Benzenepropanal, 2-methyl-4-(2-methylpropyl)-

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:

19 May, 2015 to 01 October, 2015

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study with acceptable restrictions

Qualifier:

according to guideline

Guideline:

OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)

Version / remarks:

April, 2004

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Specific details on test material used for the study:

NYMPHEAL (GR-88-0778) :
Lot No. : Batch 6
Purity : 98.6% (principal component)
Date of Expiry : 29 March, 2017

Analytical monitoring:

yes

Remarks:

GC-MS

Details on sampling:

A semi-static set-up was employed.

Samples of the 5 exposure levels, C1 to C5, were taken for extraction and analysis, as follows :
- Fresh exposure medium : Time 0 and 24 hours;
- Aged exposure medium : 24 hours and 48 hours.

Samples of the Control and Solvent Control were sampled for analysis at Time 0 (fresh) and 48 hours (aged).

Vehicle:

yes

Remarks:

Stock solutions prepared in Acetone. Maximum loading in exposure media = 0.1 mL/L.

Details on test solutions:

Following a Range-Finding study, the Following Nominal test concentrations were chosen for the definitive study :
C1 0.476 mg/L
C2 0.857 mg/L
C3 1.54 mg/L
C4 2.78 mg/L
C5 5.00 mg/L

The exposure solutions were prepared using standards prepared in Acetone as a vehicle. Since NYMPHEAL is a primary aldehyde, and, therefore, susceptible to undergo rapid oxidation, it was decided to avoid long, drawn-out exposure medium preparation techniques (e.g. slow-stirring to obtain water saturated fraction).

Test organisms (species):

Daphnia magna

Details on test organisms:

Daphnia magna STRAUS (clone M10), in-house culture.

Holding Conditions :
- Vessel : Glass vessel, 1.8 L
- Medium : Elendt M4
- medium renewal Twice per week
- Temperature : 20 +/- 2°C
- Photoperiod : 16 h light / 8 h dark
- Light Intensity : 50 to 1000 Lux
- Food : Algae (D. subspicatus)

On the day of the test start, neonate daphnids were separated from the parental daphnids which were kept in the selected holding vessels.

Test type:

semi-static

Water media type:

freshwater

Remarks:

Medium : Elendt M4

Limit test:

no

Total exposure duration:

48 h

Hardness:

254 mg/L CaCO3

Test temperature:

20.4 to 20.9 °C

pH:

pH 7.7 to 7.8

Dissolved oxygen:

8.7 to 9.0 mg O2/L

Conductivity:

680 microS/cm

Nominal and measured concentrations:

The water samples were simultaneously analysed for the residue of the Parent, and the corre-sponding alcohol (GR-88-1108) and acid (GR-88-1910).

NYMPHEAL was not stable in the exposure solutions over the 24-hour renewal period. The concentrations determined in the Fresh medium samples varied in the range of 79 to 123 % of Nominal, and, 43 - 111% of Nominal in the 24 hour old medium.1

The Time-Weighted Mean Measured concentrations of the Parent over the 96-hour exposure period were, as follows :

Exposure Level Time-Weighted Mean Concn.
Control Not Detected
Solvent Control Not Detected
C1 (0.476 mg/L) 0.298 mg/L
C2 (0.857 mg/L) 0.621 mg/L
C3 (1.54 mg/L) 1.09 mg/L
C4 2.78 mg/L) 2.97 mg/L
C5 (5.00 mg/L) 5.67 mg/L

Amounts of the Acid Metabolite were detected in the 24 hour aged samples (between 10 and 20% of the sapplied dose), and, only one detect of the Alcohol metabolite. Although total equivalent concentrations have been reported in the Final report, the end-points reported hereinare related to Parent, only.

Details on test conditions:

Age of exposed Daphnids : < 24 hours old
Test duration : 48 hours
Medium : Elendt M4
Biological Parameters : Immobility
Test temperature : 18 - 22 °C
Test vessels : 60 mL glass beakers
Volume of Test Solution : 50 - 60 mL
Number of daphnids per Vessel : 5
Number of replicates per test concentration : 4
Number of Control replicates : 4
Renewal Semi-static (renewal Following 24 hours)
Photoperiod : 16 h light / 8 h dark
Aeration : None

Reference substance (positive control):

yes

Remarks:

Potassium Dichromate

Key result

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

1.01 mg/L

Nominal / measured:

meas. (TWA)

Conc. based on:

test mat.

Basis for effect:

mobility

Remarks on result:

other: 95% Confidence Interval Limits : 0.874 - 1.25 mg/L

Duration:

48 h

Dose descriptor:

NOEC

Effect conc.:

0.621 mg/L

Nominal / measured:

meas. (TWA)

Conc. based on:

test mat.

Basis for effect:

mobility

Remarks on result:

other:

Details on results:

100% of daphnids were observed to be immobilised in the two highest test concentrations by 48 hours (C4 and C5) and 60% immobilisation at C3 (nominal test concentration of 1.54 mg/L).

Results with reference substance (positive control):

The reference test with Potassium Dichromate performed in September 2014 resulted in an EC50 (24 hour) of 1.11 mg/L, which is within the values obtained in the inter-laboratory validation (0.6 to 2.1 mg/L).

Validity criteria fulfilled:

yes

Conclusions:

The 48 hour EC50 for Daphnia magna exposed to NYMPHEAL was determined to be 1.01 mg/L.

Executive summary:

The 48 hour EC50 for Daphnia magna exposed to NYMPHEAL was determined to be 1.01 mg/L

.

Description of key information

OECD 202 - Acute Daphnia Immobillisation :

EC50 (48 hr) = 1.01 mg/L

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates

Effect concentration:

1.01 mg/L

Additional information

OECD 202 - Acute Daphnia Immobillisation :

EC50 (48 hr) = 1.01 mg/L

.