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EC number: 215-170-3 | CAS number: 1309-42-8
- Life Cycle description
- Uses advised against
- Endpoint summary
- Appearance / physical state / colour
- Melting point / freezing point
- Boiling point
- Density
- Particle size distribution (Granulometry)
- Vapour pressure
- Partition coefficient
- Water solubility
- Solubility in organic solvents / fat solubility
- Surface tension
- Flash point
- Auto flammability
- Flammability
- Explosiveness
- Oxidising properties
- Oxidation reduction potential
- Stability in organic solvents and identity of relevant degradation products
- Storage stability and reactivity towards container material
- Stability: thermal, sunlight, metals
- pH
- Dissociation constant
- Viscosity
- Additional physico-chemical information
- Additional physico-chemical properties of nanomaterials
- Nanomaterial agglomeration / aggregation
- Nanomaterial crystalline phase
- Nanomaterial crystallite and grain size
- Nanomaterial aspect ratio / shape
- Nanomaterial specific surface area
- Nanomaterial Zeta potential
- Nanomaterial surface chemistry
- Nanomaterial dustiness
- Nanomaterial porosity
- Nanomaterial pour density
- Nanomaterial photocatalytic activity
- Nanomaterial radical formation potential
- Nanomaterial catalytic activity
- Endpoint summary
- Stability
- Biodegradation
- Bioaccumulation
- Transport and distribution
- Environmental data
- Additional information on environmental fate and behaviour
- Ecotoxicological Summary
- Aquatic toxicity
- Endpoint summary
- Short-term toxicity to fish
- Long-term toxicity to fish
- Short-term toxicity to aquatic invertebrates
- Long-term toxicity to aquatic invertebrates
- Toxicity to aquatic algae and cyanobacteria
- Toxicity to aquatic plants other than algae
- Toxicity to microorganisms
- Endocrine disrupter testing in aquatic vertebrates – in vivo
- Toxicity to other aquatic organisms
- Sediment toxicity
- Terrestrial toxicity
- Biological effects monitoring
- Biotransformation and kinetics
- Additional ecotoxological information
- Toxicological Summary
- Toxicokinetics, metabolism and distribution
- Acute Toxicity
- Irritation / corrosion
- Sensitisation
- Repeated dose toxicity
- Genetic toxicity
- Carcinogenicity
- Toxicity to reproduction
- Specific investigations
- Exposure related observations in humans
- Toxic effects on livestock and pets
- Additional toxicological data
Toxicity to aquatic algae and cyanobacteria
Administrative data
Link to relevant study record(s)
- Endpoint:
- toxicity to aquatic algae and cyanobacteria
- Type of information:
- experimental study
- Adequacy of study:
- key study
- Study period:
- 2010-02-17 to 2010-07-02
- Reliability:
- 1 (reliable without restriction)
- Rationale for reliability incl. deficiencies:
- guideline study
- Qualifier:
- according to guideline
- Guideline:
- OECD Guideline 201 (Alga, Growth Inhibition Test)
- Qualifier:
- according to guideline
- Guideline:
- EU Method C.3 (Algal Inhibition test)
- Qualifier:
- according to guideline
- Guideline:
- ISO 8692 (Water Quality - Fresh Water Algal Growth Inhibition Test with Scenedesmus subspicatus and Selenastrum capricornutum)
- Qualifier:
- according to guideline
- Guideline:
- other: OECD series on testing and assessment number 23
- GLP compliance:
- yes (incl. QA statement)
- Specific details on test material used for the study:
- Test substance: Magnesium hydroxide
CAS Number: 1309-42-8
Purity: 99.90 % - Analytical monitoring:
- yes
- Details on sampling:
- - Singular samples for analysis were taken from the undiluted filtrate (100 mg/L) and the control according to the schedule below:
- Frequency: at t=0, t=24 and t=72h
- Volume: 4.8mL
- Storage: Samples were stored in a freezer until analysis
- Handling: On the day of analysis, the frozen samples were defrosted at room temperature. The test samples were diluted with 0.2ml HNO3 and analysed. If neccesary, the samples were further diluted with 4%(v/v) aqueous HNO3 to obtain concentrations with the calibration range. - Vehicle:
- no
- Details on test solutions:
- PREPARATION AND APPLICATION OF TEST SOLUTION
- Method: Preparations of test solutions started with an aqueous dispersion of 100 mg/L applying 3 days of magnetic stirring. The pH of the medium was adjusted from 8.9 to 6.5 using hydrochloric acid before the start of stirring. Magnetic stirring resulted in a dispersion. The dispersion was then filtered through a 0.45µm membrane filter to remove the undissolved material.
- Test concentration separation factor: 10
- Evidence of undissolved material: no
- Other relevant information: no - Test organisms (species):
- Raphidocelis subcapitata (previous names: Pseudokirchneriella subcapitata, Selenastrum capricornutum)
- Details on test organisms:
- - Common name: Fresh water Algae
- Strain: NIVA CHL 1
- Source: In-house laboratory culture
- Reason for selection: This system is an unicellular algal species sensitive to toxic substances in the aquatic ecosystem and has been selected as an internationally accepted species.
ACCLIMATION
- Stock culture: Algae stock cultures were started by inoculating growth medium with algal cells from a pure culture on agar.The suspensions were continuously aerated and exposed to light in a climate room at a temperature of 21-24°C.
- Culturing media and conditions: 3 days before the start of the test, cells from the algal stock culture were inoculated in culture medium at a cell density of 1 x 10^4 cells/mL. The pre-culture was maintained under the same conditons as used in the test.
- Appearance of the cells: At the end of the final test microscopic observations were performed on the limit concentration to verify a normal and healthy appearance of the innoculum culture and to observe for any abmormal appearance of the algae. - Test type:
- static
- Water media type:
- not specified
- Limit test:
- yes
- Total exposure duration:
- 72 h
- Test temperature:
- 21.7 - 24.1°C
- pH:
- 6.5 - 7.1
- Nominal and measured concentrations:
- Nominal concentrations: 0.10, 1, 10 and 100 mg/L
Measured concentrations of nominal 100 mg/L: after 24h 95 mg/L, after 48h 96 mg/L - Details on test conditions:
- TEST SYSTEM
- Test vessel: glass vessels
- Material, size, fill volume: glass, 100 mL, 50 mL
- Aeration: no
- Initial cells density: 1 x 10^4 cells/mL
- Control end cells density: 103.4 x 10^4 cells/mL
- No. of vessels per concentration (replicates): 6 fro 100 mg/L, 3 for the other concentrations
- No. of vessels per control (replicates): 6
GROWTH MEDIUM
- Stock Culture Medium: M1, according to the NPR 6505 formulated using Milli-RO water.
- Pre-culture medium: M2, according to the OECD 201 Guideline, formulated using Milli-Q water and subsequently passed over activated carbon and ion-exchange cartridges preventing precipitation.
OTHER TEST CONDITIONS
- Adjustment of pH: yes, during preparation of solutions
- Photoperiod: continous
- Light intensity and quality: TLD lamps of the type "Cool-white" of 30 Watt with a light intenstiy within the range of 65 to 73 µE/m2s
EFFECT PARAMETERS MEASURED
- Determination of cell concentrations: [counting chamber; electronic particle counter; fluorimeter; spectrophotometer; colorimeter]
- Chlorophyll measurement:
- Other: pH: at the beginning and at the end of the test; Temperature: continously
TEST CONCENTRATIONS
- Spacing factor for test concentrations: 10 - Reference substance (positive control):
- yes
- Remarks:
- Potassium dichromate
- Key result
- Duration:
- 72 h
- Dose descriptor:
- EC50
- Effect conc.:
- > 100 mg/L
- Nominal / measured:
- nominal
- Conc. based on:
- test mat.
- Basis for effect:
- growth rate
- Duration:
- 72 h
- Dose descriptor:
- EC50
- Effect conc.:
- > 100 mg/L
- Nominal / measured:
- nominal
- Conc. based on:
- test mat.
- Basis for effect:
- biomass
- Key result
- Duration:
- 72 h
- Dose descriptor:
- NOEC
- Effect conc.:
- 100 mg/L
- Nominal / measured:
- nominal
- Conc. based on:
- test mat.
- Basis for effect:
- growth rate
- Details on results:
- - Exponential growth in the control (for algal test): yes. In the controls, cell density increased by an average factor of > 16 within two days
- Observation of abnormalities: no
- Unusual cell shape: no
- Colour differences: no
- Flocculation: no
- Adherence to test vessels: no
- Aggregation of algal cells: no
- Any stimulation of growth found in any treatment: no
- Any observations that might cause a difference between measured and nominal values: no, after filtration at preparation of solutions
Analyses of samples taken from the filtered 100mg/l solution showed that the measured concentration was in agreement with the nominal throughout the test period(95-96%). Hence, the precipitate that was removed from the solution before the start of the test was not test substance related.
The mean coefficient of variation for section-by-section specific growth rates in the control cultures did not exceed 35%. - Results with reference substance (positive control):
- - The EC50 of the reference substance potassium dichromate for growth rate reduction (ErC50: 0-72h) was 1.2 mg/l with a 95% confidence interval ranging from 0.77 to 2.0 mg/l. The historical ranges for growth rate reduction lie between 0.82 and2.3 mg/l. hence, the ErC50: 0-72h for the present batch corresponds with this range.
- The EC50 of the reference substance potassium dichromatefor yield inhibition (EyC50:0-72h) was 0.44 mg/l with a 95% confidence interval ranging from 0.37 to 0.54 mg/l. The historical ranges of the 72h EC50 for yield inhibition lie between 0.43 and1.1 mg/l. Hence, the EyC50: 0-72h for the present batch corresponds with this range. - Validity criteria fulfilled:
- yes
- Conclusions:
- During the aquatic ecotoxicity test with green algea the EC50 for growth rate and yield inhibition was >100 mg/L for the test substance. The NOEC is 100 mg/L.
- Executive summary:
In a 72 hour acute toxicity study, cultures of Pseudokirchneriella subcapitata were exposed to magnesium hydroxide at nominal concentrations of 0, 0.1, 1, 10 and 100 mg/L under static conditions in accordance with the OECD 201 guideline. The growth rate and yield inhibition were slightly reduced at 100 mg/L but 50% effect level were not reached. Analytical measurements were done for the highest concentrations (100 mg/L). The following values were obtained: 95 mg/L (24h) and 96 mg/L (48h). In conclusion: During the aquatic ecotoxicity test with green algea the EC50 for growth rate and yield inhibition was > 100 mg/L for the test substance, the NOEC is 100 mg/L.
Reference
Table 1 : Mean cell densities (x 104 cells/mL)
Concentration Magnesium Hydroxide (mg/L) |
Exposure time(hours) |
|||
|
0 |
24 |
48 |
72 |
Control |
1.0 |
6.6 |
24.2 |
103.4 |
0.10 |
1.0 |
6.2 |
22.6 |
99.9 |
1.0 |
1.0 |
6.5 |
23.7 |
103.7 |
10 |
1.0 |
6.7 |
23.0 |
99.9 |
100 |
1.0 |
5.7 |
19.4 |
71.0 |
Table 2: Percentage reduction of growth rate (total test period) and percentage inhibition of yield
Concentration Magnesium hydroxide (mg/L) |
Mean growth rate |
Yield (0-72 h) |
||
|
µ (0-72 h) |
Reduction (%) |
X104cells/ml |
Inhibition (%) |
Control |
0.06440 |
|
102.42 |
|
0.10 |
0.06392 |
0.7 |
98.92 |
3.4 |
1.0 |
0.06445 |
-0.1 |
102.72 |
-0.3 |
10 |
0.06391 |
0.8 |
98.93 |
3.4 |
100 |
0.05915 |
8.2 |
70.00 |
31.7 |
Table 3: Percentage reduction of growth rate at different time intervals
Concentration Magnesium Hydroxide (mg/L) |
Mean growth rate |
|||||
|
µ(0-24h) |
Reduction (%) |
µ (24-48h) |
Reduction (%) |
µ (48-72 h) |
Reduction (%) |
Control |
0.07833 |
|
0.05444 |
|
0.06044 |
|
0.10 |
0.07576 |
3.3 |
0.05409 |
0.6 |
0.06192 |
-2.4 |
1.0 |
0.07818 |
0.2 |
0..05357 |
1.6 |
0.06159 |
-1.9 |
10 |
0.07929 |
-1.2 |
0.05623 |
-3.3 |
0.06120 |
-1.3 |
100 |
0.07220 |
7.8 |
0.05128 |
5.8 |
0.05396 |
10.7 |
Description of key information
According to the key study, both the EC50 for growth rate reduction (ErC50: 0-72h) and the EC50 for yield inhibition (EyC50: 0-72h) exceeded an analytically confirmed concentration of 100 mg/L, the NOEC is 100 mg/L.
Key value for chemical safety assessment
- EC10 or NOEC for freshwater algae:
- 100 mg/L
Additional information
In a 72 hour acute toxicity study, cultures of Pseudokirchneriella subcapitata were exposed to magnesium hydroxide at nominal concentrations of 0, 0.1, 1, 10 and 100 mg/L under static conditions in accordance with the OECD 201 guideline. The growth rate and yield inhibition were slightly reduced at 100 mg/L but 50% effect level were not reached. Analytical measurements were done for the highest concentrations (100 mg/L). The following values were obtained: 95 mg/L (24h) and 96 mg/L (48h). In conclusion: During the aquatic ecotoxicity test with green algea the EC50 for growth rate and yield inhibition was > 100 mg/L for the test substance, the NOEC is 100 mg/L.
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