Aluminium tris(dihydrogen phosphate)

Long-term toxicity to fish

Link to relevant study record(s)

Reference

Endpoint:

fish short-term toxicity test on embryo and sac-fry stages

Type of information:

experimental study

Adequacy of study:

key study

Study period:

n/a

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

study well documented, meets generally accepted scientific principles, acceptable for assessment

Justification for type of information:

REPORTING FORMAT FOR THE ANALOGUE APPROACH
1. HYPOTHESIS FOR THE ANALOGUE APPROACH
In water aluminium orthophosphates will dissociate into their ionic forms (Al3+ and PO43-, which will further associate with the ionic forms of H2O). It is therefore considered acceptable to assess the aluminium and phosphate ions as separate entities.
The aluminium ion is considered to be toxic to fish under certain circumstances. The bioavailability and hence toxicity of aluminium is predominantly influenced by water quality parameters, in particular pH. The fate of Al3+ ion is of the most importance when considering whether a classification for aquatic toxicity of aluminium orthophosphates is required. In pH conditions of around neutral (as would be maintained via the use of appropriate buffers in a laboratory study) the Al3+ ion would be expected to react with the water molecules forming a weak acid (Al(OH)3)which would ultimately precipitate out of the water column rendering it not bioavailable and thus non-toxic to aquatic organisms. Since aluminium sulphate is soluble in water it is considered that the behaviour in water will be similar to the target substance and as such the data is relevant for assessing the toxicity of aluminium.
2. SOURCE AND TARGET CHEMICAL(S) (INCLUDING INFORMATION ON PURITY AND IMPURITIES)
No additional data.
3. ANALOGUE APPROACH JUSTIFICATION
On the basis of the discussion presented above the results of acute toxicity studies on aluminium sulphate-14-hydrate have been used and are justified on the basis that Al3+ ion is of concern with regards to potential toxicity and therefore the results of such a study are relevant for read-across to the target substance.
This study is submitted as part of a weight of evidence approach in accordance with REACH Annex XI, Section 1.2. When considered alongside the additional data provided for this endpoint it is considered that the ecotoxicity of the substance to be registered is adequately assessed.
4. DATA MATRIX
See full read-across justification attached under Section 13 of this dossier and summary of data included in the endpoint summary under Section 6.1 of this dossier.

Reason / purpose for cross-reference:

read-across: supporting information

Qualifier:

no guideline followed

Principles of method if other than guideline:

Tests began with fathead minnow eggs 16-40 hr old and placed into hatching baskets. All hatched fry were counted and up to ten fry of normal development were taken and released into the exposure aquaria and fed brine shrimp 3-5 times daily for the next 27 days. Observations were made on mortality, length, and weight.

GLP compliance:

no

Analytical monitoring:

yes

Details on sampling:

- Concentrations: all concentrations
- Sampling method: samples were taken from aquaria centers three times per week. Samples were drawn into 15 ml tubes and acidified with 1 drop of 1.0 N HNO3.

Vehicle:

not specified

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION
- Method: Concentrated stock solutions were made for each test. Aliquots were diluted to concentrations of the highest toxicant level tested mechanically on each cycle by the diluters

Test organisms (species):

Pimephales promelas

Details on test organisms:

TEST ORGANISM
- Common name: fathead minnow
- Source: Duluth-Newtown laboratory strain, maintained in the Fisheries Laboratories

METHOD FOR PREPARATION AND COLLECTION OF FERTILIZED EGGS
- Method of collection of fertilised eggs: removed from hatchery tiles and viable ones used for testing
- Subsequent handling of eggs: placed in hatching baskets at rate of 20 per basket

Test type:

flow-through

Water media type:

freshwater

Limit test:

no

Total exposure duration:

28 d

Remarks on exposure duration:

posthatch

Hardness:

Hard, value not reported

pH:

7.27 (mean)

Dissolved oxygen:

6.98 mg/L (mean)

Nominal and measured concentrations:

Range of treatment means (mg/L): 2.32-53.81

Details on test conditions:

TEST SYSTEM
- Test vessel:
- Material, size, headspace, fill volume: glass aquaria approximately 5.1 L with a stainless steel screen restricting the fish to a 4.1 L volume.
- Aeration: Diluent water was initially heated and oxygenated in a head tank prior to entering the diluter
- Type of flow-through (e.g. peristaltic or proportional diluter): the diluter is a modification of that of Mount and Brungs (1967). The solenoid switch trip bucket was composed of a 250 ml beaker counter-balanced on a fulcrum. The beaker had a drainage hole which regulated the rate at which water drained out. The stock concentration was held in a stoppered marriot bottle.
- Renewal rate of test solution: The diluter was designed to deliver 2 liters of treatment water to each concentration per cycle, with the 95% turnover time in the test chambers of 5.8 hours.
- No. of fertilized eggs/embryos per vessel: 20, 10 fry selected for further exposure
- No. of vessels per concentration (replicates): 4
- No. of vessels per control (replicates): 4

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: well water tapping the Jordan sandstone stratum underlying the Minneapolis-St. Paul metropolitan area, with iron catalytically removed
- Alkalinity: 233 mg/L
- Culture medium different from test medium: no
- Intervals of water quality measurement: daily from random exposures

EFFECT PARAMETERS MEASURED: survival determined every 7 days, lengths and weights measured at day 28 posthatch

Duration:

28 d

Dose descriptor:

NOEC

Effect conc.:

7.1 mg/L

Nominal / measured:

meas. (not specified)

Conc. based on:

other: total Al

Basis for effect:

mortality

Remarks:

fry

Duration:

28 d

Dose descriptor:

LOEC

Effect conc.:

11.9 mg/L

Nominal / measured:

meas. (not specified)

Conc. based on:

other: total Al

Basis for effect:

mortality

Remarks:

fry

Duration:

28 d

Dose descriptor:

NOEC

Effect conc.:

4.7 mg/L

Nominal / measured:

meas. (not specified)

Conc. based on:

other: total Al

Basis for effect:

weight

Remarks:

mean

Duration:

28 d

Dose descriptor:

LOEC

Effect conc.:

7.1 mg/L

Nominal / measured:

meas. (not specified)

Conc. based on:

other: total Al

Basis for effect:

weight

Remarks:

mean

Duration:

28 d

Dose descriptor:

NOEC

Effect conc.:

4.7 mg/L

Nominal / measured:

meas. (not specified)

Conc. based on:

other: total Al

Basis for effect:

length

Remarks:

mean

Duration:

28 d

Dose descriptor:

LOEC

Effect conc.:

7.1 mg/L

Nominal / measured:

meas. (not specified)

Conc. based on:

other: total Al

Basis for effect:

length

Remarks:

mean

Duration:

28 d

Dose descriptor:

NOEC

Effect conc.:

23.1 mg/L

Nominal / measured:

meas. (not specified)

Conc. based on:

other: total Al

Basis for effect:

number hatched

Remarks:

as percent

Duration:

28 d

Dose descriptor:

LOEC

Effect conc.:

53.8 mg/L

Nominal / measured:

meas. (not specified)

Conc. based on:

other: total Al

Basis for effect:

number hatched

Remarks:

as percent

Details on results:

- Fish weights and lengths (mean values) on day 28: see Table 6
- Effect concentrations exceeding solubility of substance in test medium: all metals remained in solution

Reported statistics and error estimates:

All chronic test data were examined by one-way analysis of variance with treatment differences separated by Dunnett's procedure (one-tailed) at an alpha = 0.05 (Steele and Torre, 1960).

Table 1. Mean terminal lengths (mm) and weights (gm) of the fathead minnow embryo-larval tests.

Mean Al (mg/L)	Mean Length (mm)	Mean Weight (g)
Control	25.4	0.140
2.3	24.9	0.130
4.7	24.8	0.124
7.1	23.1 *	0.098 *
11.9	19.7 *	0.055 *
23.1	- *	- *
53.3	- *	- *

* significantly different at p = 0.05

Description of key information

NOEC (28 d):  4.7 to 23.1 mg/L (read across)

Key value for chemical safety assessment

Fresh water fish

Fresh water fish

Effect concentration:

4.7 mg/L

Additional information

Data on the chronic toxicity of aluminium tris(dihydrogen phosphate) (CAS 13530-50-2) to fish are not available. In accordance with Annex XI, 1.5, of Regulation (EC) No 1907/2006, read-across to the structurally related substances substance aluminium sulphate hexadecahydrate (CAS 10043-01-3) was conducted to fulfil the standard information requirements. In accordance with Article 13 (1) of Regulation (EC) No 1907/2006, "information on intrinsic properties of substances may be generated by means other than tests, provided that the conditions set out in Annex XI are met.” In particular for aquatic toxicity, information shall be generated whenever possible by means other than vertebrate animal tests, which includes the use of information from structurally related substances (grouping or read-across). According to Annex XI, Item 1.5, of Regulation (EC) No 1907/2006 substances can be considered to be similar if their physicochemical, toxicological and ecotoxicological properties are likely to be similar or follow a regular pattern as a result of structural similarity. For further details please see chapter 6.1 of the IUCLID file.

The chronic toxicity of aluminium sulphate hexandecahydrate (CAS 10043-01-3) to fish was investigated in a study on (sub)lethal effects on Pimephales promelas. Hatched fry were exposed to the substance for 28 days in a flow-through system. The exposure concentrations were 2.32-53.81 mg/L. NOECs and LOECs were determined for mortalities of the fry, weight, length, and number hatched. Based on the measured total Al NOECs were in the range of 4.7 to 23.1 mg/L and LOECs in the range of 7.1 to 53.8 mg/L.

 

Thus, based on the available data chronic toxic aluminium tris(dihydrogen phosphate) (CAS 13530-50-2) is not anticipated.