Butyraldehyde

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:

11 October 2022 to 28 February 2023

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2023

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)

Version / remarks:

April 2004

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Reference substance name:

Butyraldehyde

EC Number:

204-646-6

EC Name:

Butyraldehyde

Cas Number:

123-72-8

Molecular formula:

C4H8O

IUPAC Name:

butanal

Test material form:

liquid: volatile

Specific details on test material used for the study:

Identification: Butyraldehyde
CAS Number: 123-72-8
EC Number: 204-646-6

Molecular Formula: CH3CH2CH2CHO
Solubility: 50 g/L at 20 ℃
Vapour Pressure: 14.4 kPa at 20 ℃
pH: 3.8 as 10% (v/v) solution in water
Composition: Mono-constituent substance

Physical state / Appearance: Colorless liquid

Sampling and analysis

Analytical monitoring:

yes

Details on sampling:

- Concentrations: nominal concentrations were 10, 18, 32, 56, and 100 mg/L
- Sampling method: sampling was performed every 24h during the renewal period. Both new and aged samples were collected and analytically measured. The measured concentrations collected at the respective nominal tested concentrations were recorded.
- Sample storage conditions before analysis: Samples were instantly analyzed

Test solutions

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
the test item was prepared with the reconstituted water and Elendt M4 medium

Test organisms

Test organisms (species):

Daphnia magna

Details on test organisms:

TEST ORGANISM
- Common name: Daphnia magna
- Strain/clone: first instar Daphnia magna derived from in-house laboratory cultures

- Age at study initiation (mean and range, SD): <24h old

- Stage and instar at study initiation: first instar

- Method of breeding: Parthenogenesis
- Source: Labcorp in-house laboratory
- Feeding during test: Yes
- Food type: mixture of algal suspension (Raphidocelis subcapitata) and GEMMA Micro 300 fish food suspension
- Frequency: Each culture was fed daily

ACCLIMATION
- Acclimation period:
- Acclimation conditions (same as test or not):18 to 22 °C temperature, 16:8h light:dark condition
- Health during acclimation (any mortality observed): No

Any immobilization or adverse reactions to exposure were recorded at 24 and 48 hours after the start of exposure. The criterion of effect used was that Daphnia were considered to be immobilized if they were unable to swim within 15 seconds after gentle agitation

Study design

Test type:

semi-static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

48 h

Remarks on exposure duration:

test media renewal at 24 hours

Post exposure observation period:

N/A

Test conditions

Hardness:

2.5 mmol/L (= 250 mg/L as CaCO3)

Test temperature:

18 to 22 °C with a maximum deviation of ± 1 °C and a photoperiod of 16 hours light and 8 hours darkness for a period of 48 hours with 20-minute dawn and dusk transition periods.

pH:

7.7 to 8.2

Dissolved oxygen:

8.5 to 9.3

Salinity:

freshwater

Nominal and measured concentrations:

nominal concentrations of 10, 18, 32, 56, and 100 mg/L for 48 hours which were replaced by the mean measured concentrations of 7.4, 15, 26, 49 and 71 mg/L. respectively due to low recovery (less than 80%).

Details on test conditions:

TEST SYSTEM
- Test vessel: 120 mL glass vessels completely sealed and filled with 120 mL of test preparation were used
- Type (delete if not applicable): closed
- Material, size, headspace, fill volume: No headspace, completely sealed
- Volume of solution:120L
-Test water: Reconstituted water was prepared according to the OECD 202 TG (Elendt M4 medium) used for both the range-finding and definitive tests
- Aeration: No aeration was provided

- Type of flow-through (e.g. peristaltic or proportional diluter): semi-static condition
- Renewal rate of test solution (frequency/flow rate): 24h renewal
- No. of organisms per vessel: 5 animals in each replicate
- No. of vessels per concentration (replicates): Four replicates for the test concentrations
- No. of vessels per control (replicates): duplicates for control
- No. of vessels per vehicle control (replicates): no
- Biomass loading rate: N/A

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: Reconstituted water
- Alkalinity: 0.9 mmol/L
- Water hardness: 2.5mmol/L

- Salinity: N/A
- Culture medium different from test medium: No
- Intervals of water quality measurement: 24h

OTHER TEST CONDITIONS
- Adjustment of pH: No
- Photoperiod: 16:8h light:dark
- Light intensity: 904 to 951 Lux

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) : mobility of individual daphnid

VEHICLE CONTROL PERFORMED: No

RANGE-FINDING STUDY
- Test concentrations: nominal test concentrations of 1.0, 10 and 100 mg/L in a duplicate

- Results used to determine the conditions for the definitive study:
five daphnids were placed in each test and control vessel and maintained in a temperature controlled room maintaining the water temperature at 18 to 22 °C with a maximum deviation of ± 1 °C and a photoperiod of 16 hours light and 8 hours darkness. A semi-static condition was used with 24h renewal. test concentrations were freshly prepared.
A sample of each test concentration was taken for immediate chemical analysis at 0, 24 and 48 hours in order to determine the stability of the test item under test conditions

Reference substance (positive control):

yes

Remarks:

potassium dichromate as the reference item at concentrations of 0.32, 0.56, 1.0, 1.8 and 3.2 mg/L. The positive control was conducted between 22 March 2022 and 24 March 2022. Please refer to the Table 3, result section

Results and discussion

Effect concentrations

Effect concentrations 1

Key result

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

20 mg/L

95% CI:

18 - 22

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

mobility

Effect concentrations 2

Duration:

48 h

Dose descriptor:

NOEC

Effect conc.:

15 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

mobility

Effect concentrations 3

Duration:

48 h

Dose descriptor:

LOEC

Effect conc.:

26 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

mobility

Details on results:

The geometric mean measured test concentrations of the samples were calculated as follows:
0 1 C C = GM
Where:
GM = geometric mean measured test concentration (mg/L)
C0 = measured concentration at the start of the period of media renewal (mg/L)
C1 = measured concentration at the end of the period of media renewal (mg/L)
The geometric mean measured concentrations for each period of media renewal were determined (0 to 24 and 24 to 48 hour) and the mean of the two values calculated

No sub-lethal effects of exposure were observed in the control, 7.4 or 15 mg/L test concentrations throughout the test. Reduced mobility was observed at test concentrations of 26, 49 and 71 mg/L at 24 hours

Results with reference substance (positive control):

N/A

Reported statistics and error estimates:

The EC50 values and associated confidence limits at 24 and 48 hours and the slope of the response curve and its standard error were calculated by Probit analysis using Linear Maximum-Likelihood regression. The Lowest Observed Effect Concentration (LOEC) and the No Observed Effect Concentration (NOEC) at 24 and 48 hours were calculated using the Step-down Cochran-Armitage Test Procedure incorporating Tarone’s Test Procedure and Qualitive Trend Analysis by Contrasts. All results were calculated using the ToxRat Professional computer software package.

Any other information on results incl. tables

Table 1: Cumulative Immobilization Data and Observations in the Range-finding Test

Nominal Concentration (mg/L)	Observations (Initial Population: 5 Per Replicate)
	24 Hours				48 hours
	Cumulative Immobilized Daphnia		Observations		Cumulative Immobilized Daphnia		Observations
	R1	R2	R1	R2	R1	R2	R1	R2
Control	0	0	5N	5N	0	0	5N	5N
1.0	0	0	5N	5N	0	0	5N	5N
10	0	0	5N	5N	0	0	5N	5N
100	5	5	AI	AI	5	5	AI	AI

R = Replicate
N = Normal
AI = All Daphnia immobilized

Table 2 Cumulative Immobilization Data and Observations in the Definitive Test

 

Geometric Mean Measured Test Concentration (mg/L)	24 Hours
	Cumulative Immobilized Daphnia (Initial Population: 5 Per Replicate)						Observations
	R1	R2	R3	R4	Total	%	R1	R2	R3	R4
Control	0	0	0	0	0	0	5N	5N	5N	5N
7.4	0	0	0	0	0	0	5N	5N	5N	5N
15	0	0	0	0	0	0	5N	5N	5N	5N
26	3	2	0	0	5	25	2R	3R	2R3N	4R1N
49	5	3	1	1	10	50	AI	2R	2R2N	1R3N
71	5	4	1	4	14	70	AL	1R	4R	1R

 

Geometric Mean Measured Test Concentration (mg/L)	48 Hours
	Cumulative Immobilized Daphnia (Initial Population: 5 Per Replicate)						Observations
	R1	R2	R3	R4	Total	%	R1	R2	R3	R4
Control	0	1	0	0	1	5	5N	4N	5N	5N
7.4	0	0	0	0	0	0	5N	5N	5N	5N
15	0	0	0	0	0	0	5N	5N	5N	5N
26	5	5	5	5	20	100	AI	AI	AI	AI
49	5	5	5	5	20	100	AI	AI	AI	AI
71	5	5	5	5	20	100	AI	AI	AI	AI

Rx = Replicate
N = Normal
R = Reduced mobility
AI = All Daphnia immobilized

Table 3: Potassium Dichromate (Positive control) result

Time points (hours)	EC50 (mg/L)	95% Confidence Limits (mg/L)	No Observed Effect Concentration (mg/L)	Lowest Observed Effect Concentration (mg/L)
24	1.3	1.2-1.5	1.0	1.8
48	0.96	0.82-1.1	0.32	0.56

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Remarks:

The results of the test are considered valid if the following performance criteria are met: 1. No more than 10% of the control daphnids show immobilization 2.The DO concentration at the end of the test is > 3 mg/L in Control & test vessels

Conclusions:

Exposure of freshwater invertebrate Daphnia magna to the test item has been investigated and the NOEC and EC50 was derived based on the mean measured concentrations. The endpoint was the mobility of the daphnia sp.
EC50: 20 mg/L, 95% confidence limit (18 to 22 mg/L)

Executive summary:

Daphnia sp., 48-Hour Acute Immobilization Test-OECD 202 was performed on n-Bal. In the study, <24h old daphnia were used. A range-finding study was performed with 3 different concentrations 1.0, 10, and 100mg/L. a definitive study with 5 different concentrations was conducted thereafter to investigate the EC50 (mg/L) where the selected nominal concentrations were 10, 18, 32, 56, and 100 mg/L for 48 hours which were replaced by the mean measured concentrations of 7.4, 15, 26, 49 and 71 mg/L. respectively due to low recovery (less than 80%). The EC50 derived was based on the immobility of daphnia which is 20 mg/L, (95% confidence limit 18 to 22 mg/L).