Iron orthophosphate

Short-term toxicity to fish

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

short-term toxicity to fish

Type of information:

experimental study

Adequacy of study:

weight of evidence

Study period:

2006

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: GLP guideline study, data originate in part from a secondary source

Qualifier:

according to guideline

Guideline:

OECD Guideline 203 (Fish, Acute Toxicity Test)

GLP compliance:

yes

Analytical monitoring:

yes

Details on sampling:

- Concentrations: control and 100 mg/L. Samples were taken after 1, 24, 48, 72, and 96 hours.

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
- Method: Tap water was passed through a membrane filter (1 μm) to remove particulate matter and then a high-grade activated carbon filter to remove any organic contaminants. Preliminary solubility trials indicated that this test substance did not produce test solution of 100 mg/L using organic solvents such as acetone, dimethyl sulfoxide (DMSO), ethanol, and N,N-dimethylformamide (DMF). Therefore, the test solution was prepared by direct addition of the test substance to dilution water.

Test organisms (species):

Oryzias latipes

Details on test organisms:

TEST ORGANISM
- Common name: Japanese rice fish
Source: Korea Institute of Toxicology (KIT), KRICT, Deajeon, Korea
- Age at study initiation (mean and range, SD): 3-4 month
- Length at study initiation (length definition, mean, range and SD): 2.0±1.0 cm
- Weight at study initiation (mean and range, SD): 0.19 g (S.D. = 0.03 g)
- Feeding during test: none


ACCLIMATION
- Acclimation period: 7 days
- Acclimation conditions: same as in test
- Feeding frequency: not fed 24 hours prior to test

Test type:

static

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

96 h

Hardness:

10-250 mg/L CaCO3

Test temperature:

23.3 ± 0.1 °C

pH:

7.18-7.97

Dissolved oxygen:

5.2-8.5 mg/L

Salinity:

<0.01 mg/L (residual chlorine)

Nominal and measured concentrations:

Nominal test substance concentration: 100 mg/L
The concentrations of the test substance were measured to be 13.0-14.2 mg/L at a nominal concentration of 100 mg/L (13.0-14.2% of nominal concentration) at 0, 48, and 96 hours.

Details on test conditions:

TEST SYSTEM
- Aeration:none
- No. of organisms per vessel: 7
- No. of vessels per concentration (replicates): 1
- No. of vessels per control (replicates): 1

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: Filtered tap water (1 µm, membrane filter), residual chlorine or organic substances were removed by filtering through an activated carbon filter.
- Chlorine: < 0.01 mg/L


OTHER TEST CONDITIONS
- Photoperiod: 16:8 h day-night regime
- Light intensity: 990-1060 lux

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) :
Mortality and abnormality after 1, 24, 48, 72, and 96 hours

TEST CONCENTRATIONS
- Range finding study
- Test concentrations: 0.1, 1, 10, and 100 mg/L
- Results used to determine the conditions for the definitive study: no mortality observed at 100 mg/L

Reference substance (positive control):

no

Duration:

96 h

Dose descriptor:

LC50

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Duration:

96 h

Dose descriptor:

LC50

Effect conc.:

> 13.5 mg/L

Nominal / measured:

meas. (not specified)

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Duration:

96 h

Dose descriptor:

NOEC

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Duration:

96 h

Dose descriptor:

NOEC

Effect conc.:

> 13.5 mg/L

Nominal / measured:

meas. (not specified)

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Details on results:

There were no mortalities and adverse effects observed in any of the fish exposed to control and 13.5 mg/L treatment effect group during the test. All results were expressed in terms of the mean measured concentration.

Reported statistics and error estimates:

No statistics performed

Sublethal observations / clinical signs:

Table 1. Cumulative mortality of Oryzias latipes

Nominal concentration (mg/L)	Mean measured concentration (mg/L)	Number of organisms tested	Cumulative number of dead fish
			24-hour	48-hour	72-hour	96-hour
Control	ND	7	0	0	0	0
100	13.5	7	0	0	0	0

* ND : Not detected

Table 2. Symptoms of intoxication of the test substance to Oryzias latipes

Nominal concentration (mg/L)	Mean measured concentration (mg/L)	Symptoms of Intoxication
		24-hour	48-hour	72-hour	96-hour
Control	ND	NOR(7)	NOR(7)	NOR(7)	NOR(7)
100	13.5	NOR(7)	NOR(7)	NOR(7)	NOR(7)

* ND : Not detected

* ( ) : Number of fish

* NOR : Normal

Reference 2

Endpoint:

short-term toxicity to fish

Type of information:

experimental study

Adequacy of study:

weight of evidence

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study without detailed documentation

Qualifier:

according to guideline

Guideline:

OECD Guideline 203 (Fish, Acute Toxicity Test)

Version / remarks:

1992

GLP compliance:

no

Remarks:

Conduction of studies under GLP conditions is not a requirement for peer reviewed publications.

Analytical monitoring:

yes

Remarks:

AAS

Details on sampling:

- Concentrations: All concentrations were sampled.
- Sampling method: Samples of water were taken before and immediately after each solution renewal for metal analysis.
- Sample storage conditions before analysis: Each sample of water was acidified to 1% with ARISTAR (BDH, Singapore) nitric acid (HNO3, 65%) before metal analysis.

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION
- Method: Standard stock solutions (100 mg/L) were prepared from analytical grade iron chloride (FeCl3, Merck, Darmstadt, Germany). The stock solution was prepared with deionized water in a 1 L volumetric flask. The 5 concentration solutions were prepared by diluting the stock solution using dechlorinated tap water.
- Differential loading: no
- Controls: Dechlorinated tap water alone was used as control.

Test organisms (species):

other: Rasbora sumatrana (Cyprinidae) and Poecilia reticulata (guppy; Poeciliidae)

Details on test organisms:

TEST ORGANISM
- Source: R. sumatrana were purchased from aquarium shops in Bangi, Selangor, Malaysia, and P. reticulata were sampled from canals in the University Kebangsaan Malaysia
- Age at study initiation (mean and range, SD): Adult fish were used.
- Length and weight at study initiation (length definition, mean, range and SD): R. sumatrana (average lengths 4.0–5.0 cm; average weights 3–5 g) and P. reticulata (average lengths 2.0–3.5 cm and average weights 1.5–2.5 g).

ACCLIMATION
- Acclimation period: 1 week
- Acclimation conditions: acclimatized to the laboratory conditions (28–30 °C, 12 h light/ 2 h darkness, 50 L stocking tanks, dechlorinated tap water (filtered by several layers of sand and activated carbon; T.C. Sediment Filter), aerated through an air).
- Type of food during acclimation: Commercial fish food Tetramin (Tetra Werke, Melle, Germany).
- Feeding frequency during acclimation: not specified

Test type:

semi-static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

96 h

Hardness:

20.32 ± 2.20 mg/L as calcium carbonate (CaCO3)

Test temperature:

Room temperature (28 - 30°C)

pH:

6.5 ± 0.01

Dissolved oxygen:

6.30 ± 0.11 mg/L

Conductivity:

150.1 ± 1.6 mS/cm

Nominal and measured concentrations:

5 concentrations up to 100 mg/L. No further details given.

Details on test conditions:

TEST SYSTEM
- Test vessel: 500 mL glass beaker (Schott Duran) containing 400 mL of solution.
- Renewal rate of test solution: Renewal of the solution for every 2 d.
- No. of organisms per vessel: 2
- No. of vessels per concentration (replicates): 5
- No. of vessels per control (replicates): 5


TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: tap water
- Culture medium different from test medium: no
- Intervals of water quality measurement: Water quality parameters were measured every 2 days using portable meters.

OTHER TEST CONDITIONS
- Adjustment of pH: not mentioned
- Photoperiod: 12 h light / 12 h darkness
- Light intensity: fluorescent lights (334–376 lx)

EFFECT PARAMETERS MEASURED: Mortality was recorded every 3 - 4 h for the first 2 d and then at 12 – 24 h intervals for the remainder of the test period.

TEST CONCENTRATIONS
- Range finding study : yes (no further details)

Reference substance (positive control):

no

Duration:

96 h

Dose descriptor:

LC50

Effect conc.:

1.46 mg/L

Nominal / measured:

meas. (initial)

Conc. based on:

other: metal concentration

Basis for effect:

mortality (fish)

Remarks on result:

other: P. reticulata

Remarks:

95% CI: 0.47–2.57 mg/L

Duration:

96 h

Dose descriptor:

LC50

Effect conc.:

1.71 mg/L

Nominal / measured:

meas. (initial)

Conc. based on:

other: metal concentration

Basis for effect:

mortality (fish)

Remarks on result:

other: R. sumatrana

Remarks:

95% CI: 0.035–4.46 mg/L

Details on results:

- Mortality of control: 90% survival for the fish in the control water until the end of the study (for both species).
- Samples of water were taken before and immediately after each solution renewal for metal analysis. Measured concentrations were within 95–105% from nominal values. A median was calculated for the determination of the LC50 value.

Validity criteria fulfilled:

yes

Reference 3

Endpoint:

short-term toxicity to fish

Type of information:

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

Remarks:

Summary of available data used for the endpoint assessment of the target substance

Adequacy of study:

weight of evidence

Justification for type of information:

Please refer to the analogue justification attached to chapter 13.

Reason / purpose for cross-reference:

read-across source

Reason / purpose for cross-reference:

read-across source

Duration:

96 h

Dose descriptor:

LC50

Effect conc.:

> 13.5 mg/L

Nominal / measured:

meas. (not specified)

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Remarks on result:

other: O. latipes

Remarks:

Source CAS 7757-96-9

Duration:

96 h

Dose descriptor:

LC50

Effect conc.:

1.46 mg/L

Nominal / measured:

meas. (initial)

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Remarks on result:

other: P. reticulata, 95% CI: 0.47–2.57 mg/L

Remarks:

Source Fe3+

Validity criteria fulfilled:

not applicable

Description of key information

No acute effects towards fish up to the limit of water solubility.

Additional information

Iron (III) orthophosphate (CAS 10045-86-0) is a poorly water-soluble substance, as shown by a transformation/dissolution test according to the OECD guideline 29. The short-term toxicity of Iron (III) orthophosphate towards fish was evaluated in a weight of evidence approach with read across data. The short term effects by dissolved Fe³⁺were assessed using a soluble iron (III) form (FeCl₃) while the acute fish toxicity of PO4^3-was assessed based on the reference substance Calcium hydrogenorthophosphate (CAS 7757-93-9). An extensive read across justification is provided in IUCLID chapter 13.

The potential toxicity of dissolved iron (III) was assessed in a study by Shuhaimi-Othman et al. (2015) conducted according to the OECD guideline 203. The fish species Rasbora sumatrana (Cyprinidae) and Poecilia reticulata (guppy) were exposed under semi-static conditions to five test item (FeCl₃) concentrations up to 100 mg/L for 96 h. An analytical monitoring was performed via AAS. Samples of water were taken before and immediately after each solution renewal for metal analysis. Measured concentrations were within 95–105% of nominal values. The LC50 values for P. reticulate and R. sumatrana were 1.46 and 1.71 mg Fe/L (measured) respectively. These results are based on a well soluble Iron (III) source (FeCl₃), which represents a worst case. Released iron (III) will be rapidly converted to poorly water soluble precipitates. The transformation/dissolution test according to OECD 29 showed that the release of iron from the substance after 7 days was lower than the LOD of 0.1682 µg/L at a loading of 1 mg/L (pH 6). This concentration is far below the conservative effect concentrations found in the study with FeCl₃as reference substance (ecotoxicity reference value - ERVcompound: 4.03 mg/L). Therefore, no acute toxic effects are expected from dissolved iron (III) released from the substance up to its water solubility.

The acute toxicity of Calcium hydrogenorthophosphate (CAS 7757-93-9) to fish was investigated in a study according to the OECD guideline 203 (2013). The limit test was conducted under static conditions. Fish of the species Oryzias latipes were exposed to a nominal test substance concentration of 100 mg/L. The analytical recovery rate of the test substance was 13.0-14.2% of the nominal concentration. During the test period of 96 h, mortality and abnormal behavior of the test organisms were examined after 1, 24, 48, 72, and 96 h. Mortality or adverse effects of the test substance were not observed. Based on the mean measured concentration an LC50 (96 h) > 13.5 mg/L (nominal: LC50 (96 h) >100 mg/L) was determined. Since Calcium hydrogenorthophosphate will dissociate to its ions calcium and phosphate and its solubility is much higher than iron (III) orthophosphate, it is concluded that similarly no effects are expected by the phosphate ions resulting from Iron (III) orthophosphate. 

In addition, the publically available Renewal Assessment Report (2013) for use of ferric phosphate in plant protection products also concludes based on experimental data with the active substance that the substance is not acutely toxic to fish up to a loading rate of 100 mg/L. The study was conducted according to the OECD guidelines 203 and GLP. These data support the above conclusions from the read across data.

In conclusion based on the above described results, no short term effects by Iron (III) orthophosphate towards fish are expected.