Glyoxylic acid

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

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

EU Method C.2 (Acute Toxicity for Daphnia)

Deviations:

no

Qualifier:

according to guideline

Guideline:

OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Remarks:

RCC Ltd - Zelgliweg 1 - 4452 Itingen/Switzerland

Analytical monitoring:

yes

Details on sampling:

For the determination of the actual test item concentrations, duplicate samples were taken from each treatment befor the start of the test and at the end of the test after 48 hours.
For the 48-hour stability samples, the contents of the respective replicates were combined prior to sampling.
All samples were stored deep-frozen (at about -20 °C) immediately after sampling.

Vehicle:

yes

Details on test solutions:

The test medium of the highest nominal concentration of 200 mg/L was prepared by dissolving 301.7 mg of test item completely in 1500 mL of test water using intense stirring for 15 minutes at room temperature. Adequate volumes of this test medium were diulted with test water to prepare the test media with the lower test item concentrations. The test media were prepared just before introduction of the daphnids (i.e., start of the test).

Test organisms (species):

Daphnia magna

Details on test organisms:

The study was performed with young daphnids of the species Daphnia magna Straus. A clone of this species (defined by the supplier as clone 5) was originally supplied by the University of Sheffield/UK in 1992. Since that time, the clone has been bred in the Laboratories of RCC in reconstitued water of the quality identical to the water quality used in the tests (in respect to pH, main ions, and total hardness) and under temperature and light conditiosn identical to those of the test. A the start of the test, the organisms used in the test were 6-24 hours old and were not first brood progeny.
For evaluation of the quality of the daphnia clone and the experimental conditions, potassium dichromate is tested as a positive control twice a year.

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

48 h

Post exposure observation period:

48 h

Hardness:

2.5

Test temperature:

20 °C

pH:

The pH of the test medium with the highest test concentration of nominal 200 mg/L was 4.0 after the test item application. The pH was adjusted to 6.2 with 25 drops of a 1 M sodium hydroxide solution.

Nominal and measured concentrations:

The following nonimal concentrations of Glyoxylic acid 50 % were tested: 9.3, 20, 43, 93 and 200 mg/L.
Additionally, a control was tested in parallel (test water without test item). Nominal concentrations above 200 mg/L were not tested.

Details on test conditions:

For each treatment, 20 daphnids were used divided into four replicates of five daphnids each.
The volume of test solution provided for each daphnia was 10 mL. Thus, the requirement of the test guidelines for the minimum volume of 2 mL test medium per daphnia was fulfilled. The daphnids were randomly distributed to the test vessels at initiation of the test.
For further information see section "Any other information on materials and methods incl. tables".

Reference substance (positive control):

yes

Remarks:

potassium dichromate

Duration:

48 h

Dose descriptor:

NOEC

Effect conc.:

200 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Duration:

48 h

Dose descriptor:

EC0

Effect conc.:

200 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

> 200 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Duration:

48 h

Dose descriptor:

EC100

Effect conc.:

> 200 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Duration:

48 h

Dose descriptor:

NOEC

Effect conc.:

> 200 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Details on results:

The analytically determined concentration of the test item in the analyzed test medium (nominal 200 mg/L test item) at the start and the end of the test was 85 and 81 % of the nominal value, respectively. Under the conditions of the test, the test item Glyoxylic acid 50 % was sufficiently stable during the test period of 48 h.
Therefore, all reported results are related to the nominal concentration of the test item Glyoxylic acid 50 % and Glyoxylic acid (concentration in brackets).
In the control and at the test concentrations up to and including the nominal concentration of 200 mg/L (100.3 mg/L), no immobilized test organisms were observed during the test period of 48 hours.
Therefore, the 48-hour NOEC and the 48-hour EC0 to Daphnia magna were determined to be at least 200 (100.3) mg/L.
The 48-hour NOEC and the 48-hour EC0 might even be higher but concentrations above 200 (100.3) mg/L. The 48-hour EC50 and the 48-hour EC100 were clearly hiher than 200 (100.3) mg/L.
These values could not be quantified due to the absence of toxicity at the test concentration up to and including the nominal concentration of 200 (100.3) mg/L.
No remarkable observations were made concerning the appearance of the test media. All test media were clear solutions throughout the entire test duration.
At the beginning and the end of the test period, the dissolved oxygen concentrations in the test media and the control were at least 8.1 mg/L, the pH value of the test medi was in the range of 6.2 to 7.8 (after adjustment) and the water temperature during the test was in the range of 20°C.

Results with reference substance (positive control):

For evaluation of the quality of the daphnia clone and the experimental conditions, potassium cichromate is tested as a positive control twice a year.
- Results with reference substance valid: yes, (historical range of the RCC laboratory 1996-2007: 48-h EC50 : 0.53-1-1 mg/L)
- EC50/LC50: 0.84 mg/L (last test June 2007)

Validity criteria fulfilled:

yes

Conclusions:

The 48-hour NOEC and the 48-hour EC0 to Daphnia magna were determined to be at least 200 (100.3) mg/L.
The 48-hour EC50 and the 48-hour EC100 were clearly higher than 200 (100.3) mg/L.
These values could not be quantified due to the absence of toxicity at the test concentration up to and including the nominal concentration of 200 (100.3) mg/L

Executive summary:

The acute toxicity of the test item Glyoxylic acid 50 % to Daphnia magna was determined in a 48 -hour static test according to the EU Commission Directive 92/69/EEC, Part C.2 (1992) and the OECD Guideline for Testing of Chemicals, No 202 (2004).

The nominal test item (Glyoxylic acid 50 %) concentrations tested were 9.3, 20, 43, 93 and 200 mg/L. A control group was tested in parallel.

The analytically determined concentration of the test item in the analyzed test medium (nominal 200 mg/L) at the start and the end of the test was 85 and 81 % of the nominal value, respectiveley. Under the conditions of the test, the test item Glyoxylic acid 50 % was sufficiently stable during the test period of 48 hours. Therefore, all reported results are related to the nominal concentration of the test item Glyoxylic acid 50 % and Glyoxylic acid (concentration in brackets).

In the control and at the test concentrations up to and including the nominal concentration of 200 mg/L (100.3 mg/L), no immobilized test organisms were observed during the test period of 48 hours.

Therefore, the 48-hour NOEC and the 48-hour EC0 to Daphnia magna were determined to be at least 200 (100.3) mg/L. The 48-hour NOEC and the 48-hour EC0 might even be higher but concentrations above 200 (100.3) mg/L were not tested. The 48 -hour EC50 and the 48 -hour EC100 were clearly higher than 200 (100.3) mg/L. These values could not be quantified due to the absence of toxicity at the test concentration up to and including the nominal concentration of 200 (100.3) mg/L.

Description of key information

In the control and at the test concentrations up to and including the nominal concentration of 200 mg/L (100.3 mg/L), no immobilized test organisms were observed during the test period of 48 hours.

Therefore, the 48-hour NOEC and the 48-hour EC0 to Daphnia magna were determined to be at least 200 (100.3) mg/L. The 48-hour NOEC and the 48-hour EC0 might even be higher but concentrations above 200 (100.3) mg/L were not tested. The 48 -hour EC50 and the 48 -hour EC100 were clearly higher than 200 (100.3) mg/L. These values could not be quantified due to the absence of toxicity at the test concentration up to and including the nominal concentration of 200 (100.3) mg/L.

Additional information

The acute toxicity of the test item Glyoxylic Acid 50 % to Daphnia magna was determined in a 48 -hour static test according to OECD TG 202 (2004) and GLP.

The nominal test item (Glyoxylic Acid 50 %) concentrations tested were 9.3, 20, 43, 93 and 200 mg/L. A control group was tested in parallel.

The analytically determined concentration of the test item in the analyzed test medium (nominal 200 mg/L) at the start and the end of the test was 85 and 81 % of the nominal value, respectiveley. Under the test conditions Glyoxylic Acid 50 % was sufficiently stable during the test period of 48 hours. Therefore, all reported results are related to the nominal concentration of the test item Glyoxylic Acid 50 % and Glyoxylic Acid (concentration in brackets).