Fatty acids, safflower-oil, Et esters

Toxicity to microorganisms

Administrative data

Endpoint:

activated sludge respiration inhibition testing

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2010-07-01

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: GLP guideline study without restrictions

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2010

Report date:

2010

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

OECD Guideline 209 (Activated Sludge, Respiration Inhibition Test

Version / remarks:

, 1984

Deviations:

no

Test guideline 2

Qualifier:

according to guideline

Guideline:

ISO 8192 (Water quality - Test for inhibition of oxygen consumption by activated sludge for carbonaceous and ammonium oxidation)

Version / remarks:

, 2007

Deviations:

no

GLP compliance:

yes

Test material

Test material information

Constituent 1

Reference substance name:

Fatty acids, safflower-oil, Et esters

EC Number:

293-106-3

EC Name:

Fatty acids, safflower-oil, Et esters

Cas Number:

91051-53-5

IUPAC Name:

Fatty acids, safflower-oil, Et esters

Details on test material:

- Name of test material (as cited in study report): C-SAT 100042
- Analytical purity: 75 % ethyl linoleate
- Lot/batch No.: S300660001
- Physical state: hazy yellow liquid

Sampling and analysis

Analytical monitoring:

no

Test solutions

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION:
Since the test substance was hardly soluble in water test concentrations were prepared separately in Milli-RO water. Two 1-litre test bottles were filled with 250 mL of test substance mixtures with initial loading rates of 200 mg/L. These mixtures were stirred in closed dark brown glass bottles for 25 hours. Following overnight stirring period the synthetic sewage feed (16 mL) and the activated sludge (200 mL) were added to the test substance mixture. Milli-RO water was added to provide a final volume of 500 mL with a final test substance loading of 100 mg/L. Two controls without test substance were tested in each test series. Optimal contact between the test substance and test medium was ensured applying continuous aeration and stirring during the 3-hour exposure period. Thereafter, oxygen consumption was measured and recorded for approximately 10 minutes.

Test organisms

Test organisms (species):

activated sludge, domestic

Details on inoculum:

- Laboratory culture: Activated sludge from the municipal sewage treatment plant “Waterschap As en Maas”, s-Hertogenbosch, The Netherlands, receiving predominantly domestic sewage.
- Preparation of inoculum for exposure: The sludge was coarsely sieved washed and diluted with ISO-medium. A small amount of the sludge was weighed and dried overnight at ca. 150°C to determine the amount of suspended solids (3.8 g/L of sludge as used for the test). The batch of sludge was used one day after collection; 50 mL of a synthetic sewage feed was added per litre of activated sludge at the end of the collection day. The sludge was kept aerated at test temperature until use.
Initial biomass concentration: Number of microorganisms was determined as amount of Mixed Liquor Suspended Solids (MLSS) per litre test medium.
Adjusted ISO medium: formulated using RO-water (tap-water purified by reverse osmosis, GEON Waterbehandeling, Berkel-Enschot, The Netherlands)

Study design

Test type:

static

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

3 h

Test conditions

Test temperature:

18.3 - 18.9 °C

Nominal and measured concentrations:

Nominal: 100 mg/L

Details on test conditions:

TEST SYSTEM
- Test vessel (size): 1-litre
- Oxygen bottles (size): approximately 300 mL
- Material, size, headspace, fill volume: glass, 500 mL (fill volume)
- Aeration: no
- No. of vessels per concentration (replicates): 2
- No. of vessels per control (replicates): 2
- Biomass loading rate: 3.8 g/L activated sludge

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: Milli-RO/Milli-Q water (Tap-water purified by reverse osmosis (Milli-RO) and subsequently passed over activated carbon and ion-exchange cartridges (Milli-Q) (Millipore Corp. Bedford Mass. USA)).

Reference substance (positive control):

yes

Remarks:

3,5-dichlorophenol

Results and discussion

Effect concentrations

Duration:

3 h

Dose descriptor:

EC50

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

inhibition of total respiration

Remarks:

respiration rate

Results with reference substance (positive control):

The EC50 of 3,5-dichlorophenol is in the range of 5 - 30 mg/L.

Applicant's summary and conclusion

Validity criteria fulfilled:

yes