2-chlorobenzaldehyde

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:

1986-08-05 - 1986-08-06

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: well performed study with some limitations in the experimental design (e.g. exposure period was 24h only)documentation (e.g oxygen concentrations in the vessels were not reported)

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)

Deviations:

yes

Remarks:

Test duration 24h

Qualifier:

equivalent or similar to guideline

Guideline:

ISO 6341 (Water quality - Determination of the Inhibition of the Mobility of Daphnia magna Straus (Cladocera, Crustacea))

Deviations:

yes

Remarks:

Test duration 24h

Principles of method if other than guideline:

The reevaluation/validation of older data from Hoechst (Report date 2008-09-04) is based on the raw data from 6.1.3/Hoechst_1986-08-27/W86-254. The test was performed according to DIN 38412, Part 11, a method related to OECD guideline 202 (I) but with a test duration of only 24 instead of 48 hours.

GLP compliance:

no

Analytical monitoring:

no

Vehicle:

no

Details on test solutions:

-Stock solution: saturated solution prepared by stirring a batch in water at room temperature and filtrating it through a folded paper filter;
- Concentration of stock solution: 630 mg DOC/L, correspoinding to 1053.3 mg/l 2-Chlorobenzaldehyde;

Test organisms (species):

Daphnia magna

Details on test organisms:

TEST ORGANISM
- Strain: Daphnia magna Straus
- Source: own laboratory breed
- Age at study initiation (mean and range, SD): >3h < 24h
- Method of breeding: Adult animals were cultivated in glass vessels (volume: 4 litres). The medium was changed once a week. Twice daily the animals were fed with algae (Scenedesmus supspicatus).

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

24 h

Test temperature:

21°C

pH:

Measured in additional test vessels of each test concentration

Dissolved oxygen:

Measured in additional test vessels of each test concentration

Nominal and measured concentrations:

Nominal concentrations: Dilution of the stock solution with 630 mg DOC/L, correspoinding to 1053.3 mg/l 2-Chlorobenzaldehyde
1:20 corresponding to 53 mg/L test substance;
1:25 corresponding to 42 mg/L test substance;
1:35 corresponding to 30 mg/L test substance;
1:44 corresponding to 24 mg/L test substance;
1:50 corresponding to 21 mg/L test substance;

Details on test conditions:

TEST SYSTEM
- Test vessel: 100 ml glass vessels;
- Test volume: 50 ml;
- No. of organisms per vessel: 10
- No. of vessels per concentration (replicates): 2
- No. of vessels per control (replicates): 4

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: Synthetic water according to DIN 38 412 Part 11
- Culture medium identical to test medium;

OTHER TEST CONDITIONS
- Photoperiod: 24h dark

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) : Immobilization after 24h

TEST CONCENTRATIONS
- Spacing factor for test concentrations: 1.25

Reference substance (positive control):

yes

Remarks:

Potassium dichromate

Duration:

24 h

Dose descriptor:

EC0

Effect conc.:

21 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Duration:

24 h

Dose descriptor:

EC10

Effect conc.:

24 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Key result

Duration:

24 h

Dose descriptor:

EC50

Effect conc.:

30 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Duration:

24 h

Dose descriptor:

EC100

Effect conc.:

53 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Results with reference substance (positive control):

After 24 hours the EC50 of potassium dichromate was between 0.9 mg/l to 1.9 mg/l which is in line with the range of 0.6 mg/l and 2.1 mg/l as required by OECD 2002 (2004).

Reported statistics and error estimates:

The EC0/EC10, EC50 and EC90/EC100 values were estimated graphically in a plot on the probability net.

Table 1: Immobilization rates of Daphnia magna exposed to 2-Chlorobenzaldehyde over a period of 24 hours

Dilution of the stock solution	Replicate	Number of daphnids exposed	Number of immobilized daphnids 24 h	Percentage of immobilized daphnids 24 h	Mean [%] 24 h
Control	1	10	0	0	0
	2	10	0	0
	3	10	0	0
	4	10	0	0
01:20	1	10	10	100	100
	2	10	10	100
01:25	1	10	9	90	95
	2	10	10	100
01:30	1	10	8	80	75
	2	10	7	70
01:40	1	10	5	50	40
	2	10	3	30
01:50	1	10	0	0	0
	2	10	0	0

Table 2: Number and percentage of immobilization of Daphnia magna after 24 hours exposed to the reference substance Potassium dichromate

Nominal test concen- tration [mg/l]	Replicate	Number of daphnids exposed	Number of immobilized daphnids	Percentage of immobilized daphnids	Mean [%]
0.9	1	10	3	30	30
	2	10	3	30
1.9	1	10	8	80	75
	2	10	7	70

−After 24 hours the EC50 of potassium dichromate was between 0.9 mg/l to 1.9 mg/l which is in line with the range of 0.6 mg/l and 2.1 mg/l as required by OECD 2002 (2004).

−The percentage of immobilized daphnids in the control was below 10%.

−Incubation time was only 24 hours, not 48 hours as required by OECD 2002 (2004).

The EC0/EC10, EC50 and EC90/EC100 values were estimated graphically in a plot on the probability net.

Results-Table 3: ECx values for the immobilization rate of Daphnia magna exposed to 2-Chlorobenzaldehyde over a period of 24 hours

Effect	24 h, Dilution of the stock solution	24 h, mg DOC/l	24 h, mg/l
EC0	01:50	12.6	21
EC10	01:44	14.3	24
EC50	01:35	18.0	30
EC90	01:25	25.2	42
EC100	01:20	31.5	53

Validity criteria fulfilled:

yes

Conclusions:

With the indicated test data the EC50 of 2-Chlorobenzaldehyde to Daphnia magna under the conditions of the test was estimated to be 30 mg/l. No immobilization was observed at the lowest test concentration of 21 mg/l.

Executive summary:

A toxicity test for 2 -Chlorobenzaldehyde with Daphnia magna Straus was performed close to OECD-guideline 202, albeit with 24h instead of 48h duration. The application of a reference substance (potassium dichromate) resulted in 24h EC50 between 0.9 and 1.9 mg/L, which is in line with the range of 0.6 mg/L and 2.1 mg/L as required by OECD guideline 202 (2004). Not more than 10 % of the daphnids of the control had been immobilized (mean of 4 controls 0% immobilization after 24h) and the dissolved oxygen had been measured albeit data are not recorded. With the indicated test data the EC50 of 2-Chlorobenzaldehyde (tested batch) to Daphnia magna under the conditions of the test was estimated to be 30 mg/l. No immobilization was observed at the lowest test concentration of 21 mg/l.

Description of key information

Test organism: Daphnia magna;
Test guideline: close to OECD 202;
Test duration: 24h;
EC50 Daphnia 30 mg/L 
Endpoint: immobilization;

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates

Effect concentration:

30 mg/L

Additional information

The reliable (with restrictions, RL 2) experimental key study was performed close to guideline OECD 202. The test duration however is only 24h (according to OECD 202 part I (1984)) insead of 48 h. The validity criteria are fulfilled and a reference substance (potassium dichromate) confirms the reliability of the study. The values for acute toxicity of 2 -Chlorobenzaldehyde on Daphnia magna are

EC0 = 21 mg/L

EC10 = 24 mg/L

EC50 = 30 mg/L.

No other experimental studies are available. QSAR results are not assignable due to the missing information on validation criteria. The result from the Danish EPA QSAR Database is 39 mg/L and based on the MULTICASE ACUTE AQUATIC TOXICITY model for which substance and organism are confirmed to be inside the model domain. This is very close to the experimental result.