Reaction mass of [[(2-hydroxyethyl)imino]dimethylene]bisphosphonic acid, sodium salt and 4-(Phosphonomethyl)-2-hydroxy-2-oxo-1,4,2-oxazaphosphorinane, sodium salt

Short-term toxicity to aquatic invertebrates

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

short-term toxicity to aquatic invertebrates

Type of information:

experimental study

Adequacy of study:

key study

Study period:

between 1999-01-20 and 1999-01-22

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: The study was conducted according to an appropriate national standard method. It was compliant with GLP however no analytical monitoring was carried out.

Qualifier:

according to guideline

Guideline:

other: ISO TC147SC5/WG2 "Water quality, determination of acute lethal toxicity to marine copepods (Copepoda crustacea)".

Deviations:

no

GLP compliance:

yes

Analytical monitoring:

no

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION

- Method: 400 mg of test material (= 200 mg active ingredient) was dissolved in synthetic sea water and the volume adjusted to 2 L to give the 100 mg active ingredient (ai)/L test concentration. Aliquots of this concentration were separately dispersed in synthetic sea water and the volume adjusted to 1 L to give the remaining test concentrations.

Test organisms (species):

other aquatic arthropod: Acartia tonsa

Details on test organisms:

TEST ORGANISM

- Source: Guernsey Sea Farms Ltd, Parc Lane, Vale, Guernsey, UK

- Age at study initiation (mean and range, SD): stage 5, adults

- Method of breeding: not reported

- Feeding during test: none


ACCLIMATION

- Acclimation period: not reported

- Acclimation conditions (same as test or not): same temperature and salinity as study

- Type and amount of food: mixed culture of marine algae

- Feeding frequency: not reported

- Health during acclimation (any mortality observed): not reported

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

48 h

Test temperature:

21⁰C

pH:

range: 6.4 to 8

Dissolved oxygen:

5.9 to 6.3 mg O2/L

Nominal and measured concentrations:

Nominal concentrations: 1.8, 3.2, 5.6, 10, 18, 32, 56 and 100 mg active ingredient (ai)/L

Details on test conditions:

TEST SYSTEM

- Test vessel: jars

- Material, size, fill volume: 50 ml glass jars filled with 25 ml solution

- Aeration: none

- 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: the test water was prepared using a commercially available formulation, manufactured by Dr Biener GmbH, Aquarientechnik, 36367 Wartenberg, Germany and supplied by CJ Skilton, Chelmsford, UK.

- Culture medium different from test medium: yes

- Intervals of water quality measurement: temperature was recorded throughout


OTHER TEST CONDITIONS

- Adjustment of pH: not reported

- Photoperiod: 16 h light: 8 h darkness with 20 mi dusk and dawn transition periods

- Light intensity: not reported


EFFECT PARAMETERS MEASURED (with observation intervals if applicable) : the number of immobile animals were recorded after 24 and 48 hours.


TEST CONCENTRATIONS

- Spacing factor for test concentrations: ca. 1.8

- Range finding study

- Test concentrations: 0.01 to 100 mg/l

- Results used to determine the conditions for the definitive study: no mortalities were observed at test concentrations up to 10 mg a.i./L. However, mortalities were observed at 100 mg a.i./L.

Reference substance (positive control):

yes

Remarks:

potassium dichromate

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

64 mg/L

Nominal / measured:

nominal

Conc. based on:

act. ingr.

Remarks:

acid

Basis for effect:

mobility

Remarks on result:

other: 95% CL 55-75 mg a.i./L

Duration:

24 h

Dose descriptor:

EC50

Effect conc.:

82 mg/L

Nominal / measured:

nominal

Conc. based on:

act. ingr.

Remarks:

acid

Basis for effect:

mobility

Remarks on result:

other: 95 % CL 64-104

Results with reference substance (positive control):

- Results with reference substance valid? yes

- EC50/LC50: 6.2 mg/l

Reported statistics and error estimates:

The LC50 was determined by the moving average method of Thompson (1947)

Table 1. Summary of findings.

Nominal concentrations (mg a.i./L)	Mortalities (%)
	24 h	48 h
Control	0	0
1.0	0	0
1.8	0	0
3.2	0	0
5.6	0	0
10	0	0
18	0	0
32	0	0
56	20	35
100	70	90

Validity criteria fulfilled:

yes

Conclusions:

A 48h EC50 value of 64 mg active acid/L has been reported for the effects of the test substance on the mobility of the freshwater copepod Acartia tonsa based on nominal concentrations.

Reference 2

Endpoint:

short-term toxicity to aquatic invertebrates

Type of information:

read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

key study

Justification for type of information:

Please refer to Annex 3 of the CSR or IUCLID Section 13 for justification of read-across within the HEBMP category.

Reason / purpose for cross-reference:

read-across source

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

64 mg/L

Nominal / measured:

nominal

Conc. based on:

act. ingr.

Remarks:

active acid

Basis for effect:

mortality

Remarks on result:

other: 95% CL 55-75 mg a.i./L

Description of key information

No data are available for the registration substance. A reliable test result of 48 hour EC₅₀ 64 mg/L, A. tonsa, nominal concentrations of active acid is available for the HEBMP-H. The result is read-across to HEBMP-xNa.

Key value for chemical safety assessment

Marine water invertebrates

Marine water invertebrates

Dose descriptor:

EC50

Effect concentration:

64 mg/L

Additional information

A 48-hour EC₅₀ value of 64 mg active acid/L has been reported for the effects of HEBMP acid on the mobility of the marine copepod Acartia tonsa based on nominal concentrations. This result is interpreted as 64 mg/l as active acid. Whilst the proportion of cyclic and linear constituents was not measured for the tested sample, it is conservatively interpreted that the cyclic constituent could have been present at ca. 50% w/w.

The acid and sodium salts in the HEBMP category are freely soluble in water. The HEBMP anion can be considered fully dissociated from its sodium cation when in dilute solution. Under any given conditions, the degree of ionisation of the HEBMP species is determined by the pH of the solution. At a specific pH, the degree of ionisation is the same regardless of whether the starting material was HEBMP-H, HEBMP-xNa, or another salt of HEBMP.

 

Therefore, when a salt of HEBMP is introduced into test media or the environment, the following is present (separately):

1. HEBMP is present as HEBMP-H or one of its ionised forms. The degree of ionisation depends upon the pH of the mediaand not whether HEBMP-xNa salt, HEBMP-H (acid form), or another salt was used for dosing.
2. Disassociated sodium cations. The amount of sodium present depends on which salt was added.
3. It should also be noted that divalent and trivalent cations would preferentially replace the potassium ions. These would include calcium (Ca²⁺), magnesium (Mg²⁺) and iron (Fe³⁺).