Reaction mass of 3-phenoxybenzyl (1R,3R)-2,2-dimethyl-3-(2-methylprop-1-en-1-yl)cyclopropanecarboxylate and 3-phenoxybenzyl (1R,3S)-2,2-dimethyl-3-(2-methylprop-1-en-1-yl)cyclopropanecarboxylate (4:1)

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:

2002

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: GLP / guideline study without deviations

Qualifier:

according to guideline

Guideline:

OECD Guideline 201 (Alga, Growth Inhibition Test)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Analytical monitoring:

yes

Details on sampling:

The test concentration was measured at 0 and 72 hours.

Vehicle:

yes

Details on test solutions:

0 and 5mg/L, applied dissolved in dimethylformamide.

Test organisms (species):

Desmodesmus subspicatus (previous name: Scenedesmus subspicatus)

Details on test organisms:

Scenedesmus subspicatusCHODAT, Strain No. 86.81 SAG. Algae had been grown in the RCC laboratories under standardized conditions.

Test type:

static

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

72 h

Post exposure observation period:

no

Hardness:

0.24 mml l-1 as CaCO3

Test temperature:

23°C (flasks in water bath)

pH:

8.2 at the beginning of the test, increasing to 9.0.

Dissolved oxygen:

not available

Salinity:

not available

Nominal and measured concentrations:

Nominal: 5 mg/L
Measured:
1.96 mg/L at the beginning of the test (39% of nominal)
5.28 mg/L at the end of the test (106% of nominal)

Details on test conditions:

- Photoperiod: Continuous
- Light intensity and quality: Illumination at about 8600 Lux

Reference substance (positive control):

yes

Remarks:

potassium dichromate

Key result

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

> 5 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Duration:

72 h

Dose descriptor:

EC10

Effect conc.:

> 5 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Duration:

72 h

Dose descriptor:

EC10

Effect conc.:

> 5 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

biomass

Key result

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

> 5 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

> 5 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

biomass

Details on results:

The analytical determined test item concentration in the analyzed test medium samples amounted to 1.96 mg /L (39% of nominal) at the start of the test. On the surface of the test medium an oily film was observed at the start of the test. However, after 24 hours, the test medium was clear and no remarkable observations were made concerning the appearance of the test medium. In the test medium, incubated under conditions during the test period (but without algae), 106% of the nominal concentration was found at the end of the test.
The mean algal cell densities in the test medium were at all counting dates identical with or even slightly higher than those in parallel solvent control cultures. Thus d-Phenothrin had no inhibitory effect on the growth of Scenedesmus subspicatus after the exposure period of 72-h at a concentration of 5 mg/L. This test concentration was therefore determined as the 72-h NOEC. The NOEC might even be higher but concentrations in excess have not been tested.
The 72-hour LOEC, EbC10, EbC50 and ErC10, ErC50 could not be calculated due to the absence of a toxic effect of the test item

Results with reference substance (positive control):

The positive control is used in the lab at least once a year to validate the systems.

Cell concentration data

Nominal concentration (mg/L)		Density of algal cells (cell number x 10^4/mL) after
		24 h		48 h		72 h
Control		4.1	4.0	6.7	5.9	46.7	46.2
		4.3	3.4	5.8	6.1	50.3	51.7
		3.1	3.4	7.0	6.4	44.3	43.5
	A. M. S. D.	3.72 0.42		6.32 0.38		47.12 3.60
Solvent control		3.4	3.5	5.7	5.4	38.5	38.6
		3.4	3.4	6.9	6.9	42.3	40.2
		3.5	3.6	6.1	5.8	42.5	42.0
		3.8	3.6	6.5	6.3	50.7	50.3
		5.0	4.1	6.1	6.0	46.2	45.5
		3.8	3.6	6.4	6.5	48.0	46.8
	A. M. S. D.	3.73 0.42		6.22 0.47		44.30 4.40
5.0		4.2	3.6	6.3	6.9	50.9	52.0
		3.5	3.5	5.7	5.3	40.5	41.1
		4.5	3.6	6.3	5.8	50.5	49.4
	A. M. S. D.	3.82 0.28		6.05 0.55		47.40 5.76

A.M.: arithmetic mean

S.D.: standard deviation

Validity criteria fulfilled:

yes

Conclusions:

It can be concluded that d-Phenothrin had no toxic effect on the algae up to its water solubility limit (<2 mg/L).

Executive summary:

d-Phenothrin had no toxic effect on the algae up to its water solubility limit (<2 mg/L).

Description of key information

d-Phenothrin was assessed for toxicity towards freshwater algae in a study performed according to OECD 201 and was found having no inhibitory effect on the algae up to its water solubility limit (>5 mg/L nominal concentration).

Key value for chemical safety assessment

EC50 for freshwater algae:

5 mg/L

EC10 or NOEC for freshwater algae:

5 mg/L