[nitrilotris(methylene)]trisphosphonic acid, ammonium salt

Long-term toxicity to aquatic invertebrates

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

long-term toxicity to aquatic invertebrates

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: The study was conducted according to an appropriate national standard method but full details are not available. It was not conducted under GLP and no analytical monitoring was carried out.

Qualifier:

according to guideline

Guideline:

other: US EPA Methods for acute toxicity tests with fish, macroinvertebrates, and amphibians. EPA 66013-75-009. April 1975.

Deviations:

not specified

GLP compliance:

no

Analytical monitoring:

no

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)

- Method: The test substance was diluted to make a stock solution of 100 mg/ml. In a 6 L flask well water and food was mixed. The solution was transferred into 1L volumetric flasks, mixed well, then 200 ml were drawn into the test vessels.

Test organisms (species):

Daphnia magna

Details on test organisms:

TEST ORGANISM

- Common name: water flea

- Feeding during test: The daphnids were fed at a concentration of 10 mg/l at each test medium renewal.

Test type:

semi-static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

28 d

Nominal and measured concentrations:

Nominal test concentrations: 3.37, 6.75, 12.5 and 25 mg active acid/L.

Details on test conditions:

TEST SYSTEM

- Test vessel:

- Material, size, headspace, fill volume: 250 ml test beakers filled with 200 ml test solution.

- Renewal rate of test solution (frequency): 2 day renewal

- 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 of dilution water: Well water


EFFECT PARAMETERS MEASURED (with observation intervals if applicable) : survival and reproduction (offspring produced) at every water renewal (ca. 2 days).



RANGE-FINDING STUDY
A Range Finding study is said to have been conducted previous to the test in order to narrow down the range of concentrations in the test, however details were not reported. A short term acute test with Daphnia was also conducted which determined a 48 h EC50 equivalent to 883 mg active acid/L.

Reference substance (positive control):

no

Duration:

28 d

Dose descriptor:

NOEC

Effect conc.:

>= 25 mg/L

Nominal / measured:

nominal

Conc. based on:

act. ingr.

Basis for effect:

other: adult survival and reproduction (no. of offspring)

Details on results:

- Mortality of parent animals: see Table 1 for details.

- Time to first brood release or time to hatch: the data reported shows that offspring were produced by day 9 in all treatment groups.

Reported statistics and error estimates:

For chronic data NOECs were determined by comparing means and standard errors in control vs. treated.

Table 1: Effect of ATMP on growth and survival of D. magna after 28 days (average of 4 replicates).

Nominal concentrations (mg a.a./L)	Mortality of parents		Cumulative number of offspring
	No. Alive	% mortality
Control	4.3 ± 1.2	14	143.7
25	4.0 ± 0.8	20	128.3
12.5	4.2 ± 1.5	16	139.5
6.75	4.2 ± 1.0	16	141.6
3.37	4.7 ± 0.5	6	155.4

 

Result expressed as nominal concentration. Properties of the test substance and evidence from other studies (where concentrations were 

measured) indicate that nominal and measured concentrations are likely to be in good agreement.

Not enough information is reported on water quality, however the frequency of water renewals suggests the parameters to be in acceptable ranges.

 

Validity criteria fulfilled:

not specified

Conclusions:

A 28 day NOEC value of >= 25 mg/L (as active acid) has been determined for the effects of the test substance on adult survival and reproduction of D. magna.

Reference 2

Endpoint:

long-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 and IUCLID Section 13 for justification of read-across within the ATMP category.

Reason / purpose for cross-reference:

read-across source

Duration:

28 d

Dose descriptor:

NOEC

Effect conc.:

>= 25 mg/L

Nominal / measured:

nominal

Conc. based on:

act. ingr.

Basis for effect:

other: adult survival and reproduction (no. of offspring)

Description of key information

There are no test data for ATMP-xNH₄, however data have been read-across from ATMP-H and ATMP-xNa.

28-day NOEC ≥25 mg active acid/L, Daphnia magna

Ammonia: 29-day NOEC 0.066 mg NH₃-N/L, Deleatidium sp.

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates

Dose descriptor:

NOEC

Effect concentration:

>= 25 mg/L

Fresh water invertebrates

Dose descriptor:

NOEC

Remarks:

toxicity data for ammonia

Effect concentration:

0.066 mg/L

Additional information

ATMP-xNH₄ will dissociate when it is released into aqueous environments to yield ATMP and ammonia. No data is available for ATMP ammonium salts, therefore data are read-across from ATMP-H and ATMP-xNa.

A 28-day NOEC value of ≥25 mg active acid/L has been determined for the effects of the test substance on adult survival and reproduction of D. magna (Monsanto, 1976). The study represents the lowest reliable value available for this endpoint.

A study of unknown reliability determined a NOEC of 3 mg/L for the effects on ATMP-xNa to D. magna (Henkel, 1984). However the pattern of results was erratic and not enough information was provided in the report to determine the cause.

A 96-hour NOEC value of 96 mg active acid/L has also been determined for the effects of ATMP-H on the growth of the marine eastern oyster Crassostrea virginica (EG&G, 1977).

Ammonia: A 29-day NOEC value of 0.066 mg NH₃-N/L has been determined for the effects of unionised ammonia on Deleatidium sp., reported in 'Environment Agency Proposed EQS for Water Framework Directive Annex VIII Substances: Ammonia (unionised) 2007' (EA, 2007).

ATMP-xNH₄ will dissociate as it is released into the aquatic environment and it is therefore necessary to assess the hazard properties and derive PNECs for ATMP and ammonia separately.

For hazard classification, ATMP-xNH₄ has been assessed based on the available aquatic data for the whole substance.

The influence of the ammonium salt is discussed in IUCLID Section 6.0 Ecotoxicological Information and Section 7.0 of the CSR.

The acid, sodium, potassium and ammonium salts in the ATMP category are freely soluble in water. The ATMP anion can be considered fully dissociated from its sodium, potassium or ammonium cations when in dilute solution. Under any given conditions, the degree of ionisation of the ATMP 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 ATMP-H, ATMP.4Na, ATMP.7K or another salt of ATMP.

 

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

1. ATMP is present as ATMP-H or one of its ionised forms. The degree of ionisation depends upon the pH of the media and not whether ATMP (3-5K) salt, ATMP (3-5Na) salt, ATMP-H (acid form), or another salt was used for dosing.
2. Disassociated potassium, sodium or ammonium cations. The amount of potassium or sodium present depends on which salt was dosed.
3. It should also be noted that divalent and trivalent cations would preferentially replace the sodium or potassium ions. These would include calcium (Ca²⁺), magnesium (Mg²⁺) and iron (Fe³⁺). These cations are more strongly bound by ATMP than potassium, sodium and ammonium. This could result in ATMP-dication (e.g. ATMP-Ca, ATMP-Mg) and ATMP-trication (e.g. ATMP-Fe) complexes being present in solution.

In this context, for the purpose of this assessment, read-across of data within the ATMP Category is considered to be valid.