alkylphenol isomere mixture

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:

2021-08-24 until 2021-11-11 (experimental phase)

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

EU Method C.2 (Acute Toxicity for Daphnia)

Version / remarks:

Version: 2008

Qualifier:

according to guideline

Guideline:

OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)

Version / remarks:

Version: 2004

GLP compliance:

yes (incl. QA statement)

Analytical monitoring:

yes

Details on sampling:

Sampling method: 1, 4 at 0 and 48 hours and 16 mg/L at 0 and 24 hours, control at 48 hours
Sample storage conditions before analysis: The samples were analysed immediately after sampling.

Vehicle:

no

Details on test solutions:

A stock solution was prepared to give the desired series of test concentrations. 100.4 mg of the test item were added to a 1 litre portion of dilution water, treated for 60 seconds at 8000 rpm with an ultra turrax and stirred for 24 h on a magnetic stirrer. Undissolved particles of the test item were removed by filtration using a folded filter with a pore size of 7 - 12 µm and an aseptic filter Sartobran sterile capsules (membrane material: cellulose acetate) with a pore size of 0.45 µm (pre-filter) + 0.2 µm (main filter).
The solution was dissolved and no particles were still visible (no Tyndall effect was observed). The pH was measured to be 7.9.

To produce the different test item concentrations appropriate amounts of the stock solution were diluted with dilution water to a volume of 500 mL. 50 mL of the prepared solutions were taken per replicate and 0.5 mL of dilution water containing 5 daphnids was given to all replicates resulting in the final nominal concentrations. For each test item exposure concentration and for the control exposure 4 replicates were prepared.

Test organisms (species):

Daphnia magna

Details on test organisms:

Daphnia magna STRAUS, parthenogenetic females
Source: Strain of Bundesgesundheitsamt Berlin
Maintenance and Acclimatisation : A population of parthenogenetic females of synchronized age structure has been maintained for more than 20 years in the test facility under constant temperature conditions (20 +/- 2 °C) at a 16 : 8 hour light : dark photoperiod (light intensity: < 20 μE x m-2 x s-1). The culture water (so-called 'M4 medium') was partly renewed once a week. The Daphnia were exclusively fed unicellular green algae (Desmodesmus subspicatus) 'ad libitum'. Mortalities of parent Daphnia during the culture period were recorded daily. The neonates were separated from their parent Daphnia by filtration prior to the acute test.

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

48 h

Hardness:

The total hardness of the dilution water, measured at test start, was 13.8 °dH (= 246 mg/L CaCO3).

Test temperature:

20.8 - 21.8 °C

pH:

7.9 - 8.1

Dissolved oxygen:

8.6 - 8.8 mg/L

Nominal and measured concentrations:

1, 2, 4, 8 and 16 mg/L (nominal)
corresponding to 0.681, 1.245, 2.453, 4.979 and 9.172 mg/L (initial measured values)
Comments: The test item concentrations 2 and 8 mg/L were based on the analytical mean of the nominal test item concentrations 1, 4 and 16 mg/L at test start.

Details on test conditions:

TEST SYSTEM
- Test vessel: 100 mL glass beakers
- Type (delete if not applicable): closed: covered with watch glasses
- Material, size, headspace, fill volume: 50 mL test medium in glass beakers
- Aeration: none
- No. of organisms per vessel: 5 neonates
- No. of vessels per concentration (replicates): 4 replicates
- No. of vessels per control (replicates): 4 replicates

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: Reconstituted water (so-called 'M4 medium' according to OECD 202 and EC Method C.2, annex 1) was used for the maintenance of the test animals and for the preparation of stock and test solutions of the test item.

OTHER TEST CONDITIONS
- Adjustment of pH: none
- Photoperiod: 16 h light: 8 h dark
- Light intensity: < 20 µE x m-2 x s-1

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) : The criterion of adverse effects used in this study was the item-induced alteration of the normal mobility behaviour and the loss of locomotory actions of the neonates, observed at 24 and 48 hours.

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

5 mg/L

Nominal / measured:

meas. (initial)

Conc. based on:

test mat. (dissolved fraction)

Basis for effect:

mobility

Remarks on result:

other: see details on results

Details on results:

Measured test item exposure concentrations ranged from 57.2 % to 68.2 % of their nominal target values at 0 hours, from 53.5 % to 54.1 % of their nominal target values at 24 hours and from 55.2 % to 62.3 % of their nominal target values at 24 hours.

The effect concentrations were calculated by probit analysis based on the mean measured initial start concentrations.

The EC 50 was calculated by probit analysis using the statistics programme ToxRatPro Version 2.10 (released 2010-09-10). Additionally, any abnormal behaviour or appearance of the Daphnia was reported.

Validity criteria fulfilled:

yes

Remarks:

- immobilisation/ other abnormalities in the controls did not exceed 10 % by the end of the test. - dissolved oxygen concentration remained above 3 mg/L - the pH of exposure solutions did not change by more than ± 1.5 units from their initial values

Conclusions:

The acute toxicity of 'reaction products of m-cresol and propene, high boiling alkylphenol isomers' to Daphnia magna STRAUS was assessed in a study under static conditions. A 48h-EC50-value of 5.0 mg/L was determined.

Executive summary:

A study was performed to assess the acute toxicity of 'reaction products of m-cresol and propene, high boiling alkylphenol isomers' to Daphnia magna STRAUS under static conditions. The study was conducted in accordance with the Council Regulation (EC) No 440/2008, Method C.2 ‘Acute toxicity for Daphnia’ (2008) which is equivalent to OECD Guideline for Testing of Chemicals No. 202 'Daphnia sp., Acute Immobilisation Test' (adopted April 13, 2004).

The Daphnia were exposed to a range of concentrations, nominally 1, 2, 4, 8 and 16 mg/L corresponding to 0.681, 1.245, 2.453, 4.979 and 9.172 mg/L (initial measured values) of m-cresol and propene, high boiling alkylphenol isomers dissolved in dilution water. Auxiliaries used to prepare the test media were an ultra turrax, a magnetic stirrer and a folded filter (pore size 7-12 µm) and an aseptic filter (pore size 0.45 µm (pre-filter) + 0.2 µm (main filter).

Observations were made on the swimming ability and the percentage immobilised, respectively, after 24 and 48 hours of exposure. The following effect related value was determined: 48h-EC50: 5.0 mg/L.

The results are expressed in terms of measured initial concentrations. Since the recoveries of the analysis accompanying the test are in the same range at the end of the test as at the start of the test, reference is made to the initial concentration at the start of the test.

Description of key information

A study was performed to assess the acute toxicity of 'reaction products of m-cresol and propene, high boiling alkylphenol isomers' to Daphnia magna STRAUS under static conditions. The study was conducted in accordance with the Council Regulation (EC) No 440/2008, Method C.2 ‘Acute toxicity for Daphnia’ (2008) which is equivalent to OECD Guideline for Testing of Chemicals No. 202 'Daphnia sp., Acute Immobilisation Test' (adopted April 13, 2004).

The Daphnia were exposed to a range of concentrations, nominally 1, 2, 4, 8 and 16 mg/L corresponding to 0.681, 1.245, 2.453, 4.979 and 9.172 mg/L (initial measured values) of m-cresol and propene, high boiling alkylphenol isomers dissolved in dilution water. Auxiliaries used to prepare the test media were an ultra turrax, a magnetic stirrer and a folded filter (pore size 7-12 µm) and an aseptic filter (pore size 0.45 µm (pre-filter) + 0.2 µm (main filter).

Observations were made on the swimming ability and the percentage immobilised, respectively, after 24 and 48 hours of exposure. The following effect related value was determined: 48h-EC50: 5.0 mg/L.

The results are expressed in terms of measured initial concentrations. Since the recoveries of the analysis accompanying the test are in the same range at the end of the test as at the start of the test, reference is made to the initial concentration at the start of the test.

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates

Dose descriptor:

EC50

Effect concentration:

5 mg/L