17β-hydroxy-1α-methylandrost-4-ene-3-one

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:

Oct 1996

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: According to OECD 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:

1998

Report date:

1998

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:

17β-hydroxy-1α-methylandrost-4-ene-3-one

EC Number:

210-063-8

EC Name:

17β-hydroxy-1α-methylandrost-4-ene-3-one

Cas Number:

604-26-2

Molecular formula:

C20H30O2

IUPAC Name:

17-hydroxy-1-methylandrost-4-en-3-one

Details on test material:

- Name of test material (as cited in study report): 1-Alpha-Methyltestosteron
- Analytical purity: 98.9%
- Lot/batch No.: 21600303

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

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

2.8 mg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

test mat.

Basis for effect:

growth rate

Any other information on results incl. tables

The EC50 for biomass could not be calculated due to the pattern of the concentration effect curve.

Table 1: Inhibition of the growth of Scenedesmus subspicatus after 72 hours exposure to ZK 9227

		Inhibition (%)
Dilution of ZK 9227	Concentration (mg/L)	Biomass	Growth
0	0	0	0
1:100	0.2	18.3	8.9
1:50	0.3	-104.1	-16.3
1:25	0.7	-227.5	-22.7
1:12.5	1.3	-84.9	-10.5
1:6.25	2.7	54.2	27.6
1:3.125	5.4	86.8	69.6

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Conclusions:

ZK 9227 had an inhibitory effect on the growth of Scenedesmus subspicatus close to a
saturated solution. The EC50 for biomass could not be calculated due to the pattern of the
concentration effect curve. The ErC50 (growth rate) was 2.8 mg/L (confidence intervals could not
be calculated). ZK 9227 was toxic to algal growth.

Executive summary:

The purpose of this study was to determine the effects of the test compound 1 -Alpha-Methyltestosteron (ZK 9227) on the

growth of the green algae Scenedesmus subspicatus. The study was conducted in agreement with the OECD guideline no. 201.

The test substance was incubated in an aqueous solution including nutrients with an algae population of Scenedesmus subspicatus for a test duration of appraximately 72 hours. The nutrient solution was made up of mainly nitrate, phosphates and some trace elements.

The test concentrations were dilutions of a saturated solution 1 :3.13, 1 :6.3, 1: 12.5, 1 :25 and 1 :50 and a control. The algae were exposed to each concentration in triplicate. Six vessels were prepared for the control.

The substance content of the saturated solution was determined on the basis of a TOC-analysis (16.8 mg/L).

The algae were incubated in an incubator shaker under continuous light.

As a parameter tor the growth of the algae population, the cell concentrations of the test and control solutions were counted with an electranic particle counter ("Coulter Counter").

The increase of biomass and the growth rate were calculated on the basis of the cell counts. The calculated biomass and growth rate of each concentration were compared to those of the controls, and the inhibition was calculated.

The cell counts showed a decrease at 0.2 mg/I, an increase of algae cells at 0.3 and 0.7, while

in the higher test concentrations a decrease in cell growth could be observed. However, due to the large variation in the replicates particularly of the controls, an effect could only be established at the highest test concentration.

The ErC50 (growth rate) was 2.8 mg/L (confidence intervals could not be calculated).