tetraammine platinum (II) hydrogen carbonate

Toxicity to microorganisms

Link to relevant study record(s)

Reference

Endpoint:

activated sludge respiration inhibition testing

Type of information:

experimental study

Adequacy of study:

key study

Study period:

7 April 2006

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Not a full guideline study, although based on OECD TG209, and carried out to GLP. Considered scientifically acceptable.

Qualifier:

according to

Guideline:

OECD Guideline 209 (Activated Sludge, Respiration Inhibition Test

Deviations:

yes

Remarks:

A contact time of 30 mins only was used, whereas the current guideline requires a 3 hr contact time. Only one concentration (100 mg/L) tested, in duplicate. For a preliminary test, current guidelines recommend three concentrations are tested in triplicate

Qualifier:

according to

Guideline:

ISO 8192 (Water quality - Test for inhibition of oxygen consumption by activated sludge for carbonaceous and ammonium oxidation)

Deviations:

not specified

GLP compliance:

yes

Analytical monitoring:

no

Details on sampling:

Not applicable

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
- Method: A stock solution of 0.5 g/L was prepared by adding 504.9 mg of test material (white crystalline powder) to 1 L of Milli-RO water. 25 minutes of magnetic stirring was used to accelerate the dissolution and to ensure homogeneity. A concentration of 100 mg/L, corresponding to 100 mL stock solution in a 500 mL final volume, was used for the test.
- Eluate: Not applicable
- Differential loading: Not applicable
- Controls: Test medium without test substance
- Chemical name of vehicle (organic solvent, emulsifier or dispersant): Not applicable
- Concentration of vehicle in test medium (stock solution and final test solution(s) including control(s)): Not applicable
- Evidence of undissolved material (e.g. precipitate, surface film, etc): Test material was completely soluble in test medium.

Test organisms (species):

activated sludge of a predominantly domestic sewage

Details on inoculum:

- Laboratory culture: Sludge was obtained from a municipal sewage treatment plant: Waterschap de Maaskant, 's-Hertogenbosch, the Netherlands, receiving predominantly domestic sewage.
- Method of cultivation: No data
- Preparation of inoculum for exposure: The sludge was coarsely sieved, washed and diluted with tap-water. A small amount of the sludge was weighted and dried at 105 deg C to determine the amount of suspended solids. The pH was 7.6 on the day of sampling and 7.9 on the day of testing.
- Pretreatment: No data
- Initial biomass concentration: 3.3 g/L as suspended solids

Test type:

not specified

Water media type:

freshwater

Limit test:

no

Total exposure duration:

30 min

Remarks on exposure duration:

See 'Any other information on materials and methods incl. tables' below

Post exposure observation period:

None

Hardness:

No data

Test temperature:

19.6 - 20.9 deg C

pH:

7.2 initially, rising to 8.3 at the end of the test.

Dissolved oxygen:

6.5-7.8 mg O2/L at the start of the test

Salinity:

Not applicable

Nominal and measured concentrations:

100 mg/L nominal (measured concentration was not analysed).

Details on test conditions:

TEST SYSTEM
- Test vessel: All-glass, approximately 300 mL oxygen bottles and 1 L test bottles
- Type (delete if not applicable): closed
- Material, size, headspace, fill volume: All-glass, approximately 300 mL oxygen bottles and 1 L test bottles
- Aeration: Aerated using a pipette during the contact time but not during measurement.
- Type of flow-through (e.g. peristaltic or proportional diluter): No data
- Renewal rate of test solution (frequency/flow rate): No data
- No. of organisms per vessel: No data
- No. of vessels per concentration (replicates): 2
- No. of vessels per control (replicates): 2
- No. of vessels per vehicle control (replicates): Not applicable
- Biomass loading rate: No data

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: Milli Q water

OTHER TEST CONDITIONS
- Adjustment of pH: pH was adjusted from 6.8 to 7.2 using 1M NaOH
- Photoperiod: No data
- Light intensity: No data

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) : Inhibition of respiration

TEST CONCENTRATIONS
- Spacing factor for test concentrations: Not applicable
- Justification for using less concentrations than requested by guideline: Not applicable
- Range finding study: No
- Test concentrations: Not applicable
- Results used to determine the conditions for the definitive study: Not applicable

Reference substance (positive control):

yes

Remarks:

3,5-Dichlorophenol

Duration:

30 min

Dose descriptor:

NOEC

Effect conc.:

100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

inhibition of total respiration

Remarks:

respiration rate

Duration:

30 min

Dose descriptor:

EC50

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

inhibition of total respiration

Remarks:

respiration rate

Details on results:

- Any observations (e.g. precipitation) that might cause a difference between measured and nominal values: No data
- Effect concentrations exceeding solubility of substance in test medium: Not applicable

Results with reference substance (positive control):

- Results with reference substance valid? Yes, the EC50 for 3,5-dichlorophenol was within the accepted range (5-30 mg/L)
- Relevant effect levels: EC50 of 14 mg/L

Reported statistics and error estimates:

No data

Table 1: Reference substance and control data on pH, oxygen concentration, oxygen consumption and respiratory inhibition.

Flask	Concentration (mg/L)	Initial oxygen concentration (mg O2/L)	Oxygen consumption (mg O2/L/hr)	% Inhibition	pH
Control 1	0	7.0	35	-	8.1
Control 2	0	7.4	35	-	8.2
Mean control			35
Reference 1	3.2	7.1	30	14	8.1
Reference 2	10	7.7	21	40	8.1
Reference 3	32	8.1	10	71	8.2

Table 2: Test substance and control data on pH, oxygen concentration, oxygen consumption and respiratory inhibition.

Flask	Concentration (mg/L)	Initial oxygen concentration (mg O2/L)	Oxygen consumption (mg O2/L/hr)	% Inhibition	pH
Control 3	0	7.8	34	-	8.3
Control 4	0	7.5	33	-	8.2
Mean control			34
Test 1	100	7.0	37	-10	8.3
Test 2	100	6.5	37	-10	8.2

Validity criteria fulfilled:

yes

Conclusions:

In a study based on OECD TG209, to GLP, the 30-min EC50 of platinum (2+) tetraammine diacetate to activated sludge respiration is greater than 100 mg/L (>46.95 mg Pt/L; considered the study NOEC).

Executive summary:

The inhibitory effect of platinum (2 +) tetraammine diacetate on the respiration rate of aerobic wastewater micro-organisms of activated sludge was investigated in a 30 minute respiration inhibition test based on OECD guidelines (TG 209) and carried out to GLP.

A single nominal limit concentration of 100 mg/L was tested. In addition, four controls and three different concentrations of the reference substance 3, 5 -dichlorophenol in the range from 3.2 to 32 mg/L were tested in parallel. The 30 -min EC50 of the reference substance 3,5 -dichlorophenol was calculated to be 14 mg/L and was within the accepted range of 5–30 mg/L; thus, confirming suitability of the activated sludge. 

At the nominal limit concentration of 100 mg/L, platinum (2 +) tetraammine diacetate had no inhibitory effect on the respiration rate of activated sludge after an incubation period of 30 minutes (considered the study NOEC). Therefore, the 30-min EC50 could not be quantified but is evidently higher than 100 mg/L (nominal), equivalent to >46.95 mg Pt/L, under these study conditions.

Description of key information

In a study based on OECD TG209, to GLP, the 30-min EC50 of platinum (2+) tetraammine diacetate to activated sludge respiration is greater than 100 mg/L (>46.95 mg Pt/L; considered the study NOEC) (Desmares-Koopmans, 2006).

Key value for chemical safety assessment

EC10 or NOEC for microorganisms:

46.95 mg/L

Additional information

The inhibitory effect of platinum (2 +) tetraammine diacetate on the respiration rate of aerobic wastewater micro-organisms of activated sludge was investigated in a 30 minute respiration inhibition test based on OECD guidelines (TG 209) and carried out to GLP.

A single nominal limit concentration of 100 mg/L was tested. In addition, four controls and three different concentrations of the reference substance 3, 5 -dichlorophenol in the range from 3.2 to 32 mg/L were tested in parallel. The 30 -min EC50 of the reference substance 3,5 -dichlorophenol was calculated to be 14 mg/L and was within the accepted range of 5–30 mg/L; thus, confirming suitability of the activated sludge. 

At the nominal limit concentration of 100 mg/L, platinum (2 +) tetraammine diacetate had no inhibitory effect on the respiration rate of activated sludge after an incubation period of 30 minutes (considered the study NOEC). Therefore, the 30 -min EC50 could not be quantified but is evidently higher than 100 mg/L (nominal), equivalent to >46.95 mg Pt/L, under these study conditions (Desmares-Koopmans, 2006).