Triethyl phosphonoacetate

Short-term toxicity to aquatic invertebrates

Link to relevant study record(s)

Reference

Endpoint:

short-term toxicity to aquatic invertebrates

Type of information:

experimental study

Adequacy of study:

key study

Study period:

from 2012-08-01 to 2012-2012-06-18

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 202 (Daphnia sp. Acute Immobilisation Test)

Deviations:

no

Qualifier:

according to guideline

Guideline:

EU Method C.2 (Acute Toxicity for Daphnia)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Remarks:

2011-08-31

Analytical monitoring:

yes

Details on sampling:

Water samples were taken from the control 1.0, 3.2, 10, 32 and 100 mg/L test groups (replicates R1-R4 pooled) at 0 and 48h for quantitative analysis. All 0-hour samples were stored at approximately -20°C prior to analysis.
Duplicate samples and samples of the 1.8, 5.6, 18 and 56 mg/L test groups were taken and stored at approximately -20 °C for further analysis if necessary.

Details on test solutions:

The test item was dissolved directly in water.

An amount of test item (250 mg) was dissolved in reconstituted water and the volume adjusted to 2.5 litters to give 100 mg/L test concentration from which a series of dilutions was made to give further test concentrations of 56, 32, 18, 10, 5.6, 3.2 1.8 and 1.0 mg/L.
Each prepared concentration was inverted several times to ensure adequate mixing and homogeneity.

The concentration of the test item in the test preparations were verified by chemical analysis at 0 and 48 hours.

Test organisms (species):

Daphnia magna

Details on test organisms:

TEST ORGANISM
- Common name: Daphnia magna
- Strain: No data
- Source: Derived from in-house laboratory cultures
- Age at study initiation (mean and range, SD): less than 24h old
- Method of breeding: In-house laboratory. Culture conditions ensure that reproduction was by parthenogenesis
- Feeding during test: No

ACCLIMATION
- Acclimation period: No
- Type and amount of food: mixture of algal suspension (Desmodesmus subspicatus) and Tetramin flake food suspension
- Feeding frequency: no data
- Health during acclimation (any mortality observed): No data

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

48 h

Hardness:

250 mg/L of CaCO3

Test temperature:

21°C

pH:

7.9 to 8.1

Dissolved oxygen:

0h: 9.2 to 9.4 and 48h: 7.9 to 8.1

Salinity:

not applicable

Nominal and measured concentrations:

nominal concentrations: 0, 1.0, 1.8, 3.2, 5.6, 10, 18, 32, 56 and 100 mg/L
Measured concentration: See results tables

Details on test conditions:

TEST SYSTEM
- Test vessel: glass jars
- Type (delete if not applicable): closed
- Material, size, headspace, fill volume: 250 mL filled at 200mL
- Aeration: No
- No. of organisms per vessel: 5
- No. of vessels per concentration (replicates):4
- No. of vessels per control (replicates):4
- No. of vessels per vehicle control (replicates):4

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: Reconstituted water:
Stock solution :
CaCl2 . 2H2O 1.76 g/L, MgSO4 . 7H2O 4.93 g/L, NaHCO3 : 2.59 g/L, KCl : 0.23 g/L
Preparation
An aliquot (25mL) of each solution a-d was added to each litre (Final volume) of deionized water with a conductivity of <5µS/cm. The reconstituted water had a pH of 7.8 ± 0.2 adjusted (if necessary) with NaOH or HCl and was aerated until the dissolved oxygen concentration was approximately air-saturated value.
The reconstituted water had an approximate theoretical total hardness of 250 mg/L as CaCO3
- Conductivity: 5µS/cm

OTHER TEST CONDITIONS
- Adjustment of pH: yes if necessary
- Photoperiod: 16hours light and 8hours darkness cycle with 20 minute dawn and dusk transition period
- Light intensity: 903 to 990 Lux over the test period

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) :immobilization measured every day

TEST CONCENTRATIONS
- Test concentrations: 0, 1.0, 1.58, 3.2, 5.6, 10, 18, 32, 56 and 100 mg/L
- Justification for using less concentrations than requested by guideline:
- Range finding study; Yes
- Test concentrations: 0.1, 1, 10 and 100 mg/L
- Results used to determine the conditions for the definitive study: No immobilization at 0.1 and 1.0 mg/L. However 10 and 100 mg/L, immobilization was observed

Reference substance (positive control):

yes

Remarks:

Potassium Dichromate (Study number: 41104946)

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

3.9 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Remarks on result:

other: 3.6-4.3 mg/L

Details on results:

Cumulative immobilization data from the exposure of Daphnia magna to the test item are given in table 2.

The EC50 after 24h and 48h exposure were 7.3 (6.9-7.7) and 3.9 (3.6-4.3) respectively.
The NOEC after 24h and 48h exposure were 3. 2mg/L and 1.8 mg/L respectively. Due to unsuitable nature of the data, it was not possible to calculate the slope and error of response curve at 24 and 48 hours.

All control and test preparations were observed to be clear colourless solutions throughout the duration of the test.

Temperature was maintained at 20°C to 21°C throughout the test, whilst the light intensity was observed to range from 903 to 990 lux over test period. There were no treatment related differences for oxygen concentration or pH.

The oxygen concentration in some of test 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-saturating the diluent and was considered not to have had an impact on the outcome or integrity of the test as no adverse effect were observed on the control group.

Analysis of the test preparation at 0 and 48 hours showed measured test concentrations to be near nominal with exception of the 32 mg/L test sample at 48 hours which showed a measured test concentration of 76% of nominal was obtained. As the overall measured concentrations were within 80 to 120 % of nominal, it was considered appropriate to calculate the results based on the nominal test concentrations only.

Results with reference substance (positive control):

The study was conducted between 29 November 2011 and 01 December 2011.
concentration: 0.32, 0.56, 1.0, 1.8 and 3.2 mg/L.
Analysis of the immobilization data by the geometric mean method at 24 hours and the trimmed Spearman-Karber method at 48 hours based on the nominal test concentration gave the following results:
The EC50 after 24h and 48h exposure were 1.3 (1.0-1.8) and 1.4 (1.0-1.3) respectively.
The NOEC after 24h and 48h exposure were 1.0 mg/L and 0.56 mg/L respectively.

The results from the positive control with potassium dichromate were within the normal range for this reference item.

Table 2 : Cumulative immobilisation data

 

Nominal concentration (mg/L)	Cumulative immobilised Daphnia (initial population : 5 per replicate)
	24 hours						48 hours
	R1	R2	R3	R4	Total	%	R1	R2	R3	R4	Total	%
Control	0	0	0	0	0	0	0	0	0	0	0	0
1.0	0	0	0	0	0	0	0	0	0	0	0	0
1.8	0	0	0	0	0	0	0	0	0	0	0	0
3.2	0	0	0	0	0	0	1	1	1	0	3	15
5.6	1	0	0	0	5	5	5	5	5	5	20	100
10	5	5	5	5	20	100	5	5	5	5	20	100
18	5	5	5	5	20	100	5	5	5	5	20	100
32	5	5	5	5	20	100	5	5	5	5	20	100
56	5	5	5	5	20	100	5	5	5	5	20	100
100	5	5	5	5	20	100	5	5	5	5	20	100

R1 – R4 : Replicates 1 to 4

 

Concentrations of test item in aqueous test media samples determined using HPLC-MS Analysis

 

Sample	Nominal concentration (mg/L)	Concentration found (mg/L)	Expressed as a percentage of the nominal concentration (%)
0 hours	Control	<LOQ	-
	1.0	0.898	90
	3.2	2.79	87
	10	8.66	87
	32	23.6	82
	100	87.8	88
48 hours	Control	<LOQ	-
	1.0	0.834	83
	3.2	2.70	84
	10	8.14	81
	32	24.5	76
	100	82.0	82

 

Physico-chemical measurements

 

Nominal concentration (mg/L)		0 hours				24 hours	48 hours
		pH	Mg O2/L	% ASV *	T (°C)	T  (°C)	pH	Mg O2/L	% ASV *	T (°C)
Control	R1	8.0	9.3	102	20	21	8.1	9.1	102	21
	R2	8.0	9.3	102	20	21	8.1	9.1	102	21
	R3	8.0	9.3	102	20	21	8.1	9.0	101	21
	R4	8.0	9.3	102	20	21	8.1	9.0	101	21
1.0	R1	8.0	9.3	102	20	21	8.1	9.0	101	21
	R2	8.0	9.3	102	20	21	8.1	8.9	100	21
	R3	8.0	9.3	102	20	21	8.1	9.0	101	21
	R4	8.0	9.3	102	20	21	8.1	8.9	100	21
1.8	R1	8.0	9.3	102	20	21	8.1	8.9	100	21
	R2	8.0	9.3	102	20	21	8.1	8.9	100	21
	R3	8.0	9.3	102	20	21	8.1	8.9	100	21
	R4	8.0	9.3	102	20	21	8.1	8.9	100	21
3.2	R1	8.0	9.3	102	20	21	8.0	8.9	100	21
	R2	8.0	9.3	102	20	21	8.1	8.9	100	21
	R3	8.0	9.2	101	20	21	8.1	8.9	100	21
	R4	8.0	9.3	102	20	21	8.1	8.9	100	21
5.6	R1	8.0	9.3	102	20	21	8.0	8.9	100	21
	R2	8.0	9.3	102	20	21	8.0	8.9	100	21
	R3	8.0	9.3	102	20	21	8.0	8.9	100	21
	R4	8.0	9.3	102	20	21	8.0	8.9	100	21
10	R1	8.0	9.3	102	20	21	8.0	8.9	100	21
	R2	8.0	9.3	102	20	21	8.0	8.9	100	21
	R3	8.0	9.3	102	20	21	8.0	8.8	99	21
	R4	8.0	9.3	102	20	21	8.0	8.9	100	21
18	R1	8.0	9.4	103	20	21	8.0	8.8	99	21
	R2	8.0	9.3	102	20	21	8.0	8.8	99	21
	R3	8.0	9.3	102	20	21	8.0	8.8	99	21
	R4	8.0	9.4	103	20	21	8.0	8.8	99	21
32	R1	8.0	9.3	102	20	21	8.0	8.8	99	21
	R2	8.0	9.3	102	20	21	8.0	8.8	99	21
	R3	8.0	9.3	102	20	21	8.0	8.8	99	21
	R4	8.0	9.4	103	20	21	8.0	8.8	99	21
56	R1	8.0	9.3	102	20	21	8.0	8.8	99	21
	R2	8.0	9.3	102	20	21	8.0	8.8	99	21
	R3	8.0	9.3	102	20	21	8.0	8.8	99	21
	R4	8.0	9.3	102	20	21	8.0	8.8	99	21
100	R1	8.0	9.3	102	20	21	8.0	8.8	99	21
	R2	8.0	9.3	102	20	21	7.9	8.7	98	21
	R3	8.0	9.2	101	20	21	8.0	8.7	98	21
	R4	8.0	9.3	102	20	21	7.9	8.7	98	21

* ASV = Dissolved oxygen concentration expressed as a percentage of air saturation value

R1 – R4 : Replicates 1 to 4

Validity criteria fulfilled:

yes

Conclusions:

The acute toxicity of the test item to the freshwater invertebrate Daphnia magna has been investigated and gave a 48-hour EC50 value of 3.9 mg/L. 95% confidence limits 3.6-4.3 mg/L. The NOEC at 48 hours was 1.8 mg/L.

Executive summary:

The acute toxicity of TEPA to Daphnia magna was studied under static conditions according to the OECD guideline 202 and GLP.  Daphnids were exposed to control and test chemical at measured concentration of 1.0, 1.8, 3.2, 5.6, 10, 18, 32, 56 and 100 mg/L for 48 hr.  Mortality was observed daily. 

The 48–hour EC₅₀ was 3.9 mg/L (3.6 -4.3 mg/L).

The study satisfies the guideline requirements for an acute toxicity study with freshwater invertebrates.

 

Results Synopsis

 Test Organism: Daphnia magna

NOEC 1.8 mg/L   

EC5O 3.9 mg/L      

Description of key information

The 48–hr-acute toxicity of TEPA to Daphnia magna was studied under static conditions according to OECD guideline 202.  Daphnids were exposed to control and test chemical at measured concentration of 1.0, 1.8, 3.2, 5.6, 10, 18, 32, 56 and 100 mg/L for 48 hr.  Mortality was observed daily. 

The 48–hour EC50 was 3.9 mg/L. (3.6 -4.3 mg/L)

The 48-hour NOEC was 1.8 mg/L

The study satisfies the guideline requirements for an acute toxicity study with freshwater invertebrates.

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates

Dose descriptor:

EC50

Effect concentration:

3.9 mg/L