Didodecyl 1,4-dihydro-2,6-dimethylpyridine-3,5-dicarboxylate

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

Reliability:

1 (reliable without restriction)

Qualifier:

according to guideline

Guideline:

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

Qualifier:

according to guideline

Guideline:

EU Method C.3 (Algal Inhibition test)

GLP compliance:

yes (incl. QA statement)

Analytical monitoring:

yes

Remarks:

To verify the nominally applied concentration, samples were taken from the test solutions and analytically measured. The samples taken from the test vessels were transferred to the analytical test site and analysed under the responsibility of the principa

Vehicle:

no

Details on test solutions:

A stock solution at a nominal loading rate of 100 mg/L was prepared by adding 100.60 mg test item to 1000 mL test medium. This stock solution was stirred on a magnetic stirrer set at 750 rpm at ambient temperature in the dark for 23 h and 5 min. After the stirring, particles were observed. Thereafter, the stock solution was filtered, using a glass fibre filter with an average retention capacity of 0.4 µm (MN GF 5). Visual inspection of the filtrate (S2) showed no undissolved test item particles. The first 100 mL of the filtrate were discarded .

The filtrate was used to prepare the desired test item concentrations and was used immediately after preparation.

The volume of the stock solution (filtrate) was large enough to prepare the test solution and all analytical samples.

The test solutions were stirred for ca. 10 minutes on a magnetic stirrer at room temperature and placed into a temperature-controlled room for temperature adaptation.

Test organisms (species):

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

Details on test organisms:

The organisms were originally supplied by Sammlung von Algenkulturen, Albrecht-von-Haller-Institut, Universität Göttingen, Germany.

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

72 h

Test temperature:

22.8 - 23.0 °C

pH:

7.8 - 9.4

Nominal and measured concentrations:

nominal: 1.00, 3.16, 10.0, 31.6, and 100% of filtrate of a saturated solution at a loading rate of 100 mg/L and a control
geometric mean measured concentration of 0.0142, 0.0337, 0.108, 0.229 and 1.19 µg test item/L

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

0.455 µg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat. (dissolved fraction)

Basis for effect:

yield

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

1.11 µg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat. (dissolved fraction)

Basis for effect:

growth rate

Duration:

72 h

Dose descriptor:

EC10

Effect conc.:

0.22 µg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat. (dissolved fraction)

Basis for effect:

yield

Duration:

72 h

Dose descriptor:

EC10

Effect conc.:

0.407 µg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat. (dissolved fraction)

Basis for effect:

growth rate

Duration:

72 h

Dose descriptor:

LOEC

Effect conc.:

0.229 µg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat. (dissolved fraction)

Basis for effect:

yield

Duration:

72 h

Dose descriptor:

LOEC

Effect conc.:

0.229 µg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat. (dissolved fraction)

Basis for effect:

growth rate

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

0.108 µg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat. (dissolved fraction)

Basis for effect:

yield

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

0.108 µg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat. (dissolved fraction)

Basis for effect:

growth rate

Executive summary:

Summary of biological results based on measured test item concentrations in µg test item/L.

	Endpoints [µg test item/L]
Parameter	EC10	EC20	EC50	NOEC	LOEC
Yield (95% cI)	0.220 (0.163-0.296)	0.282 (0.217-0.374)	0.455 (0.338-0.617)	0.108	0.229
Growth Rate (95% cI)	0.407 (0.352-0.471)	0.574 (0.499-0.660)	1.11 (0.924-1.31)	0.108	0.229

cl: confidence limit

Key value for chemical safety assessment

EC50 for freshwater algae:

1.11 µg/L

EC10 or NOEC for freshwater algae:

0.108 µg/L