test, the EC50 (3 hours) of test item for total respiration resulted in a total of >1000 mg/L, indicating that the substance would not be of a concern, in terms of toxicity, to the sludge microorganisms which are responsible for the biodegradation of organic
material in waste water treatment plant (as the EC50 is >100 mg/L).

Executive summary:

The  study  was  conducted  to  determine  the  inhibition  effects  of Boc-phenyl glycinol on micro-organisms from activated sludge (largely bacteria) by measuring their respiration rate. The contact time for exposure was 3 hours. 

The definitive test was conducted with 4 concentrations of 10, 100, 300 and 1000 rng/L. 10, 100, 300 mg/L were tested with 1 replicate, 1000 rng/L was tested with triplicate and an abiotic control at concentration of 1000 mg/L was performed. Inoculums blank controls were performed with 4 replicates.

The specific oxygen uptake rate of the blank controls (without the test item or reference item) was 21.3 rng/(h·g SS) oxygen. The coefficient of variation of oxygen uptake rate in control replicates was 2.0% at the end of definitive test. The validity criteria have therefore been satisfied.

Based on the results of test item test, the EC50 (3 hours) of test item for respiration are as follows:

 

Inhibition of respiration	EC50 (mg/L)
Total	>1000