Boron orthophosphate

Short-term toxicity to fish

Link to relevant study record(s)

Reference

Endpoint:

short-term toxicity to fish

Type of information:

experimental study

Adequacy of study:

key study

Study period:

03.11.2014 - 09.01.2015

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: GLP guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 203 (Fish, Acute Toxicity Test)

Qualifier:

according to guideline

Guideline:

EU Method C.1 (Acute Toxicity for Fish)

GLP compliance:

yes (incl. QA statement)

Analytical monitoring:

yes

Details on sampling:

- Concentrations: 6.25, 12.5, 25, 50, and 100 mg/L
- Sampling method: Samples were taken directly after test solution preparation and at each renewal in fresh medium and at the respective end of the incubation period (48 hours).
- Sample storage conditions before analysis: Samples were stabelised by acidification and analysed after max. 11 days.

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
- Method: Preparation of WAF according to OECD guidedance No. 23 and 29.
The test item was added to the dilution water and stirred for 24 hours at ca. 20 °C. The solution was allowed to stand for 2 hours and subsequently insoluble parts were separated from the aqueous phase by filtration (0.22 μm PES membrane). The test solution were obtained by dilution of the highest test concentration.The test solutions were freshly prepared before test start and renewal of test solution.

Test organisms (species):

Danio rerio (previous name: Brachydanio rerio)

Details on test organisms:

TEST ORGANISM
- Common name: zebra fish
- Source: Test facility bred
- Length at study initiation (length definition, mean, range and SD): 2.1 – 2.4 cm
- Weight at study initiation (mean and range, SD): 0.07 - 0.11 g
- Feeding during test: no

ACCLIMATION
- Acclimation period: ≥12 days
- Acclimation conditions (same as test or not): same as test conditions
- Type and amount of food: brine shrimp (Artemia spp.) nauplii and ground flake food TetraMinR (Tetra Werke, Melle, Germany)
- Feeding frequency: daily
- Health during acclimation (any mortality observed): < 5% one week before test start

Test type:

semi-static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

96 h

Hardness:

1.3 mmol/L

Test temperature:

22.9 – 23.1 °C

pH:

8.5 – 8.8

Dissolved oxygen:

94 - 98 %

Nominal and measured concentrations:

Nominal substance concentration: 6.25, 12.5, 25, 50, and 100 mg/L
The nominal substance concentrations correspond to: 0.64, 1.27, 2.55, 5.10, and 10.19 mg boron/L
Mean measured test substance concentrations: 0.0075, 0.0142, 0.0213, 0.0483, 0.207 mg boron/L

Details on test conditions:

TEST SYSTEM
- Test vessel: glass aquaria
- Material, size, fill volume: glass, 10 L nominal volume, 10 l fill volume
- Aeration: slightly aeration via a glass capillary
- Renewal rate of test solution (frequency): every 48 hours
- No. of organisms per vessel: 7
- No. of vessels per concentration (replicates): 1
- No. of vessels per control (replicates): 1
- Biomass loading rate: < 1g/L

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: purified drinking water according to the OECD-Guideline
- Alkalinity: 2.2 mmol/L
- Conductivity: 188 μS/cm

OTHER TEST CONDITIONS
- Adjustment of pH: no
- Photoperiod: 12/12 hours day-night regime

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) :
Mortality and abnormal behaviour after 3 h, 24 h, 48 h, 72 h and 96 h.

Duration:

96 h

Dose descriptor:

LC10

Effect conc.:

> 0.207 mg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

other: mg boron/L

Basis for effect:

mortality (fish)

Duration:

96 h

Dose descriptor:

LC50

Effect conc.:

> 0.207 mg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

other: mg boron/L

Basis for effect:

mortality (fish)

Details on results:

- Behavioural abnormalities: no
- Observations on body length and weight: no
- Other biological observations: no
- Mortality of control: no
- Abnormal responses: no

Reported statistics and error estimates:

Statistical calculations were performed using the computer programme ToxRat®

Additional information

The influence of Boron orthophosphate (CAS 13308-51-5) on acute toxicity of fish of the species Danio rerio was investigated in a semi static OECD 203 test under GLP conditions.

 Effects on survival were determined after 3, 24, 48, 72 and 96 hours. Samples of fresh and aged test solutions were measured for total boron concentrations. Since the test item is of low water solubility, the test media were prepared using the Water Accommodated Faction (WAF) approach according to the OECD guidance documents No. 23 and 29 to obtain the maximal solubility of the test item under the test conditions. The aqueous solutions were prepared individually by addition of respective amount of test substance to dilution water. Subsequently the insoluble parts were separated respectively by filtration using 0.2 µm membranes, and obtaining the nominal concentrations of 6.25, 12.5, 25, 50 and 100 mg/L. For the determination of fish acute mortality a total of seven fish in a single replicate of each test concentration and a control were exposed. The concentrations of boron in the test media were determined at the start and at the end of the test using ICP-OES (LOQ 3.58 μg B/L). At test start and in fresh media at renewal, the measured boron concentrations were between 0.7 and 2.2 % of nominal loading. The boron concentration maintained stable in all test solutions throughout the test period (0.8 – 2.2 % in aged media). During the preparation of test solution, it was observed that the test substance achieved the maximum solubility in the test media, but dissolved boron concentration was increased with increasing of the nominal test substance concentrations. This indicted that the dissolved boron did not achieve saturation. Thus, the test results are reported with both nominal test substance concentrations and the measured boron concentrations respectively. The mean measured boron concentrations were 0.008, 0.014, 0.021 0.048 and 0.207 mg/L (between 0.8 and 2.0 % of nominal loading). There were no concentration-dependent effects on survival up to the highest test concentrations of 0.207 mg boron per liter. The LC50 value for mortality was set to be higher than the highest test concentration of 0.207 mg boron per liter (> 100 mg/L test item nominal).