[No public or meaningful name is available]

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:

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)

Specific details on test material used for the study:

SOURCE OF TEST MATERIAL
- Source and lot/batch number of test material: 4133/00-K0
- Expiration date of the lot/batch: June 07, 2021
- Purity test date: Certificate of analysis dated December 03, 2020
- Content: 1.82 % Pt
- Form: liquid
- Appearance: Clear, yellowish liquid

Analytical monitoring:

yes

Details on sampling:

Samples with five different nominal concentrations of 6.25, 12.5, 25.0, 50.0 and 100 mg test item/L were analysed. Sampling took place at the test start, after 24 hours and at the end of the test (48 h).

Vehicle:

no

Details on test solutions:

For preparation of test solutions, at first a stock solution was prepared by adding an appropriate amount of the test item to 1 L dilution water (Table 2). This stock solution served as highest test concentration (100 mg/L). The stock solution was stirred for 2 hours at room temperature. Due to its sensitivity to light a brown glass bottle was used additionally covered with aluminium foil.
Afterwards, the test solution was diluted with dilution water to obtain the lower test concentrations. The test was performed under semi-static test conditions. Test solutions were renewed after 24 hours. The test solutions were freshly prepared before test start and before media renewal.

Test organisms (species):

Daphnia magna

Details on test organisms:

TEST ORGANISM
- Source: German Federal Environment Agency, Institut für Wasser-, Bodenund Lufthygiene
- Age of parental stock: 3 weeks old
- Age of test organisms at test initiation: 4 - 24 hours old
- Feeding during test: none

ACCLIMATION
- Acclimation period: few hours
- Health during acclimation (any mortality observed): not reported

METHOD FOR PREPARATION AND COLLECTION OF EARLY INSTARS OR OTHER LIFE STAGES: Adult Daphnia, at least 3 weeks old, were separated from the stock population by sieving. Batches of 30 to 50 animals were held at room temperature in ca. 1.8 L dilution water for one week. During this week the daphnids were fed daily with an algal suspension (Desmodesmus subspicatus) and ArtemioFluid (JBL). Algae growing in the log-phase were centrifuged and the pellet was re-suspended in a few mL of medium. 5 mL of this suspension was given to 1.8 L Daphnia medium. The water was changed three times per week. Newborn D. magna were separated by sieving, the first generation was discarded. Individuals applied in the test were transferred with a bore Pasteur pipette a few hours after sieving to ensure applying only healthy specimens.

Test type:

semi-static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

48 h

Hardness:

1.1 mmol/l

Test temperature:

19.0 - 19.5 °C

pH:

7.58 – 8.17

Dissolved oxygen:

8.54 mg/L - 9.81 mg/L (96.8 – 108 % of air saturation)

Conductivity:

257 µS/cm

Nominal and measured concentrations:

nominal concentrations: Control, 6.25, 12.5, 25.0, 50.0 and 100 mg test item/L (spacing factor 2)

Details on test conditions:

TEST SYSTEM
- Test vessel: 50-mL glass beakers, filled with about 50 mL test solution and covered with glass panes
- Aeration: none
- Renewal rate of test solution (frequency/flow rate): freshly prepared test solutions were used after 24 hours
- No. of organisms per vessel: 5
- No. of vessels per concentration (replicates): 4
- No. of vessels per control (replicates): 4

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water:
Purified, Cu-reduced drinking water was used as holding- and dilution water. The purification includes filtration with activated charcoal and aeration. To avoid copper contamination, plastic water pipes are used for the testing facilities.
Hardness of the Cu-reduced water is below the recommended range (>140 mg/L as CaCO3) for Daphnia magna indicated in the guideline. Therefore, the Cu-reduced dilution water is enriched with an appropriate amount of CaCl2 to increase the hardness, resulting in values of about 250 – 350 mg CaCO3/L.
- Total Hardness: 1.1 mmol/L
- Chlorine: < 0.02 mg/L
- Alkalinity: 1.8 mmol/L
- Conductivity: 257 μS/cm
- Intervals of water quality measurement: oxygen concentration, pH and temperature of the test solutions were checked at test start, at media renewal and at test end.

OTHER TEST CONDITIONS
- Photoperiod: 16 hours light and 8 hours dark
- Light intensity: 777 - 816 lux

EFFECT PARAMETERS MEASURED
The numbers of immobile daphnids were visually determined daily and immobile daphnids were removed. Any abnormalities in appearance and behaviour were recorded.

RANGE-FINDING STUDY
- Test concentrations: 1.0, 10.0 and 100 mg/L test item
- Results used to determine the conditions for the definitive study:
The non-GLP range-finding test was conducted with four replicates with five daphnids per beaker under semi-static test conditions with renewal of test solution once after 24 hours.
At test end, no mortality occurred in the control and in the two lowest test concentrations of 1.0 and 10.0 mg/L. In the highest test concentration of 100 mg/L, 100% of the introduced daphnids died.

Reference substance (positive control):

no

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

65.1 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

1.18 mg/L

Nominal / measured:

nominal

Conc. based on:

element

Remarks:

Pt

Basis for effect:

mobility

Duration:

48 h

Dose descriptor:

NOEC

Effect conc.:

50 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Duration:

48 h

Dose descriptor:

NOEC

Effect conc.:

0.91 mg/L

Nominal / measured:

nominal

Conc. based on:

element

Remarks:

Pt

Basis for effect:

mobility

Duration:

48 h

Dose descriptor:

LOEC

Effect conc.:

100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Duration:

48 h

Dose descriptor:

LOEC

Effect conc.:

1.82 mg/L

Nominal / measured:

nominal

Conc. based on:

element

Remarks:

Pt

Basis for effect:

mobility

Details on results:

A study was performed to investigate the influence of the test item Pt concentrate P on the mobility of Daphnia magna. The test was conducted under semi-static conditions over a period of 48 hours with one media exchange after 24 hours. Effects on immobilization were determined daily.
The daphnids were placed in water containing the test item in nominal concentrations of 6.25, 12.5, 25.0, 50.0 and 100 mg test item/L. Considering the platinum (Pt) content of 1.82 %, 0.114, 0.228, 0.455, 0.910 and 1.82 mg Pt/L were introduced.
Cu-reduced dilution water enriched with CaCl2 was used as test medium. A control with test medium only was run in parallel.
The concentrations of the test item in the media were confirmed by measurements of platinum (Pt) concentrations at beginning of the test, before and after media renewal at 24 hours and at test end using an ICP-MS system.
Concentrations of freshly prepared test media showed recovery rates between 96.4 and 107 % of nominal concentrations. Concentrations in aged test media showed recovery rates between 98.8 and 108 % of nominal concentrations. During incubation in the test, test concentrations remained stable with 99.2 to 110 % of initial concentrations. The measured concentrations were within a range of 80 – 120 % of nominal concentrations and remained stable during the test. Thus, the evaluation of effects was based on the nominal concentrations.
At test end, one daphnid was dead in the control resulting in 5% immobilisation. Still immobilisation was below 10 % in the control. The dissolved oxygen content was > 3 mg/L in control and test vessels throughout the test. The mean water temperature was in the range of 20 ± 2 °C. Thus, the test was considered valid according to OECD 202.
The test item had a statistically significant effect on the immobilization of the daphnids in the highest test concentrations of 100 mg test item /L. The EC50 was calculated to be 65.1 mg test item/L (1.18 mg Pt/L), the NOEC was set to 50.0 mg test item/L (0.91 mg Pt/L).

Reported statistics and error estimates:

The results were statistically analyzed to determine the EC50 and EC10 value together with 95 % confidence intervals using Probit-analysis assuming log-normal distribution of the values. However, as results showed inhibition of less than 50%, the EC50 value was extrapolated.
The NOEC and LOEC values were determined using appropriate statistical methods (Step-down Cochran-Armitage Test procedure).
The computer program ToxRat was used for statistical evaluations

   

Table: Mobile and immobile daphnids after 48 h and percent immobilization compared to the controls. Concentrations given as nominal test item and Pt concentrations.

Nominal concentration Test item [mg/L]	Nominal concentration Pt [mg/L]	Total Introduced	Mobile	Immobile	% Immobility
Control	Control	20	19	1	5.0
6.25	0.114	20	19	1	5.0
12.5	0.228	20	20	0	0.0
25.0	0.455	20	20	0	0.0
50.0	0.910	20	19	1	5.0
100	1.820	20	0	20	100.0

Validity criteria fulfilled:

yes

Conclusions:

The test item Pt concentrate P showed a significant effect on the test organism Daphnia magna in a 48-hour acute toxicity test. Based on the nominal concentrations, the EC50 for immobilization of the test organisms was calculated to be 65.1 mg test item/L, equivalent to 1.18 mg Pt/L. The NOEC was determined at 50.0 mg test item/L, equivalent to 0.91 mg Pt/L.

Executive summary:

A 48-h acute immobilisation Daphnia magna study is available for Pt concentrate P. The study is reliable without restrictions, being GLP-compliant and having followed standard test guidelines (OECD 202 and EU Method C.2).

A semi-static test system was followed, where test solutions were renewed after 24 hours. Five test concentrations were used, and these were analysed for platinum with ICP-MS at beginning of the test, before and after media renewal at 24 hours and at test end.

Concentrations of freshly prepared test media showed recovery rates between 96.4 and 107 % of nominal concentrations. Concentrations in aged test media showed recovery rates between 98.8 and 108 % of nominal concentrations. During incubation in the test, test concentrations remained stable with 99.2 to 110 % of initial concentrations.

The measured concentrations were within a range of 80 – 120 % of nominal concentrations and remained stable during the test. Thus, the evaluation of effects was based on the nominal concentrations.

All validity criteria were met.

The test item had a statistically significant effect on the immobilization of the daphnids in the highest test concentrations of 100 mg test item /L. The EC50 was calculated to be 65.1 mg test item/L (1.18 mg Pt/L), the NOEC was set to 50.0 mg test item/L (0.91 mg Pt/L).

Description of key information

The test item Pt concentrate P showed a significant effect on the test organism Daphnia magna in a 48-hour acute toxicity test. Based on the nominal concentrations, the EC50 for immobilization of the test organisms was calculated to be 65.1 mg test item/L, equivalent to 1.18 mg Pt/L. The NOEC was determined at 50.0 mg test item/L, equivalent to 0.91 mg Pt/L.

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates

Effect concentration:

mg/L

Additional information

A 48-h acute immobilisation Daphnia magna study is available for Pt concentrate P. The study is reliable without restrictions, being GLP-compliant and having followed standard test guidelines (OECD 202 and EU Method C.2).

A semi-static test system was followed, where test solutions were renewed after 24 hours. Five test concentrations were used, and these were analysed for platinum with ICP-MS at beginning of the test, before and after media renewal at 24 hours and at test end.

Concentrations of freshly prepared test media showed recovery rates between 96.4 and 107 % of nominal concentrations. Concentrations in aged test media showed recovery rates between 98.8 and 108 % of nominal concentrations. During incubation in the test, test concentrations remained stable with 99.2 to 110 % of initial concentrations. The measured concentrations were within a range of 80 – 120 % of nominal concentrations and remained stable during the test. Thus, the evaluation of effects was based on the nominal concentrations.

All validity criteria were met.

The test item had a statistically significant effect on the immobilization of the daphnids in the highest test concentrations of 100 mg test item /L. The EC50 was calculated to be 65.1 mg test item/L (1.18 mg Pt/L), the NOEC was set to 50.0 mg test item/L (0.91 mg Pt/L).