Pyridine-2-carbaldehyde

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:

2001-10-03 to 2001-10-05

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)

Deviations:

no

Qualifier:

according to guideline

Guideline:

EU Method C.2 (Acute Toxicity for Daphnia)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Remarks:

(THE DEPARTMENT OF HEALTH OF THE GOVERNMENT OF THE UNITED KINGDOM)

Analytical monitoring:

yes

Details on sampling:

- Concentrations : Water samples were taken from the control (replicates R1 — R2 pooled) and the 1.0, 3.2, 10, 32 and 100 mg/l test groups (replicates R1 — R2 pooled) at 0 and 48 hours for quantitative analysis.

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
- Method:
An amount of test material (200 mg) was dissolved in reconstituted water with the aid of ultrasonic disruption for approximately 5 minutes and the volume adjusted to 2 litres to give the 100 mg/l test concentration from which dilutions were made to give the remainder of the test series of 1.0, 1.8, 3.2, 5.6, 10, 18, 32 and 56 mg/I.
Each prepared concentration was inverted several times to ensure adequate mixing and homogeneity.
The Sponsor indicated that the test material might be light sensitive and therefore the test material was weighed under a non-actinic light source.

Test organisms (species):

Daphnia magna

Details on test organisms:

TEST ORGANISM
- Common name : water flea
- Strain : in-house culture
- Age at study initiation : < 24 h
- Feeding during test : none

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

48 h

Hardness:

The reconstituted water had an approximate theoretical total hardness of 250 mg/l as CaCO3.

Test temperature:

21°C , measured at test start and after 24 and 48 h in every test vessel and the control .

pH:

7.9 - 8.3 , measured at test start and after 48 h in every test vessel and the control .

Dissolved oxygen:

8.1 - 8.4 mg O2/l , (91 - 94% saturation) , measured at test start and after 48 h in every test vessel and the control .

Nominal and measured concentrations:

Analysis of the test preparations at 0 and 48 hours (see table 1) showed measured test concentrations to range from 95% to 120% of nominal value with the exception of the 1.0 mg/I test concentration that showed a measured value of 63% of nominal at 48 hours. Given that at 0 hours a measured value of 101% of nominal was obtained and that this test concentration was below the No Observed Effect Concentration of 1.8 mg/1, it was considered that this low result did not affect the validity or integrity of the results. Therefore it was considered justifiable to calculate the EC50 values in terms of the nominal test concentrations only.

Details on test conditions:

TEST SYSTEM
- Test vessel
- Type : Test vessels were covered to reduce evaporation .
- Material, size, fill volume: 250 ml glass jars containing approximately 250 ml test solution .
- Aeration: no
- Renewal rate of test solution : The test solutions were not renewed
- No. of organisms per vessel: 10
- No. of vessels per concentration (replicates): 2
- No. of vessels per control (replicates): 2
- The test vessels were shielded from the light.

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: reconstituted water *
* Stock Solutions
a) CaCl2 . 2H2O : 11.76 g/l
b) MgSO4 . 7H2O : 4.93 g/l
c) NaHCO3 : 2.59 g/l
d) KCl : 0.23 g/l
Preparation: An aliquot (25 ml) of each solution a-d were added to each litre (final volume) of deionised water with a conductivity of < 5 µS cm-1 . The reconstituted water had a pH of 7.8 +/- 0.2 , adjusted (if necessary) with NaOH or HCl and was aerated until the dissolved oxygen concentration was approximately air-saturation value .

OTHER TEST CONDITIONS


EFFECT PARAMETERS MEASURED : Any immobilisation 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 immobilised if they were unable to swim for approximately 15 seconds after gentle agitation.

TEST CONCENTRATIONS
- Range finding study
- Test concentrations: 0.10 , 1.0 , 10 and 100 mg/l
An amount of test material (100 mg) was dissolved in reconstituted water with the aid of ultrasonic disruption for approximately 5 minutes and the volume adjusted to 1 litre to give the 100 mg/I test concentration from which serial dilutions were made to give the remainder of the test series of 0.10, 1.0 and 10 mg/l .
Each prepared concentration was inverted several times to ensure adequate mixing and homogeneity.
The Sponsor indicated that the test material might be light sensitive and therefore the test material was weighed under a non-actinic light source.

- Results used to determine the conditions for the definitive study: No immobilisation was observed at the test concentrations of 0.10 and 1.0 mg/l . However, after 24 and 48 hours exposure, 30% and 100% immobilisation respectively was observed at the test concentration of 100 mg/l and 100% immobilisation was observed at 10 mg/l after 48 hours . Based on this information test concentrations of 1.0, 1.8, 3.2, 5.6, 10, 18, 32, 56 and 100 mg/l were selected for the definitive study.

Reference substance (positive control):

no

Duration:

24 h

Dose descriptor:

EC50

Effect conc.:

80 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Remarks on result:

other: 95% Confidence limit : 66-100 mg/l

Key result

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

6.9 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Remarks on result:

other: 95% Confidence limit : 5.6-8.3 mg/l

Duration:

24 h

Dose descriptor:

NOEC

Effect conc.:

32 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

other: zero immobilisation

Duration:

48 h

Dose descriptor:

NOEC

Effect conc.:

1.8 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

other: zero immobilisation

Validity criteria fulfilled:

yes

Remarks:

The study was performed in compliance with UK GLP standards (Schedule 1, Good Laboratory Practice Regulations 1999 (SI 1999/3106)). These Regulations are in accordance with GLP standards published as OECD Principles on Good Laboratory Practice

Conclusions:

The study is regarded as a valid guideline study with certificated GLP compliance. The acute toxicity of Pyridine-2-aldehyde to the freshwater invertebrate Daphnia magna has been investigated and resulted in a 48-h EC50 value of 6.9 mg/L with 95% confidence limits of 5.6-8.3 mg/L. The 48-h NOEC was determined with 1.8 mg/L.

Executive summary:

The acute toxicity to aquatic invertebrates of Pyridine-2-aldehyde was tested according to OECD guideline 202 and EU Method C.2 in a static freshwater test with Daphnia magna as test organisms, which is a freshwater invertebrate representative of a wide variety of natural habitats, and can therefore be considered as an important non-target organism in freshwater ecosystems. The study was conducted under certificated GLP compliance. In-house laboratory cultures of the test animals were used, whereby young daphnids, less than 24 h old were used for testing. These daphnids were not individually identified and received no food. The test concentration to be used in the definitive test was determined by a preliminary range-finding test. Based on this range-finding study, the definitive test was conducted with test concentrations of 1.0, 1.8, 3.2, 5.6, 10, 18, 32, 56 and 100 mg/L. Duplicate test vessels were used for each test and control group. No aeration was performed.The Sponsor indicated that the test material might be light sensitive and therefore the test material was weighed under a non-actinic light source and the test vessels were shielded from the light. No evidence of undissolved substance was observed, since all preparations were clear, colourless solutions. This solutions were not renewed during the exposure period. The vessels were covered to reduce evaporation and maintained at 21.0 °C in a temperature controlled room for a test duration of 48 hours. No reference substance is required in accordance to the test guideline.

The EC50 value was determined as 6.9 mg/L with 95 % Confidence limits of 5.6-8.3 mg/L. The corresponding NOEC was determined with 1.8 mg/L. Gas Chromatography (GC) was the analytical method of choice. Analysis of the test preparations at 0 and 48 hours showed measured test concentrations to range from 95% to 120% of nominal value with the exception of the 3.2 mg/L test concentration that showed a measured value of 63% of nominal at 48 hours. Given that at 0 hours a measured value of 101% of nominal was obtained and that this test concentration was below the NOEC of 1.8 mg/L, it was considered that this low result did not affect the validity or integrity of the results. Therefore it was considered justifiable to calculate the EC50 values in terms of the nominal test concentrations only.

Description of key information

A 48 -h EC50 value of 6.9 mg/L for the freshwater invertebrate Daphnia magna was determined for the test item under the conditions of the test. It was determined in a reliable study conducted according to an appropriate standard test method (OECD 202).

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates

Effect concentration:

6.9 mg/L