Diphosphoric acid, compound with 1,3,5-triazine-2,4,6-triamine

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:

12 - 14 November 2004

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: GLP study conducted in accordance with an internationally recognised method

Qualifier:

according to guideline

Guideline:

OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)

GLP compliance:

yes (incl. QA statement)

Analytical monitoring:

yes

Details on sampling:

- Concentrations: data available from a preliminary range finding study identified the 48 hour EC50 as being approximately >100mg/1 and after discussions with the client, the definitive test concentrations were prepared as 0 (control), 10, 18, 32, 56 and 100mg/1.


- Sampling method: samples of the test solutions in which the daphnia were exposed were taken for analytical verification at the start of the definitive study, before and after renewal of solutions at 24 and 48 hours of the exposure period.

- Sample storage conditions before analysis: test substance specific analysis of each test concentration was carried out as soon as possible after sampling.

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
- Method: for the definitive test, a 100 mg/1 stock solution of MPP was prepared in reconstituted water. The sample was stirred well to produce a homogeneous solution. The test concentrations were prepared by addition of the appropriate volume of the stock solution to the dilution water to give the required concentrations for the test.
- Controls: as for test solution but without addition of test substance
- Chemical name of vehicle (organic solvent, emulsifier or dispersant): none used
- Concentration of vehicle in test medium (stock solution and final test solution): not applicable
- Evidence of undissolved material (e.g. precipitate, surface film, etc): none, a homogeneous solution was tested

Test organisms (species):

Daphnia magna

Details on test organisms:

TEST ORGANISM
- Common name: Daphnia
- Strain: Magna
- Source: reputable supplier
- Age at study initiation: less than 24 hours
- Method of breeding: the stocks of animals were cultured , and the tests performed, in reconstituted water, of typical hardness 156mg/l CaC03• The water was adjusted to 20 ± 1 °C, aerated until the dissolved oxygen concentration had reached a minimum of 60% air saturation and the pH stabilised between 7.8 ± 0.2.
- Feeding during test: no
- Feeding during culture: yes
- Food type: suspension of Chlorella vulgaris
- Amount:1 mg organic carbon / litre of culture water.
- Frequency: daily

ACCLIMATION
Not applicable, daphnia less than 24 hours old at study initiation

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

48 h

Hardness:

156mg/L CaCO3

Test temperature:

20 ± 1 °C

pH:

7.8 ± 0.2

Dissolved oxygen:

minimum of 60% of air saturation

Salinity:

not applicable - freshwater study

Nominal and measured concentrations:

Nominal: 0, 10, 18, 32, 56 and 100mg/I.
Measured: -, 0%, 7%, 22%, 58% and 80%

Details on test conditions:

TEST SYSTEM
- Test vessel: dish covered with transparent perspex sheet
- Size/ fill volume: 50 ml capacity filled to 25ml
- Aeration: no
- Type of flow-through (e.g. peristaltic or proportional diluter): none, static test
- Renewal rate of test solution (frequency): renewed at 24 hours
- No. of organisms per vessel: 5
- No. of vessels per concentration (replicates): 4
- No. of vessels per control (replicates): 4

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: CaCl2.2H2O (11.76g/L), MgSO4.7H2O (4.93 g/L), NaHCO3 (2.59 g/L), KCl (0.23 g/L). 25 ml of each solution combined and made to 1 litre with distilled water.
- Culture medium different from test medium: no

OTHER TEST CONDITIONS
- Adjustment of pH: if necessary pH was adjusted with NaOH or HCl to give a pH of 7.8 ± 0.2
- Photoperiod: 16 hours light and 8 hours dark
- Light intensity: not reported

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) :
The number of immobilised Daphnia was recorded after 24 and 48 hour exposure periods.


TEST CONCENTRATIONS
- Spacing factor for test concentrations: 1.8
- Range finding study: yes
- Test concentrations: 0 (control), 10, 18, 32, 56 and 100mg/L.
- Results used to determine the conditions for the definitive study: data available from a preliminary range finding study identified the 48 hour EC5, as being approximately >100mg/L

Reference substance (positive control):

yes

Remarks:

potassium dichromate

Duration:

48 h

Dose descriptor:

LC50

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Remarks on result:

other: not possible to determine confidence limits

Duration:

48 h

Dose descriptor:

NOEC

Effect conc.:

100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Details on results:

- Behavioural abnormalities:
- Observations on body length and weight:
- Other biological observations:
- Mortality of control:
- Other adverse effects control:
- Abnormal responses:
- Any observations (e.g. precipitation) that might cause a difference between measured and nominal values:
- Effect concentrations exceeding solubility of substance in test medium:

Results with reference substance (positive control):

- Results with reference substance valid? yes

24 hour EC50: 0.6 mg/L (0.5 -0.7mg/l)*
48 hour EC50: 0.3 mg/L (0.3 — 0.4mg/l)*
48 hour NOEC: 0.18 mg/L
48 hour 100% mortality: 1.0 mg/L

* denotes 95% confidence limits

Analysed exposure concentrations:

Nominal Concentration mg/1	0	10	18	32	56	100
	Measured Concentration (mg/l)
Time Zero	0	*	1	10	39	86
24 hours (aged solutions)	0	*	*	3 .)	29	75
24 hours (fresh solutions)	0	*	4	14	40	88
48 Hours (end of study)	0	*	*	1	22	69
Mean Exposure Cone.	0	*	3	7	33	80
Recovery( %) of nominal	-	0%	7%	22%	58%	80%

* Indicates recovery of MPP from aqueous test solutions was below the statistically derived LOD (Limit of Detection) for MPP derived from analytical measurement of the Pyrophosphate ion.

Limit of Detection = 0.19mg/l as P207 or 0.42mg/l as MPP

As can be seen from the data in the table, the percentage recovery of MPP was good from the test solutions at the highest exposure concentration, i.e. >80% recovery at 100 mg/1 for both the 0 and 24 hours freshly prepared samples. However there was some reduction in recovery after each of the 24 hour aging periods at this concentration and throughout the full concentration range. It is also noted that the percentage recovery dropped as the nominal concentrations decreased. The OECD guidelines state that if the percentage recovery calculated from the mean measured exposure concentrations is not within 20% of the nominal concentrations the mean measured concentrations should be used in the calculation of EC50 and LOEC and NOEC values. However, as the test material is clearly non-toxic to daphnia and the mean measured concentration recovery of the test material at the highest exposure concentration was equal to 80%, it is thought reasonable to state the EC50 value as greater than a nominal concentration of 100 mg/1.

Validity criteria fulfilled:

yes

Remarks:

no mortality in controls. Test temperature, pH and dissolved oxygen all within acceptable limits

Conclusions:

The 48 hour EC50 for MPP was estimated to be >100mg/l based upon nominal concentrations.

Description of key information

The 48 hour EC50 for aquatic invertebrates was estimated to be >100mg/l based upon nominal concentrations.

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates

Dose descriptor:

EC50

Effect concentration:

100 mg/L

Additional information

The results of an acute toxicity study showed MPP to be non-toxic to Daphnia magna. The 48 hour EC50 value was estimated to be >100mg/l based upon nominal concentrations. The highest no observed effect concentration (NOEC) after 48 hours was 100mg/l. The lowest test concentration that immobilised all twenty Daphnia within 48 hours could not be determined as there was 0% immobilisation at the highest test concentration.