7,7,9(or 7,9,9)-trimethyl-4,13-dioxo-3,14-dioxa-5,12-diazahexadecane-1,16-diyl bismethacrylate

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:

31/08/2009 - 04/09/2009

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: GLP-study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2009

Report date:

2009

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 201 (Alga, Growth Inhibition Test)

Deviations:

yes

Remarks:

The temperature in the reference study was higher than stated in the guideline. The temperature in the main study was higher than stated in the guideline. The pH of the control in the main study changed a little bit more than 1.5 units.

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Reference substance name:

7,7,9(or 7,9,9)-trimethyl-4,13-dioxo-3,14-dioxa-5,12-diazahexadecane-1,16-diyl bismethacrylate

EC Number:

276-957-5

EC Name:

7,7,9(or 7,9,9)-trimethyl-4,13-dioxo-3,14-dioxa-5,12-diazahexadecane-1,16-diyl bismethacrylate

Cas Number:

72869-86-4

Molecular formula:

C23H38N2O8

IUPAC Name:

7,7,9(or 7,9,9)-trimethyl-4,13-dioxo-3,14-dioxa-5,12-diazahexadecane-1,16-diyl bismethacrylate

Details on test material:

Batch no.: 81106228
Purity: min. 96%, effective 96.99%

Sampling and analysis

Analytical monitoring:

yes

Test solutions

Vehicle:

yes

Details on test solutions:

As the test item is not sufficiently water-soluble, the water-accommodated fractions (WAF) of the concentrations to be tested were prepared. This was done by weighing the respective nominal load, adding the appropriate amount of deionised water and shaking for 24 hours. After membrane filtration, the solutions were used to prepare the treatments. Since the solutions were diluted by algal pre-culture and nutrient medium, 1.25 times the nominal amount was used in preparation of the WAFs.

Test organisms

Test organisms (species):

Desmodesmus subspicatus (previous name: Scenedesmus subspicatus)

Details on test organisms:

Genus, Species Desmodesmus subspicatus
Strain CHODAT
Family Chlorophyceae
Order Chlorococcales

Study design

Test type:

static

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

72 h

Post exposure observation period:

no post exposure observation

Test conditions

Test temperature:

28 to 32 degree C

pH:

7.6 to 9.2

Reference substance (positive control):

yes

Remarks:

K2Cr2O7

Results and discussion

Effect concentrations

Effect concentrations 1

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

> 210 µg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

dissolved

Basis for effect:

growth rate

Effect concentrations 2

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

> 210 µg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

dissolved

Basis for effect:

other: AUC (integral of the biomass)

Effect concentrations 3

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

> 210 µg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

dissolved

Basis for effect:

other: Yield (biomass at the end of exposure minus biomass at the start)

Effect concentrations 4

Duration:

72 h

Dose descriptor:

LOEC

Effect conc.:

680 µg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

dissolved

Basis for effect:

growth rate

Effect concentrations 5

Duration:

72 h

Dose descriptor:

LOEC

Effect conc.:

680 µg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

dissolved

Basis for effect:

other: AUC (integral of the biomass)

Effect concentrations 6

Duration:

72 h

Dose descriptor:

LOEC

Effect conc.:

680 µg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

dissolved

Basis for effect:

other: Yield (biomass at the end of exposure minus biomass at the start)

Effect concentrations 7

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

> 680 µg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

dissolved

Basis for effect:

growth rate

Effect concentrations 8

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

> 680 µg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

dissolved

Basis for effect:

other: AUC (integral of the biomass)

Effect concentrations 9

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

> 680 µg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

dissolved

Basis for effect:

other: Yield (biomass at the end of exposure minus biomass at the start)

Results with reference substance (positive control):

Biological Results of the Positive Control
Parameter Value 95%-confidence-interval Range of interlaboratory test (EU C.3)
NOEC 72 h 0.16 mg/L not determinable not stated
LOEC 72 h 0.25 mg/L not determinable not stated
72h ErC50 0.85 mg/L 0.68 – 1.12 mg/L 0.60 – 1.03 mg/L
72h EbC50 0.31 mg/L 0.24 – 0.39 mg/L 0.20 – 0.75 mg/L
72h EyC50 0.25 mg/L 0.20 – 0.30 mg/L not stated

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Conclusions:

The following results for the test item PC-Cure P-1001 were determined:

Endpoint NOEC LOEC EC50
Growth Rate 0.21 mg/L 0.68 mg/L > 0.68 mg/L
AUC 0.21 mg/L 0.68 mg/L > 0.68 mg/L
Yield 0.21 mg/L 0.68 mg/L > 0.68 mg/L
Note: 0.68 mg/L should be considered as the highest achievable concentration under the condition of the test.

Executive summary:

Two experiments were performed. In the first experiment, a limit test using one concentration containing 100 mg/L, inhibition was observed. Therefore, a main study using five concentrations was performed.

As the test item is poorly soluble in water, the water-accommodated fractions were tested. This was done by shaking the respective nominal load with the appropriate amount of deionised water for 24 hours, followed by membrane filtration.

The main study was performed using five concentrations ranging from 4.6 to 100 mg/L. The treatments were used to incubate the unicellular freshwater green algaDesmodesmus subspicatusfor a period of 72 hours. The cell concentration of each replicate was determined by measuring the absorption of the cuvettes at 440 nm every 24 hours with a spectral photometer. With these measured values, the number of cells was calculated (linear correlation between cell concentration and absorption given). Then the growth rate µ, the area under the growth curve (AUC[1]) and the Yield[2]were determined.

At the start and at the end of the test, the content of the test item in the test solutions was determined using HPLC-determination. In treatments 4.6 – 22 mg/L the measured values were lower than LOQ (with the exception of treatment 10 mg/L at 0 hours). As only in the highest concentrated treatment inhibition could be observed, this was stated as uncritical.

For treatments 46 and 100 mg/L the recovery after 72 hours was in a range of 23 and 28 % of the start concentration, the measured concentration at the beginning of the test between 1.0 % and 1.3 % and at the end of the test between 0.2 % and 0.4 % of the nominal concentration, respectively. Therefore, the determination of the biological results was based on the mean of the measured concentration.

The EC50s of potassium dichromate were tested in a current reference test. The values lay within the normal range of the laboratory.

The following results for the test item PC-Cure P-1001 were determined:

 

Endpoint	NOEC	LOEC	EC50
Growth Rate	0.21 mg/L	0.68 mg/L	> 0.68 mg/L
AUC	0.21 mg/L	0.68 mg/L	> 0.68 mg/L
Yield	0.21 mg/L	0.68 mg/L	> 0.68 mg/L

Note: 0.68 mg/L should be considered as the highest achievable concentration under the condition of the test.

[1]AUC (Area Under the Curve according to EU Method C.3) means the integral of the biomass. Calculation see 8.2.

[2]Yield (according to OECD Guideline 201) is defined as the biomass at the end of the exposure period minus the biomass at the start of the exposure period. Calculation see 8.3