Methyl hydrogen octadecylphosphonate

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:

2006

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2006

Report date:

2006

Materials and methods

Test guideline

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Reference substance name:

Methyl hydrogen octadecylphosphonate

EC Number:

246-905-6

EC Name:

Methyl hydrogen octadecylphosphonate

Cas Number:

25371-55-5

Molecular formula:

C19H41O3P

IUPAC Name:

methoxy(octadecyl)phosphinic acid

impurity 1

Reference substance name:

Octadecylphosphonic acid

EC Number:

225-216-4

EC Name:

Octadecylphosphonic acid

Cas Number:

4724-47-4

Molecular formula:

C18H39O3P

IUPAC Name:

octadecylphosphonic acid

impurity 2

Reference substance name:

Dimethyl octadecylphosphonate

EC Number:

246-904-0

EC Name:

Dimethyl octadecylphosphonate

Cas Number:

25371-54-4

Molecular formula:

C20H43O3P

IUPAC Name:

dimethyl octadecylphosphonate

Test material form:

solid

Details on test material:

Test Item Identification: X#15249Batch: 04055A001Purity: >91%Description: White waxy solid blockStorage conditions: room temperature in the dark

Specific details on test material used for the study:

Test Item Identification: X#15249Batch: 04055A001Description: White waxy solid block

Sampling and analysis

Analytical monitoring:

yes

Details on sampling:

Water samples were taken from the solvent stock solution at 0 hours, solvent control (replicates R1 - R4 pooled) and all the test groups (replicates R1 - R2 and R3 - R4 pooled) at 0 and 48 hours for quantitative analysis. However, the 48 hour samples were not analysed as the test item could not be analyzed at 0 hours since it was below the limit of detection. Duplicate samples were taken and stored at approximately -20°C for further analysis if necessary.

Test solutions

Vehicle:

yes

Remarks:

dimethylformamide

Details on test solutions:

No definitive experimental determination of the water solubility was possible due to the surface active properties of the test material. However, testing indicated that the water solubility of the major component of the test material was less than or equal to 2.2E-04 g/L. Preliminary solubility work showed that the highest attainable test concentration (by visual inspection) that could be prepared was 0.20 mg/1 by spiking reconstituted water with an aliquot (100 ul/l) of a solvent stock solution prepared in dimethylformamide. At higher test concentrations precipitation of the test material was observed on addition of the test material solvent stock solution to water.Based on this information the test material fell into the category of a 'difficult substance' as defined by the OECD Guidance Document on Aquatic Toxicity Testing of Difficult Substances and Mixtures (OECD 2000). Therefore a media preparation trial was conducted in order to determine the solubility of the test material under test conditions and whether prolonged stirring of the preparations increased the dissolved test material concentration. An amount of test material (100 mg) was dissolved in dimethyformamide and the volume adjusted to 50 ml to give a 100 mg/50 ml solvent stock solution. An aliquot (500 ul) of this solvent stock solution was dispersed in 5 litres of culture medium with the aid of magnetic stirring for approximately 10 minutes to give the required test concentration of 0.20 mg/L.The range finding test used nominal concentrations of 0.020 and 0.02 mg/L test substance with a solvent control of 100 ul/L of dimethylformamide. The test material was suspected to adhere to glassware. Therefore, in order to saturate any active sites, the test vessels were pre-conditioned with the test concentration to be used in the test, approximately 24 hours prior to the test start.Based on the results of the range finding test, the definative test was a "limit" test at 0.20 mg/L. An amount of test material (100 mg) was dissolved in dimethyformamide with the aid of ultrasonication for approximately 2 minutes and the volume adjusted to 50 ml to give a 100 mg / 50 ml solvent stock solution. An aliquot (200 ul) of the 100 mg / 50 ml solvent stock solution was dispersed in a final volume of 2 litres of reconstituted water to give the 0.20 mg/L test concentration.The control and solvent control groups were maintained under identical conditions but not exposed to the test material. The solvent control group was exposed to 100 ul/L of dimethyformamide.

Test organisms

Test organisms (species):

Daphnia magna

Details on test organisms:

TEST ORGANISM- Common name: Daphnia magna- Source: in house cultures- Age at study initiation: <24 hours old (first instar daphnids)- Feeding during test: animals were not fed during the testACCLIMATION- Acclimation period: acclimitisation from birth- Acclimation conditions (same as test or not):animals were held in water of the same quality and conditions as test water

Study design

Test type:

static

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

48 h

Test conditions

Hardness:

250 mg/L as CaCO3

Test temperature:

20.6 - 20.9 °C

pH:

7.9

Dissolved oxygen:

8.8 - 8.9 mg/l

Salinity:

N/A

Nominal and measured concentrations:

0.02 mg/L and 0.2 mg/L for the range finding test and 0.2 mg/L for the definative test - nominal concentrations

Details on test conditions:

TEST SYSTEM- Test solution volume: 200 mL (in 250 mL glass jars) - Type: Closed; vessels were covered to reduce evaporation- Renewal rate of test solution (frequency/flow rate): Not applicable (static test)- No. of organisms per vessel: 5 (definitive test) or 10 (range-finding test)- No. of vessels per concentration (replicates):4 replicates- No. of vessels per vehicle control (replicates): 4 replicatesOTHER TEST CONDITIONS- Photoperiod:16 hours light/8 hours dark with 20 minute transition periods at dusk and dawnEFFECT PARAMETERS MEASURED (with observation intervals if applicable) :immobilization or adverse reactions were recorded at 24 and 48 h after start of exposure.TEST CONCENTRATIONS- range finding test: 0.02 and 0.2 mg/L (nominal)- definitive test: 0.2 mg/L (nominal)The control & solvent control groups were maintained under identical conditions but not exposed to test material. The solvent control group was exposed to 100 uL/L of dimethylformamide.

Reference substance (positive control):

yes

Remarks:

The positive control is conducted once every six months using potassium dichromate (48-h EC50: 0.97 mg/L)

Results and discussion

Effect concentrations

Effect concentrations 1

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

> 0.2 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Effect concentrations 2

Duration:

48 h

Dose descriptor:

NOEC

Effect conc.:

0.2 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Details on results:

There was no immobilization observed in either the range-finding or definitive tests.

Results with reference substance (positive control):

The No Observed Effect Concentration after 24 and 48 hours was 0.56 mg/1. The 48-h EC50 was 0.97 mg/L. The results from the positive control with potassium dichromate were within the normal range for this reference material. The mean 48-Hour EC50 value calculated from all positive controls was 0.84 mg/1 (sd = 0.24).

Reported statistics and error estimates:

Not applicable

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Conclusions:

The acute toxicity of the test material to the freshwater invertebrate Daphnia magna has been investigated and gave a 48-Hour EC50 > 0.20 mg/L (the highest attainable nominal concentration). Correspondingly the No Observed Effect Concentration was 0.20 mg/L.

Executive summary:

A 48-hour static toxicity test with Daphnia magna was performed in a test designed to meet the requirements OECD Test Guideline 202. Preliminary investigation showed that maximum limit of water solubility for the test item under the test conditions was 0.2 mg/L (nominal). A range-finding test was first conducted at nominal concentrations of 0.02 and 0.2 mg/L. As no immobilization was observed in the range-finding test, the definitive test was conducted as a limit test at a nominal concentration of 0.2 mg/L (highest attainable concentration).

In the definitive test, 20 daphnids (4 replicates of 5 daphnids) were exposed to a single nominal loading rate of 0.2 mg/L as a limit test, while a second group of 20 daphnids (also 4 replicates of 5) was exposed to dilution test water only (control group) and a third group of 20 daphnids (also 4 replicates of 5) were exposed to 100 uL/L of the dimthylformamide solvent. No test item was added to either of the control groups.

The test solutions remained unchanged for the duration of the test. Immobilization in the range finding and the definitive test was recorded at 0, 24 and 48 hours.

No immobilization was observed in any of the test or control groups during the range finding test or definitive test. The 48-h EC50 derived from the limit test was > 0.2 mg/l (nominal) and the NOEC was 0.2 mg/l (nominal), the highest attainable concentration in this test. As no immobilization was observed in any of the groups and the dissolved oxygen concentration was > 3 mg/L, the validity criteria were satisfied.