[nitrilotris(methylene)]trisphosphonic acid, 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:

1995-10-18 to 1995-10-20

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study with acceptable restrictions

Remarks:

Test procedure in accordance with national standard methods (based on ISO guideline) with acceptable restrictions. No data on GLP or analytical monitoring available. The test was conducted in a reputable and established laboratory according to an appropriate guideline, on the basis of this we can assign a reliability of 2 since no deviations from the guideline are stated even though the data presented is from a summary report only.

Qualifier:

equivalent or similar to guideline

Guideline:

other: draft method ISO/CD 14669

Deviations:

no

Qualifier:

according to guideline

Guideline:

other: Brixham Environmental Laboratory SOP BA207:03.

Deviations:

no

GLP compliance:

not specified

Analytical monitoring:

no

Vehicle:

no

Test organisms (species):

other: Acartia tonsa

Details on test organisms:

TEST ORGANISM

- Common name: Acartia

- Age at study initiation (mean and range, SD): 24.5 (+/-3) days

Test type:

static

Water media type:

saltwater

Limit test:

no

Total exposure duration:

48 h

Post exposure observation period:

none

Hardness:

Not reported, assumed to meet guideline criteria.

Test temperature:

20 deg C (+/- 1)

pH:

Not reported, assumed to meet guideline criteria.

Dissolved oxygen:

Not reported, assumed to meet guideline criteria.

Salinity:

Not reported, assumed to meet guideline criteria.

Nominal and measured concentrations:

Nominal test concentrations were 56, 100, 180, 320, 560 and 1000 mg/l (as test substance).  

Details on test conditions:

TEST SYSTEM

- No. of organisms per vessel: 20

Reference substance (positive control):

yes

Remarks:

3,5, dichlorophenol

Duration:

48 h

Dose descriptor:

LC50

Effect conc.:

94 mg/L

Nominal / measured:

nominal

Conc. based on:

act. ingr.

Basis for effect:

mortality

Remarks on result:

other: (95% CL 74.5-115)

Details on results:

- Mortality of control: 5%

Reported statistics and error estimates:

Not reported, assumed to meet guideline criteria.

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.

Percentage mortality at each test concentration at the end of the test  (48 hours):

Table 1. Results

Nominal conc. (mg/L)	% mortality
	24 h	48 h
3,5 Dichlorophenol (1 mg/L)	40	100
Control	0	5
56	0	5
100	0	20
180	0	10
320	100	100
560	100	100
1000	100	100

24 LC-50 (95% confidence intervals): 240 (180-320) mg/L as test substance. Equivalent to 120 mg active acid/L.

Validity criteria fulfilled:

not specified

Remarks:

not enough data to validate, assumed to meet guideline criteria.

Conclusions:

A 48 h LC50 value of 94 mg/L (as active acid) has been determined for the effects of the test substance on mortality of the marine invertebrate Acartia tonsa.

Reference 2

Endpoint:

short-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:

guideline study with acceptable restrictions

Remarks:

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: In house protocol: MIC Environmental Assessment Method for Conducting Acute Toxicity Tests with Daphnia magna (see note below)

Deviations:

no

Qualifier:

according to guideline

Guideline:

other: US EPA (1975) Methods for acute toxicity tests with fish, macroinvertebrates and amphibians. EPA 660/3-75-009.

Deviations:

no

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)

Deviations:

not applicable

Principles of method if other than guideline:

The In house protocol references Grueber and Adams (1980)

GLP compliance:

no

Analytical monitoring:

no

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION

- Method: For each test concentration the appropriate amount of the test compound was pipetted into 1L of dilution water and shaken vigorously for 1 min. The solution was then divided into 2 200 ml aliquots in triplicate beakers to provide the appropriate replication. The remaining 400 ml were used for 0 h DO, pH, alkalinity and hardness determinations.

- Controls: Just dilution water.

Test organisms (species):

Daphnia magna

Details on test organisms:

TEST ORGANISM

- Common name: water flea

- Source:  The daphnids used in the test were obtained from a laboratory culture at the MIC laboratory.

- Age at study initiation (mean and range, SD): <24 h

- Method of breeding: according to lab SOP

- Feeding during test: no


ACCLIMATION

- Acclimation period: not reported

- Acclimation conditions (same as test or not): not reported

- Type and amount of food: Daphnia were fed a mixture of Purina trout chow and alfalfa daily.

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

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

48 h

Hardness:

The alkalinity ranged from 236 to 304 mg/L and 250 to 300 mg/L in the low and high test concentration vessels respectively.

Test temperature:

Average temperature of 21.2 degrees C.

pH:

The pH in the control medium ranged between 7.2-8.4. The pH in the test media ranged between 2.0 and 8.2.

Dissolved oxygen:

The dissolved concentrations for the treatments were not reported due to measurement interference from the test materials. However, DO on the control water ranged from 6.2-9.4 mg/L. DO was measured by the Winkler titration method.

Nominal and measured concentrations:

Nominal test concentrations were 125, 250, 500, 1000 and 2000 mg/l as active acid

Details on test conditions:

TEST SYSTEM

- Test vessel: beaker

- Material, size, headspace, fill volume: 250 ml beakers containing 200 ml of test medium. 

- Aeration: no

- No. of organisms per vessel: 10

- No. of vessels per concentration (replicates): 3

- No. of vessels per control (replicates): 3



TEST MEDIUM / WATER PARAMETERS

- Source/preparation of dilution water: well water from St. Peters, Missouri.

- Alkalinity: 303 mg/L CaCO3, hardness 297 mg/L CaCO3

- Culture medium different from test medium: not reported

- Intervals of water quality measurement:  DO, pH, alkalinity, hardness and temperature of test solutions were monitored at the initiation (control only) and termination of the test in the high, middle and low concentrations. 


OTHER TEST CONDITIONS

- Adjustment of pH: no

- Photoperiod: not reported

- Light intensity: not reported


EFFECT PARAMETERS MEASURED (with observation intervals if applicable) : immobility at 0, 24 and 48 h.


TEST CONCENTRATIONS

- Spacing factor for test concentrations: 2

- Range finding study

- Test concentrations: not reported

- Results used to determine the conditions for the definitive study: EC50 833 mg/L

Reference substance (positive control):

no

Duration:

48 h

Dose descriptor:

NOEC

Effect conc.:

125 mg/L

Nominal / measured:

nominal

Conc. based on:

act. ingr.

Basis for effect:

other: immobility

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

297 mg/L

Nominal / measured:

nominal

Conc. based on:

act. ingr.

Basis for effect:

other: immobility

Remarks on result:

other: 95% CL 262-342

Duration:

24 h

Dose descriptor:

EC50

Effect conc.:

545 mg/L

Nominal / measured:

nominal

Conc. based on:

act. ingr.

Basis for effect:

other: immobility

Details on results:

- Mortality of control: 0%

Reported statistics and error estimates:

EC50 values and 95% confidence intervals calculated using an LC50 computer programme developed by Stephen et al (1978).   

Table 1. Summary of findings (average).

Nominal concentrations (mg/L)	Percent immobilisation
	24 h	48 h
Control	0	0
125	0	6.7
250	0	13.3
500	40	60
1000	100	100
2000	100	100

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.

The pH data suggest that the acidity of the higher concentration test solutions is likely to have contributed to the effects observed in the test.

Validity criteria fulfilled:

no

Remarks:

pH very low at the highest concentrations tested. However the reported EC50 value is high enough to determine toxicity that the test substance is of low intrinsic toxicity.

Conclusions:

A 48 h EC50 value of 297 mg active acid/L has been determined for the effects of ATMP acid on the immobility of the freshwater flea D. magna.

Reference 3

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

Reason / purpose for cross-reference:

read-across source

Reason / purpose for cross-reference:

read-across source

Duration:

48 h

Dose descriptor:

LC50

Effect conc.:

94 mg/L

Nominal / measured:

nominal

Conc. based on:

act. ingr.

Basis for effect:

mortality

Remarks on result:

other: (95% CL 74.5-115)

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

297 mg/L

Nominal / measured:

nominal

Conc. based on:

act. ingr.

Basis for effect:

other: immobility

Remarks on result:

other: 95% CL 262-342

Description of key information

A 48-hour EC₅₀ value of 297 mg active acid/L has been determined for the effects of ATMP-H on mobility of the freshwater flea Daphnia magna. 

A 48-hour LC₅₀ value of 94 mg active acid/L has been determined for the effects of ATMP-H on mortality of the marine invertebrate Acartia tonsa.

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates

Effect concentration:

297 mg/L

Marine water invertebrates

Marine water invertebrates

Effect concentration:

94 mg/L

Additional information

Several studies are available for the short-term toxicity of ATMP to aquatic invertebrates

 

In a reliable, 48-hour exposure to Daphnia magna, an EC₅₀ value of 297 mg active acid/L was determined for the effects of the read-across substance, ATMP-H, on mobility (Monsanto, 1981). This study reflects the lowest freshwater values that are available for this endpoint. The pH of the test media ranged between 2.0 and 8.2 and so the mortalities observed could be an effect of the pH of the test medium, rather than a reflection of true toxicity. Therefore, these results should be treated with caution as they may overestimate the toxicity of the test substance. However, aquatic invertebrates are not the most sensitive trophic level and these values are not used for Classification and Labelling, or PNEC derivation. Also, as these results are likely to overestimate toxicity, it is considered more conservative to use these values than higher values.

 

A reliable study reports a 48-hour LC₅₀ value of 94 mg active acid/L for the effects of the read-across substance, ATMP-H, on the mortality of the marine invertebrate, Acartia tonsa (Zeneca, 1995a). This value represents the lowest value available for the marine compartment for this endpoint.

 

Several other supporting studies are available.

Henkel (1972) reports a 24-hour EC₅₀ value of 375mg/L for the toxicity of ATMP-H to the mobility of Daphnia magna however, little information on the study methodology was reported and so the study was assigned a Reliability score of 4.

A 48-hour EC₅₀ value of 833 mg active acid/L has been reported for the effects of ATMP-H to the mobility of Daphnia magna however, the documentation was insufficient for a reliability assessment and the study was assigned Reliability 4 accordingly (Monsanto, 1976a).

A 48-hour EC₅₀ value of 883 mg active acid/L was reported for the effects of ATMP-H on the mobility of Daphnia magna. Documentation was insufficient for a reliability assessment and so the study was assigned a Reliability score of 4 (Monsanto, 1976b).

Three reliable studies have been conducted by EG&G, reporting EC₅₀ values of (48-hour) 4574, (48-hour) 11400 and (96-hour) 201 mg/L for the effects of ATMP-H on Palaemonetes pugio, Chironomus tentans and Crassostrea sp., respectively (EG&G 1976a, 1976b and 1977, respectively).

A review article reported a 24-hour EC₀ of 300 mg/L for the effects of ATMP-H on the mobility of Daphnia magna however, the documentation of the methodology was not sufficient and the study was assigned a Reliability score of 4 (Schoberl & Huber, 1988).

Lastly, a 48-hour LC₅₀ value of >291 mg active acid/L was reported for the effects of ATMP-5Na on the mortality of Acartia tonsa (TNO, 1997).

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.