Trisodium dihydrogen -N,N-[bis[2-[bis(carboxylatomethyl)amino]ethyl]]glycinate

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:

Not stated

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study

Justification for type of information:

The target substance (DTPA 3Na) is the trisodium salt of the source substance (DTPA). The purity/impurity profile for the source substance (supplied by Fluka Chemical Co.) is not reported in the source publication (Arch. Environ. Contam. Toxicol. 31, 433-443 (1996)), but since the target substance is > 99.9% pure and contains no detectable impurities, the extrapolation of short-term aquatic toxicity properties from the source material to the target material is considered valid as a ‘worst case' scenario. The source material short-term Daphnia toxicity test was conducted according to OECD guideline 202 and was considered reliable with restrictions (Category 2).

Reason / purpose for cross-reference:

read-across: supporting information

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)

Version / remarks:

1984

Deviations:

yes

Remarks:

LC50s rather than EC50s used as the endpoint

GLP compliance:

not specified

Specific details on test material used for the study:

Supplied by Fluka Chemical Co.

Analytical monitoring:

no

Vehicle:

no

Test organisms (species):

other: Daphnia carinata

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

48 h

Hardness:

Not specified

Test temperature:

20 +/- 1 degrees Centigrade

pH:

6.8-7.0

Dissolved oxygen:

> 70% (6.5 mg/l)

Salinity:

Not applicable

Conductivity:

Not specified

Nominal and measured concentrations:

Nominal concentration: 0, 25, 50, 100, 200, 4000, 800 mg/L DTPA.

Details on test conditions:

Keating's MS animal medium (Keating 1986) used as the test system

Reference substance (positive control):

no

Duration:

24 h

Dose descriptor:

LC50

Effect conc.:

332.9 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality

Key result

Duration:

48 h

Dose descriptor:

LC50

Effect conc.:

245 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality

Remarks on result:

other: Geometric mean of the lowest and highest concentrations giving 0 or 100% mortality

Results with reference substance (positive control):

Not applicable

Reported statistics and error estimates:

24h LC50 was 342.9 (168.5-678.6 mg/L 95% confidence limits) and 48 h LC50 245.0 (200-400 95% confidence limits)

Validity criteria fulfilled:

not specified

Conclusions:

The 48h LD50 of the test substance to Daphnia Carinata is 245 mg/L

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:

The target substance (DTPA 3Na) is the trisodiun salt of the source substance Diethylenetriaminepentaacetic acid (DTPA), and is therefore structurally similar. The two substances have high water solubility and would be dissociated in the aquatic environment. It is manufactured by the addition of an appropriate molar ratio of sodium hydroxide to the parent acid to give a neutral solution. The target substance is pH 7.5 +/- 0.5 in solution which is comparable to the test conditions used for the short-term Daphnia toxicity test with the acid (pH 6.8-7.0). The common organic acid moiety has a chelating mode of action and would be expected to exert long-term, non-specific adverse, systemic effects by the sequestration of essential metal ions, rather than acute toxicity. The extrapolation of short-term aquatic toxicity potential from the source to the target substance is therefore considered valid.

Reason / purpose for cross-reference:

read-across source

Specific details on test material used for the study:

>99% purity

Key result

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

284 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Conclusions:

The EC50 to Daphmia carinata is predicted to be 284 mg/L.

Executive summary:

Using a read-across approach from a study conducted on the structural analogue DTPA acid, the EC50 of DTPA trisodium salt to Daphnia carinata is predicted to be 284 mg/L (on stoichiometric basis). The two substances are structurally very similar, particularly when ionised in the aqueous environment. Moreover, the Daphnia carinata acute toxicity study of DTPA acid was undertaken at a pH (6.8-7.0) equivalent to the netural pH of the test substance.

Description of key information

Using a read-across approach from a study conducted on the structural analogue DTPA acid, the EC50 of DTPA trisodium salt to Daphnia carinata is predicted to be 284 mg/L (on stoichiometric basis). The two substances are structurally very similar, particularly when ionised in the aqueous environment. Moreover, the Daphnia carinata acute toxicity study of DTPA acid was undertaken at a pH (6.8-7.0) comperable to the netural pH of the test substance (7.5 +/- 0.5).

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates

Effect concentration:

284 mg/L