Androst-4-ene-3,17-dione, 1-methyl-, (1.alpha.)-

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:

May - Sept 2000

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: According to guideline under GLP

Cross-reference

Cross-reference 1

Reason / purpose for cross-reference:

reference to same study

Cross-reference 2

Reason / purpose for cross-reference:

reference to other study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2001

Report date:

2001

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 201 (Alga, Growth Inhibition Test)

Deviations:

no

Principles of method if other than guideline:

Not relevant

GLP compliance:

yes

Test material

Test material information

Constituent 1

Reference substance name:

1 alpha-Methyl-4-androstene-3,17-dione

EC Number:

609-915-5

Cas Number:

4136-62-3

Molecular formula:

C20 H28 O2

IUPAC Name:

1 alpha-Methyl-4-androstene-3,17-dione

Details on test material:

- Name of test material (as cited in study report): 1-Alpha-Methylandrostendion
- Analytical purity: 98.7%
- Lot/batch No.: 1365

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.:

0.014 mg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

test mat.

Basis for effect:

biomass

Effect concentrations 2

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

0.057 mg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

test mat.

Basis for effect:

growth rate

Any other information on results incl. tables

Table 1: Inhibition of biomass and the growth rate (%) of Desmodesmus subspicatus after 72 hours exposure to ZK 62096

		Inhibition in %
Dilution of ZK 62096 of saturated solution	Concentration of ZK 62096 (mg/L)	Biomass	Growth rate
0	0,0 (control)	0	0
1:800	0,05	64,8	40
1:400	0,11	87,5	91,1
1:200	0,21	84,9	94,5
1:100	0,42	89,9	112,4
1:50	0,85	91,9	120,4
1:30	1,41	94,8	137,7

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Conclusions:

ZK 62096 had a concentration-depended inhibitory effect on the growth of Desmodesmus subspicatus. The EbC50 (biomass) was 0.014 mg/L
(95% confidence limits were not calculated). The ErCso (growth rate) was 0.057 mg/L (95% confidence limits were not calculated) on the basis
of concentrations extrapolated from TOC measurement of the stock solution. Consequently, ZK 62096 was considered to be very toxic to the
green algae Desmodesmus subspicatus, since the EbC50/ ErC50 were below 1 mg/L.

Executive summary:

The purpose of this study was to determine the effects of the test compound ZK 62096 on the growth of the green algae Desmodesmus subspicatus. 1-Alpha-Methylandrostendion is an intermediate of the synthesis of mesterolone. The study was conducted in agreement with the test guideline OECD no. 201.

The test substance 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. The nutrient solution was made up of mainly nitrate, phosphates and some trace elements. For the preparation of the test solutions a suspension with a nominalloading of 100 mg/L test substance in water was treated in an ultrasonic bath for 30 minutes and thereafter stirred for 24 hours at room temperature. This suspension was filtered through a glassfibre filter. The resulting solution (stock solution) was diluted

1 :20 (predilution). This predilution was further diluted 1: 1.5, 1 :2.5, 1 :5, 1: 1 0, 1 :20 and 1 :40 with demineralized water. Additionally, a control solution was prepared with demineralized water without test material. The organic carbon concentration of the undiluted stock solution was analyzed with a TOC analyzer at the start of the incubation. The substance concentration was calculated on the basis of the molecular formula. It was 42.4 mg/L. The further test concentrations were extrapolated from the result of the TOC-analysis and are shown in the table below. The algae were exposed to each concentration in triplicate. Six vessels were prepared for the control. The algae were incubated under continuous light, controlled temperature and standard conditions. As a parameter for the growth of the algae population, the fluorescence of the algal cells was measured with a fluorescence-photometer. The increase of biomass and the growth rate were calculated on the basis of the fluorescence. The calculated biomass and growth rate of each concentration were compared to those of the controls, and the inhibition was calculated.

The biomass and growth rate was inhibited at all concentrations (65 to 95% for the biomass and 40 to 100% for the growth rate). This was considered to be a compound related effect.