[ethane-1,2-diylbis[nitrilobis(methylene)]]tetrakisphosphonic acid

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

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: 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 Dequest products. 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: details of the range finding studies were 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.:

205 mg/L

Nominal / measured:

nominal

Conc. based on:

act. ingr.

Basis for effect:

other: immobility

Key result

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

510 mg/L

Nominal / measured:

nominal

Conc. based on:

act. ingr.

Basis for effect:

other: immobility

Remarks on result:

other: 95% CL

Duration:

24 h

Dose descriptor:

EC50

Effect conc.:

710 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	0
500	0	36.7
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 510 mg active acid/L has been determined for the effects of EDTMP acid on the immobility of the freshwater flea D. magna. The results should be treated with caution since the authors report that the mortalities seen are an effect of the pH of the test medium, rather than a reflection of true toxicity. However the results to indicate that the substance is of low short term toxicity to aquatic invertebrates.

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 OECD test guideline. It was compliant with GLP however no analytical monitoring was carried out.

Qualifier:

according to guideline

Guideline:

other: in house protocol (1980)

Deviations:

no

Qualifier:

equivalent or similar to guideline

Guideline:

EPA OPPTS 850.1020 (Gammarid Acute Toxicity Test)

Deviations:

not applicable

GLP compliance:

yes

Analytical monitoring:

no

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION

- Method: 1000 mg of test substance was accurately weighed out and dissolved in 1L of natural sea water by ultrasonic treatment. This was directly used as the test solution. Fresh test solution was prepared daily throughout the test period.

Test organisms (species):

other aquatic crustacea: Chaetogammarus marinus

Details on test organisms:

TEST ORGANISM

- Common name: gammaris shrimp

- Source: cultured in the laboratory

- Length at study initiation (length definition, mean, range and SD): average 4.1 ± 0.6 mm

- Method of breeding: cultured in the laboratory under standard conditions, according to the relevant SOP. The culture has been initiated with animals collected in the field on September 1991.

- Feeding during test

- Food type: Artemia nauplii

- Amount: few

- Frequency: daily

ACCLIMATION
not reported

Test type:

semi-static

Water media type:

saltwater

Limit test:

yes

Total exposure duration:

96 h

Test temperature:

range: 14.7 to 15.3⁰C

pH:

range: 7.7 and 8.9

Dissolved oxygen:

at least 83%

Salinity:

33.6‰

Details on test conditions:

TEST SYSTEM

- Test vessel: scintillation vials

- Type (delete if not applicable): closed

- Material, fill volume: 20 ml of exposure medium was placed in the glass test vessels

- Aeration: none

- Renewal rate of test solution (frequency/flow rate): daily

- No. of organisms per vessel: 10

- No. of vessels per concentration (replicates): 10

- No. of vessels per control (replicates): 10


TEST MEDIUM / WATER PARAMETERS

- Source/preparation of dilution water: natural seawater, filtered (sand, carbon and mesh), kept in storage tanks in the laboratory. The stock is regularly supplied with seawater, originating from the Eastern Scheldt, a virtually unpolluted area in the Netherlands.

- Culture medium different from test medium: no

- Intervals of water quality measurement: pH and DO were measured daily


OTHER TEST CONDITIONS

- Adjustment of pH: none reported

- Photoperiod: 16 h light and 8 h dark, with 2 transition periods of 0.5 h twilight.

- Light intensity: not reported


EFFECT PARAMETERS MEASURED: mortalities were observed every 24 hours.


TEST CONCENTRATIONS

- Spacing factor for test concentrations: not applicable

- Justification for using less concentrations than requested by guideline: limit test

- Range finding study

- Test concentrations: up to 1000 mg/l

- Results used to determine the conditions for the definitive study: LC50 >1000 mg/l

Reference substance (positive control):

no

Duration:

96 h

Dose descriptor:

LC50

Effect conc.:

> 340 mg/L

Nominal / measured:

nominal

Conc. based on:

act. ingr.

Remarks:

active acid

Basis for effect:

mortality

Duration:

96 h

Dose descriptor:

LC50

Effect conc.:

> 1 000 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality

Details on results:

- Mortality of control: 0%

Reported statistics and error estimates:

The LC50 and their confidence intervals were calculated by means of a parametric model developed by Kooijman.

Validity criteria fulfilled:

yes

Conclusions:

A 96 h LC50 value of >340 mg active acid/l has been reported for the effects of the test substance on the mortality of the marine shrimp Chaetogammarus marinus based on nominal concentrations.

Description of key information

48 h EC₅₀: 510 mg active acid/l, D. magna, reliability 2 (Monsanto, 1981).

96 h LC₅₀: >340 mg active acid/l, C. marinus, reliability 2 (read across from EDTMP-xCayNa) (TNO, 1993).

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates

Effect concentration:

510 mg/L

Marine water invertebrates

Marine water invertebrates

Effect concentration:

340 mg/L

Additional information

A 48 h EC₅₀ value of 510 mg active acid/L has been determined for the effects of EDTMP acid on the mobility of the freshwater flea Daphnia magna (Monsanto, 1981). The results should be treated with caution since the authors report that the mortalities seen are an effect of the pH of the test medium, rather than a reflection of true toxicity. However the results do indicate that the substance is of low short term toxicity to aquatic inverterbates. This study has been selected as key as it is the lowest reliable EC₅₀ value with freshwater invertebrates and it uses the preferred species Daphnia magna.

A 96 h LC₅₀ value of >340 mg active acid/l has been reported for the effects of the structurally analogous substance EDTMP-xCayNa on the mortality of the marine shrimp Chaetogammarus marinus based on nominal concentrations (TNO, 1993).

A 96 h EC₅₀ value of 58 ppm, equivalent to 70 mg active acid/L, has been determined for the effects of the EDTMP acid on shell deposition of the eastern oyster Crassostrea virginica (EG&G, 1977). This test measures shell growth of the organisms, a sub-lethal endpoint, and is thus more sensitive than the standard invertebrate organisms test. The shell deposition is dependent on nutrient availability. Phosphonates have complexing properties and it is therefore likely that shell growth was inhibited due to a lack of bioavailable nutrients, even though the study was conducted under flowthrough conditions and the results should not be interpreted as inherent toxicity effects.

Three other reliable studies report supporting EC₅₀ values in the range 1500 to 7300 mg/l with aquatic invertebrates:

48 h EC₅₀: 527 mg active acid/l (Monsanto, 1976).

48 h EC₅₀: 7300 mg active acid/l (EG&G, 1976, (6.1.3.004)).

48 h EC₅₀: 1240 mg active acid/l (EG&G, 1976 (6.1.3.001)).