Ammonium dihydrogen citrate

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:

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

Adequacy of study:

weight of evidence

Justification for type of information:

Please see the 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:

48 h

Dose descriptor:

EC50

Effect conc.:

1 503 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Remarks on result:

other: based on the pure substance

Remarks:

as the target substance is an aqueous solution, this value needs to be multiplied by at least a factor of 1.8

Details on results:

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 daphnia magna at concentrations of 100 mg/L and higher. 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. 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.

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 daphnia magna at concentrations of 100 mg/L and higher. 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. 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, is was shown that marine species tended to be more sentitive to ammonium sulfate than freshwater species.

Reference 2

Endpoint:

short-term toxicity to aquatic invertebrates

Type of information:

experimental study

Adequacy of study:

key study

Study period:

17-19 May 2006

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study with acceptable restrictions

Remarks:

No analytical support was included in the test. For validity justification, please see "overall remarks"

Qualifier:

according to guideline

Guideline:

other: ISO 14669 (1999) Water Quality-Determination of acute lethal toxicity to marine copepods (Copepoda; Crustacea)

Deviations:

no

Qualifier:

according to guideline

Guideline:

other: ISO 5667-16 (1998) Water Quality Sampling- Guidance on biotesting of samples

Deviations:

no

GLP compliance:

yes

Specific details on test material used for the study:

Soluble at 1000 mg/L in seawater after 20 hours stirring

Analytical monitoring:

no

Remarks:

see "overall remarks"

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION
As the material was classified as soluble, a dilution series was prepared, where an appropriate weight of test material is added to prepare an initial stock. Appropriate volumes are taken from this stock to prepare subsequent test concentrations, brought to volume with filtered treated seawater (see attached background material)

Test organisms (species):

other: Acartia tonsa (marine copepod)

Details on test organisms:

TEST ORGANISM
- Strain: CCAP 1077/5
- Source: Initially the culture was received from Dunstaffnage Marine Laboratory in 1995. Test organisms were obtained from age standardised cohorts and were 19 days old at definitive test commencement.
- The culture system was maintained with flowing 0.45 μm filtered ultra violet treated sea water, supplied by pump from Scapa Flow in Orkney. The cultures were maintained on a mixed algal diet comprising of between 2 and 4 species.
- Feeding during test: not indicated

Test type:

static

Water media type:

saltwater

Limit test:

no

Total exposure duration:

48 h

Test temperature:

19.0 - 21.0 ºC

pH:

at start: 7.87 - 8.03
over 48h: 7.87 - 8.08

Dissolved oxygen:

96 - 99%

Salinity:

Not indicated

Conductivity:

49.9 - 53.7 mS/cm

Nominal and measured concentrations:

1000, 1800, 3200, 5600 and 10000 mg/L nominal

Details on test conditions:

TEST SYSTEM
- Test vessel: 100 ml capacity borosilicate glass crystallising dishes, each containing 50 ml of test medium covered with soda glass watch covers.
- Aeration: no information
- No. of organisms per vessel: 10
- No. of vessels per concentration (replicates): 2
- No. of vessels per control (replicates): 4

TEST MEDIUM / WATER PARAMETERS
Natural seawater is supplied by pump from Scapa Flow, Orkney. All seawater is UV sterilised and filtered to 0.2 μm.

OTHER TEST CONDITIONS
- Adjustment of pH: yes, the pH of the stock solution of 1000 mg/L was adjusted from 6.77 to 8.17 at test commencement; the pH of the stock solution of 10000 mg/L was adjusted from 3.5 to 7.87 at test commencement.
- Photoperiod: no information
- Light intensity: no information

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) : Measurement of water quality (dissolved oxygen, pH and temperature) are carried out in one replicate at each concentration at 0h, 24h, and 48h. Observation of mortalities are carried out at 24h and 48h. Conductivity is carried out in one control and also in the highest and lowest test concentration, one replicate only at 0h and 48h.

RANGE-FINDING STUDY
- Test concentrations: 1000, 100, 10 and 1 mg/L, plus four control vessels.
- Results used to determine the conditions for the definitive study: the range-finding test exhibited no significant effect at 1000 mg/L after 48h (dilution series).

Reference substance (positive control):

yes

Remarks:

3,5 DCP at 0.32, 0.56, 1.0, 1.8 and 3.2 mg/L

Key result

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

1 503 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Remarks on result:

other: 95% CI 1490 - 1532 mg/L

Details on results:

At 48h, 80% of the copepods were immobile at a nominal test concentration of 1800 mg/L. 100% immobility was observed at test concentrations of 3200 mg/L and higher (see attached background material)

Results with reference substance (positive control):

The 48h LC50 was 1.06 mg/L. This within the international standard range (48h LC50 of 0.4 to 1.5 mg/L)

Reported statistics and error estimates:

Mortalities are detemined in each vessel at 24 and 48h. The number of dead or immobile copepods are expressed as a proportion of the total number exposed.
Where sufficient response is observed, the 24 and 48h LC50, 48h LC90 and 48h NOEC values are calculated using an appropriate statistical method from the ToxCalc Version 5 software.

Validity of the test (ISO 14669)

- dissolved oxygen concentration at the end of the test was 96 -99% ( and thus > 80%)

- the mortality in the controls was 7.5% (and thus < 10%)

- the toxicity of the reference material was within the range specified in the international standard.

Validity criteria fulfilled:

yes

Remarks:

see "any other information"

Conclusions:

Ammonium citrate dibasic exhibited a 48h LC50 value of 1503.23 mg/L (nominal concentration) to the marine copepod Acartia tonsa in the aqueous phase (dilution series).

Executive summary:

In a 48 -h acute toxicity study conducted according to ISO 14669 (1999) and ISO 5667-16 (1998) guidelines and GLP principles, Acartia tonsa (marine copepod) were exposed to the test substance under static conditions at the nominal concentrations of 1000, 1800, 3200, 5600 and 10000 mg/L and a blank seawater control (4 copepods per vessel, 2 replicates per concentration, 4 replicates for control).

Exposure concentrations were not analytically verified but this was considered not to invalidate the study. The 48h-LC50 for mobility was 1503 mg/L based on nominal concentrations. The study is considered to be reliable with restrictions.

Reference 3

Endpoint:

short-term toxicity to aquatic invertebrates

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):

Daphnia magna

Test type:

flow-through

Water media type:

freshwater

Total exposure duration:

96 h

Test temperature:

20 +/- 1 ºC

pH:

6.5 - 8.5

Duration:

96 h

Dose descriptor:

EC50

Effect conc.:

> 100 mg/L

Nominal / measured:

not specified

Conc. based on:

test mat.

Remarks:

expressed in terms of (NH4)2SO4 concentrations

Basis for effect:

not specified

Remarks on result:

other: Ewell et al. (1986)

Details on results:

For freshwater species all LC50 values were > 100 mg (NH4)2SO4/L.
A lower LC50 (96 h) of 47.7 mg (NH4)2SO4/L is observed for young green mussels (Perna viridis), a warm water marine species, at temperatures of 28 to 30 °C and an ambient pH of 8.0 to 8.3, also in a static test (Reddy and Menon, 1979).

Validity criteria fulfilled:

not specified

Conclusions:

For freshwater species all LC50 values were > 100 mg (NH4)2SO4/L.
Results on marine species indicate a higher sensitivity than freshwater species.

Reference 4

Endpoint:

short-term toxicity to aquatic invertebrates

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 test species were presented in the SIDS

Details on test organisms:

Daphnia magna (freshwater)
Carcinus maenas (saltwater) (crab)

Duration:

24 h

Dose descriptor:

EC50

Effect conc.:

1 535 mg/L

Nominal / measured:

not specified

Conc. based on:

test mat.

Basis for effect:

not specified

Remarks on result:

other: neutralized

Remarks:

daphnia magna

Duration:

24 h

Dose descriptor:

EC50

Effect conc.:

85 mg/L

Nominal / measured:

not specified

Conc. based on:

test mat.

Basis for effect:

not specified

Remarks on result:

other: not neutralized

Remarks:

daphnia magna

Dose descriptor:

LC0

Effect conc.:

80 mg/L

Nominal / measured:

not specified

Conc. based on:

not specified

Remarks on result:

other: daphnia

Remarks:

exposure period not stated

Dose descriptor:

LC100

Effect conc.:

120 mg/L

Nominal / measured:

not specified

Conc. based on:

not specified

Basis for effect:

not specified

Remarks on result:

other: daphnia magna

Remarks:

exposure period not stated

Duration:

48 h

Dose descriptor:

LC50

Effect conc.:

160 mg/L

Nominal / measured:

not specified

Conc. based on:

not specified

Basis for effect:

mortality

Remarks on result:

other: Carcinus maenas (crab)

Remarks:

saltwater

Details on results:

Daphnia magna (freshwater) EC0 = 80 mg/L and EC100 = 120 mg/L: “long-time exposure in soft water”, exposure period and method not stated
Carcinus maenas (saltwater) (crab): method not stated

Validity criteria fulfilled:

not specified

Conclusions:

In freshwater, citric acid appears to be of low toxicity to daphnia and other aquatic acute test invertebrate organisms, with consistent LC50/EC50 values of several hundred milligrams per litre.
The marine species for which data are available is the crab with an acute LC50 over 100 mg/L (160 mg/L).

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 pure target substance ammonium dihydrogen citrate can be considered not to be acutely toxic to daphnia magna at concentrations of 100 mg/L and higher. The 48h-EC50 was 1503 mg/L. 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.

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 invertebrates toxicity endpoint.

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates

Effect concentration:

1 503 mg/L

Marine water invertebrates

Marine water invertebrates

Effect concentration:

1 503 mg/L