Barium oxide (BaO), solid soln. with calcium oxide, magnesium oxide, phosphorus oxide (P2O5), strontium oxide and zinc oxide, copper-doped

Short-term toxicity to aquatic invertebrates

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

short-term toxicity to aquatic invertebrates

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

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

Qualifier:

no guideline followed

Principles of method if other than guideline:

Acute toxicity of Cu to Ceriodaphnia dubia was tested at three pH values: pH 6.3, 7.3 and 8.3 in very hard reconstituted water (hardness 280-300 mg/L as CaCO3).

GLP compliance:

no

Specific details on test material used for the study:

Copper was tested as a metal salt: Cu(NO3) . 3H2O

Analytical monitoring:

yes

Vehicle:

no

Details on test solutions:

Stock solutions were prepared in Millipore water. The stock solutions were adjusted to the desired pH (6.25 and 7.25, 8.25 remained unadjusted) with analytical grade HCl.

Test organisms (species):

Ceriodaphnia dubia

Details on test organisms:

TEST ORGANISM
- Common name: daphnia
- Source: Daphnids were cultured at the U.S. Environmental Protection Agency laboratory in Duluth, Minnesota, USA
- Age at time of testing: <= 48h
- Feeding during test: yes
- Food type: Fed 100 µl of a yeast-Cerophyl (Agri-Tech, Kansas City, M0)-fermented Purina Brand (St. Louis, MO) Trout Chow solution
- Amount: Final concentration was 6 mg/L solids

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

48 h

Hardness:

Tests were conducted in very hard reconstituted water: 280-300 mg/L CaCO3.

Test temperature:

25°C

pH:

Initial and final pH values in the toxicity tests:
pH 6.0-6.5 test: 6.00 - 6.47
pH 7.0-7.5 test: 7.00 - 7.27
pH 8.0-8.5 test: 8.50 - 8.71

Dissolved oxygen:

Dissolved oxygen was measured at the end of the test and was never below 5 mg/L (60% saturation).

Salinity:

N/A

Nominal and measured concentrations:

Test concentrations not reported. Test concentrations were prepared using a 50% dilution series with very hard reconstituted water.

Details on test conditions:

TEST SYSTEM
- Type: polystyrene cups sealed with 35 mm polystyrene culture dish bottoms; test conducted at pH 8.25 were left unsealed
- Material, size, headspace, fill volume: 30 mL polystyrene cups, filled with 30 mL
- No. of replicates: Tests were conducted in duplicate or triplicate
- No. of organisms per replicate: 5 organisms per replicate

TEST CONCENTRATIONS
- Spacing factor for test concentrations: Test concentrations were prepared using 50% dilution series

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: Very hard reconstituted water
- Hardness 280-300 mg/L CaCO3
- Alkalinity: 225-245 mg/L CaCO3

OTHER TEST CONDITIONS
- Photoperiod: 16:8h light:dark
- stock and dilution water solutions were adjusted to the desired test pH with analytical grade HCl; the test pH values drifted from the target value by < 0.25 pH units when measured at the end of the test

Reference substance (positive control):

not specified

Duration:

48 h

Dose descriptor:

LC50

Effect conc.:

9.5 µg/L

Nominal / measured:

meas. (not specified)

Conc. based on:

element

Basis for effect:

mortality

Remarks on result:

other: confidence limits: 7-13 µg/L; pH 6.0-6.5 test

Duration:

48 h

Dose descriptor:

LC50

Effect conc.:

28 µg/L

Nominal / measured:

meas. (not specified)

Conc. based on:

element

Basis for effect:

mortality

Remarks on result:

other: confidence limits: 19-41 µg/L; pH 7.0-7.5 test

Duration:

48 h

Dose descriptor:

LC50

Effect conc.:

200 µg/L

Nominal / measured:

meas. (not specified)

Conc. based on:

element

Basis for effect:

mortality

Remarks on result:

other: confidence limits: 150-270 µg/L; pH 8.0-8.5 test

Reported statistics and error estimates:

LC50s and the corresponding 95% C.I. were calculated using the trimmed Spearman Karber method.

Validity criteria fulfilled:

not specified

Conclusions:

The LC50 values after 48 hours were 9.5 µg/L at pH 6.0-6.5, 28 µg/L at pH 7.0-7.5 and 200 µg/L at pH 8.0-8.5.

Executive summary:

A non-guideline static toxicity study with Ceriodaphnia dubia was performed. Acute toxicity of Cu to C. dubia was tested at three pH values: pH 6.3, 7.3 and 8.3. Five daphnids ≤48-h old per replicate were exposed to the test material in very hard reconstituted water (hardness 280-300 mg/L as CaCO3) for 48 hours and the median lethal concentrations (LC50s) were determined using the trimmed Spearman-Karber method.

The LC50 values after 48 hours for C. dubia were 9.5 µg/L at pH 6.0-6.5, 28 µg/L at pH 7.0-7.5 and 200 µg/L at pH 8.0-8.5.

This is a non-GLP experimental study and there are minor restrictions in reporting (test concentrations are not reported) but it follows standard methods for acute toxicity to invertebrates and was published in a peer-reviewed journal and therefore is considered reliable with restrictions.

Reference 2

Endpoint:

short-term toxicity to aquatic invertebrates

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

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

Reason / purpose for cross-reference:

read-across: supporting information

Qualifier:

no guideline followed

Principles of method if other than guideline:

The study was not conducted according to standard guideline but meets generally accepted scientific standards. The methodology is well documented and described. In an acute study, 10 daphnids, 12 +/- 2 hr old were placed in duplicate test chambers and exposed to test items for 48 hours.

GLP compliance:

no

Specific details on test material used for the study:

SrCl2.6H2O
Analytical purity: Americal Chemical Society reagent-grade

Analytical monitoring:

no

Vehicle:

no

Test organisms (species):

Daphnia magna

Details on test organisms:

TEST ORGANISM
- Common name: Daphnia magna
- Strain: laboratory clone
- Source: University of Michigan
- Age at study initiation (mean and range, SD): 12h +/- 12h
- Feeding during test: no

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

48 h

Remarks on exposure duration:

In addition, a chronic study was conducted for a period of 3 weeks.

Hardness:

45.2 mg/L as CaCO3

Test temperature:

18 +/- 1 °C

pH:

7.74 (for test water)

Dissolved oxygen:

Near saturation at all times. ~ 9 mg O2/L (dawn)

Nominal and measured concentrations:

Nominal/measured test concentrations not reported: geometric series of 5-12 concentrations (not specified for Sr)

Details on test conditions:

TEST SYSTEM
- No. of organisms per vessel: 10
- No. of vessels per concentration (replicates): 2
- No. of vessels per control (replicates): not reported

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: Lake Superior water; unfiltered water strained through a #20 bolting cloth
- Metals: 14 µg Ba/L ; 16 µg Sr/L ; 0.78 µg Zn/L ; <0.5 µg Ni/L ; 1.51 µg Cu/L ; <0.5 µg Co/L ; < 0.01 g Hg/L ; < 0.1 µg Cd/L
- Chloride: 1.22 mg/L
- Alkalinity: 42.3 mg/L as CaCO3
- Ca: 13.7 mg /L
- Mg: 3.12 mg/L
- K: 0.53 mg/L
- Na: 1.13 mg/L

OTHER TEST CONDITIONS
- Photoperiod: 16 hr photoperiod
- Light intensity: ~115 foot-candles at the air-water interface

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) : complete immobilisation or death
In the chronic study, the surviving animals were weighed and prepared for protein and GOT analyses at the end of the exposure period. Reproduction was assessed by counting the young daphnids produced each week.

Reference substance (positive control):

no

Key result

Duration:

48 h

Dose descriptor:

LC50

Effect conc.:

125 000 µg/L

Nominal / measured:

nominal

Conc. based on:

element

Basis for effect:

mortality

Details on results:

Chemical characteristics of Lake Superior water were monitored during the testing period according to procedures outlined by the American Public Health Association and procedures employing atomic absorption spectroscopy.

Reported statistics and error estimates:

Results were statistically evaluated with the method of Litchfield and Wilcoxon (1949). LC50 was used for survival and represents an interpolation from three or more partial-effect concentrations.

Validity criteria fulfilled:

not specified

Conclusions:

An LC50 of 125000 µg Sr/L was determined after 48 hours.

Executive summary:

In an acute toxicity study, 10 daphnids, 12 +/- 2 hr old were placed in duplicate test chambers and exposed to test item for 48 hours. Immobilisation or death of daphnids was recorded and the LC50 after 48 hours was determined.

This is a non-GLP experimental study and there are minor restrictions in reporting (test concentrations of strontium are not reported) but it follows standard methods for acute toxicity to invertebrates and was published in a peer-reviewed journal and therefore is considered reliable with restrictions.

An LC50 of 125000 µg Sr/L was determined after 48 hours.

Description of key information

For copper, the lowest LC50 value of 9.5 µg Cu/L was determined at pH 6.3 in a non-guideline static acute study with Ceriodaphnia dubia (Schubauer-Berigan et al. 1993).

For strontium, the 48h-EC50 of 125,000 µg Sr/L was determined in a non-guideline study with Daphnia magna (Biesinger and Christensen 1972).

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates

Effect concentration:

9.5 µg/L

Additional information

There are no data available on acute toxicity to invertebrates for strontium apatite, copper doped.

Based on the transformation/dissolution (TD) tests conducted with strontium apatite copper doped (Martinez, 2016b), strontium apatite copper doped is expected to release the copper and strontium in the environment to a higher extent at pH 6 than at pH 8. Therefore, the results at pH 6 are taken into consideration as a worst-case scenario.

For copper and copper compounds, a large number of high quality published studies on acute toxicity to invertebrates are available at different pH. The lowest LC50 value of 9.5 µg Cu/L was determined at pH 6.3 in a non-guideline static acute study with Ceriodaphnia dubia (Schubauer-Berigan et al. 1993). This study was considered reliable with restrictions (Klimisch 2) and selected as a key study for this endpoint. Additionally, Belanger and Cherry (1990) tested acute toxicity of copper to C. dubia at different pH and water hardness. The study showed that C. dubia was consistently most sensitive at low pH and low water hardness with the lowest LC50 value of 14 µg Cu/L determined at pH 6. The study was considered reliable with restrictions and sufficient to provide supporting information on short-term toxicity of copper to aquatic invertebrates.

 

For strontium, the 48h-EC50 of 125,000 µg Sr/L was determined in a non-guideline study with Daphnia magna (Biesinger and Christensen 1972).