3,5,5-trimethylhexanal

Short-term toxicity to aquatic invertebrates

Administrative data

Endpoint:

short-term toxicity to aquatic invertebrates

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2009-01-22 until 2009-02-06

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

comparable to guideline study

Remarks:

Study conducted to GLP and in compliance with agreed protocolls, with minor deviations from standard guidelines and/or minor methodological deficiencies which does not effect the quality of the results

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2009

Report date:

2009

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Reference substance name:

3,5,5-trimethylhexanal

EC Number:

226-603-0

EC Name:

3,5,5-trimethylhexanal

Cas Number:

5435-64-3

Molecular formula:

C9H18O

IUPAC Name:

3,5,5-trimethylhexanal

Sampling and analysis

Analytical monitoring:

yes

Details on sampling:

Test substance was added in an amount above water solubility to the test water as described under Details on test solution

Test solutions

Vehicle:

no

Details on test solutions:

A stock solution was prepared by weighed out 100 mg/L and was shaken at 20 rpm for 24h at room temperature. After a separation of at least 1h the saturated solution was taken from the homogenous liquid phase. The saturated soluition were diluted 1:1 - 1:2 - 1:4 - 1:8 - 1:16.
Test concentrations were calculated from DOC analysis with the carbon content of 71.6%

Test organisms

Test organisms (species):

Daphnia magna

Details on test organisms:

TEST ORGANISM
- Common name: Daphnia magna STRAUS (Clone 5)
- Strain/clone: Straus (Clone 5)
- Source: Institut für Wasser-, Boden- und Lufthygiene (WaBoLu)TEST ORGANISM
- Age: 2 to 24 h old daphnids were used for the test. They were obtained by removing the mother animal twice within 22 h.
- Feeding during test: no

ACCLIMATION
- Acclimation period: at least 2 h in dilution water
- Acclimation conditions (same as test or not): in glass vessels with 1.8 L culture medium, 20 °C +/- 2 °C, 16 h light (20 µE/m2*s)
- Type and amount of food: unicellular green algae with a cell density of >10^6 cells/mL, ad libitum
- Feeding frequency: at least 5 times per week

Study design

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

48 h

Test conditions

Hardness:

Test medium (nominal) 0.24 mmol CaMg/l

Test temperature:

18 - 22 °C, +-1 °C constant

pH:

7.41 - 7.65

Dissolved oxygen:

7.93 - 8.19 mg/l

Salinity:

fresh water conditions

Nominal and measured concentrations:

A saturated solution was prepared by weighing out 100 mg/lwhich was shaken with 20 rpm for 24h at room temperature. After a separation phase of at least 1 h the saturated solution was taken from the homogenous liquid phase. Dilutions were tested. 1:1 - 1:2 - 1:4 - 1.8 - 1:16 ,nominal 100 - 50 - 25 - 12.5 - 6.25% of the saturated solution, concentrations verified by DOC analysis according to DIN EN 1484 at 0h and 48h.
Based on the mean measured DOC, the test item concentration were calculated to be 71.2 mg/L, 35.6 mg/L, 17.3 mg/L, 8.66 mg/L, and 4.61 mg/L, respectively

Details on test conditions:

TEST SYSTEM
- Test vessel: Glass beakers (4 cm ID x 7 cm H), 50 ml capacity
- Test volume: 20 mL
- Renewal rate of test solution (frequency/flow rate): no
- No. of organisms per vessel: 5 animals per test concentration and control
- No. of vessels per concentration (replicates): 4 samples
- No. of vessels per control (replicates): 4 samples


TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water:
- Total organic carbon:
- Culture medium different from test medium: Elendt M4 medium
- Intervals of water quality measurement: prior to the test start, the water quality parameter of the dilution water were measured (pH values, dissolved oxygen concentration, conductivity, total hardness, and temperature). The water quality parameter were also measured in the fresh media (0 h) and in the old media (48 h).

OTHER TEST CONDITIONS
- Adjustment of pH: no
- Photoperiod: 16 h light, 8 h dark cycle
- Light intensity: 20 µE/m2*s

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) : immobility

RANGE-FINDING STUDY
- Test concentrations: saturated solution 1:1 to 1:100 mg/L.
- Results used to determine the conditions for the definitive study: 100 % in the 1:1 dilution level. No immobilization at 1:10, 1:100 and in the control.

Reference substance (positive control):

yes

Remarks:

Potassium dichromate p.a. (Sigma)

Results and discussion

Effect concentrations

Effect concentrations 1

Key result

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

ca. 10.1 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Remarks on result:

other: CL 9.65 - 10.6

Effect concentrations 2

Duration:

48 h

Dose descriptor:

EC10

Effect conc.:

9 mg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

test mat.

Basis for effect:

mobility

Remarks on result:

other:

Remarks:

concentration based on DOC measurement.

Effect concentrations 3

Duration:

48 h

Dose descriptor:

NOEC

Effect conc.:

8.66 mg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

test mat.

Basis for effect:

mobility

Remarks on result:

other:

Remarks:

concentration based on DOC measurement

Details on results:

The saturated solution and all test dilutions were visually clear. The test item concentrations were calculated from the mean measured DOC concentrations taking the carbon content of 71.6 % into account.

In this study 3,5,5-trimethylhexanal was found to be toxic to Daphnia magna after 48h at concentrations of 17.3 mg/l (LOEC) and higher. The EC50 (48 h) was calculated to be 10.1 mg/L. The NOEC (48 h) is 8.66 mg/l. All effect values are based on the calculated concentration of mean measured DOC concentration.

EC10 (24/48h) 14.0 / 9.00 mg/l
EC50 (24/48h) 15.5/10.1 mg/l , 95% CL 15.1-16.0/9.65-10.6
EC100 (24/48h) 35.6/17.3 mg/l
NOEC (48h) 8.66 mg/l
LOEC (48h) 17.3 mg/l

Results with reference substance (positive control):

EC50: 1.53 mg/l (CL 1.43 - 1.65 mg/l)
In the prescribed range of 0.6 to 2.1 mg/L according to guideline.

Reported statistics and error estimates:

no

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Remarks:

No immobilized dahpnids in the control. Dissolved O2 concentration > 3mg/L.

Conclusions:

In this study 3,5,5-trimethylhexanal was found to be toxic to Daphnia magna after 48h at concentrations of 17.3 mg/l (LOEC) and higher. The NOEC is 8.66 mg/l and the EC50 was calculated with 10.1 mg/l. All values are based on DOC analysis.

Executive summary:

EC50 (48h) is calculated with 10.1 mg/l (CL 95% 9.65 - 10-6 mg/l) based on nominal concentrations.