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Ecotoxicological information

Toxicity to microorganisms

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Administrative data

Endpoint:
activated sludge respiration inhibition testing
Type of information:
experimental study
Adequacy of study:
key study
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: GLP compliant, guideline study, available as unpublished report, fully adequate for assessment..

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1995
Report date:
1995

Materials and methods

Test guidelineopen allclose all
Qualifier:
according to guideline
Guideline:
OECD Guideline 209 (Activated Sludge, Respiration Inhibition Test
Deviations:
not specified
Qualifier:
according to guideline
Guideline:
other: EEC Commission directive 87/302/EEC
Deviations:
not specified
GLP compliance:
yes (incl. QA statement)

Test material

Constituent 1
Reference substance name:
123439-82-7
Cas Number:
123439-82-7
IUPAC Name:
123439-82-7
Constituent 2
Reference substance name:
Tetrammine platinum (II) hydrogen carbonate
IUPAC Name:
Tetrammine platinum (II) hydrogen carbonate
Test material form:
solid
Remarks:
powder
Details on test material:
- Description: white powder

Sampling and analysis

Analytical monitoring:
no

Test solutions

Vehicle:
no
Details on test solutions:
- An amount of test material (4.0 g) was dissolved in water with the aid of ultrasonic disruption and the volume adjusted to 1 L to give a 4.0 g/L stock solution. Aliquots (15.6, 31.3, 62.5, 125 and 250 mL) of the 4.0 g/L stock solution were removed and dispersed with activated sewage sludge, synthetic sewage and water to give the final concentrantions of 125, 250, 500, 1000 and 2000 mg/L.
- The control was dechlorinated laboratory tap water.

Test organisms

Test organisms (species):
activated sludge of a predominantly domestic sewage
Details on inoculum:
- Laboratory culture: a mixed population of activated sewage sludge microorganisms
- Name and location of sewage treatment plant where inoculum was collected: 'Severn Trent Water Plc' at Belper, Derbyshire, UK
- Method of cultivation: not reported
- Preparation of inoculum for exposure: the activated sewage sludge sample was maintained on continuous aeration in the laboratory at a temperature of 21 °C. At 0 hours, 16 mL of synthetic sewage was diluted to 300 mL with water and 200 mL of inoculum were then added in a 500 mL conical flask. The mixture was aerated with compressed air via narrow bore glass tubes at a rate of approximately 0.5 - 1 L per minute. Thereafter, at 15-minute intervals the procedure was repeated with appropriate amounts of the test item (or reference material) being added.
- Pretreatment: none
- Initial biomass concentration: not reported

Study design

Test type:
static
Water media type:
freshwater
Limit test:
no
Total exposure duration:
3 h

Test conditions

Hardness:
100 mg/L as CaCO3
Test temperature:
21 °C
pH:
6.9
Nominal and measured concentrations:
Nominal concentrations: 125, 250, 500, 1000 and 2000 mg test item/L
Details on test conditions:
TEST SYSTEM
- Test vessel: a) 500-mL conical flasks and b) 250-mL darkened glass Biological Oxygen Demand bottles
- Aeration: aerated with compressed air via narrow bore glass tubes at approximately 0.5 - 1.0 L per minute
- No. of vessels per concentration (replicates): 1
- No. of vessels per control (replicates): 2
- Sludge concentration (weight of dry solids per volume): 3.9 suspended solids/L

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: laboratory tap water dechlorinated by passage through an activated carbon filter
- Total Hardness: 100 mg/L as CaCO3

OTHER TEST CONDITIONS
- Photoperiod: normal laboratory lighting

EFFECT PARAMETERS MEASURED: Oxygen consumption rates and percentage inhibition of respiration were measured after 30 minutes and 3 hours contact time

TEST CONCENTRATIONS
- Spacing factor for test concentrations: 2
- Range finding study
- Test concentrations: 100 and 1000 mg test item/L in the first range-finding study and 1000 and 1800 mg test item/L in the second one.
- Results used to determine the conditions for the definitive study: significant inhibition of respiration was observed at 1000 and 1800 mg/L, but no significant effects on respiration was observed at 100 mg/L.
Reference substance (positive control):
yes
Remarks:
3,5-dichlorophenol

Results and discussion

Effect concentrationsopen allclose all
Duration:
30 min
Dose descriptor:
EC50
Effect conc.:
> 2 000 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.:
> 1 012.77 mg/L
Nominal / measured:
nominal
Conc. based on:
element
Remarks:
Pt
Basis for effect:
inhibition of total respiration
Remarks:
respiration rate
Duration:
3 h
Dose descriptor:
EC50
Effect conc.:
1 400 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
inhibition of total respiration
Remarks:
respiration rate
Key result
Duration:
3 h
Dose descriptor:
EC50
Effect conc.:
709 mg/L
Nominal / measured:
nominal
Conc. based on:
element
Remarks:
Pt
Basis for effect:
inhibition of total respiration
Remarks:
respiration rate
Key result
Duration:
3 h
Dose descriptor:
EC10
Effect conc.:
84 mg/L
Nominal / measured:
nominal
Conc. based on:
element
Remarks:
Pt
Basis for effect:
inhibition of total respiration
Remarks:
respiration rate
Remarks on result:
other: self-estimated using TRAP v1.30a
Details on results:
- The variation in respiration rates of the controls after 30 minutes contact time was ± 13 %.
- The variation in respiration rates of the controls after 3 hours contact time was ± 3 %.
- After 30 minutes contact time, no concentration tested resulted in 50 % inhibition, and therefore it was considered inappropriate to extrapolate the plot of inhibition against concentration to obtain an EC50 value after 30 minutes contact time.
Results with reference substance (positive control):
After 30 minutes and 3 hours contact time, the EC50 values of 3,5-dichlorophenol were determined to be 14 mg/L and 9 mg/L, respectively.
Reported statistics and error estimates:
In order to calculate the inhibitory effect of the test item and the reference substance, the respiration rate was expressed as a percentage of the two control respiration rates. Percentage inhibition was plotted against concentration and the EC50 values were derived by inspection of the graph.

Any other information on results incl. tables

Table 1. Oxygen consumption rates and percentage inhibition values of tetraammineplatinum (2 +) hydrogencarbonate after 30 minutes contact time.

   Nominal concentration (mg/L)  O2 Consumption rates (mg O2/L/min)  % Inhibition
 Control    Replicate 1   0.40
Replicate 2  0.31 -
 Tetraammineplatinum (2 +) hydrogencarbonate              125  0.38  7*
 250  0.35  1
 500  0.35  1
 1000  0.35  1
 2000  0.31  13
Reference substance (3,5-dichlorophenol)        3.2  0.42  18*
 10  0.18  49
 32  0.09  75

* increase

Table 2. Oxygen consumption rates and percentage inhibition values of tetraammineplatinum (2 +) hydrogencarbonate after 3 hours contact time.

   Concentration (mg/L) O2 Consumption rates (mg O2/L/min)  % Inhibition 
 Control    Replicate 1  0.38 -
Replicate 2 0.36 -
 Tetraammine platinum (2 +) hydrogencarbonate             125  0.36 3
250 0.31  16 
500 0.27  27 
1000 0.24 35 
2000 0.16 57 
 Reference substance (3,5-dichlorophenol)       3.2 0.34
10 0.13 65 
32  0.06 84 

Applicant's summary and conclusion

Validity criteria fulfilled:
yes
Conclusions:
Based on nominal concentrations, the 3-hour EC50 for tetraammineplatinum (2+) hydrogencarbonate on the respiration of activated sewage sludge microorganisms was 1400 mg test item/L corresponding to 709 mg Pt/L. The 3h-EC10 value was self-estimated as 84 mg Pt/L (using TRAP v1.30a).
Executive summary:

Tetrammineplatinum (2+) hydrogencarbonate was tested for toxicity towards activated sludge of a predominantly domestic sewage. The study is reliable without restrictions, being GLP-compliant and having followed the standard test guideline (OECD 209).

In order to investigate the influence of the test substance towards activated sewage sludge, the rate of respiration was determined after 30 minutes and 3 hours contact time. Two range-finding studies were initially performed at test concentrations of 100, 1000 mg/L and 1000, 1800 mg/L. Significant inhibition of respiration was observed at 1000 and 1800 mg/L, but no significant effects on respiration were found at 100 mg/L. Therefore, nominal test concentrations of 125, 250, 500, 1000 and 2000 mg test item/L were selected for the definitive study. The substance 3,5-dichlorophenol was used as positive control. Based on nominal concentrations, the 3-h EC50 for the test item was determined to be 1400 mg test item/L corresponding to 709 mg Pt/L. The 3h-EC10 value was self-estimated as 84 mg Pt/L (using TRAP v1.30a).