p-nitrophenyl dihydrogen phosphate, compound with 2-amino-2-(hydroxymethyl)propane-1,3-diol (1:2)

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:

17 -23 November 2020

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2020

Report date:

2202

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)

Version / remarks:

13 April 2004

Deviations:

no

Test guideline 2

Qualifier:

according to guideline

Guideline:

EU Method C.2 (Acute Toxicity for Daphnia)

Version / remarks:

30 May 2008

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

impurity 1

Reference substance name:

Methanol

EC Number:

200-659-6

EC Name:

Methanol

Cas Number:

67-56-1

Molecular formula:

CH4O

IUPAC Name:

methanol

impurity 2

Reference substance name:

Acetone

EC Number:

200-662-2

EC Name:

Acetone

Cas Number:

67-64-1

Molecular formula:

C3H6O

IUPAC Name:

acetone

impurity 3

Reference substance name:

Water

EC Number:

231-791-2

EC Name:

Water

Cas Number:

7732-18-5

Molecular formula:

H2O

IUPAC Name:

Oxidane

Constituent 1

Reference substance name:

p-nitrophenyl dihydrogen phosphate, compound with 2-amino-2-(hydroxymethyl)propane-1,3-diol (1:2)

EC Number:

269-198-6

EC Name:

p-nitrophenyl dihydrogen phosphate, compound with 2-amino-2-(hydroxymethyl)propane-1,3-diol (1:2)

Cas Number:

68189-42-4

Molecular formula:

C6H6NO6P.2C4H11NO3

IUPAC Name:

4-nitrophenyl dihydrogen phosphate - 2-amino-2-(hydroxymethyl)propane-1,3-diol (1:2)

Test material form:

solid

Details on test material:

Batch / Lot No. 46587100

Specific details on test material used for the study:

Batch no. 46587100
Test item storage 2–8 °C, protected from light

Sampling and analysis

Analytical monitoring:

yes

Details on sampling:

Samples were taken from all test media including the control at the start of the test as well as after 24 and 48 hours of exposure. At the start of the test, the samples were taken from the freshly prepared single test solution as well as from the pure test water serving as control. For all subsequent sampling time points, aliquots from the respective replicates were pooled per treatment before sampling.
All samples were diluted with acetonitrile containing conc. 1% phosphoric acid to obtain a composition of sample:acetonitrile (9:1; v:v) containing 0.1% conc. phosphoric acid. Subsequently, the samples were stored deep-frozen (at about -20 °C) until analysis. In non-GLP preliminary experiments, the test item proved to be stable under these storage conditions.

Test solutions

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION
The following test vessels were set up:
• Test solution: containing test water with test item (four replicates per concentration with five daphnids each)
• Control: containing pure test water (four replicates with five daphnids each)
Since the test item is soluble, the single test solution was prepared by adding 100 mg/l of test item to test water in glassware, which readily dissolved.
The test vessels were filled with 50 ml of the respective test medium. Daphnia, aged less than 24 hours and already acclimatised to the test water, were introduced into the test media and the vessels were covered with a glass plate. The Daphnia were not fed during the test and the test vessels were not aerated.

Test organisms

Test organisms (species):

Daphnia magna

Details on test organisms:

TEST ORGANISMS
- Test organism: Daphnia magna Straus, supplied by IES Ltd., 4108 Witterswil, Switzerland
- Breeding: The daphnids are cultivated in Elendt M4 medium at 18–22 °C, controlled at ±1 °C
- Illumination: 16 h per day, about 550-1100 lux, source: overhead white fluorescent tubes
- Medium: Reconstituted water (Elendt M4 medium)
- Feed: Suspension of Desmodesmus subspicatus in Elendt M4 medium with an optical density OD680 of about 12 units. This results in a final concentration of about 0.1 units from Monday to Thursday and 0.4 units on Fridays in the culture vessel.

Study design

Test type:

static

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

48 h

Test conditions

Hardness:

2.5 mM (based on the sum of Ca2+ and Mg2+), Carbonate Alkalinity: 0.8 mM

Test temperature:

18–22°C, controlled at ±1 °C

pH:

The pH value in the control replicates remained stable over the duration of the test at 7.7(at 0h) and 7.8 after 48h.. In the 100 mg/l test concentration it went from 7.5 to 7.8 over the duration of the test.

Dissolved oxygen:

Minimum dissolved oxygen concentration for the control was between 8.1 and 8.2mg O2/l and between 8.3 and 8.2 mg O2/l for the test item with 100mg/l (required >=3 mg O2/l).

Salinity:

not reported

Conductivity:

702 µS cm-1

Nominal and measured concentrations:

NOMINAL CONCENTRATIONS
Since no significant effects were observed in the non-GLP range-finding test, the definitive test was performed as a limit-test at a nominal concentration of 100 mg/l.

MEASURED CONCENTRATIONS
The concentrations of the test substance in the test media were determined by HPLC with UV detection in the samples from the test start as well as in the samples after 24 and 48 hours of exposure. These analyses showed that the test item was correctly dosed and remained stable within 80–120% of the nominal concentration. Therefore, the effective concentrations ECx were assessed based on the nominal concentration of the test item.

Details on test conditions:

TEST SYSTEM
- Test vessel: 100 ml glass beaker containing 50 ml of test medium, covered with a glass plate to avoid evaporation and contamination of the test solutions with dust.
- Test medium: Elendt M4 medium
- Number of Daphnia: 20 individuals per test concentration and for the control divided in four groups of five individuals.
- Age: Less than 24 hours and not first brood progeny.
- Light: 16 hours photoperiod per day, about 550–1100 lux, source: overhead white fluorescent tubes.
- Temperature: 18–22 °C, controlled at ±1 °C
- pH: The pH should not vary by more than 1.5 units during the exposure.
- Feed: The daphnids are not fed during the test
- Test design: Static exposure conditions
- Test duration: 48 hours

RANGE-FINDING STUDY
Prior to the definitive test a non-GLP range finding test with nominal concentrations of 1, 10 and 100 mg/l of 4-NPP, di-TRIS was performed (two replicates for each of the test concentration and the control; five daphnids per replicate).

EFFECT PARAMETERS MEASURED
Observations of immobilised daphnids were made after 24 and 48 hours of exposure. Any abnormal behaviour or appearance was reported.

Reference substance (positive control):

yes

Remarks:

Acute reference test with potassium dichromate conducted twice a year

Results and discussion

Effect concentrations

Effect concentrations 1

Key result

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Effect concentrations 2

Key result

Duration:

48 h

Dose descriptor:

NOEC

Effect conc.:

100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Effect concentrations 3

Duration:

24 h

Dose descriptor:

EC50

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Effect concentrations 4

Duration:

24 h

Dose descriptor:

NOEC

Effect conc.:

100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Details on results:

During the first 24 hours of the test, no immobilised test organisms were determined in the control and in the single test item concentration of nominal 100 mg/l (Table 5). Thus, the 24-hour EC50 was greater than 100 mg/l.
The no observed effect concentration (NOEC) after 24 hours was determined to be 100 mg/l.
After 48 hours of exposure, no immobilised test organisms were determined in the control and the single test item concentration of nominal 100 mg/l . Thus, the 48-hour EC50 was greater than 100 mg/l.
The no observed effect concentration (NOEC) after 48 hours was determined to be 100 mg/l.

Results with reference substance (positive control):

For evaluation of the quality of the daphnia clone and the test procedure, potassium dichromate is tested as a positive control twice a year. The result of the latest positive control test performed in October 2020 showed that the sensitivity of the test system (24-h EC50 = 1.4 mg/l) lies within the recommended range of 0.6–2.1 mg/l according to ISO 6341:2012: Water quality – determination of the inhibition of the mobility of Daphnia magna Straus (Cladocera, Crustacea) – Acute toxicity test.

Reported statistics and error estimates:

The effective concentration (ECx) is the concentration leading to immobilisation of x% of the Daphnia after a defined exposure period. The effective concentration EC50 for 24 and 48 hours was estimated based on the concentration tested and immobilisation observed.

The no observed effect concentration (NOEC) is the highest test concentration for which the test item is observed to have an immobilisation rate not exceeding 10%. Thus, immobilisation rates >10% are considered to be significant.

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Remarks:

All validity criteria i.e. immobilisation in the controls <=10% and O2 concentrations at the end of the test >=3 mg/L were fulfilled.

Conclusions:

In conclusion, 4-NPP, di-TRIS had no acute toxic effects on Daphnia magna up to the nominal concentration of 100 mg/l under the conditions of the test.

Executive summary:

The acute toxicity of 4-NPP, di-TRIS (CAS no. 68189-42-4) to Daphnia magna was investigated according to the OECD guideline 202 under static exposure conditions over a period of 48 hours.
The test item 4-NPP, di-TRIS is solid, 99.03% (w/w) pure and soluble in test water up to at least 100 mg/l. The single nominal concentration tested was 100 mg/l.
The concentrations of 4-NPP, di-TRIS in the test media were determined by HPLC with UV detection in the samples from the test start as well as in the samples after 24 and 48 hours of exposure. These analyses showed that the single test solution was correctly dosed and that the test item concentrations remained within 80–120% of the nominal concentration over the duration of the test.
In the control and at the test concentration of 100 mg/l, no immobilised test organisms were observed during the test period of 48 hours.
The biological test results of 4-NPP, di-TRIS to Daphnia magna after 24 and 48 hours of exposure are summarised in the following table based on nominal concentrations:

Parameter	Immobilisation (0-24 h)	Immobilisation (0-48 h)
EC50 [mg/l]	>100	>100
NOEC [mg/l]	100	100

 

In conclusion, 4-NPP, di-TRIS had no acute toxic effects on Daphnia magna up to the nominal concentration of 100 mg/l under the conditions of the test.

 

All validity criteria were fulfilled.