Methyltriphenylphosphonium bromide

Short-term toxicity to aquatic invertebrates

Administrative data

Endpoint:

short-term toxicity to aquatic invertebrates

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2003-02-26 to 2003-06-26

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2003

Report date:

2003

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)

Version / remarks:

adopted April 4, 1984

Deviations:

no

Test guideline 2

Qualifier:

according to guideline

Guideline:

EU Method C.2 (Acute Toxicity for Daphnia)

Version / remarks:

December 1992

Deviations:

no

GLP compliance:

yes

Test material

Test material information

Constituent 1

Reference substance name:

Methyltriphenylphosphonium bromide

EC Number:

217-218-9

EC Name:

Methyltriphenylphosphonium bromide

Cas Number:

1779-49-3

Molecular formula:

C19H18P.Br

IUPAC Name:

methyl(triphenyl)phosphonium bromide

Test material form:

solid: particulate/powder

Sampling and analysis

Analytical monitoring:

yes

Details on sampling:

During the final test samples for analysis were taken from the 1.0, 3.2 and 10 mg/L test solutions. In addition, samples were taken from the controls.
Sampling: Frequency at t=0h and t=48h.
Volume: 10 mL from the approximate centre of the test vessel.
Storage: The samples were stored under deep-freeze conditions until analysis.

Test solutions

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
- Method: Preparation of the test solutions started with a stock of 100 mg/L in ISO-medium. No special treatment other than vigorous stirring was needed to completely dissolve the test substance. Lower test concentrations were prepared by subsequent dilution in test medium. All final test solutions were clear and colourless.
- Controls: Test medium without test substance or other additives (blank-control).
- Evidence of undissolved material (e.g. precipitate, surface film, etc.): No

Test organisms

Test organisms (species):

Daphnia magna

Details on test organisms:

TEST ORGANISM
- Common name: Water flea
- Strain/clone: Daphnia magna (Crustacea, Cladocera) (Straus, 1820)
- Age of parental stock (mean and range, SD): Not older than 2 weeks
- Feeding during test: No

ACCLIMATION
- Acclimation period:With new-born animals, i.e. less than 3 days old, by placing about 250 of them into 10 litres of medium in an all-glass culture vessel.
- Acclimation conditions (same as test or not): same as test
- Type and amount of food: a suspension of fresh water algae.
- Feeding frequency: daily
- Health during acclimation (any mortality observed): Daphnids originated from a healthy stock, 2nd to 5th brood, showing no signs of stress such as mortality >20%, presence of males, ephippia or discoloured
animals and there was no delay in the production of the first brood.

Study design

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

48 h

Test conditions

Hardness:

250 mg/L CaCO3

Test temperature:

20.4 to 21.9°C

pH:

6.0-8.5, constant within 1 unit in any test solution

Dissolved oxygen:

> 8.9 at the start and > 8.6 at the end of the test

Nominal and measured concentrations:

1.0, 1.8, 3.2, 5.6 and 10 mg/L.

Details on test conditions:

Test type: Static
Test duration: 48 hours
Test vessels: 100 mL, all-glass
Medium: ISO, prepared in milli-RO water
Number of daphnia: 20 per concentration
Loading: 5 per vessel containing 80 mL medium
Light: 16 hours photoperiod daily

TEST SYSTEM
- Test vessel: 100 mL, all-glass
- Material, size, headspace, fill volume: glass, size: 100 mL, 80 mL fillvolume
- Aeration: No
- No. of organisms per vessel: 5
- No. of vessels per concentration (replicates): 4
- No. of vessels per control (replicates): 4

TEST MEDIUM / WATER PARAMETERS
ISO-medium: the following chemicals (analytical grade) are dissolved in freshly prepared ultra-pure water (tap water purified by reverse osmosis (miili-RO) and subsequently passed over activated carbon and ion-exchange cartridges: Milli-Q water; Millipore Corp., Bedford, Mass., USA) (mg/L):
CaCl2 x 2H2O 293.8
MgSO x 7H2O 123.3
NaHCO3 64.8
KCI 5.8
Medium M7: trace elements, macro nutrients and vitamins are added to freshly prepared ISO-medium to reach the following concentrations: Trace elements (mg/L):
B 0.125
Fe 0.05
Mn 0.025
Li, Rb and Sr 0.0125
Mo 0.0063
Br 0.0025
Cu 0.0016
Zn 0.0063
Co and I 0.0025
Se 0.0010
V 0.0003
Na2EDTA x 2H2O 2.5
Macro nutrients (mg/L):
Na2SiO3 x 9H2O 10.0
NaNO3 0.27
KH2PO4 0.14
K2HPO4 0.18
Vitamins (µg/L):
Thiamine 75.0
B12 1.0
Biotin 0.75

The hardness: 250 mg/L expressed as CaCO3 and the pH: 8.0 ± 0.2 after aeration

OTHER TEST CONDITIONS
- Photoperiod:16 h

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) :
lmmobilisation: those animals not able to swim within 15 seconds after gentle agitation of the test vessel are considered to be immobile.
EC50: the concentration estimated to immobilise 50% of the daphnia after a defined period of exposure.
No Observed Effect Concentration (NOEC): is the highest tested concentration at which no effect (i.e. immobilisation) is recorded.

VEHICLE CONTROL PERFORMED: no

RANGE-FINDING STUDY
- Test concentrations: 0.1, 1.0, 10.0 and 100 mg/L
- Results used to determine the conditions for the definitive study:
After 24 hours of exposure all organisms exposed to 10 and 100 mg/L became immobilised, while no daphnids became immobilised in the lower test concentrations during the test. The EC50 was expected to be between 1.0 and 10 mg/L.

Reference substance (positive control):

yes

Remarks:

potassium dichromate

Results and discussion

Effect concentrations

Effect concentrations 1

Duration:

24 h

Dose descriptor:

EC50

Effect conc.:

5.2 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Effect concentrations 2

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

2.4 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Effect concentrations 3

Duration:

48 h

Dose descriptor:

NOEC

Effect conc.:

1.8 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Results with reference substance (positive control):

- Results with reference substance valid? Yes
- Relevant effect levels: The 24h-EC50 (based on the initial concentration) of potassium dichromate was within the range of 0.6 to 1.7 mg/L.
- Limit test: no

Reported statistics and error estimates:

Calculation of EC50:
The EC50-value at 24 hours of exposure was calculated from the probits of the percentages of affected daphnia and the logarithms of the corresponding test substance concentrations using the maximum likelihood estimation method (Finney, D.J., 1971: Probit analysis, Cambridge University Press, Cambridge, U.K., 3rd edition).
The 48h-EC50 was calculated as AB1/2, with A being the concentration at which not more than 10% of the daphnids were immobilized and B being the concentration with 100% effect.

Any other information on results incl. tables

ACCEPTABILITY OF THE TEST

1. In the controls, no daphnia became immobilised or trapped at the surface of the water.

2. The oxygen concentration was > 5 mg/L at the end of the test. Other test conditions (pH and temperature) were maintained within the ranges prescribed by the protocol.

3. The 24h-EC50 (based on the initial concentration) of potassium dichromate was within the range of 0.6 to 1.7 mg/L.

The pH values were stable during the test and were thus maintained within the range prescribed by the protocol (6.0-8.5, constant within 1 unit in any test solution). Oxygen concentrations were maintained at levels above the limits prescribed by the protocol (>7 mg/L and 25 mg/L at the start and the end of the test, respectively).

The temperature of the test medium measured in the blank-control varied from 20.4 to 21 .9°C, which is within the limits prescribed by the protocol (18-22°C, constant within 2°C).

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Conclusions:

Under the conditions of the present study TMP did not induce acute immobilisation of Daphnia magna at 1.8 mg/L after 48 hours of exposure (NOEC).
The 24h-EC50 was 5.2 mg/L based on nominal concentrations (95% confidence interval between 4.8 and 6.0 mg/L).
The 48h-EC50 was 2.4 mg/L based on nominal concentrations, with 10% immobility at 1.8 mg/L and 100% immobility at 3.2 mg/L.