Ammonium dihydrogen citrate

Short-term toxicity to fish

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

short-term toxicity to fish

Type of information:

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

Adequacy of study:

weight of evidence

Justification for type of information:

See Read-across justification document attached in section 13.

Reason / purpose for cross-reference:

read-across source

Reason / purpose for cross-reference:

read-across: supporting information

Reason / purpose for cross-reference:

read-across: supporting information

Specific details on test material used for the study:

The target substance contains between 45 and 86% water.

Key result

Duration:

96 h

Dose descriptor:

LC50

Effect conc.:

> 32 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Remarks on result:

other: based on the pure substance

Remarks:

As the target substance is an aqueous solution with 45 to 86% water, this value needs to be multiplied by at least a factor of 1.8

Validity criteria fulfilled:

not applicable

Conclusions:

Based on the results with the source test substance and on the supporting results from the SIDS of citric acid and ammonium sulfate, the pure target substance ammonium dihydrogen citrate can be considered not to be acutely toxic to fish at concentrations of 32 mg/L and higher. As the target substance is an aqueous solution with 45 to 86% water, this value needs to be multiplied at least by a factor of 1.8. This result is acceptable to be used for the short-term freshwater toxicity endpoint as the source substance was tested in marine species and according to the SIDS, it was shown that marine species tended to be more sensitive to ammonium sulfate than freshwater species.

Reference 2

Endpoint:

short-term toxicity to fish

Type of information:

experimental study

Adequacy of study:

key study

Study period:

6-10 June 2006

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study with acceptable restrictions

Remarks:

No analytical support was available. For justification, see "overall remarks"

Qualifier:

according to guideline

Guideline:

OECD Guideline 203 (Fish, Acute Toxicity Test)

Version / remarks:

1992

Deviations:

yes

Remarks:

see below

Principles of method if other than guideline:

The OECD 203 was adapted by OSPARCOM (ref nummer 1995-7) for marine testing of offshore chemicals. No further information was provided.

GLP compliance:

yes

Specific details on test material used for the study:

Soluble in seawater

Analytical monitoring:

no

Remarks:

see "overall remarks"

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION
- Method: directly added (at 0 h, 0.098 g and at 48h, 0.09607 g were added to 3000 mL treated seawater).
- Controls: seawater

Test organisms (species):

Cyprinodon variegatus

Details on test organisms:

TEST ORGANISM
- Common name: Sheepshead minnow
- Source: reared and maintained at Opus Plus Ltd.
- Age at study initiation (mean and range, SD): 81 days old
- Length at study initiation: 1.51 - 2.17 cm
- weight of control fish: 0.104 - 0.278 g
- Method of breeding: Sheepshead minnow were held under semi-static conditions in 50 litre capacity glass tanks, containing 1 μm filtered ultra-violet treated seawater and supplied with gentle aeration. Water quality measurements and mortality observations were conducted daily and fed food in flake form ad libitum at least twice daily.


FEEDING DURING TEST
Not indcated.

Test type:

semi-static

Water media type:

saltwater

Limit test:

yes

Total exposure duration:

96 h

Hardness:

No information

Test temperature:

19.1 - 21.9 ºC

pH:

8.01 - 8.14 in the control
7.87 - 8.09 in test substance concentrations

Dissolved oxygen:

99 - 100%

Salinity:

36 - 37 ‰

Conductivity:

No information

Nominal and measured concentrations:

Nominal test concentration: 32 mg/L

Details on test conditions:

TEST SYSTEM
- Test vessel: 10 L capacity glass tanks, containing 3 L of test media.
- Aeration: gentle aeration was supplied
- Renewal rate of test solution: replacement of media after 48h
- No. of organisms per vessel: 10
- No. of vessels per concentration (replicates): 1
- No. of vessels per control (replicates): 1
- Biomass loading rate: 0.515 g/L

TEST MEDIUM / WATER PARAMETERS
- Source of seawater: Natural local seawater is pumped to holding tanks from Scapa Flow, Orkney.
The treatment process was: sand filtered to remove particulate, filtered to 1μm, heated to 16 ºC, UV treated, degassed and held at a quantity of 3000 to 5000 litres. The water is constantly pumped through the system and trickle replenished as the water is used.

OTHER TEST CONDITIONS
- Adjustment of pH: no
- Photoperiod: constant illumination
- Light intensity: no information

EFFECT PARAMETERS MEASURED: Measurement of water quality (dissolved oxygen, pH, temperature and conductivity or salinity) are carried out at each concentration prior to and following each renewal of media. The condition of test animals were monitored at 24h intervals

TEST CONCENTRATIONS
The test concentration is based on the NOEC of the most sensitive species between Skeletonema costatum and Acartia tonsa by the test material. The algal species was noted to be the more sensitive from the allied studies.

Reference substance (positive control):

no

Key result

Duration:

96 h

Dose descriptor:

LC50

Effect conc.:

> 32 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Remarks on result:

other: see validity of results

Details on results:

- Observations on body length and weight: no information
- Mortality of control: no mortality
- No mortality was observed throughout the test duration

Reported statistics and error estimates:

Mortalities were determined in each vessel every 24h period. The number of dead organisms were expressed as a proportion of the total number exposed. Where sufficient response was observed for Rangefinding and definitive tests, the 24h, 48h, 72h and 96h LC50 values, 96h LC90 and 96h NOEC values were calculated from the proportional response data using an appropriate method (ToxCalc V5, Tidepool Scientific Software).

Sublethal observations / clinical signs:

Validity of the test:

- the mortality in the controls was 0% (and thus < 10%)

- constant conditions were maintained throughout the test and semi-static procedures were used.

- the dissolved oxygen concentration was 99 -100% (and thus > 60%) throughout the test.

- there is no evidence that the concentration of the test substance was satisfactorily maintained. However, intrinsic properties of the test substance indicate that the test substance concentrations over the 48 hours are not expected to change (see overall remarks).

Validity criteria fulfilled:

yes

Conclusions:

Ammonium Citrate Dibasic exhibited no effect at 32 mg/L after 96h (direct addition) to the marine fish Cyprinodon variegatus in the water phase.

Executive summary:

In a 96 -h acute toxicity study conducted according to OECD guideline 203 with adaptations by OSPARCOM for marine testing of offshore chemicals and GLP principles, sheepshead minnow (Cyprinodon variegatus) were exposed to the test substance under semi-static conditions (renewals at 48 h) at the nominal concentration of 32 mg/L and a blank seawater control (10 fish per vessel).

Exposure concentrations were not analytically verified but this was considered not to invalidate the study. No mortality was observed and thus the 96h-LC50 was > 32 mg/L based on nominal concentrations, The study is considered to be reliable with restrictions.

Reference 3

Endpoint:

short-term toxicity to fish

Type of information:

experimental study

Adequacy of study:

supporting study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

data from handbook or collection of data

Test organisms (species):

Salmo sp.

Details on test organisms:

Species: juvenile Salmo gairdneri
Also other species were sited in the SIDS, but only the lowest result was reported in this summary.

Test type:

flow-through

Water media type:

freshwater

Total exposure duration:

96 h

Test temperature:

12.4 - 12.5 ºC

Duration:

96 h

Dose descriptor:

LC50

Effect conc.:

ca. 173 mg/L

Nominal / measured:

not specified

Conc. based on:

test mat.

Remarks:

expressed in (NH4)2SO4 concentrations

Basis for effect:

mortality (fish)

Remarks on result:

other: Thurston and Russo, 1983

Details on results:

For freshwater species, the lowest LC50 (96 h) value of ca. 173 mg/L is observed for juvenile Salmo gairdneri in a flow through test carried out at 12.4 to 12.5 °C (Thurston and Russo, 1983).
A lower LC50 value (10 days) of 27 mg/L is observed for one or two day post hatch larvae of the warm water marine species Sciaenops ocellatus, at temperatures of 25 to 26 °C and an ambient pH of 8.0 to 8.2, also in a flow through test (Holt and Arnold, 1983).

Validity criteria fulfilled:

not specified

Conclusions:

According to the SIDS of Ammonium sulfate, the lowest LC50 (96 h) value of ca. 173 mg (NH4)2SO4/L is observed for juvenile freshwater species Salmo gairdneri in a flow through test carried out at 12.4 to 12.5 °C (Thurston and Russo, 1983).
Results on marine species indicate a higher sensitivity than freshwater species.

Reference 4

Endpoint:

short-term toxicity to fish

Type of information:

experimental study

Adequacy of study:

supporting study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

data from handbook or collection of data

Test organisms (species):

other: several freshwater species were used

Details on test organisms:

Carassius auratus, goldfish (freshwater)
Leuciscus idus, golden orfe (freshwater)
Lepomis macrochirus, bluegill (freshwater)

Test type:

not specified

Water media type:

freshwater

Dose descriptor:

LC0

Effect conc.:

625 mg/L

Nominal / measured:

not specified

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Remarks on result:

other: Carassius auratus, goldfish

Dose descriptor:

LC100

Effect conc.:

760 mg/L

Nominal / measured:

not specified

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Remarks on result:

other: Carassius auratus, goldfish

Duration:

96 h

Dose descriptor:

LC50

Effect conc.:

440 - 760 mg/L

Nominal / measured:

not specified

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Remarks on result:

other: Leuciscus idus, golden orfe

Duration:

96 h

Dose descriptor:

LC50

Effect conc.:

1 516 mg/L

Nominal / measured:

not specified

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Remarks on result:

other: Lepomis macrochirus, bluegil

Details on results:

Fish:
Carassius auratus, goldfish: “long-time exposure in hard water”, exposure period and method not stated
Leuciscus idus, golden orfe: “solution was not neutralised”, method not stated
Lepomis macrochirus, bluegill: method not stated

Validity criteria fulfilled:

not specified

Conclusions:

In freshwater, citric acid appears to be of low toxicity to fish with consistent LC50 values of several hundred milligrams per litre.

Description of key information

Based on the results with the source test substance and on the supporting results from the SIDS of citric acid and ammonium sulfate, the substance ammonium dihydrogen citrate can be considered not to be acutely toxic to fish at concentrations of 32 mg/L and higher. The 96h-LC50 > 32 mg/L. As the target substance is an aqueous solution with 45 to 86% water, this value needs to be multiplied at least by a factor of 1.8.

As the source substance was tested in marine species and according to the SIDS, it was shown that marine species tended to be more sensitive to ammonium sulfate than freshwater species, the result from the saltwater species is considered as worst-case value for the short-term freshwater fish toxicity endpoint.