Diethyl (hydroxymethyl)phosphonate

Short-term toxicity to fish

Administrative data

Endpoint:

short-term toxicity to fish

Type of information:

experimental study

Adequacy of study:

key study

Study period:

August 2015 - february 2016

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: GLP and Guideline study

Cross-reference

Reason / purpose for cross-reference:

reference to same study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2016

Report date:

2016

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

OECD Guideline 203 (Fish, Acute Toxicity Test)

Deviations:

yes

Remarks:

The range finding phase of the study employed a static (no media renewal) exposure regime, which deviated from the study protocol where a daily renewal of control and test media was stated. This deviation had no impact on the study

Test guideline 2

Qualifier:

according to guideline

Guideline:

EU Method C.1 (Acute Toxicity for Fish)

Deviations:

yes

Remarks:

See above

Principles of method if other than guideline:

Not relevant

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Reference substance name:

Diethyl (hydroxymethyl)phosphonate

EC Number:

221-391-6

EC Name:

Diethyl (hydroxymethyl)phosphonate

Cas Number:

3084-40-0

Molecular formula:

C5H13O4P

IUPAC Name:

diethyl (hydroxymethyl)phosphonate

Test material form:

other: meduim viscosity liquid

Details on test material:

E06-16 (Lot# 1041-37-6, Sample: T# 207), transparent "medium-viscoosity" liquid.

Specific details on test material used for the study:

n/a

Sampling and analysis

Analytical monitoring:

yes

Details on sampling:

Four, mid-vessel samples (10 mL) of media were taken from the control and test vessels at 0 and 72 hours (fresh media) and at 24 and 96 hours (expired media) for analysis. The samples were diluted by a factor of 4000 with dechlorinated tap water, prior to quantitation by LC-MS.

Test solutions

Vehicle:

no

Details on test solutions:

Preparation of the Diluent water:
The water used to hold the fish and for the study was laboratory tap water (two grades of dechlorinated) and softened by passage through a water purification system. It was passed through a high grade activated carbon filter, following passing through a water softener before final reverse osmosis treatment. The water were then remixed to give a supply with the desired water hardness. This water was then held in an intermediate tank where it was equilibrated to the test temperature and gently aerated before being supplied to the holding and test areas.

Test substance preparation:
The method of preparation used in the definitive test was based on the findings of the range finding test. The test substance (2000 mg) was added to dilution water (3 L) in a volumetric flask (5 L) and made up to volume with mixing to give a solution (400 mg/L). The content of the flask was added to 10 L dilution water in the test vessel (25 L glass aquarium), after which a further aliquot (5 L) of dilution water was added to give 20 L of test medium with a nominal concentration of 100 mg/L as E06-16.

Test organisms

Test organisms (species):

Oncorhynchus mykiss (previous name: Salmo gairdneri)

Details on test organisms:

Fish supplier: A commercial fish farm, UK.
Size of fish used in the definitive test: determined by weighing and measuring a sample of ten fish taken at random from the holding tank;
Mean total length was 5.57 cm and their mean wet weight was 1.523 g.
Daily feed with: TROUW (UK) Ltd; Nutra Fry 02.
No medication was given during the holding period.

Study design

Test type:

semi-static

Water media type:

other: laboratory tap water, dichlorinated.

Limit test:

yes

Total exposure duration:

96 h

Remarks on exposure duration:

A range finding test was followed by a definitive test with a single test concentration (limit test), plus a diluent water control group.

Post exposure observation period:

n/a

Test conditions

Hardness:

Control: 167 mg/L
Treatment: 173 mg/L As CaCO3

Test temperature:

Control: 13.6 - 14.6oC
Treatment: 13.8 - 14.7oC

pH:

Control: 8.00 - 8.29
Treatment: 7.85 - 8.32

Dissolved oxygen:

% ASV-
Control: 90 - 101
Treatment: 78 - 102

Salinity:

not detected

Conductivity:

not detected

Nominal and measured concentrations:

100 and 106 mg/L respectively

Details on test conditions:

Treatment and control groups were maintained at 12 to 17oC throughout the exposure period and constant to within +/- 1oC during the study. The temperature of the water in the diluent water control vessel was continuously monitored during the study.Supplementary aeration was provided via narrow bore glass tubes. A photoperiod of 16 hours light: 8 hours dark was maintained, with periods of subdued lighting at the beginning and end of each light phase. Daily records of temperature, pH and dissolved oxygen were kept for each control and test vessel together with measurements of total hardness for selected vessels at 0 hours. The fish were not fed during the 96 hour exposure period.

Results and discussion

Effect concentrations

Effect concentrations 1

Key result

Duration:

96 h

Dose descriptor:

other: LC50 and NOEC

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

other: mortality or any other treatment related effect

Effect concentrations 2

Key result

Duration:

96 h

Dose descriptor:

other: LC50 and NOEC

Effect conc.:

> 106 mg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

test mat.

Basis for effect:

other: mortality or any other treatment related effect

Details on results:

The measured concentrations of E06-16 ranged between 101 and 114% of their nominal values in samples of freshly prepared (0 and 72 hour) and expired (24 and 96 hour) media, demonstrating that the nominal concentration of the test substance had been adequately achieved and maintained throughout the test. The overall mean measured concentration of E06-16 was 106 mg/L, and this value has been used in the determination of study end-points. Furthermore, all the measurements of water quality (temperature, pH, concentrations of dissolved oxygen and total hardness) remained within acceptable limits throughout the study.

Results with reference substance (positive control):

n/a

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Conclusions:

No mortality or treatment related effects on the fish were observed.
96-hour LC50 and NOEC was > 106 mg/L (mean measured concentration).

Executive summary:

E06 -16 acute toxicity to rainbow trout

(Oncorhynchus mykiss) was assessed under semi-static conditions with daily renewal of the media.

Fish were exposed to E06-16 dissolved in water at a nominal concentration of 100 mg/L (Overall mean measured concentration- 106mg/L)(limit test).

Observation of the fish was made after approximately 3, 6, 24, 48, 72 and 96 hours of

exposure. No mortality or treatment related effects on the fish were observed throughout the

96 hours of the test. Therefore the 96-hour LC50 value could not be determined but must be

greater than 106 mg/L (mean measured concentration) and the NOEC (no observed effect

concentration) is 106 mg/L (mean measured concentration).