3'H-Cycloprop[15,16]androsta-5,15-dien-17-one, 3-(2,2-dimethyl-1-oxopropoxy)-15,16-dihydro-7-hydroxy-, (3.beta.,7.beta.,15.alpha.,16.alpha.)-

Toxicity to aquatic algae and cyanobacteria

Administrative data

Endpoint:

toxicity to aquatic algae and cyanobacteria

Type of information:

experimental study

Adequacy of study:

other information

Study period:

Sept 2000

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: According to OECD guideline under GLP

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2000

Report date:

2003

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 201 (Alga, Growth Inhibition Test)

Deviations:

no

GLP compliance:

yes

Test material

Test material information

Constituent 1

Reference substance name:

7 beta-Hydroxy-15 beta,16 beta-methylene-3 beta-pivaloyloxy-5-androsten-17-one

EC Number:

617-344-8

Cas Number:

82543-09-7

Molecular formula:

C25 H36 O4

IUPAC Name:

7 beta-Hydroxy-15 beta,16 beta-methylene-3 beta-pivaloyloxy-5-androsten-17-one

Details on test material:

- Name of test material (as cited in study report): Methylenpivalat (ZK 90506)
- Analytical purity: 98.8%
- Lot/batch No.: 14634001

Sampling and analysis

Analytical monitoring:

yes

Test solutions

Vehicle:

no

Test organisms

Test organisms (species):

Desmodesmus subspicatus (previous name: Scenedesmus subspicatus)

Study design

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

72 h

Results and discussion

Effect concentrations

Effect concentrations 1

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

0.3 mg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

test mat.

Basis for effect:

biomass

Remarks on result:

other: 0.2-0.5

Effect concentrations 2

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

> 3.6 mg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

test mat.

Basis for effect:

growth rate

Any other information on results incl. tables

Inhibition of biomass and the growth rate (%) of Desmodesmus subspicatus after 72 hours exposure to ZK90506

Dilution of ZK 90506	Concentration of ZK 90506 (mg/L)	Inhibition in percent
		Biomass (integral)	Growth
Control	control	0	0
1:100	<0,1	33	4,8
1:50	0,1	28,4	3,6
1:25	0,2	37,1	8,8
1:10	0,4	49,3	1,1
1:5	0,7	66,2	29,2
Saturated solution	2,9	79	32,6

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Conclusions:

ZK 90506 produced an inhibition effect on the growth of Scenedesmus subspicatus at almost all
concentrations. Due to the EC50 below 1 mg/L, ZK 90506 can be considered to be very toxic to
Desmodesmus subspicatus.

Executive summary:

The purpose of this study was to determine the effects of the test compound Methylenpivalat (ZK 90506) on tbe growth ofthe green algae Desmodesmus subspicatus. ZK 90506 is an intermediate ofthe synthesis of drospirenone. The study was conducted in agreement with the test guideline OECD no. 201.

The test substance ZK 90506 was incubated in an aqueous solution including nutrients with an algae population of Desmodesmus subspicatus for a test duration of approximately 72 hours in an electronically controlled dosing and incubation apparatus.

For the preparation of the test solutions a suspension with a nominal loading of 100 mg/L ZK 90506 in water was ultrasonified and constantly stirred for 24 hours at room temperature. The resulting solution served as the highest concentration (equivalent to saturated solution), which was a 1: 1.25 dilution by adding nutrient solution and inoculum. It was further diluted 1: 1 00, 1 :50, 1 :25, 1 :10 and 1:5 with demineralized water.

The biomass and growth rate was inhibited at almost all concentrations. This was considered to be a compound related effect.

ZK 90506 had a concentration-depended inhibitory effect on the growth of Desmodesmus subspicatus. The EbC50 (biomass) was 0.3 mg/L [95% confidence limits: 0.2-0.5], the ErC50 (growth rate) was higher than the solubility limit. Consequently, ZK 90506 was considered to be very toxic to the green algae Desmodesmus subspicatus, since the EC50 (biomass ) was lower than 1 mg/L.