Aluminium metaphosphate

Bioaccumulation: aquatic / sediment

Link to relevant study record(s)

Reference

Endpoint:

bioaccumulation in aquatic species: fish

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:

use of dispersant in high concentration

Justification for type of information:

The target and source substances are inorganic phosphate compounds. Due to the comparable physico-chemical properties a similar environmental fate is expected for all substances. Both target substance and the source substance aluminium dihydrogen triphosphate are poorly soluble in water. Transport and partitioning are mainly driven by their relatively low water solubility. A certain proportion of the substances will remain undissolved under environmental conditions and undergoes chemical precipitates. Precipitates of aluminium and phosphorus will be further transformed in soil and sediment systems through mineralization, hydrolytic transformation in soils. In pure water metaphosphate hydrolyses slowly to triphosphate. However the hydrolysis speeds up in presence of microorganisms and mineral contents, forming finally orthophosphate and its equilibrium compound, hydrogen- and dihydrogen phosphates, Microorganism catalysed hydrolysis promotes dissolution and transformation of metaphosphate and triphosphates in the environment compartments. As inorganic compounds, target and sources are not be removed by biotic or abiotic degradation and the ion will persist in the environment.

Reason / purpose for cross-reference:

read-across: supporting information

Qualifier:

according to guideline

Guideline:

OECD Guideline 305 (Bioconcentration: Flow-through Fish Test)

Principles of method if other than guideline:

The study was performed according to “Methods for the Study of New Chemical Substances” (Kanpogyo (Environmental Agency) Notification No 5, Yakuhatsu (Pharmaceutical Affairs Bureau) Notification No 615, Kikyoku (Basic Industries Bureau) 1974 Notification No 392, 13 July 1974, amended 8 October 1998) and “Bioconcentration: Flow-through Fish Test” (OECD Guidelines for Testing of Chemicals: Guideline 305, 14 June 1996).

GLP compliance:

yes

Details on sampling:

Fish analysis sample:
∙ Measure body weight and length
∙ Cut into small pieces (scissors)
∙ Microcut (in iced water, using a Polytron, for at least 2 min)
Microcut sample:
← Divide into 0.5 g portions (electric analyser balance)
← 4 mol/L Sodium hydroxide*7 4 mL (graduated pipette)
∙ Heat (Teflon pressure-resistant vessel, approx. 150°C, 2 hours)
∙ Cool (freezer, at least 12 hours)
← Water*6 20 mL (measuring cylinder)
∙ Centrifugation (7100 * G, 10 min)
Residue/Supernatent:
∙ Constant volume 50 mL (water*6, graduated flask)
∙ Divide into 2 mL portions
(push-button type liquid microvolume meter)
← Nitric acid 190 µL (push-button type liquid microvolume meter)
∙ Constant volume 25 mL (water*6, graduated flask)
=> AA sample

Water analysis sample:
← Water*6 18 mL (measuring cylinder) (first concentration set only)
← 2 mol/L Sodium hydroxide 400 µL
(push-button type liquid microvolume meter)
∙ Heat (hotplate, approx. 90°C, approx. 10 min)
∙ Cool (leave at room temperature)
← Nitric acid 370 µL (push-button type liquid microvolume meter)
∙ Constant volume 50 mL (water*6, graduated flask)
=> AA sample

Vehicle:

yes

Details on preparation of test solutions, spiked fish food or sediment:

PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
- Method:

- Chemical name of vehicle (dispersant): Sodium polyacrylate

First concentration set:
A stock solution of the test substance was prepared at a concentration of 1894 mg/L by dissolving the test substance and four times its volume of sodium polyacrylate in ion exchanged water using a Clearmix dispersion machine (approximately 1.8 × 104 rpm, approximately 30 minutes).

Second concentration set:
Stock solution was prepared at a test substance concentration of 189.4 mg/L by dissolving the test substance and four times its volume of sodium polyacrylate in ion exchanged water using a Clearmix dispersion machine (approximately 1.8 × 104 rpm, approximately 30 minutes).

Control set:
Stock solution was prepared at 8 g/L by dissolving sodium polyacrylate in ion-exchanged water.

Test organisms (species):

Cyprinus carpio

Details on test organisms:

TEST ORGANISM
- Common name:Carp
- Source: in house culture from CERI Kurume Laboratory 19-14 Chuo-machi, Kurume, Fukuoka (830-0023)
- Age at study initiation: young fish
- Length at study initiation: 7.5-9.7 cm
- Description of housing/holding area: Glass water tank of capacity 100 L
- Feeding during test
- Food type: Mixed feed for rearing carp
- Amount: An amount of feed equivalent to approximately 2% of the bodyweight of the fish
- Frequency: twice a day

ACCLIMATION
- Acclimation period: 31 days
- Acclimation conditions (same as test or not): same as test
- Type and amount of food: Mixed feed for rearing carp
Composition of food:
Protein content: ≥43.0%
Fat content:≥3.0%
- Feeding frequency: An amount of feed equivalent to approximately 2% of the bodyweight of the fish was divided into two portions and supplied twice a day.
- Health during acclimation: yes, In the acclimatization tank, the fish were treated in a mixed drug solution comprising Elevage 20 mg/L and sodium chloride 7 g/L, for 24 hours. In the test water tank, they were treated in a mixed drug solution comprising Elevage 20 mg/L and sodium chloride 7 g/L, for 24 hours.

Route of exposure:

aqueous

Test type:

flow-through

Water / sediment media type:

natural water: freshwater

Total exposure / uptake duration:

28 d

Test temperature:

25.3-25.9°C

pH:

8.1-8.3

Dissolved oxygen:

7.8-8.1 mg/L

Details on test conditions:

TEST SYSTEM
- Test vessel:
- Material, size, headspace, fill volume: Glass water tank of capacity 100 L
- Renewal rate of test solution (frequency/flow rate): A combination of 2 mL/min stock solution and 800 mL/min test water was supplied to the test tank at 1155 L/day
- No. of organisms per vessel: 29
- No. of vessels per concentration (replicates): 1
- No. of vessels per control: 1

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: Water was supplied using the flowing water device assembled at Kurume Laboratory

OTHER TEST CONDITIONS
- Adjustment of pH: No
- Photoperiod: 14 hours of light/10 hours of darkness
- Light intensity: Artificial illumination by white fluorescent light

Nominal and measured concentrations:

First concentration set: 4.735 mg/L
Second concentration set: 0.4735 mg/L

Type:

BCF

Value:

<= 4.8

Calculation basis:

steady state

Remarks on result:

other: Conc.in environment / dose:4.735 mg/L

Type:

BCF

Value:

<= 43

Calculation basis:

steady state

Remarks on result:

other: Conc.in environment / dose:0.4735 mg/L

Study results

Test substance concentration in the test water:

The test substance concentration in the test water remained at ≥75% of the stipulated value, as shown in Table 1. Also, the variation in test substance concentration remained within ±20% of the mean measurement value.

 

Table 1          Test substance concentration in the test water

(unit mg/L)

Concentration set	After 1 day	After 6 days	After 9 days	After 14 days	After 22 days	After 28 days	Mean (SD)
1	4.63	3.59	3.97	4.22	4.22	4.24	4.14 (0.345)
2	0.542	0.457	0.426	0.492	0.449	0.453	0.470 (0.0412)

(SD: standard deviation)

 

Bioconcentration factors

The bioconcentration factors were as shown in Table 2.

The correlation between the Table 2 bioconcentration factors and the exposure times are shown in Figure 1 and Figure 2. During exposure, the bioconcentration factor was <= 4.8 in the first concentration set and <= 43 in the second concentration set.

 

Table 2          Bioconcentration factors

 

Concentration set	After 6 days	After 9 days	After 14 days	After 22 days	After 28 days
1	<=4.8 <=4.8	<=4.8 <=4.8	<=4.8 <=4.8	<=4.8 <=4.8	<=4.8 <=4.8
2	<=43 <=43	<=43 <=43	<=43 <=43	<=43 <=43	<=43 <=43

 

Steady-state bioconcentration factors

The results show that the bioconcentration factors were far below 100, steady-state was reached after 28 days. The steady-state bioconcentration factors were therefore the bioconcentration factors after 28 days.

 

Fat content in the fish

The mean fat content in the fish was as follows.

Before starting the experiment        3.54%

After completion of the experiment 3.26%

 

Observation of the fish

No abnormalities were observed.

 

Discussion

In the second concentration set water analysis blank test, the mean level of aluminium detected was 0.761 µg. This was due to aluminium present in the test water, and corresponded to 8% of the stipulated concentration in the second concentration set. Aluminium was analysed in the present study, and so these values were not subtracted but included in the test substance exposure when the concentration of the test substance in the test water was calculated.

Description of key information

The substance has a no bioaccumulation potential (BCF ≤43) (read across)

Key value for chemical safety assessment

BCF (aquatic species):

43 dimensionless

Additional information

Aluminium metaphosphate is an inorganic phosphate and will dissociate aluminium and triphosphate ions and further hydrolysed forming various aluminium species and soluble orthophosphate (PO43-) in sewerage systems, sewage treatment plants and in the environment.

The phosphate anion (PO43-) is ubiquitous in natural waters and essential micronutrient for many organisms, it will not bioaccumulate in organisms and food chains.

The bioaccumulation potential of aluminium dihydrogen triphosphate (CAS 13939-25-8), the product of hydrolysis of aluminium metaphosphate, was tested in a GLP guideline study according to OECD 305 under the flow-through conditions. The stock solution of the test item was prepared using sodium polyacrylate as dispersant. Test fish (Cyprinus carpio) were exposed to test concentrations of 4.735 mg/L and 0.4735 mg/L respectively. The test was terminated after 28 days. At a substance concentration of 4.735 mg/L a BCF value≤43 was determined, whereas a BCF≤4.8 was determined at a test substance concentration of 0.4735 mg/L.

The study results demonstrate that the potential of aluminium metaphosphate (CAS 13776-88-0) to bioaccumulate and the risk of secondary poisoning are low.