Dimethylaminopropylmethacrylamide, dodecyl bromide

Toxicity to aquatic algae and cyanobacteria

Administrative data

Endpoint:

toxicity to aquatic algae and cyanobacteria

Type of information:

experimental study

Adequacy of study:

key study

Study period:

21/03/2016 - 07/10/2016

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2016

Report date:

2017

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 201 (Freshwater Alga and Cyanobacteria, Growth Inhibition Test)

Version / remarks:

2011

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Reference substance name:

N-(3-methacrylamidopropyl)-N,N-dimethyldodecan-1-aminium bromide

Cas Number:

129684-50-0

Molecular formula:

C21H43N2O.Br

IUPAC Name:

N-(3-methacrylamidopropyl)-N,N-dimethyldodecan-1-aminium bromide

Test material form:

liquid: viscous

Sampling and analysis

Analytical monitoring:

no

Test solutions

Vehicle:

no

Test organisms

Test organisms (species):

Raphidocelis subcapitata (previous names: Pseudokirchneriella subcapitata, Selenastrum capricornutum)

Details on test organisms:

The study was performed with the unicellular, fresh-water green algae Pseudokirchneriella subcapitata strain, cultured in the laboratories of the Test Facility and originally purchased from the Institute of Plant Physiology of the University of Göttingen, Germany.

The algae were cultured in a climatic chamber at 24 °C ± 2 °C under continuous uniform illumination in the range 4440 - 8880 Lux in the spectral range 400-700 nm. The culture medium was the same of the test medium; the stock cultures were weekly transferred to fresh medium and maintained in continuous shaking to ensure the necessary amount of CO2 and to keep algae in suspension. Cultures containing deformed or abnormal cells were discarded. Only exponentially growing algal cultures have been used to start the test.
The copy of extraction certification is attached in Appendix A.

Study design

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

72 h

Test conditions

Hardness:

Not specified (reconstituted water)

Test temperature:

The incubation temperature was continuously monitored during the course of the study by a PT100 probe installed in the environmental test chamber. It was in the range 23.9 – 24.0 °C with a mean value of 24.0 °C and a standard deviation of 0.02°C. The temperature range
provided by OECD guideline is 24 ± 2 C. The temperature values during the test were within the provided range by guideline.

pH:

At the beginning of the test period pH value was 7.91 for the negative control, for the test item solutions ranged between 7.78– 7.90.
At the end of the test, pH mean values were 9.26 for the negative control and for the test item solutions ranged between 7.84 – 9.67 (mean values among the replicates).
The pH in the negative control varied by a maximum of 1.58 units; slightly higher then the
value recommended by OECD guideline stating that the pH values should not increase more than 1.5 units during the test period.

Dissolved oxygen:

Not specified (reconstituted water)

Salinity:

Not specified (reconstituted water)

Conductivity:

Not specified (reconstituted water)

Details on test conditions:

The treatment vessels were identified by experiment number, group and replicate number. All the described procedures were conducted under a laminar flow bench to ensure the sterility of the algal cultures.
For the test concentrations and for the negative control, 100 mL capacity conical glass flasks capped with air permeable stoppers were used.
Three replicates for each test concentration, six for negative control were prepared. At test start, 50 mL of test solutions were poured into the test flasks and inoculated with algae to obtain a starting cell density of about 10E4 cells/mL.
The algal inoculum was taken from a pre-culture, started 3 days before the beginning of the test in order to ensure that the assay was performed with exponentially growing algal
population. The cell density of the inoculum was around 10E6 cels/L.
The test flasks were incubated in a climatic chamber, under continuous illumination and
constant shaking. The flasks were randomly distributed under the light and were replaced every day during the test.

Results and discussion

Effect concentrations

Effect concentrations 1

Key result

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

0.068 mg/L

95% CI:

0.06 - 0.077

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Effect concentrations 2

Key result

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

0.022 mg/L

95% CI:

0.021 - 0.022

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

yield

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Conclusions:

The EC50/Pseudokirchneriella subcapitata at 72 hours for growth rate and yield was 0.068 and 0.022 mg/L, respectively.