N,N-Diethylacrylamide

Toxicity to aquatic algae and cyanobacteria

Link to relevant study record(s)

Reference

Endpoint:

toxicity to aquatic algae and cyanobacteria

Type of information:

experimental study

Adequacy of study:

key study

Study period:

From 2014-02-03 to 2014-02-06

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 201 (Alga, Growth Inhibition Test)

Version / remarks:

2006

GLP compliance:

yes (incl. QA statement)

Specific details on test material used for the study:

Batch No.: DEPP-A
Purity: 99.95%

Analytical monitoring:

yes

Details on sampling:

- Concentrations: 100 mg/L
- Sample storage conditions before analysis:kept in a refrigerator (2~8 °C ), the test solution be prepared just prior to the exposure

Vehicle:

no

Details on test solutions:

PREPARATION of test solution
-Preliminary test (solution test): prior to range-finding test, solubility test was conducted to identify the solubility of test in dilution water (OECD medium). As a result of solubility test, it's identified that the test substance is soluble with dilution water (OECD medium) at the concentration of 500 mg/L.
-Range finding and limit test: the range finding and limit test are conducted at the nominal concen tration of 27.908, 33.490, 40.188, 48.225, 57.870, 69.444, 83.333 and 100 mg/L. Each test solution of nominal concentration was prepared by dil ution of stock solution in the morning of exposure date.
-Definitive test: the definitive test be conducted at the nominal concentration of 100 mg/L on the basis of range finding and limit test. Each test solution of nominal concentration was prepared by dilution of stock solution in the morning of exposure date.

TEST method:
(1) Pre-culture was prepared to obtain the algal culture for the test, the conditions of incubation were measured during the pre-culture period.
(2) The test was started by incolating 5000 cells/mL in 200 mL conical flask containing 100 mL of test solution under sterile condition. Algal biomass was determined using hemocytometer and inverted microscope.
(3) Test vessels were covered to reduce the loss of water due to evaporation and no avoid the entry of dust into the test solutions.
(4) The exposure period was 72 hours, the test carried out under static system.

Test organisms (species):

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

Details on test organisms:

TEST ORGANISM
- Common name: Pseudokirchneriella subcapitata
- Source (laboratory, culture collection): American Type Culture Collection

Test type:

static

Water media type:

other: dilution water

Limit test:

yes

Total exposure duration:

72 h

Test temperature:

23 ~ 24 °C

pH:

8.55, 8.45 at the beginning of definitive test, 7.73, 7.83 at the end of the test.

Nominal and measured concentrations:

Nominal concentration: 100 mg/L
Measured concentration: 94.692 mg/L

Details on test conditions:

Test condition
-temperture: 23 ~24 °C
-light intensity: 6300 ~ 6750 lux
-rotatory speed: 100 times/min
-Control: OECD medium was used for negative control
-Replicate: three replicates for the control, six replicates for nominal concentration of 100 mg/L
-Initial cell concentration: 5000 cell / mL
-Test solution volume: 100 mL test solution per replicate

Reference substance (positive control):

yes

Remarks:

potassium dichromate

Key result

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Details on results:

Exponential growth rate: at the end of the test, each biomass of the control and the nominal concentration of 100 mg/L was increased by 31.3 and 34.6 times in comparison with the initial biomass, respectively.

Inhibition of yield and average specific growth rate: as the result of test, the growth inhibition rate of -10.8% (yield) and -2.9% (average specific growth rate) were observed at normal concentration of 100 mg/L.

Normal appearance: there were no abnormal appearance in the control and the nominal concentration of 100 mg/L.

Appearance: appearance change by test substance was not observed.

Algae biomass as dry weight: 0.27 mg/L

Concentration of the test substance in the test solutions: the geometric mean of measured concentration for the test substance in the nominal concentration (100 mg/L) was 94.692 mg/L and 94.7% of the nominal concentration.

Results with reference substance (positive control):

As the result if acute toxicity test of potassium dichromate as positive control, the 72h EC50 based on the nominal concentration were 0.559 mg/L (yield, 95% confidence limit: 0.510~0.613 mg/L) and 0.845 mg/L (average specific growth rate, 95% confidence limit: 0.781~0.921mg/L). The 72h EC50 based on the measured concentration were 0.578 mg/L (yield, 95% confidence limit: 0.527~0.633mg/L) and 0.852 mg/L (average specific growth rate, 95% confidence limit: 0.793~0.919mg/L). The 72h EC 50 values by the measured concentration were within permissible range based on the historical data of testing facility (yield: 0.529~0.869 mg/L, average specific growth rate:0.706~1.862 mg/L).

Validity criteria fulfilled:

yes

Conclusions:

For test item, 72h EC50 of yield and average specific growth rate based on nominal concentration were greater than 100 mg/L. The 72h EC50 of yield and average specific growth rate based on measured concentration were greater than 94.692 mg/L.

Executive summary:

The study was performed to assess the growth inhibition of test item to Pesudokirchneriella Subcapitata according to the OECD Guideline for Testing of Chemicals No. 201 (2006).

 

1)      During the test period, temperature and light intensity in the incubator were 23 ~ 24°C and 6300 ~ 6750 Lux, respectively.

2)      pH values of the control and nominal were 8.55, 8.45 at the beginning of definitive test, 7.73, 7.83 at the end of the test. pH changes in the control and nominal concentration during the test period were -0.82 and -0.62, respectively.

3)      The test solutions were clear at the beginning of the test. The test solutions were turned green by the growth of test species at the end of the test. appearance change by test substance was not observed.

4)      There were no abnormal appearance in all the test solutions at the end of the test.

5)      The geometric mean of measured concentration for test substance in the nominal concentration (100 mg/L) was 94.692 mg/L.

 

As the results of growth inhibition test of test item, the 72h EC50 of yield and average specific growth rate based on nominal concentration were greater than 100 mg/L. The 72h EC50 of yield and average specific growth rate based on measured concentration were greater than 94.692 mg/L.

 

Description of key information

The 72h EC50 of yield and growth rate based on nominal concentration were greater than 100 mg/L (measured concentration 94.692 mg/L).

Key value for chemical safety assessment

EC50 for freshwater algae:

100 mg/L