Triethyl phosphonoacetate

Short-term toxicity to fish

Link to relevant study record(s)

Reference

Endpoint:

short-term toxicity to fish

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2011-10-11 to 2012-05-09

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Remarks:

Study conducted in compliance with international standard guidelines under GLP conditions. The study report was well documented with all mandatory information included.

Qualifier:

according to guideline

Guideline:

OECD Guideline 203 (Fish, Acute Toxicity Test)

Deviations:

not specified

Qualifier:

according to guideline

Guideline:

EU Method C.1 (Acute Toxicity for Fish)

Deviations:

not specified

GLP compliance:

yes (incl. QA statement)

Remarks:

2011-08-31

Analytical monitoring:

yes

Details on sampling:

- Concentrations: 100 mg/L for the definitive test
- Sampling method: 0 (fresh media) and 24h and 96h ( old media)
- Sample storage conditions before analysis: -20° c

Vehicle:

no

Details on test solutions:

An amount of test item (2000 mg) was dissolved in directly dechlorinated tap water (500 mL) to give a 4000 mg/L stock solution. The entire volume of this solution was added to a final volume of 20L of dechlorinated tap water and stirred using a flay bladded mixer for approximately 1 minute, to give the 100 mg/L test concentration.

Test organisms (species):

Oncorhynchus mykiss (previous name: Salmo gairdneri)

Details on test organisms:

TEST ORGANISM
- Common name: rainbow trout
- Source: Brown Fisheries Limited Hebden, near Skipton, Yorkshire, UK
- Age at study initiation (mean and range, SD): No data
- Length at the end of the study (length definition, mean, range and SD): 4.0 cm ± 0.3 cm
- Weight at the end of the study (mean and range, SD): 0.82 g ± 0.23 g
- Method of breeding: 16h light and 8 hours darkness cycle with 20 minutes dawn and dusk transition periods
- Feeding during test: No

ACCLIMATION
- Acclimation period: Yes (from 8 February 2012 to 20 February 2012)
- Acclimation conditions (same as test or not): Yes
- Type and amount of food: commercial trout pellets
- Feeding frequency: no
- Health during acclimation (any mortality observed): Less than 1% mortality in the 7 days prior the start

Test type:

semi-static

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

96 h

Hardness:

140mg/L as CaCO3

Test temperature:

14°C to 15°C (measured every 24h)

pH:

7.9 to 8.1 (measured every 24h)

Dissolved oxygen:

9.2 to 11.7 mg O2/L (measured every 24h)

Salinity:

Not applicable

Nominal and measured concentrations:

Nominal: 100 mg/L
Measured: 86.6 mg/L (87%) to 92.2 mg/L (92%)

Details on test conditions:

TEST SYSTEM
- Test vessel: glass fiber tank
- Type (delete if not applicable): open but covered to prevent evaporation
- Material, size, headspace, fill volume: 20 L corresponding to a loading rate of 0.29g bodyweight per liter
- Aeration: aerated via narrow bore glass tube
- Renewal rate of test solution (frequency/flow rate): daily
- No. of organisms per vessel: 7
- No. of vessels per concentration (replicates): 1
- No. of vessels per vehicle control (replicates): 1

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: Laboratory tap water dechlorinated by a passage through an activated carbon filter (Purite series 500) and partly softened (Elga Nimbus 1248 D Duplex Water Softener) Then, the water was passed through a series of computer controlled plate heat exchangers to achieve the required temperature.
- Total organic carbon: 0.92 mg/L
- Particulate matter: No data
- Metals: No data
- Pesticides: No data
- Chlorine: dechlorinated by a passage through an activated carbon filter (Purite series 500)
- Alkalinity: No data
- Ca/mg ratio: No data
- Conductivity: 419 µS/cm at 20 °C
- Culture medium different from test medium: No
- Intervals of water quality measurement: daily throughout the test

OTHER TEST CONDITIONS
- Adjustment of pH: No
- Photoperiod: 16 hours light and 8 hours darkness with 20 minute down end dust transition period
- Light intensity: No data

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) :
Mortality or sub-lethal effects after 3h, 5h, 24h, 48h, 72h and 96h

TEST CONCENTRATIONS
- Spacing factor for test concentrations: 10
- Justification for using less concentrations than requested by guideline:
- Range finding study: Yes
- Test concentrations: 1; 10 and 100 mg/L
- Results used to determine the conditions for the definitive study: No observations of mortalities, or sub-lethal effects at 100 mg/L in the range finding test.

Reference substance (positive control):

no

Duration:

96 h

Dose descriptor:

LC50

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Duration:

96 h

Dose descriptor:

NOEC

Effect conc.:

100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Details on results:

There were no sub-lethal effects of exposure during the range finding test at 1.0, 10 and 100 mg/L.
Based on this information,, a single test concentration, in duplicate, of 100 mg/L was selected for the definitive test.(limit test)

Chemical analysis of the test preparation at 0 and 24h showed measured concentrations of 93% and 96% of nominal respectively indicating that the test item was stable under test condition.

There were no mortality and no sub-lethal effects in 7 fish exposed at 100 mg/L for a period of 96h.

The test preparation were observed to be clear, colourless solution throughout the duration of the test.

The results of the physicochemical measurements are given in Appendix 4. Temperature was maintained at approximately 14°C throughout the test, while there were no treatment related differences for oxygen concentration or pH.
The oxygen concentration in some of vessels was observed to have an air saturation value (ASV) in excess of 100%. this was considered to be due to the presence of microscopic air bubbles in the media super-saturing the diluent and was considered not to have had an impact on the outcome or integrity of the test as no adverse effects were observed

Analysis of the test preparation at, 0, 24h, and 96h showed measured test concentrations to range from 87% to 92% of nominal and so it was considered justifiable to estimate the LC50 values in terms of nominal test concentration only.

Sublethal observations / clinical signs:

Table 2: Cumulative mortality data in the definitive test

 

Nominal concentration (mg/L)	Cumulative mortality (initial population = 7)						% mortality
	3 hours	6 hours	24 hours	48 hours	72 hours	96 hours	96 hours
Control	0	0	0	0	0	0	0
100	0	0	0	0	0	0	0

 

 

Appendix 4: Physico-chemical Measurements

 

Nominal concentration (mg/L)	Time (Hours)
	0 Hours (Fresh media)				24 Hours (Fresh media)				24 Hours (Old media)
	pH	Mg O2/L	% ASV*	T °C	pH	Mg O2/L	% ASV*	T °C	pH	Mg O2/L	% ASV*	T °C
Control	7.9	11.7	114	14	8.1	9.9	96	14	7.9	11.5	112	14
100	7.9	11.7	114	14	8.2	10.0	97	14	7.9	11.6	113	14

 

Nominal concentration (mg/L)	Time (Hours)
	48 Hours (Fresh media)				48 Hours (Old media)				72 Hours (Fresh media)
	pH	Mg O2/L	% ASV*	T °C	pH	Mg O2/L	% ASV*	T °C	pH	Mg O2/L	% ASV*	T °C
Control	7.9	9.6	93	14	7.8	11.2	109	14	8.0	9.6	95	15
100	8.0	9.8	95	14	7.9	11.4	111	14	8.1	9.8	97	15

 

Nominal concentration (mg/L)	Time (Hours)
	72 Hours (Old media)				96 Hours (Old media)
	pH	Mg O2/L	% ASV*	T °C	pH	Mg O2/L	% ASV*	T °C
Control	7.8	11.2	109	14	8.1	9.2	91	15
100	7.8	11.3	110	14	8.1	9.8	97	15

 

* ASV = Dissolved oxygen concentration expressed as a percentage of Air Saturation Value

Validity criteria fulfilled:

yes

Conclusions:

The acute toxicity of the test item to the freshwater fish rainbow trout (Oncorhynchus mykiss) has been investigated and gave a 96-Hours LC50 greater than 100 mg/L. The NOEC was 100 mg/L

Executive summary:

In a 96-h acute toxicity study, rainbow trout (Oncorhynchus mykiss) were exposed to TEPA (Triethyl phosphono acetate) at 100 mg/L nominal concentrations (limit test) under semi-static conditionsaccording to the OECD guideline 203 (1992). 

The 96-h LC₅₀ was >100 mg/L

The NOEC value, based on mortality/sublethal effects, was 100mg/L.

No sublethal effects were observed. Based on the results of this study, TEPA is not harmful to fish.

 

LC₅₀ >100 mg /L      

NOEL = 100 mg /L

Description of key information

In a 96-h acute toxicity study, rainbow trout (Oncorhynchus mykiss) were exposed to TEPA (Triethyl phosphono acetate) at 100 mg/L nominal concentrations under semi-static conditions according to the OECD guideline 203 (1992). 

The 96-h LC50 was >100 mg/L

The NOEL value, based on mortality/sublethal effects, was 100 mg/L.

No sublethal effects were observed. Based on the results of this study, TEPA would be not classified for fish. 

Key value for chemical safety assessment

Fresh water fish

Fresh water fish

Dose descriptor:

EC50

Effect concentration:

> 100 mg/L