Aluminum magnesium oxide

Short-term toxicity to aquatic invertebrates

Link to relevant study record(s)

Reference

Endpoint:

short-term toxicity to aquatic invertebrates

Type of information:

experimental study

Adequacy of study:

key study

Study period:

21 September 2018 - 31 October 2018

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Reason / purpose for cross-reference:

reference to other study

Qualifier:

according to guideline

Guideline:

OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)

Version / remarks:

2004

Deviations:

no

Qualifier:

according to guideline

Guideline:

other: Guidance document on aqueous-phase aquatic toxicity testing of difficult test chemicals, OECD series on testing and assessment number 23

Version / remarks:

2018

Deviations:

no

GLP compliance:

yes

Analytical monitoring:

yes

Remarks:

ICP-MS (based on aluminium detection)

Details on sampling:

- Concentrations: all test concentrations and the control
- Sampling method: 4.8 mL from the approximate centre of the test vessels; at the start of the test (t=0) and at the end of the test (t=48). Additionally, reserve samples of 4.8 mL were taken for possible analysis.
- Sample storage conditions before analysis: in a freezer (≤-15°C) at the analytical laboratory of the Test Facility
- At the end of the exposure period, the replicates were pooled at each concentration before sampling.

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
- Method: direct addition of test item to test medium through weighing onto and addition to medium by means of a watch glass yielding individually prepared loading rates; 3-day magnetic stirring period to ensure maximum dissolution of the test item in medium, followed by filtration through a 0.45 µm membrane filter (RC55, Whatman) to give clear and colourless aqueous Water Accommodated Fractions (WAFs), which were used as test concentrations
- Differential loading: yes - loading rates at 1.0, 10 and 100 mg/L
- Controls: Test medium without test item or other additives
- Evidence of undissolved material (e.g. precipitate, surface film, etc.): no (based on visual inspection)

Test organisms (species):

Daphnia magna

Details on test organisms:

TEST ORGANISM
- Common name: Daphnia magna (Crustacea, Cladocera) (Straus, 1820)
- Source: In-house laboratory culture with a known history. At least third generation, obtained by a cyclical parthenogenesis under specified breeding conditions.
- Age of parental stock: > two weeks old
- Age of test organisms at test start: < 24 hours
- Feeding during test: no
- Validity of batch: Daphnids originated from a healthy stock, 2nd to 5th brood, showing no signs of stress such as mortality >20%, presence of males, ephippia or discoloured animals and there was no delay in the production of the first brood.
- Daphnids were introduced to the test solutions within 34 minutes after preparation of the test solutions.

BREEDING
- Method of breeding: start of each batch with newborn daphnids, i.e. less than 3 days old, by placing about 250 of them into 5 litres of M7 medium in an all-glass culture vessel.
- Feeding: Daily, a suspension of fresh water algae
- Temperature of medium: 18-22°C
- Renewal of the cultures: after 7 days of cultivation half of the medium twice a week

Test type:

static

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

48 h

Hardness:

180 mg/L (expressed as CaCO3)

Test temperature:

20°C

pH:

measured in the control and 100 mg/L WAF
start: 8.0 - 84
end: 8.2

Dissolved oxygen:

measured in the control and 100 mg/L WAF
start: 8.7 - 8.8
end: 9.1 - 9.2

Nominal and measured concentrations:

Nominal concentrations: untreated control and WAFs individually prepared at loading rates of 1.0, 10 and 100 mg/L (corrected for purity).
Measured concentrations (based on Al detection and expressed in terms of test item): at test start - 0.47, 3.8 and 0.21 mg/L, resp.; measured concentrations changed to 128, 91 and 57% of initial at the end of the test.
Average exposure concentrations (geometric means) were calculated to be 0.53, 3.7 and 0.16 mg/L, resp.

See 'Any other information on materials and methods' for calculation of average exposure concentrations and 'Any other information on results' for details on measured concentrations.

Details on test conditions:

TEST SYSTEM
- Test vessel: 60 mL, all-glass, fill volume: 50 mL
- Aeration: no
- No. of organisms per vessel: 5
- No. of vessels per concentration (replicates): 4 for WAF prepared at 100 mg/L loading rate; 2 for WAFs prepared at 1.0 and 10 mg/L loading rate
- No. of vessels per control (replicates): 4

TEST MEDIUM / WATER PARAMETERS
- Medium: ISO medium.
- Culture medium different from test medium: yes, M7 medium
- Intervals of water quality measurement: pH and dissolved oxygen: at the beginning and at the end of the test, for all concenctrations and the control; Temperature of the medium: continuously in a temperature control vessel, beginning at the start of the test.

OTHER TEST CONDITIONS
- Adjustment of pH: no
- Photoperiod: 16 hours per day

EFFECT PARAMETERS MEASURED (with observation intervals if applicable):
- Immobility (including mortality): at 24 and 48 hours.

TEST CONCENTRATIONS
- Combined limit/range-finding test: WAFs individually prepared at 1.0, 10 and 100 mg/L.
- Results used to determine the conditions for the definitive study: no definite study needed

Reference substance (positive control):

yes

Remarks:

Potassium dichromate (performed Nov 2018)

Key result

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

> 0.16 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat. (dissolved fraction)

Basis for effect:

mobility

Remarks on result:

other: based on measured conc in WAFs prepared at the highest loading rate

Duration:

48 h

Dose descriptor:

EL50

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Remarks on result:

other: based on loading rate

Details on results:

- Behavioural abnormalities: none observed in the control group
- No immobility was observed in the control and at any of the test concentrations throughout the exposure period.
- The measured concentrations at the start and end of the test were highest in the intermediate WAF (10 mg/L loading rate), and lowest in the highest WAF (100 mg/L loading rate). An explanation for this finding cannot be given.
- Other: All water quality parameters remained within the requirements as laid down in the study plan throughout the test.

Results with reference substance (positive control):

The 48h-EC50 was 0.40 mg/L with a 95% confidence interval between 0.33 and 0.48 mg/L.
The actual responses in this reference test with K2Cr2O7 are generally within the ranges of the expected responses at the different concentrations, i.e. the 48h-EC50 was between 0.28 and 0.90 mg/L. Hence, the sensitivity of this batch of D. magna was in agreement with the historical data collected at the Test Facility.

Reported statistics and error estimates:

Not relevant as the test item proved to be non-toxic, i.e. EC50 > solubility limit in test medium.

Table 1: Test Samples Analysis Results

Time of sampling [hours]		Date of sampling		Date of analysis^1		Loading rate^2 [mg/L]		Concentration analyzed [mg/L]		Relative to initial [%]
0		24 Sep 2018		01 Oct 2018		0		n.d.^3
				30 Oct 2018		1.0		0.467
				30 Oct 2018		10		3.83
				01 Oct 2018		100		0.206
48		26 Sep 2018		01 Oct 2018		0		n.d.^3		n.a.
				30 Oct 2018		1.0		0.595		128
				30 Oct 2018		10		3.50		91
				01 Oct 2018		100		0.117		57

¹      Samples were stored in the freezer (≤ -15°C) until the day of analysis.

²      Awater accommodated fraction (WAF)prepared at the loading rate.

³     A negative concentration at m/z 27 (isotope for quantification of the test item) was detected in the control sample. This negative concentration was below the intercept of the calibration curve and at approximately the same level of the analytical blanks. Therefore, this was considered as not detected (n.d.).

n.d.Not detected.

n.a.     Not applicable

Table 2: Average Exposure Concentration Versus Loading Rate

KW-2200 Loading Rate (mg/L)	Measured concentrations (mg/L)		Average exposure conc. (mg/L)
	t=0h	t=48h
1.0	0.47	0.60	0.53
10	3.8	3.5	3.7
100	0.21	0.12	0.16

Table 3: Number of Introduced Daphnids and Incidence of Immobility in the Combined limit/Range-finding Test

Time (h)	Replicate	KW-2200 Average exposure conc. (mg/L)
		Control	0.53	3.7	0.16
0	A	5	5	5	5
	B	5	5	5	5
	C	5	5	5	5
	D	5	5	5	5
	Total introduced	20	20	20	20
24	A	0	0 (1)	0	0 (1)
	B	0	0	0	0 (1)
	C	0			0 (1)
	D	0			0
	Total immobilised	0	0	0	0
	Effect %	0	0	0	0
48	A	0	0	0	0 (1)
	B	0	0	0 (1)	0
	C	0			0 (1)
	D	0			0
	Total immobilised	0	0	0	0
	Effect %	0	0	0	0

( ) between brackets: number of daphnids observed trapped at the surface of the test solutions. These organisms were reimmersed into the respective solutions before recording of mobility.

Validity criteria fulfilled:

yes

Remarks:

See 'Overall remarks' for details on validity criteria.

Conclusions:

The 48h-EC50 of the substance to Dapnhia magna was determined to be above the solubility limit of the test item in medium (i.e. >0.16 mg/L, based on average exposure concentrations (geometric means, based on detection of aluminium), as determined in the highest WAF tested (loading rate 100 mg/L)).

Executive summary:

In a static 48 h acute toxicity test conducted according to OECD guideline 202, Daphnia magna were exposed in a combined limit/range-finding test to Water Accommodated Fractions of the test substance individually prepared at loading rates of 1.0, 10 and 100 mg/L and an untreated control (4 replicates with 5 dapnids/replicate per control and highest WAF, 2 replicates with 5 daphnids/replicate per intermediate WAFs).

 

Measured concentrations (based on Al detection and expressed in terms of test item) were 0.47, 3.8 and 0.21 mg/L, resp., at test start in the WAFs prepared at loading rates of 1.0, 10 and 100 mg/L and changed to 128, 91 and 57% of initial at the end of the test.

Average exposure concentrations (geometric means) were calculated to be 0.53, 3.7 and 0.16 mg/L, resp.

 

No immobility was observed in the control and any of the test solutions throughout the exposure period. Therefore the 48h-EC50 for immobility was concluded to be beyond the range of concentrations tested, and hence derived to be above the solubility limit of the test item in medium (i.e. >0.16 mg/L based on average exposure concentrations (geometric means)).

The study met all validity criteria and is considered to be reliable without restrictions.

Description of key information

48 h-EC50 is >0.16 mg/L (measured concentration of test item, based on aluminium detection)

48 h-EL50 is >100 mg/L (based on nominal test item loading rate)

Additional information

In a static 48 h acute toxicity test conducted according to OECD guideline 202, Daphnia magna were exposed in a combined limit/range-finding test to Water Accommodated Fractions of the test substance individually prepared at loading rates of 1.0, 10 and 100 mg/L and an untreated control (4 replicates with 5 dapnids/replicate per control and highest WAF, 2 replicates with 5 daphnids/replicate per intermediate WAFs).

 

Measured concentrations (based on Al detection and expressed in terms of test item) were 0.47, 3.8 and 0.21 mg/L, resp., at test start in the WAFs prepared at loading rates of 1.0, 10 and 100 mg/L and changed to 128, 91 and 57% of initial at the end of the test.

Average exposure concentrations (geometric means) were calculated to be 0.53, 3.7 and 0.16 mg/L, resp.

 

No immobility was observed in the control and any of the test solutions throughout the exposure period. Therefore the 48h-EC50 for immobility was concluded to be beyond the range of concentrations tested, and hence derived to be above the solubility limit of the test item in medium (i.e. >0.16 mg/L based on average exposure concentrations (geometric means)).

The study met all validity criteria and is considered to be reliable without restrictions.