Reaction product of 2-hydroxybenzoic acid, styrene and oxozinc

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:

2011-02-09 to 2011-05-02

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)

Qualifier:

according to guideline

Guideline:

EU Method C.2 (Acute Toxicity for Daphnia)

Qualifier:

according to guideline

Guideline:

EPA OPPTS 850.1010 (Aquatic Invertebrate Acute Toxicity Test, Freshwater Daphnids)

GLP compliance:

yes (incl. QA statement)

Analytical monitoring:

yes

Details on sampling:

- Concentrations:
Nominal Concentrations [% v/v saturated conc] = Control / 7.2 / 12.2 / 20.8 / 35.3 / 60
Geometric mean [mg/L] = 0.0 / 2.9 / 4.7 / 8.5 / 14.1 / 23.8

- Sampling: For determination of the test item concentration, samples were taken from test concentrations and control at start and end of the test.
- Storage of the Samples: The samples were analysed directly after sampling.
- Analytical Method: The quantification of the test item was performed by using an LC-MS method on a Zorbax Eclipse C18 column.

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION
Preliminary Test
As the test item could not be directly dissolved in the test medium (ISO medium) the test solutions were prepared by saturated solution method. A supersaturated test item stock solution (nominally 1000 mg/L) was prepared by dispersing/dissolving the test item amount into the test medium (ISO medium) one day before the start of the study (on day -1). This solution was shaken for about 24 hours, and thereafter the non-dissolved test material was removed by filtration through a fine filter to give the 100 % v/v saturated solution. The test solutions were prepared by appropriate diluting of the stock solution.

Main Test
A supersaturated test item stock solution (nominally 1000 mg/L) was prepared by dispersing/dissolving the test item amount into the test medium (ISO medium) one day before the start of the study (on day -1). This solution was shaken for about 24 hours and thereafter the non-dissolved test material was removed by filtration through a fine (pore size: 0.45 µm) filter to give the 100 % v/v saturated solution. The test solutions were prepared by appropriate diluting of the stock solution.

Test organisms (species):

Daphnia magna

Details on test organisms:

Daphnia magna (Straus)
- Less than 24 hours old
- Female
- Origin: National Institute of Public Health, Hungary

Breeding Conditions:
The Daphnia were bred in the laboratories of LAB Research Ltd. under similar temperature and light conditions as in the test, and in reconstituted water of a similar quality regarding to pH, components of the main ions and total hardness as the test water used in the test.

Acclimation:
- Conditions: Brood Daphnids were maintained in ISO medium under test conditions prior to the start of the test.
- Type and amount of food: a few mL of centrifuged algae suspension (Pseudokirchneriella subcapitata)
- Feeding frequency: daily

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

48 h

Post exposure observation period:

NA

Hardness:

CaCO3 = 249 mg/L

Test temperature:

20.7 – 21.2 °C (test vessels)
20.6 - 21.4 °C (climate chamber )

pH:

7.74 – 7.96

Dissolved oxygen:

6.7 – 6.9 mg/L

Nominal and measured concentrations:

Because a significant toxic response was observed during the preliminary range-finding test, five test concentrations in a geometric series (factor 1.7) and one control were used in the main test. The concentrations in the definitive test are based on the results of the preliminary range-finding test and were: 7.2; 12.2; 20.8; 35.3 and 60 % v/v saturated solution. The corresponding measured geometric mean test item concentrations were: 2.9; 4.7; 8.5; 14.1 and 23.8 mg/L. All reported biological results are related to the geometric mean of the measured test item concentrations during the experiment.

Details on test conditions:

TEST SYSTEM
- Test vessel: glass beakers, 40 mL test medium
- Renewal rate of test solution (frequency/flow rate): static
- No. of organisms per vessel: 5 animals
- No. of vessels per concentration (replicates): 4
- No. of vessels per control (replicates): 4

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: Test water -> Reconstituted Water: ISO media (during the breeding and during the test).
The ISO medium (according to OECD 202, 2004) was prepared by adding 25 mL each of the following stock solutions to deionised water.

OTHER TEST CONDITIONS
- Adjustment of pH: no
- Photoperiod: The test was carried out in 16-hour light and 8-hour dark cycle.

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) :
The immobility or mortality of the Daphnia was determined by visual observation after 24 and 48 hours. Those animals not able to swim within 15 seconds after gentle agitation of the test beaker were considered to be immobile.

TEST CONCENTRATIONS
- Spacing factor for test concentrations: 1.7
- Range finding study: yes
- Range finding study: Test concentrations (nominal): Control; 0.1; 1.0; 10; 50; 100 % v/v saturated solution
- Results used to determine the conditions for the definitive study: 0.0 (10/0); 0.1 (10/0); 1.0 (10/0); 10 (10/0); 50 (10/10); 100 (10/10) [ % v/v saturated solution]

Reference substance (positive control):

yes

Duration:

48 h

Dose descriptor:

EC100

Effect conc.:

14.1 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

mobility

Duration:

48 h

Dose descriptor:

LOEC

Effect conc.:

4.7 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

mobility

Duration:

48 h

Dose descriptor:

NOEC

Effect conc.:

2.9 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

mobility

Duration:

24 h

Dose descriptor:

EC50

Effect conc.:

5.4 mg/L

95% CI:

4.7 - 6.2

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

mobility

Key result

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

4.6 mg/L

95% CI:

4 - 5.3

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

mobility

Details on results:

- No behavioural abnormalities resp. other biological observations
- Immobility of control: 5%
- Other adverse effects control: none
- Abnormal responses: none

Results of range finding study used to determine the conditions for the definitive study:
0.0 (10/0); 0.1 (10/0); 1.0 (10/0); 10 (10/0); 50 (10/10); 100 (10/10) [ % v/v saturated solution]


Results main study:
0.0 (20/1); 7.2 (20/1); 12.2 (20/12); 20.8 (20/19); 35.3 (20/20); 60 (20/20) [ % v/v saturated solution], corresponding to measured mean concentrations of 0.0; 2.9; 4.7; 8.5; 14.1 mg/L

Results with reference substance (positive control):

The date of the last study with reference substance Potassium dichromate (K2Cr2O7) was 16-17 December 2010.
24h EC50: 1.61 mg/L (95 % confidence limits: 1.34 – 1.93 mg/L)

Reported statistics and error estimates:

The EC50 values were calculated by Probit analysis with 95 % confidence limits using TOXSTAT software. The NOEC (EC0), the LOEC and the EC100 were determined directly from the raw data. Biological results are related to the geometric mean of the measured test item concentrations during the test.

Validity criteria fulfilled:

yes

Conclusions:

In this 48-hour static acute toxicity test with Daphnia magna the 48 h EC50 value was determined as 4.6 mg/L, and the 48 h NOEC was determined as 2.9 mg/L. The results are based on the measured geometric mean concentrations.

Executive summary:

The purpose of this study was to evaluate the influence of the test item Reaction product of 2-hydroxybenzoic acid, styrene and oxozinc on the mobility respectively survival of Daphnia magna according to OECD TG 202 under GLP compliance. Young Daphnia were exposed in a static test to the test item for 48 hours. Test concentrations were prepared by appropriate diluting of a saturated stock solution. In a pre-test nominal concentrations up to 100, in the main study nominal concentrations of 7.2; 12.2; 20.8; 35.3 and 60 % v/v saturated solution, corresponding to calculated test item concentrations (based on the analytical measurements) of 2.9; 4.7; 8.5; 14.1 and 23.8 mg/L, respectively. The 48 h EC50 value was determined as 4.6 mg/L and the 48 h NOEC as 2.9 mg/L. The results are based on the measured geometric mean concentrations.

Description of key information

For Reaction product of 2-hydroxybenzoic acid, styrene and oxozinc the 48 h EC50 value was determined as 4.6 mg/L, the 48 h NOEC as 2.9 mg/L.

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates

Dose descriptor:

EC50

Effect concentration:

4.6 mg/L

Additional information

The purpose of this study was to evaluate the influence of the test item Reaction product of 2-hydroxybenzoic acid, styrene and oxozinc on the mobility respectively survival of Daphnia magna according to OECD TG 202 under GLP compliance. Young Daphnia were exposed in a static test to the test item for 48 hours. Test concentrations were prepared by appropriate diluting of a saturated stock solution. In a pre-test nominal concentrations up to 100, in the main study nominal concentrations of 7.2; 12.2; 20.8; 35.3 and 60 % v/v saturated solution, corresponding to calculated test item concentrations (based on the analytical measurements) of 2.9; 4.7; 8.5; 14.1 and 23.8 mg/L, respectively. The 48 h EC50 value was determined as 4.6 mg/L and the 48 h NOEC as 2.9 mg/L. The results are based on the measured geometric mean concentrations.