Diphosphorus pentaoxide

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

Study period:

2010-02-03 to 2010-02-05

Reliability:

1 (reliable without restriction)

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2010

Report date:

2010

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)

Deviations:

no

GLP compliance:

yes

Test material

Test material information

Constituent 1

Reference substance name:

Diphosphorus pentaoxide

EC Number:

215-236-1

EC Name:

Diphosphorus pentaoxide

Cas Number:

1314-56-3

Molecular formula:

O10P4

IUPAC Name:

tricyclo[3.3.1.1³,⁷]tetraphosphoxane-1,3,5,7-tetrone

Details on test material:

- Name of test material (as cited in study report): Phosphorpentoxid
- Molecular formula: P4O10
- Molecular weight: 283.9 g/mol
- Physical state: Solid, white powder
- Analytical purity: 99.7 % (m/m)
- Purity test date: 2009-09-23
- Lot/batch No.: DEH2 018965
- Expiration date of the lot/batch: 2011-09-08
- Storage condition of test material: Stored in a desiccator at room temperature, protected from light.

Sampling and analysis

Analytical monitoring:

yes

Details on sampling:

- Concentrations: All concentration levels, the pH control and the control were analytically verified in the fresh media (0 h) and old media (48 h) via UV-spectrophotometry using the phosphate pipette test (LCK 349, HACH LANGE).
- Sampling method: For the old media, additional replicates of all concentration levels, the pH-control end control without test organisms were prepared and incubated under test conditions.
- Sample storage conditions before analysis: No storage due to direct analysis

Test solutions

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
- Method: A stock solution of 100 mg/L was freshly prepared with dilution water and agitated.
- Eluate: Dilution water
- Differential loading: 6.25 - 12.5 - 25.0 - 50.0 - 100 mg/L
- Controls: Dilution water without test item tested under the same conditions as the test groups.

Test organisms

Test organisms (species):

Daphnia magna

Details on test organisms:

TEST ORGANISM
- Common name: Daphnia magna (STRAUS)
- Strain: Clone 5
- Source: Institut für Wasser-, Boden- Lufthygiene (WaBoLu), further own breeding
- Age at study initiation (mean and range, SD): 2 to 24 h
- Method of breeding: In 2-3 L glass vessels with appr. 1.8 L culture medium, at 20 +/- 2 °C, in an incubator, 16 h illumination, illumination strength max. 20 µExm-2 x s-1
- Feeding during test: No feeding

ACCLIMATION
- Acclimation period: 2 h
- Acclimation conditions (same as test or not): Same as test
- Type and amount of food: No feeding
- Health during acclimation (any mortality observed): Healthy, no mortality observed

Study design

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

48 h

Post exposure observation period:

No

Test conditions

Hardness:

Dilution water at test start: 267 (mg CaCO3/L)

Test temperature:

20.1 °C

pH:

Water Quality Parameters at the Beginning of the Test (0 h, Fresh Media)
(measured in one additional replicate per concentration level, pH-control and control)
Nominal concentration
of the test item
Phosphorpentoxid
[mg/L] pH-Value


100 (pH control)* 7.03
100 3.32
50.0 5.45
25.0 6.64
12.5 6.98
6.25 7.20
Control 7.83

Water Quality Parameters at the End of the Test (48 h, Old Media)
(measured in all replicates)
Nominal concentration
of the test item
Phosphorpentoxid
[mg/L] pH-Values
Replicates
1 2 3 4
100 (pH control)* 7.21 7.20 7.10 7.12
100 3.30 3.27 3.27 3.28
50.0 6.12 6.16 6.19 5.99
25.0 7.07 7.00 7.04 7.02
12.5 7.21 7.10 7.20 7.16
6.25 7.22 7.26 7.25 7.22
Control 7.46 7.50 7.48 7.41

Dissolved oxygen:

Water Quality Parameters at the Beginning of the Test (0 h, Fresh Media)
(measured in one additional replicate per concentration level, pH-control and control)
Nominal concentration
of the test item
Phosphorpentoxid
[mg/L] O2-Concentration

[mg/L]
100 (pH control)* 7.63
100 7.62
50.0 7.68
25.0 7.76
12.5 7.80
6.25 7.78
Control 8.20

Water Quality Parameters at the End of the Test (48 h, Old Media)
(measured in all replicates)
Nominal concentration
of the test item
Phosphorpentoxid
[mg/L] O2 -Conc. [mg/L]
Replicates
1 2 3 4
100 (pH control)* 7.75 7.68 7.57 7.57
100 7.85 7.91 7.96 7.89
50.0 7.40 7.64 7.50 7.66
25.0 7.59 7.68 7.45 7.26
12.5 7.31 7.39 7.41 7.56
6.25 7.29 7.27 7.40 7.33
Control 7.97 7.87 7.84 7.80

Salinity:

Freshwater

Nominal and measured concentrations:

Please refer to "Any other information on materials and methods"

Details on test conditions:

TEST SYSTEM
- Test vessel: Glass beakers, 50 mL
- Type (delete if not applicable): closed with parafilm
- Material, size, headspace, fill volume: Glass beakers (4 cm ID x 7 cm H), 50 mL
- Aeration: No
- Renewal rate of test solution (frequency/flow rate): One application at test start, static test
- 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): None


TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: Acc. to Directive 92/69/EEC Method C.2, Annex 1
- Conductivity: Dilution water at test start: 640 µS/cm
- Culture medium different from test medium: Elendt M4 acc. to ELENDT (1990), modified to a total hardness of 160 to 180 mg CaCO3/L
- Intervals of water quality measurement: At test start and test end


OTHER TEST CONDITIONS
- Adjustment of pH: No
- Photoperiod: 16:8 light:dark cycle
- Light intensity: Diffuse light, illumination strength max. 20 µE x m-2 x s-1


EFFECT PARAMETERS MEASURED (with observation intervals if applicable) :


TEST CONCENTRATIONS
- Spacing factor for test concentrations: None, limit test
- Range finding study
Immobilization Rates of the Preliminary Range Finding Test [%]
(n = 20, divided into 2 replicates 10 daphnids each)
Nominal
Test Item
Concentration
[mg/L] IMMOBILIZATION [%]
24 h 48 h
Replicates Replicates
1 2 MV 1 2 MV
100 (pH control)* 0 0 0 0 0 0
100 100 100 100 100 100 100
10 0 0 0 0 0 0
Control 0 0 0 0 0 0

Reference substance (positive control):

yes

Remarks:

Potassium dichromate

Results and discussion

Effect concentrations

Duration:

48 h

Dose descriptor:

NOEC

Effect conc.:

100 other: mg/L (with pH adjustment); 50.0 mg/L (without adjustment)

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Details on results:

- Behavioural abnormalities: None
- Mortality of control: 0%
- Other adverse effects control: None
- Abnormal responses: None
- Any observations (e.g. precipitation) that might cause a difference between measured and nominal values: None

Results with reference substance (positive control):

- Results with reference substance valid? Yes
- EC50/LC50: 1.60 (CI 1.44 - 1.84) mg/L

Reported statistics and error estimates:

EC50-values were calculated as the geometric mean of the lowest concentration causing 100 % immobilization (100 mg/L) and the highest concentration causing 0 % immobilization (50.0 mg/L), because only 0 and 100 % immobilization was observed. These concentration levels were also used as confidence limits.

Any other information on results incl. tables

Percentage of Daphnids Incapable of Swimming after 24 and 48 h of Exposure

              (n = 20, divided into 4 replicates with 5 daphnids each)

Nominal Concentration of the Test Item Phosphorpentoxid	IMMOBILIZATION [%]
	24 h					48 h
	Replicates					Replicates
[mg/L]	1.	2.	3.	4.	MV	1.	2.	3.	4.	MV
100 (pH control)*	0	0	0	0	0	0	0	0	0	0
100	100	100	100	100	100	100	100	100	100	100
50.0	0	0	0	0	0	0	0	0	0	0
25.0	0	0	0	0	0	0	0	0	0	0
12.5	0	0	0	0	0	0	0	0	0	0
6.25	0	0	0	0	0	0	0	0	0	0
Control	0	0	0	0	0	0	0	0	0	0

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Conclusions:

Based on the nominal concentrations of the test item Phosphorpentoxid the 48-hour EC50 for Daphnia magna was estimated to be 70.7 mg/L (95 % confidence limits: 50.0 - 100 mg/L).
The NOEC after 48 h was assessed at 50.0 mg test item/L as the highest tested concentration with no biologically significant effect. The LOEC was determined to be 100 mg test item/L.

Executive summary:

The acute immobilization of the test item Phosphorpentoxid (batch number: DEH2 018965) to Daphnia magna(STRAUS) was determined according to OECD 202 (2004) from 2010-02-03 to 2010-02-05 at Dr.U.Noack-Laboratorien, Käthe-Paulus-Str. 1, D-31157 Sarstedt, Germany.
The study was conducted with 5 nominal test item concentrations ranging from 6.25 to 100 mg/L set up in a geometric series with a dilution factor of 2 under static conditions over a period of 48 h. Additionally a pH control was tested. 20 test organisms were exposed to each test concentration and control.

The phosphate content as a component of the test item Phosphorpentoxid was analysed via UV-spectrophotometry with a pipette test at all test item concentrations, the pH control and the control after 0 h and 48 h. Details of the analytical method are given in part 10. The recovery rates in the fresh (0 h) and old media (48 h) of the tested concentration levels were in the range of 86 % to 98 % of the nominal values. All effect values are given based on the nominal concentrations of the test item Phosphorpentoxid. Phosphorpentoxid only caused a pH-related toxic effect at the concentration level 100 mg/L whereas a concentration of 100 mg/L with adjustment of the pH-value from 3.32 to 7.03 did not cause any effects.
Water quality parameters (pH-value and dissolved oxygen concentration), measured at 0 h and 48 h, were determined to be within the acceptable limits. The validity criteria of the test guideline were fulfilled.

Table 1:    EC₁₀-, EC₅₀- (with Confidence Interval), EC₁₀₀- Values, NOEC and LOEC

(based on the nominal concentrations of the test item Phosphorpentoxid)

		Values with Adjustment of pH	Values without Adjustment of pH
	Test Duration [h]	Nominal Concentration of the Test Item Phosphorpentoxid [mg/L]
EC10	24	> 100	Not applicable
	48	> 100	Not applicable
EC50 with 95 % confidence limits (Cl)	24	> 100 (Cl: Not applicable)	70.7 (Cl: 50.0 – 100)
	48	> 100 (Cl: Not applicable)	70.7 (Cl: 50.0 – 100)
EC100	24	> 100	100
	48	> 100	100
NOEC	48	100	50.0
LOEC	48	> 100	100