Androsta-1,4-diene-17-carbothioic acid, 6,9-difluoro-11-hydroxy-16-methyl-3-oxo-17-(1-oxopropoxy)-, (6.alpha.,11.beta.,16.alpha.,17.alpha.)-

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:

20th May 2003 - 3rd April 2004

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)

Deviations:

no

GLP compliance:

yes

Specific details on test material used for the study:

Test Substance:
Test substance name: Thio-Acid Propionate
Sponsor batch number: H030714
Purity: 100%
Description: White/off-white crystalline solid
Storage: 10-20°C (avoid prolonged storage at elevated temperatures above 20°C). Avoid direct sunlight.
Expiry date: Not stated
Water solubility: <10g/l at 20°C
Date received: 26 April 2003

Details on sampling:

Juvenile Daphnia magna, (less than 24 hours old), were taken from a laboratory culture maintained at Covance Laboratories Ltd. The culture was originally obtained from Sheffield University, Sheffield, UK.
The water in each culture was renewed weekly. All cultures, prior to and during toxicity tests, were maintained under fluorescent lighting on a 16-hour light: 8-hour dark photo-period.

Details on test solutions:

At the start of the exposure period, the prepared test media appeared as a colourless solution. After 48 hours, the appearance of the test media was unchanged.

Test organisms (species):

Daphnia magna

Details on test organisms:

The daphnia magna were cultured in 600mL glass beakers containing 500mL of standard hard water. Each culture vessel and its contents were referred to as a "culture". New cultures were started with juvenile Daphnia magna (less than 24 hours old), at a density of approximately 20 animals per litre. Each of the cultures was fed daily with a concentrated suspension of Chlorella culgaris (a unicellular green algae). The Chorewlla vulgaris was obtained from a fermenter-based culture, grown under semi-axenic conditions at Covance Laboratories Ltd in accordance with Covance's Standard Operating Procedures. A seaweed extract (Ascophyllum nodosum) prepared in accordance with Covance's Standard Operating Procedures was added once a week (at medium renewal) to each culture as a dietary supplement.

Test type:

static

Water media type:

other: ASTM water

Total exposure duration:

48 h

Remarks on exposure duration:

After 24 and 48 hours, the numbers of immobilised Daphnia magna were recorded. The Daphnia magna were considered immobile if, when the contents of the test vessel were agitated, active swimming was not observed during a 15-second period of observation.

Hardness:

Total hardness as CaCO3 (mg/L): 163

Test temperature:

20-21.1°C

pH:

7.4-7.7

Dissolved oxygen:

Dissolved oxygen (% air saturated value): 85-97

Nominal and measured concentrations:

The definitive test was conducted at the nominal Thio-Acid propionate exposure concentrations of 6.3, 12.5, 25, 50 and 100mg/L.

Key result

Duration:

24 h

Dose descriptor:

EC50

Effect conc.:

> 100 mg/L

Conc. based on:

test mat.

Key result

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

> 100 mg/L

Conc. based on:

test mat.

Details on results:

At the start of the exposure period, the prepared test media appeared as a colourless solution. After 48 hours, the appearance of the test media was unchanged.

Toxicity to Daphnia Magna:
At 24 hours, immobile Daphnia magna were observed in the control, 6.3, 25, 50 and 100 mg/L treatments. In the 12.5mg/L treatment, there were 3 Daphnia magna recorded immobile out of 20 exposed, corresponding to 15% immobility.

At 48 hours, no immobile Daphnia magna were observed in the control, 50 and 100 mg/L treaments. In the 6.3, 12.5 and 25mg/L treatments there were 1, 2 and 3 immobile Daphnia magna recorded respectively, corresponding to 5, 10 and 15% immobility respectively.

As there was no signficant immobility observed during the definitive test, the 24 and 48 hour EC50 values, and the corresponding no observed effect concentration (NOEC) for Daphnia magna exposed to Thio-Acid Propionate could not be determined. Therefore the 24 and 48 hour EC50 values are considered to be >100 mg/L, the highest nominal exposure concentration in the definitive test.

Observations of Daphnia magna after 24 hours exposure to Thio-Acid Propionate:

Nominal Thio-Acid Propionate concentration (mg/L)	Number of Daphnia magna	Mobile Daphnia (Bottom)	Mobile Daphnia (Surface)	Immobile Daphnia (Bottom)	Immobile Daphnia (Surface)
Control	20	20	-	-	-
6.3	20	20	-	-	-
12.5	20	17	-	3	-
25	20	20	-	-	-
50	20	20	-	-	-
100	20	20	-	-	-

Observations of Daphnia magna after 48 hours exposure to Thio-Acid Propionate:

Nominal Thio-Acid Propionate concentration (mg/L)	Number of Daphnia magna	Mobile Daphnia (Bottom)	Mobile Daphnia (Surface)	Immobile Daphnia (Bottom)	Immobile Daphnia (Surface)
Control	20	20	-	-	-
6.3	20	19	-	1	-
12.5	20	18	-	2	-
25	20	17	-	3	-
50	20	20	-	-	-
100	20	20	-	-	-

Validity criteria fulfilled:

yes

Conclusions:

As there was no significant immobility observed during the definitive test, the 24 and 48 hour EC50 values, and the corresponding no observed effect concentration (NOEC) for Daphnia magna exposed to Thio-Acid Propionate could not be determined. Therefore the 24 and 48 hour EC50 values are considered to be >100 mg/L, the highest nominal exposure concentration in the definitive test.

Executive summary:

The acute toxicity of Thio-Acid Prionate to Daphnia magna was determined at 20 +/- 2°C in a 48-hour static (without renewal of the test media) definitive test.

The definitive test was conducted at the nominal Thio-Acid propionate exposure concentrations of 6.3, 12.5, 25, 50 and 100mg/L. The range of concentrations was selected based on the results of a range finding limit test, which is not reported.

Four replicate vessels were prepared at each concentration with each vessel containing five juvenile Daphnia magna.

In the definitive test, the 100mg/L test media was prepared by adding 0.1048g to a 1 litre volumetric flask and making up to volume with ASTM. The flask contents were treated with ultrasound for 30 minutes and stirred for approximately 1 hour on a magnetic stirrer. The remaining exposure concentrations were prepared by serial dilution of the 100mg/L test medium.

Due to the low numbers of Daphnia magna immobilised during the test, a 48 hour EC₅₀toxicity value could not be calculated. Therefore, the 48 hour EC₅₀value and corresponding no observed effect concentration (NOEC) are assumed to be >100mg/L for Thio-Acid Propionate, the hightest nominal exposure concentration tested.

Description of key information

The acute toxicity of Thio-Acid Prionate to Daphnia magna was determined at 20 +/- 2°C in a 48-hour static (without renewal of the test media) definitive test.

The definitive test was conducted at the nominal Thio-Acid propionate exposure concentrations of 6.3, 12.5, 25, 50 and 100mg/L. The range of concentrations was selected based on the results of a range finding limit test, which is not reported.

Four replicate vessels were prepared at each concentration with each vessel containing five juvenile Daphnia magna.

In the definitive test, the 100mg/L test media was prepared by adding 0.1048g to a 1 litre volumetric flask and making up to volume with ASTM. The flask contents were treated with ultrasound for 30 minutes and stirred for approximately 1 hour on a magnetic stirrer. The remaining exposure concentrations were prepared by serial dilution of the 100mg/L test medium.

Due to the low numbers of Daphnia magna immobilised during the test, a 48 hour EC₅₀toxicity value could not be calculated. Therefore, the 48 hour EC₅₀value and corresponding no observed effect concentration (NOEC) are assumed to be >100mg/L for Thio-Acid Propionate, the hightest nominal exposure concentration tested.