Estr-5(10)-en-17-one, 3,3-dimethoxy-

Short-term toxicity to aquatic invertebrates

Link to relevant study record(s)

Reference

Endpoint:

short-term toxicity to aquatic invertebrates

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2000

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Reason / purpose for cross-reference:

reference to same study

Reason / purpose for cross-reference:

reference to other study

Qualifier:

according to guideline

Guideline:

OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)

Deviations:

no

Principles of method if other than guideline:

not relevant

GLP compliance:

yes

Analytical monitoring:

yes

Vehicle:

no

Test organisms (species):

Daphnia magna

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

48 h

Key result

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

10 mg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

test mat.

Basis for effect:

mobility

Remarks on result:

other: 7.8 - 12.2

Duration:

48 h

Dose descriptor:

NOEC

Effect conc.:

4.8 mg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

test mat.

Basis for effect:

mobility

Table 1: Cumulative immobilization (%) of Daphnia magna (n = 20) after exposure to ZK 235382

Dilution/measured concentration of ZK 235382 (mg/L)	24 hours	48 hours
Control (tap water) / 0	0	0
1:16 / 1,1	0	0
1:8 / 2,6	0	5
1:4 / 4,8	0	5
1:2 / 10,0	15	50
Saturated solution / 20,0	90	100

Validity criteria fulfilled:

yes

Conclusions:

The EC50/48 hours of Dimethoxyketal to Daphnia magna was calculated to be 10.0 mg/L [95% confidence limits (7.8-12.2)] on the basis of
measured concentrations. The highest concentration with no (substance-related) effects was 4.8 mg/L. Accordingly, ZK 235382 can be considered as toxic to Daphnia magna.

Executive summary:

The purpose of the study was to determine the acute toxicity (immobilization, EC50/48 hours) of Dimethoxyketal (ZK 235382) with Daphnia magna in order to evaluate the aquatic toxicity. ZK 235382 is an intermediate of the synthesis of norgestrel. The study was conducted as a definitive test according to the following guidelines of the OECD, no 202.

20 juvenile Daphnia magna were used for each test solution of ZK 235382 and 20 for the tap water control. The Daphnia were exposed for a period of 48 hours under static conditions. Immobilization was recorded at 24 hours and 48 hours. Controlled standard conditions regarding oxygen, pH and temperature were maintained. For the preparation of the test solutions a suspension with a nominal loading of 100 mg/L was kept from 15 min in an ultrasonic bath and stirred for 24 hours. This suspension was filtered through a glassfibre filter. It was further diluted 1 :2, 1 :4, 1:8 and 1 :16 to produce the test solutions. Samples for the concentration analysis by HPLC in combination with UV detection were taken at o and 48 hours after start of exposure. The analytical results gave a mean concentration of 20.0 mg/L for the saturated solution and the expected dilution pattern.

Immobilized Daphnia were observed at the test concentration 2.6 mg/L and higher.

Description of key information

The EC50/48 hours of Dimethoxyketal to Daphnia magna was calculated to be 10.0 mg/L [95% confidence limits (7.8-12.2)] on the basis of

measured concentrations. The highest concentration with no (substance-related) effects was 4.8 mg/L. Accordingly, ZK 235382 can be considered as toxic to Daphnia magna.

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates

Dose descriptor:

EC50

Effect concentration:

10 mg/L

Additional information

48h-NOEC: 4.8 mg/L