Phenylphosphonic acid

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

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2018

Materials and methods

Test guideline

Qualifier:

according 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:

Phenylphosphonic acid

EC Number:

216-388-1

EC Name:

Phenylphosphonic acid

Cas Number:

1571-33-1

Molecular formula:

C6H7O3P

IUPAC Name:

phenylphosphonic acid

Test material form:

solid: particulate/powder

Details on test material:

Lot number LKF6065

Specific details on test material used for the study:

Appearance: White crystalline powder
Batch: LKF6065
Test item storage: At room temperature protected from light
Stable under storage conditions until: 09 June 2018 (expiry date)

Sampling and analysis

Analytical monitoring:

yes

Details on sampling:

Samples for possible analysis were taken from all test concentrations and the control according to the schedule below.
Frequency at t=0 h and t=48 h
Volume 2.0 mL from the approximate centre of the test vessels
Storage Samples were stored in a freezer (≤-15°C) until analysis at the analytical laboratory of the Test Facility.
At the end of the exposure period, the replicates were pooled at each concentration before sampling.
Additionally, reserve samples of 2.0 mL were taken for possible analysis. If not used, these samples were stored in a freezer (≤-15°C) for a maximum of three months after delivery of the draft report, pending on the decision of the sponsor for additional analysis.

Test solutions

Vehicle:

no

Details on test solutions:

The batch of Phenyl Phosphonic Acid tested was a white crystalline powder with a purity of 100.0% which was completely soluble in test medium at the concentrations tested. No correction was made for the purity/composition of the test item.

Preparation of test solutions started with the highest concentration of 100 mg/L in the combined limit/range-finding test and 1st full test, and 180 mg/L in the 2nd full test, applying approximately 10 minutes of magnetic stirring to accelerate dissolution of the test item in medium. Lower test concentrations were prepared by subsequent dilutions of the highest concentration in test medium. All test solutions were clear and colorless at the end of the preparation procedure.

It should be noted that in the 2nd full test the pH of the highest concentration was adjusted from 3.5 to 6.7 with 1 M NaOH (Merck, Darmstadt, Germany) before preparation of the lower test concentrations.

Test organisms

Test organisms (species):

Daphnia magna

Details on test organisms:

Test System
Species: Daphnia magna (Crustacea, Cladocera) (Straus, 1820), at least third generation, obtained by a cyclical parthenogenesis under specified breeding conditions.
Source: In-house laboratory culture with a known history.
Reason for selection: This system has been selected as an internationally accepted invertebrate species.
Validity of batch: 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.
Characteristics: For the test selection of young daphnids with an age of < 24 hours, from parental daphnids of more than two weeks old.

Breeding
Start of each batch: With newborn daphnids, i.e. less than 3 days old, by placing about 250 of them into 5 litres of medium in an all-glass culture vessel.
Maximum age of the cultures: 4 weeks
Renewal of the cultures: After 7 days of cultivation half of the medium twice a week.
Temperature of medium: 18-22°C
Feeding: Daily, a suspension of fresh water algae.
Medium: M7, as prescribed by Dr. Elendt-Schneider (Elendt, B.-P., 1990: Selenium deficiency in Crustacea. An ultrastructural approach to antennal damage in Daphnia magna Straus. Protoplasma 154, 25-33).

Study design

Test type:

static

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

48 h

Test conditions

Hardness:

The hardness: 180 mg/L expressed as CaCO3 and the pH: 7.7 ± 0.3.

Test temperature:

The temperature continuously measured in a temperature control vessel varied between 19 and 20°C during the test, and complied with the requirements as laid down in the study plan (18-22°C, constant within 2°C).

pH:

pH: 6-9, not varying by more than 1.5 units

Dissolved oxygen:

oxygen: > or = 3 mg/L at the end of the test

Salinity:

Not specified

Conductivity:

Not specified

Nominal and measured concentrations:

Combined Limit/Range-Finding Test
The project started with a combined limit/range-finding test. Twenty daphnids per concentration (four replicates, 5 daphnids per vessel) were exposed to a control and a concentration of 100 mg/L. Test procedure and conditions were similar to those applied in the 2nd full test with the following exception:
•Ten daphnids per concentration (in duplicate, 5 per vessel) were exposed to 0.10, 1.0 and 10 mg/L in the combined range-finding test.

Full Test
Test Concentrations
Phenyl Phosphonic Acid: 1st Full test: 10, 18, 32, 56 and 100 mg/L.
2nd Full test: 10, 18, 32, 56, 100 and 180 mg/L.

Combined Limit/Range-Finding Test
Samples taken from nominally 10 and 100 mg/L were analysed. The actual concentrations were 11 and 109 mg/L at the start of the test, respectively. Measured concentrations remained stable throughout the test (i.e. were 100 and 98% of initial.

Measured Concentrations
Samples taken from nominally 100 mg/L were analysed. Measured concentrations were at the level of nominal (97%) throughout the exposure period.

Details on test conditions:

Test Procedure and Conditions
Test duration: 48 hours
Test type: Static
Test vessels: 60 mL, all-glass
Medium: Adjusted ISO medium
Number of daphnids: 20 per concentration
Loading: 5 per vessel containing 50 mL of test solution
Light: 16 hours photoperiod daily
Feeding: No feeding
Aeration: No aeration of the test solutions.
Introduction of daphnids: Within 50 (1st full test) and 20 (2nd full test) minutes after preparation of the test solutions.

Controls: Test medium without test item or other additives.

Reference substance (positive control):

yes

Remarks:

potassium dichromate

Results and discussion

Effect concentrations

Key result

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

> 180 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Details on results:

Since no immobility was observed in the two full tests, it was concluded that the test item is not toxic for the daphnids up to an analytically confirmed nominal concentration of 180 mg/L.

Results with reference substance (positive control):

The actual responses in the reference test with K2Cr2O7 were within the ranges of the expected responses at the different concentrations, i.e. the 48h-EC50 was between 0.3 and 1.0 mg/L. Hence, the sensitivity of the batch of D. magna was in agreement with the historical data collected at Charles River Den Bosch.
The 24h-EC50 was 0.87 mg/L with a 95% confidence interval between 0.80 and 0.95 mg/L.
The 48h-EC50 was 0.54 mg/L with a 95% confidence interval between 0.49 and 0.61 mg/L.

Reported statistics and error estimates:

No EC50 could be calculated because the test item proved to be non-toxic (EC50 > maximum concentration tested).

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Conclusions:

In conclusion, the 48h-EC50 for Daphnia magna exposed to Phenyl Phosphonic Acid was beyond the range tested, i.e. exceeded the analytically confirmed nominal concentration of 180 mg/L.

Executive summary:

The objective of the study was to evaluate Phenyl Phosphonic Acid for its ability to generate acute toxic effects on the mobility of Daphnia magna during an exposure period of 48 hours and, if possible, to determine the EC₅₀at 24 and 48 hours of exposure.

The study procedures described in this report were based on the OECD guideline No. 202, 2004.

The batch of Phenyl Phosphonic Acid tested was a white crystalline powder with a purity of 100.0% which was completely soluble in test medium at the concentrations tested.

A final test was performed based on a preceding combined limit/range-finding and 1^stfull test.Twenty daphnids per group (5 per replicate, quadruplicate) were exposed to an untreated control and to test item concentrations of 10, 18, 32, 56, 100 and 180 mg/L. The total exposure period was 48 hours and samples for analytical confirmation of exposure concentrations were taken at the start and at the end of the test.

No immobility was observed in the control and at any of the test concentrations during the test period.

Samples taken from all test concentrations were analysed. The measured concentrations were at the level of nominal (98-102%) throughout the test. Based on these results, the effect parameters were based on the analytically confirmed nominal concentrations.

The study met the acceptability criteria prescribed by the study plan and was considered valid.

In conclusion, the 48h-EC₅₀forDaphnia magnaexposed to Phenyl Phosphonic Acid was beyond the range tested, i.e. exceeded an analytically confirmed nominal concentration of 180 mg/L.