Estr-4-ene-3,17-dione

Toxicity to microorganisms

Link to relevant study record(s)

Reference

Endpoint:

activated sludge respiration inhibition testing

Type of information:

experimental study

Adequacy of study:

key study

Study period:

1995

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Reason / purpose for cross-reference:

reference to other study

Qualifier:

according to guideline

Guideline:

DIN 38412-8 (Pseudomonas Zellvermehrungshemmtest)

Deviations:

no

GLP compliance:

yes

Analytical monitoring:

yes

Vehicle:

no

Details on test solutions:

Preparation of the test solutions:
- A suspension with a nominal concentration of 1000 mg/l was stirred for 24 hours and filtered through a glassfibre filter to give a saturated solution and to serve as the highest test concentration
- The stock solution was further diluted (1:10, 1:100, and 1:1000)
- One control without the test substance was used

Test organisms (species):

Pseudomonas putida

Details on inoculum:

I. Culturing of the test organism and preparation of inoculum
- Source: German Collection of Microorganisms and Cell Cultures, Braunschweig (Germany)
- Maintenance and Acclimatisation: kept on slant agar containing a nutrient solution at approximately 25 °C, during culturing transferred weekly

II. Preparation of the pre-culture for the inoculum:
- Age: microorganisms for the pre-culture were taken from a stock up to seven days old, approximately 7 hours prior to the start of the incubation
- Maintenance and Acclimatisation: kept in a pre-culture nutrient solution consisting of 25 mL solution 1, 25 mL solution 3 and 50 ml solution 4; . 900 mL sterile distilled water were added
- Turbidity of the pre-culture: 0.054 extinction units (equivalent to approximately TE/F 10) on the spectrophotometer
- Incubation time: 7 hours at room temperature
- Turbidity of the pre-culture after the incubation period: diluted to 0.214 extinction units (equivalent to approximately TE/F 50) with the pre-culture
medium

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

16 h

Hardness:

No data

Test temperature:

21.1 °C (at the beginning)
21.5 °C (at the end)

pH:

No data

Dissolved oxygen:

n.a.

Salinity:

n.a.

Nominal and measured concentrations:

10, 100, and 1000 mg/L (nominal)
1000 mg/L (nominal) corresponding to 189 mg/L (TOC)

Details on test conditions:

TEST DESIGN:
- All test solutions including the control were incubated in triplicate
- For each test concentration one test vessel was incubated without addition of the inoculum in order to analyse the inherent turbidity of the test compound
- The concentration of the stock solution was estimated by a TOC-analysis (189 mg/L)
- The temperature of one control test vessel was measured at the beginning and at the end of the exposure time
- As a parameter for the growth of the bacterial population, the turbidity of the test and control solutions was analysed photometrically at a wave-Iength of 436 nm

Reference substance (positive control):

no

Key result

Duration:

16 h

Dose descriptor:

EC10

Effect conc.:

> 189 mg/L

Nominal / measured:

meas. (initial)

Conc. based on:

test mat.

Basis for effect:

growth inhibition

Validity criteria fulfilled:

yes

Conclusions:

Estr-4-ene-3,17-dione in a saturated solution (approximately 189 mg/L) had no inhibitory effect on the growth of Pseudomonas putida. The increase in growth is not considered relevant in terms of aquatic toxicity. Furthermore, the test is not designed for the evaluation of growth-stimulating effects .

Executive summary:

The purpose of this study was to determine the effects on the growth of the bacterium Pseudomonas putida. The study was conducted in agreement with the standard DIN 38412 L8, March 1991. The test substance was incubated in an aqueous solution including nutrients with a bacterial population of Pseudomonas putida for a test duration of approximately 16 hours. The nutrient solution was made up of mainly nitrate, phosphates, carbohydrates, some trace elements and vitamins. For the preparation of the test solutions a suspension with a nominal concentration of 1000 mg/L was prepared and stirred for 24 hours. This suspension was filtered through a glassfibre filter to give a saturated solution and to serve as the highest test concentration. In order to prepare the additional test solutions, the stock solution was further diluted (1:10, 1:100, and 1:1000). Additionally, one control without the test substance was used. All test solutions including the control were incubated in triplicate. Furthermore, for each test concentration one test vessel was incubated without addition of the inoculum in order to analyse the inherent turbidity of the test compound. The concentration of the stock solution was estimated by a TOC-analysis and subsequent calculation based on the structural formula. It was estimated with approximately 189 mg/L. As a parameter for the growth of the bacterial population, the turbidity of the test and control solutions was analysed photometrically at a wave-length of 436 nm. The measurements showed that there was no growth inhibition of the bacterial population. The growth was highest in the saturated solution.

Description of key information

The substance in a saturated solution (approximately 189 mg/L) had no inhibitory effect on the growth of Pseudomonas putida. The increase in growth is not considered relevant in terms of aquatic toxicity. Furthermore, the test is not designed for the evaluation of growth-stimulating effects .

Key value for chemical safety assessment

EC10 or NOEC for microorganisms:

189 mg/L

Additional information

"Should read: > 189 mg/L"