Dialuminium zinc tetraoxide

Long-term toxicity to aquatic invertebrates

Link to relevant study record(s)

Reference

Endpoint:

long-term toxicity to aquatic invertebrates

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: GLP Guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 211 (Daphnia magna Reproduction Test)

GLP compliance:

yes

Analytical monitoring:

yes

Details on sampling:

- Concentrations: The concentrations of the metallic elements in all test groups were analyzed in all test concentrations of the when freshly prepared and the aged media. One test vessel was selected from each test vessel (i.e. replicate) randomly. One 10 mL-test sample taken from this test vessel were used to analyze the concentrations of the metallic elements.
- Sample storage conditions before analysis: The samples were stored at 5±3℃

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
According to the WSFs (water soluble fractions) method, loading rates of 0.190, 0.430, 0.900, 2.10, 4.50 and 10.0 mg/L were prepared and stirred (using a magnetic stirrer) in the dark for 72 h at 700 rpm. The media were then filtered using a 0.45 μm nitrocellulose membrane.

Test organisms (species):

Daphnia magna

Test type:

semi-static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

21 d

Hardness:

140 - 170 mg/L

Test temperature:

19.8 - 20.3 °C

pH:

7.0 - 7.9

Dissolved oxygen:

8.11 - 9.20 mg/L

Nominal and measured concentrations:

Nominal concentrations: 0.190, 0.430, 0.900, 2.10, 4.50 and 10.0 mg/L
Measured Al: 5.88, 6.02, 7.72, 10.9, 16.7 and 25.7 ng/mL
Measured Zn: 6.31, 6.68, 9.19, 13.8, 24.0 and 44.3 ng/mL

Details on test conditions:

TEST SYSTEM
- Test vessel:
- Material, size, headspace, fill volume: 75 mL glass vessels, fill volume: ca. 60 mL
- No. of organisms per vessel: 1
- No. of vessels per concentration (replicates): 10
- No. of vessels per control (replicates): 10

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: deionized water
- Culture medium different from test medium: no
- Intervals of water quality measurement:Oxygen concentration, temperature, hardness and pH values were measured once a week, in the fresh and old media, in of the control(s) and in the highest test substance concentration.

OTHER TEST CONDITIONS
- Adjustment of pH: no
- Photoperiod: light∶dark = 16 hours∶8 hours
- Light intensity: 1200 lux

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) :The numbers of living offspring were counted and the presence of aborted eggs or dead offspring were recorded. Mortality among the parent animals was recorded.

VEHICLE CONTROL PERFORMED: no vehicle

Reference substance (positive control):

no

Duration:

21 d

Dose descriptor:

NOEC

Effect conc.:

0.19 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Remarks:

filtered test solution

Basis for effect:

reproduction

Details on results:

- Mortality of parent animals: 10% mortality was observed at the highest loading. No mortality occurred at lower test concentrations or in the control.
- No. of offspring produced per day per female: see Table under Any other information on results incl. tables

Reported statistics and error estimates:

The estimation of the LOELR and NOELR was analyzed by the Bonferroni Test and Fisher's Exact Test. Statistical analysis of the data was accomplished with Toxcalc v5.0.26.

Number of live offspring:

Loading rate（mg/L）	Cumulative No. of offspring after 21 days	Parallel group
		1	2	3	4	5	6	7	8	9	10
Control	Total	107	102	98	127	94	108	101	134	93	103
0.190	Total	95	101	100	98	101	102	103	121	120	84
0.430	Total	67	75	86	80	80	92	70	81	70	72
0.900	Total	67	73	92	75	36	71	84	70	88	70
2.10	Total	96	70	65	93	70	68	67	109	89	74
4.50	Total	44	80	M	83	89	73	72	65	64	85
10.0	Total	103	94	67	70	43	68	75	81	84	74

M: mortality

Description of key information

Nominal:
NOEC (21d) = 0.19 mg/L (Daphnia magna, OECD 211)
This value is taken into account for the PNEC derivation.
Measured (TWA):
Al: NOEC (21d) = 6.02 ng/mL (Daphnia magna, OECD 211)
Zn: NOEC (21d) = 6.88 ng/mL (Daphnia magna, OECD 211)

Additional information

One study on the long-term toxicity of Zinc aluminium oxide to aquatic invertebrates is available. This key study was performed according to OECD Guideline 211, in a semi-static system, using Daphnia magna as test organism (2013).Nominal concentrations of 0.190, 0.430, 0.900, 2.10, 4.50 and 10.0 mg/L were prepared. The solutions were stirred for 72 hours and subsequently filtered. The daphnids were exposed to the filtered test solutions for 21 days. Mortality of parent animals (10%) was only observed at the highest loading. A NOEC of 0.19 mg/L based on reproduction was derived, corresponding to measured aluminium and zinc concentrations (time-weighted mean) of 6.02 ng/mL and 6.88 ng/mL, respectively.