Strontium hydroxide

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

Study period:

From September 12, 2002 to December 25, 2002

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study with acceptable restrictions

Remarks:

GLP Guideline study, basic data provided but no detailed test protocol available as the studies initiated by the Japanese authorities as part of the existing chemicals survey are only published as final report. Validity criteria are met. However some differences compared to OECD 305 since the depuration phase was not included and BCF not expressed in relation to the total lipid content.

Reason / purpose for cross-reference:

read-across: supporting information

Qualifier:

according to guideline

Guideline:

other: In accordance with "Testing Methods for New Chemical Substances" (Environmental Protection Industry No. 5, Pharmaceutical Development No. 615, 49th Foundation No. 392, 1974; corrected by the Ministry of Justice 1998)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Specific details on test material used for the study:

SOURCE OF TEST MATERIAL
- Lot number: TMC5546
- Purity: 99.9%
- Appearance: White powder

IDENTIFICATION OF TEST MATERIAL
The test materials (specimens) supplied by the consignor were subjected to x-ray diffraction measurements.
The test substance was confirmed by the fact that the spectrum matched the analysis pattern of the PDF card (International Centre Diffraction Data).

STABILITY AND STORAGE CONDITIONS OF TEST MATERIAL
- Solubility of the test material: slightly soluble in water 43.5/100g at 0 °C, ethanol, acetone
- Storage condition of test material: in a desiccator, at room temperature
- Stability of the test material during storage: After the experiment, x-ray diffraction was measured and compared with the spectrum measured before the start of the test. As a result, the test substance was stable under the storage conditions since there was no change in the spectrum.
- Stability in feed stock solution: After 10 days, 107% (9550 mg/L- 10180mg/L) of the initial concentration was still detected and the test substance was stable in the fluid stock solution.

Radiolabelling:

no

Details on sampling:

DETERMINATION OF CONCENTRATION OF TEST SUBSTANCE IN WATER:
Samples were taken at the beginning of uptake (day 0), day 5, day 7, day 14, day 21, and day 28, and the concentration of the test substance was determined as follows:
1) High concentration zone:
- Dilute test water 10x with dilution water
- Collect 0.2 mL
- Add 0.1 mL HNO3, 0.05 µg internal standard Y, and make the volume to 10 mL with purified water
- Measure by ICP-MS
2) Low concentration zone:
- Collect 0.2 mL of test water
- Add 0.1 mL HNO3, 0.05 µg internal standard Y, and make the volume to 10 mL with purified water
- Measure by ICP-MS

DETERMINATION OF CONCENTRATION OF TEST SUBSTANCE IN FISH:
Four carps were sampled at days 5, 7, 14, 21, and 28 and the concentration of the test substance was determined as follows (two batches of two fishes for each):
- Weighing of 2 fish (approx. 10 g)
- Shred with scissors
- Add purified water (same volume as fish weight (mL))
- Homogenize (5 min, rotational speed approx. 10 000 rpm)
- Collect 1.00 g of fish slurry in a Teflon container
- Add 5 mL HNO3 and 1 mL H2O2
- Microwave decomposition, then water cooling for at least 10 minutes
- Make the volume up to 100 mL by addition of purified water
- Sample 0.08 mL
- Add 0.1 mL HNO3, 0.05 µg internal standard Y, and make the volume to 10 mL with purified water
- Measure by ICP-MS

Vehicle:

no

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

High concentration zone:
- take 25 g of test substance
- make the volume to 250 mL with purified water
- filtration with filter 0.45 µm

Low concentration zone:
- 25 mL of filter stock solution in the high concentration zone
- make the volume to 250 mL with purified water

Preparation frequency: approximateely every 8 days.

Feed stock solution prepared as described above was supplied to the dilution mixing pipe using a metering pump for feed stock solution supply, and mixed with dilution water supplied by a metering pump for dilution water supply to reach the prescribed test concentration before being supplied to the test water tank.

Test organisms (species):

Cyprinus carpio

Details on test organisms:

- Carp (Cyprinus carpio, Carpidae)
- Sourced from: Sankyo Suisan Co. (1-1 Ichiyatamachi, Shinjuku-ku, Tokyo)
- Lot Number: 02-K-0701
- Preliminary Treatment: The specimens were visually observed at the time of acquisition, and any abnormalities were removed and kept under running water conditions. No medicated baths were performed during the standardization period.
- Total length: 8 ± 4cm
- Weight: Approx. 5g
- Age: Fish within 1 year of hatching

Route of exposure:

aqueous

Test type:

flow-through

Water / sediment media type:

natural water: freshwater

Total exposure / uptake duration:

28 d

Test temperature:

Measurements were taken on the day of test water sampling: 24 ± 2°C

pH:

Measurements were taken at the beginning and end of intake: 6.0 - 8.5 (appropriate range for fish rearing environements)

Dissolved oxygen:

Measurements were taken on the day of test water sampling: at least 60% of saturated dissolved oxygen concentration (at least 5 mg/L at 24°C).

Details on test conditions:

TEST SYSTEM
- Aeration: yes
- Dilution water supply: 400 L/day (8 water changes/day)
- Feed stock solution feed rate: 20 mL/day
- Number of organisms in the high concentration zone: 28 fishes/50 L test water (1L per 1.0 g/day or more)
- Number of organisms in the low concentration zone: 28 fishes/50 L test water (1L per 1.0 g/day or more)
- Number of organisms in the control zone: 24 fishes/50 L test water (1L per 1.0 g/day or more)

TEST MEDIUM / WATER PARAMETERS
The test water was dechlorinated by treating Yokohama City tap water with activated carbon and then adding sodium thiosulfate solution to the diluted water to neutralize the extremely small amount of free chlorine that could not be removed by the activated carbon (the amount added was about 0.08 mg/L as the concentration in the water). The water was then dechlorinated by heating it to 24°C. The diluted water was heated or cooled to 24°C and aerated (the quality of the diluted water was tested every 6 months to confirm that it complied with the water quality standards for fisheries use).
The water quality of the diluted water was tested every 6 months to confirm that it complied with the water quality standards for marine products.

OTHER TEST CONDITIONS
- Photoperiod: Approx. l6hr/day
- Light intensity: Hf fluorescent lamp (wavelength 400-700nm)

RANGE-FINDING / PRELIMINARY STUDY
The 96hr-LC50 was measured according to OECD Chemicals Test Guideline 203 "Fish Acute Toxicity Test". The concentration of the test substance in the test solution was not measured and the results (LC50) were calculated based on the set concentration.
Fish species: Oryzias latipes, killifish (Oryzias latipes, killifish family)
Lot Number: 02-H-0729
Preliminary Treatment: The fish were visually observed at the time of acquisition and any abnormalities were removed and reared under running water conditions.
Total length: 2 ± 1cm
Weight: Approx. 0.2 g
Density: 10 fish/concentration area
Test water max: 3.0L
Water temperature: 24 ± 1°C
Liquid replacement: None
Aeration: Yes
Dissolved oxygen concentration: Saturated dissolved oxygen concentration of 60% or more
Feeding: None
Testing period: 96 hours
Test concentrations: 0 and 1000 mg/L
- Results used to determine the conditions for the definitive study: the 96hr-LC 50 for the test substance was >1000 mg/L. Therefore, the concentrations of the test substance in the water in the enrichment test were set to 5 and 0.5 mg/L, which are less than 1/100 and 1/1000 of the 96hr-LC 50 value.

Nominal and measured concentrations:

High concentration zone: 5 mg/L
Low concentration zone: 0.5 mg/mL
Control zone: 0 mg/mL

Reference substance (positive control):

no

Details on estimation of bioconcentration:

CALCULATION OF CONCENTRATION FACTOR
Calculate the concentration factor at each measurement using the following formula:
BCF = Cf (average) at each measurement / Cw (average) at each measurement (average)

When the steady-state condition is reached, the concentration factor at the steady-state condition is also calculated by the following formula:
BCFss = Cf (average) at steady state / Cw (average) at steady state

BCF: Concentration factor at each measurement
BCFss : Concentration factor at steady state
Cf : Concentration in fish (µg/g)
Cw : Concentration in test water (mg/L)
Steady State: Steady state is considered to have been reached when the variation of the concentration factor in 3 consecutive measurements at intervals of 48 hours or more is within
20%. The average of Cf and Cw is calculated from the last 3 consecutive measurements until the end of uptake. However, if the enrichment factor during the test period is less than 100 times, a steady state shall be considered to have been reached even if the variation of the enrichment factor is more than 20%. In this case, BCFss is not calculated.

CONCENTRATION FACTOR MEASUREMENT LIMIT
The results of the fish blank test showed that the detection limit was 17 µg/g. The detection limit varied depending on the weight of the fish. Although it varies depending on the weight of the fish, the concentration factor can be measured at a concentration of 5 mg/L (high concentration zone) and 0.5 mg/L (low concentration zone), which is about 4 and 34 times higher, respectively.

Lipid content:

4.6 %

Time point:

start of exposure

Lipid content:

4.8 %

Time point:

end of exposure

Remarks on result:

other: The mean lipid content at the end of the study was within ± 25% of the starting lipid content.

Conc. / dose:

0.5 mg/L

Type:

BCF

Value:

< 59 L/kg

Basis:

whole body w.w.

Calculation basis:

steady state

Remarks on result:

other: The average concentrations during the 28-day intake period were 0.513 mg/L and <16-30 µg/g in the test water and in fish, respectively.

Conc. / dose:

5 mg/L

Type:

BCF

Value:

>= 7 - <= 43 L/kg

Basis:

whole body w.w.

Calculation basis:

steady state

Remarks on result:

other: The average concentrations during the 28-day intake period were 4.80 mg/L and 32-204 µg/g in the test water and in fish, respectively.

Details on results:

- Mortality of test organisms: Mortality or abnormalities were <10% for all concentrations during the experimental period.
- Behavioural abnormalities: No abnormalities in shape, swimming, feeding, etc. were observed in the surviving fish during the experimental period, confirming that the fish were reared normally.

Capturing period		Day 5	Day 7	Day 14	Day 21	Day 28
High concentration zone	Average concentration in water (mg/L)	4.77	4.76	4.68	4.78	4.80
	BCFss (L/kg) 1	7	9	13	16	20
	BCFss (L/kg) 2	7	12	17	43	18
Low concentration zone	Average concentration in water (mg/L)	0.520	0.514	0.512	0.512	0.513
	BCFss (L/kg) 1	<32	<32	<32	<59	<32
	BCFss (L/kg) 2	<32	<32	<32	<32	<38

Validity criteria fulfilled:

yes

Conclusions:

Based on the results, the concentration of the test substance in fish is low, indicating that the test substance is unlikely to be concentrated in fish. It is therefore concluded that Strontium chloride does not possess significant bioaccumulation characteristics.

Executive summary:

The bioconcentration of Strontium chloride was studied in Cyprinus carpio under flow-through conditions for 28 days. The study was performed according to "Methods for Testing New Chemical Substances" (Environmental Protection No. 5, Pharmaceutical Notification No. 615 No., 49 Base Station No. 392, 1974; partially revised 1998) and GLP. Cyprinus carpio was exposed to two concentrations of the test substance (5 and 0.5 mg/L) and at a temperature of 24 ± 2°C. The test concentrations were selected based on a preliminary acute toxicity test with Oryzias latipes (LC50 (96 h) > 1000 mg/L). During 28-day exposure period, the test concentrations were measured regularly in the test water and in fish to determine the BCF. The measured concentrations were maintained on a constant level throughout the test (flow-through exposure). Lipid content were 4.6% and 4.8% at start and at the end of exposure, respectively. The bioconcentration factor (BCF) was between 7 and 43 and <32 ~ 59 for the 5 and 0.5 mg/L test concentrations, respectively. The concentration of the test substance in fish is low, indicating that the test substance is unlikely to be concentrated in fish. It is therefore concluded that Strontium chloride does not possess significant bioaccumulation characteristics.

Description of key information

Strontium chloride does not possess significant bioaccumulation characteristics.

Based on the read-across from Strontium chloride, Strontium hydroxide is not expected to possess significant bioaccumulation characteristics.

Key value for chemical safety assessment

BCF (aquatic species):

59 L/kg ww