Dihydrogen hexahydroxyplatinate, compound with 2-aminoethanol (1:2)

Toxicity to aquatic algae and cyanobacteria

Link to relevant study record(s)

Reference

Endpoint:

toxicity to aquatic algae and cyanobacteria

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2016

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 201 (Alga, Growth Inhibition Test)

GLP compliance:

yes (incl. QA statement)

Analytical monitoring:

yes

Details on sampling:

- Concentrations: 0.200, 0.633, 2.00, 6.33 and 20.0 mg test item/L (nominal)
- Sampling method:
Pt: 2 x 20 mL were taken directly from the solutions and transferred into disposable polyethylene vials.
2AE: the samples were added into glass vials.
An aliquot of each test solution was filtered (0.2 μm polyethylene sulfonic acid (PES) syringe filter, e.g. Nalgene)
- Sample storage conditions before analysis:
Pt: All samples were acidified with HNO3 (2.5 mL concentrated HNO3, final concentration presumably 10 %) and stored in a refrigerator (about 4 °C) until further analysis.
2AE: Analyses were performed at the day of sampling, if possible. Otherwise, the samples were stored frozen (at -20°C) until analysis.

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
- Method: The highest test concentration was prepared by adding 20 mg test item to 1 litre growth medium, and stirred for two hours at room temperature. This was then diluted in order to prepare the other test concentrations
- Controls: Dilution water
- Chemical name of vehicle (organic solvent, emulsifier or dispersant): None
- Concentration of vehicle in test medium (stock solution and final test solution(s) or suspension(s) including control(s)): None
- Evidence of undissolved material (e.g. precipitate, surface film, etc.): Test solutions were not filtered as they appeared clear and free from any precipitate. At test end, solutions were filtered before analysis as precipitates could have formed during the test.

Test organisms (species):

Raphidocelis subcapitata (previous names: Pseudokirchneriella subcapitata, Selenastrum capricornutum)

Details on test organisms:

TEST ORGANISM
- Common name: unicellular green alga
- Strain: Chlorophycea, Chlorophyta
- Source (laboratory, culture collection): SAG, Culture Collection of Algae at Pflanzenphysiologisches Institut of the University at Göttingen, Albrecht von Haller Institut, Untere Klarspüle 2, D- 37073 Göttingen, Catalog No 61.81 SAG.
- Age of inoculum (at test initiation): 3 days
- Method of cultivation: Not stated

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

72 h

Hardness:

Not applicable

Test temperature:

21.5 - 22.0 C

pH:

7.84 - 8.59

Dissolved oxygen:

Not stated

Salinity:

Not applicable

Conductivity:

Not stated

Nominal and measured concentrations:

Nominal: 0.200, 0.633, 2.00, 6.33 and 20.0 mg/L; equivalent to nominal concentrations of 0.034, 0.109, 0.343, 1.09 and 3.43 mg Pt/L and 0.022, 0.068, 0.215, 0.680 and 2.15 mg 2-amino-ethanol/L.
Mean measured platinum concentrations: 0.006, 0.016, 0.046, 0.134, 0.453 mg Pt/L
Mean measured 2-AE concentrations: 0.014, 0.051, 0.166, 0.530, 1.73 mg 2AE/L
Test item concentrations were also calculated based on measured platinum concentrations

Details on test conditions:

TEST SYSTEM
- Test vessel: Conical flasks
- Type: open
- Material, size, headspace, fill volume: 250 mL conical glass flasks covered with air-permeable silicone-sponge caps.
- Aeration: Not stated
- Type of flow-through (e.g. peristaltic or proportional diluter): None
- Renewal rate of test solution (frequency/flow rate): None
- Initial cells density: 2.9 - 8.0 x 10 (4) cells/mL
- Control end cells density: 162.7 x 10 (4) /mL
- No. of vessels per concentration (replicates): 4
- No. of vessels per control (replicates): 7
- No. of vessels per vehicle control (replicates): Not applicable

GROWTH MEDIUM
- Standard medium used: yes
- Detailed composition if non-standard medium was used: not applicable

OTHER TEST CONDITIONS
- Sterile test conditions: no
- Adjustment of pH: no
- Photoperiod: Not stated
- Light intensity and quality: 93.00 – 99.24 µE(1)m(-2)s
- Salinity (for marine algae): Not applicable

EFFECT PARAMETERS MEASURED (with observation intervals if applicable):
- Determination of cell concentrations: electronic particle counter (CASY® TT, Innovatis, Germany).

TEST CONCENTRATIONS
- Spacing factor for test concentrations: 3.15
- Justification for using less concentrations than requested by guideline: Not applicable
- Range finding study: Yes
- Test concentrations: 1.0, 10 and 50 mg test item (0.172, 17.72 and 8.58 mg Pt/L, equivalent to 0.107, 1.07 and 5.37 mg 2AE/L)
- Results used to determine the conditions for the definitive study: Yes

Reference substance (positive control):

yes

Remarks:

sensitivity of test organism routinely checked with 3,5-dichlorophenol (last tested February 2016)

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

0.117 other: mg Pt/L

Nominal / measured:

meas. (not specified)

Conc. based on:

element

Basis for effect:

growth rate

Remarks on result:

other: 95%-CL lower = 0.080 mg Pt/L. 95%-CL upper = 0.185 mg Pt/L

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

0.021 other: mg Pt/L

Nominal / measured:

meas. (not specified)

Conc. based on:

element

Basis for effect:

other: Yield

Remarks on result:

other: 95%-CL lower = 0.017 mg Pt/L. 95%-CL upper = 0.026 mg Pt/L.

Duration:

72 h

Dose descriptor:

EC10

Effect conc.:

0.007 other: mg Pt/L

Nominal / measured:

meas. (not specified)

Conc. based on:

element

Basis for effect:

growth rate

Remarks on result:

other: 95%-CL lower = 0.022 mg Pt/L. 95%-CL upper = 0.013 mg Pt/L

Duration:

72 h

Dose descriptor:

EC10

Effect conc.:

0.09 other: mg Pt/L

Nominal / measured:

meas. (not specified)

Conc. based on:

element

Basis for effect:

other: yield

Remarks on result:

other: 95%-CL lower = 0.05 mg Pt/L. 95%-CL upper = 0.013 mg Pt/L

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

0.433 other: mg 2AE/L

Nominal / measured:

meas. (not specified)

Conc. based on:

other: 2AE

Basis for effect:

growth rate

Remarks on result:

other: 95%-CL lower = 0.294 mg 2AE/L. 95%-CL upper = 0.681 mg 2AE/L

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

0.073 other: mg 2AE/L

Nominal / measured:

meas. (not specified)

Conc. based on:

other: 2AE

Basis for effect:

other: Yield

Remarks on result:

other: 95%-CL lower = .0.45 mg 2AE/L. 95% CL-upper = 0.117 mg 2AE/L

Duration:

72 h

Dose descriptor:

EC10

Effect conc.:

0.021 other: mg 2AE/L

Nominal / measured:

meas. (not specified)

Conc. based on:

other: 2AE

Basis for effect:

growth rate

Remarks on result:

other: 95%-CL lower = 0.006 mg 2AE/L. 95%CL- upper = 0.042 mg 2AE/L

Duration:

72 h

Dose descriptor:

EC10

Effect conc.:

0.032 other: mg 2AE/L

Nominal / measured:

meas. (not specified)

Conc. based on:

other: 2AE

Basis for effect:

other: Yield

Remarks on result:

other: 95%-CL lower = 0.022 mg 2AE/L. 95%-CL upper = 0.048 mg 2AE/L

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

0.682 mg/L

Nominal / measured:

meas. (not specified)

Conc. based on:

test mat.

Basis for effect:

growth rate

Remarks on result:

other: 95%-CL lower = 0.466 mg/L 95%-CL upper = 1.08 mg/L. Test item concentration calculated based on measured Pt concentrations.

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

0.125 mg/L

Nominal / measured:

meas. (not specified)

Conc. based on:

test mat.

Basis for effect:

other: Yield

Remarks on result:

other: 95%-CL lower = 0.101 mg/L. 95%-CL upper = 0.149 mg/L. Test item concentration calculated based on measured Pt concentrations.

Duration:

72 h

Dose descriptor:

EC10

Effect conc.:

0.039 mg/L

Nominal / measured:

meas. (not specified)

Conc. based on:

test mat.

Basis for effect:

growth rate

Remarks on result:

other: 95%-CL lower = 0.012 mg/L. 95%-CL upper = 0.077 mg/L. Test item concentration calculated based on measured Pt concentrations.

Duration:

72 h

Dose descriptor:

EC10

Effect conc.:

0.055 mg/L

Nominal / measured:

meas. (not specified)

Conc. based on:

test mat.

Basis for effect:

other: Yield

Remarks on result:

other: 95%-CL lower = 0.032 mg/L. 95%-CL upper= 0.073 mg/L. Test item concentration calculated based on measured Pt concentrations.

Details on results:

- 72-hour NOECs: 0.016 mg Pt/L (growth rate), <0.006 mg Pt/L (yield). 0.051 mg 2AE/L (growth rate), <0.014 mg 2AE/L (yield). 0.092 mg test item/L (growth rate), <0.034 mg test item/L (yield)
- Observation of abnormalities (for algal test): 46.1 μg Pt/L = Large cell agglomerates, cell debris, still intact cells; 134 and 453 μg Pt/L = Small cell agglomerates, cell debris, barely intact cells. 15.8. 5.75, control μg Pt/L = Normal appearance of intact cells, almost no cell debris

Results with reference substance (positive control):

Results from February 2016:
ErC50: 2.83 mg/L, in agreement with results from an international ring test

Reported statistics and error estimates:

The evaluation of the test was based on mean measured concentrations of platinum since the measured concentrations of platinum in the unfiltered test solution did not deviate more than 20 % from the nominal values at start. However, there was a loss of test item after filtration and therefore the test evaluation was based on the mean measured test concentrations. An EC50, EC20 and EC10 value together with 95 % confidence intervals were determined using non-linear regression (3-parametric cumulative distribution function according to Bruce and Versteeg (1992)). Individual replicate responses were used for the regression analysis. The computer program ToxRat was used for statistical evaluations.

Validity criteria fulfilled:

yes

Conclusions:

Based on measured Pt concentrations, the 72 hour ErC50 and the ErC10 values (growth rate) were 0.117 and 0.007 mg Pt/L, respectively. The 72 hour EyC50 and the EyC10 values (yield) were 0.021 and 0.009 mg Pt/L, respectively. The NOEC for growth rate was set to be 0.016 mg Pt/L by expert judgment, whereas the NOEC for yield was calculated to be < 0.006 mg Pt/L.

Based on measured 2-amino-ethanol concentrations, the 72 hour ErC50 and the ErC10 values (growth rate) were 0.433 and 0.021 mg 2-amino-ethanol/L, respectively. The 72 hour EyC50 and the EyC10 values (yield) were 0.073 and 0.032 mg 2-amino-ethanol/L, respectively. The NOEC for growth rate was set to be 0.051 mg 2AE/L by expert judgment, whereas the NOEC for yield was calculated to be < 0.014 mg 2AE/L.

Based on test item concentrations calculated from measured Pt concentrations, the 72 hour ErC50 and the ErC10 values (growth rate) were 0.682 and 0.039 mg test item/L, respectively. The 72 hour EyC50 and the EyC10 values (yield) were 0.125 and 0.055 mg test item/L, respectively. The NOEC for growth rate was set to be 0.092 mg test item/L by expert judgment, whereas the NOEC for yield was calculated to be < 0.034 mg test item/L.

Executive summary:

A 72-h algal growth inhibition study was conducted for dihydrogen hexahydroxyplatinate, compound with 2-aminoethanol (1:2). The study is reliable without restrictions, being GLP-compliant and having followed standard test guidelines (OECD 201).

There were concentration-dependent effects on the growth of the green algae over the range of the tested concentrations. Based on measured Pt concentrations, the 72 hour ErC50 and the ErC10 values (growth rate) were 0.117 and 0.007 mg Pt/L, respectively. The 72 hour EyC50 and the EyC10 values (yield) were 0.021 and 0.009 mg Pt/L, respectively. The NOEC for growth rate was set to be 0.016 mg Pt/L by expert judgment, whereas the NOEC for yield was calculated to be < 0.006 mg Pt/L.

Based on measured 2-amino-ethanol concentrations, the 72 hour ErC50 and the ErC10 values (growth rate) were 0.433 and 0.021 mg 2-amino-ethanol/L, respectively. The 72 hour EyC50 and the EyC10 values (yield) were 0.073 and 0.032 mg 2-amino-ethanol/L, respectively. The NOEC for growth rate was set to be 0.051 mg 2AE/L by expert judgment, whereas the NOEC for yield was calculated to be < 0.014 mg 2AE/L.

Based on test item concentrations calculated from measured Pt concentrations, the 72 hour ErC50 and the ErC10 values (growth rate) were 0.682 and 0.039 mg test item/L, respectively. The 72 hour EyC50 and the EyC10 values (yield) were 0.125 and 0.055 mg test item/L, respectively. The NOEC for growth rate was set to be 0.092 mg test item/L by expert judgment, whereas the NOEC for yield was calculated to be < 0.034 mg test item/L.

Description of key information

Based on mean measured platinum concentrations the EC50 was 0.117 mg Pt L^-1, the EC10 was 0.007 mg Pt L^-1and the NOEC was 0.016 mg Pt L^-1. Based on 2-aminoethanol concentrations the EC50 was 0.433 mg 2-AE L^-1, the EC10 was 0.021 mg 2-AE L^-1and the NOEC was 0.051 mg 2-AE L^-1.

Additional information

An algal toxicity study with Pseudokirchneriella subcapitata following OECD test guideline 201 is available for this substance (Wenzel 2016). Five test concentrations were included, with four replicates of each and eight replicates of the control. Both platinum and 2-aminoethanol concentrations were analysed in the test solutions at the start and end of the test, by ICP-OES and ICP-MS, respectively. Both filtered and unfiltered test solutions were analysed for platinum, and the measured concentrations in the filtered test solutions were used for the evaluation of effects, as these represent the soluble platinum concentrations. Measured concentrations of 2-aminoethanol were 76.8 to 81.0% of nominal at test start and 53.3 to 79.7% of nominal after 72 hours. Results were expressed based on platinum concentrations, 2-aminoethanol concentrations and test item concentrations, calculated based on measured platinum concentrations. Based on mean measured platinum concentrations the EC50 was 0.117 mg Pt L^-1, the EC10 was 0.007 mg Pt L^-1 and the NOEC was 0.016 mg Pt L^-1. Based on 2-aminoethanol concentrations the EC50 was 0.433 mg 2-AE L^-1, the EC10 was 0.021 mg 2-AE L^-1 and the NOEC was 0.051 mg 2-AE L^-1.

Based on calculated test item concentrations the EC50 was 0.682 mg test item L^-1, the EC10 was 0.039 mg test item L^-1and the NOEC was 0.092 mg test item L^-1.