Reaction mass of Willemite, white and zinc iron chromite brown spinel

Short-term toxicity to aquatic invertebrates

Administrative data

Endpoint:

short-term toxicity to aquatic invertebrates

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2013-10-22 to 2013-10-24

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: GLP guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2014

Report date:

2014

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)

Version / remarks:

adopted 2004-04-13

Deviations:

no

Test guideline 2

Qualifier:

according to guideline

Guideline:

EU Method C.2 (Acute Toxicity for Daphnia)

Version / remarks:

adopted 2008

Deviations:

no

Test guideline 3

Qualifier:

according to guideline

Guideline:

other: OECD Series on testing and assessment, Number 29. Guidance document on transformation/dissolution of metals and metal compounds in aqueous media. ENV/JM/MONO (2001)9, 23-July 2001.

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Remarks:

signed 2011-02-07

Test material

Test material information

Constituent 1

Reference substance name:

dichromium(3+) diiron(3+) lambda2-iron(2+) trizinc(2+) octaoxidandiide silicate

EC Number:

936-897-9

Cas Number:

1373399-58-6

Molecular formula:

(Zn, Fe)(Fe, Cr)2O4-Zn2SiO4

IUPAC Name:

dichromium(3+) diiron(3+) lambda2-iron(2+) trizinc(2+) octaoxidandiide silicate

Test material form:

solid: particulate/powder

Details on test material:

- Name of test material (as cited in study report): Reaction mass of willemite, white and zinc iron chromite brown spinel
- Substance type: inorganic pigment
- Physical state: solid, light brown powder, odourless
- Storage condition of test material: store separate from food and drinks, dry in closed containers and protected places. Keep containers air-tight.
- Relative density: 4.58

Sampling and analysis

Analytical monitoring:

yes

Details on sampling:

- Sampling method / Sample storage conditions before analysis:
The concentration of the test item was assessed by chemical analysis of aluminium, chromium, iron and zinc at the start and the end of the test. Dissolved aluminium, chromium, iron and zinc concentrations were measured in all test solutions sampled at the beginning of the test prior to addition of the daphnids and in pooled samples from each treatment level after 48 hours of exposure.
Duplicate samples of approximately 20 mL were taken. The solutions were examined for soapy bubbles or particles floating on the surface. The samples were filtered (0.2 μm polyether-sulphone membrane syringe filter) at room temperature (20 - 25°C). The solutions were then transferred into disposable polyethylene vials (Scintillation vials), acidified with HNO3 (final concentration 1 – 3 % HNO3), and stored at 4°C until further analysis.
The concentrations of dissolved aluminium, chromium, iron and zinc were determined by ICP-OES (depending on concentrations and potential interferences). The results were assured by recovery experiments and analysis of certified reference materials.

Test solutions

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
- Method:
Since the test item is a multi-component substance and of low water solubility, toxicity was determined using water accommodated fractions (WAFs). The WAFs for the various test concentrations were prepared individually in accordance with the OECD guidance document on transformation/dissolution of metals and metal compounds in aqueous media No. 29 (2001)*.
Appropriate amounts of reaction mass of willemite, white and zinc iron chromite brown spinel were transferred into glass flasks and were brought to the volume of 0.5 L with dilution water to obtain the nominal loadings.
The contents of the bottles were shaken at 100 rpm for 7 days at room temperature (21 ± 1.5°C). After this time the insoluble part of solutions was separated from the aqueous phase by filtration through a 0.2 μm filter (Polyether sulfone, PES). The filtrated WAF solutions were subsequently used as test media in the acute toxicity test.

- Controls: a control consisting of dilution water only was used as the negative control treatment.

*Reference:
- OECD Series on testing and assessment, Number 29. Guidance document on transformation/dissolution of metals and metal compounds in aqueous media. ENV/JM/MONO (2001)9, 23-July 2001.

Test organisms

Test organisms (species):

Daphnia magna

Details on test organisms:

TEST ORGANISM
- Species: Daphnia magna (Branchiopoda, Daphniidae); Clone V
- Source: German Federal Environment Agency, Location Berlin-Marienfelde, Ecotoxicology Lab., 12307 Berlin, Germany
- Age: 4-24 hours old (juvenile)
- Method of holding: batches of 30 to 50 D. magna were held at room temperature in approximately 1.8 L of dilution water. The water was changed once per week. Newborn D. magna were separated by sieving, the first generation was discarded. Individuals applied in the test were transferred from this culture with a bore Pasteur pipette a few hours after sieving from the population to ensure selection of healthy specimens.

- Type and amount of food: daphnids were fed with an algal suspension (Desmodesmus subspicatus) and Artemio® Fluid (JBL, Germany). Algae growing in the log-phase were centrifuged and the pellet was re-suspended with Artemio® Fluid. Of this suspension, 30 mL were given to 1 L of D. magna medium.
- Feeding frequency: daily
The daphnids were not fed during the test.

Study design

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

48 h

Test conditions

Hardness:

total hardness (dilution and holding water): 1.1 mmol/L

Test temperature:

Control vessels / Test vessels:
- test start: 20.8°C
- at test end: 20.7°C

pH:

Control vessels:
- test start: 8.46
- at test end: 8.62
Test vessels:
- test start: 8.36 - 8.50
- at test end: 8.48 - 8.58

Dissolved oxygen:

Control vessels:
- test start: 8.1 mg O2/L
- at test end: 8.6 O2/L
Test vessels
- test start: 7.8 - 8.2 mg O2/L
- at test end: 8.6 - 8.9 mg O2/L

Salinity:

not applicable

Nominal and measured concentrations:

Nominal concentration: 1.0, 10.0, 32.0, 100 and 320 mg/L

Details on test conditions:

TEST SYSTEM
- Test vessel: 60 mL glass beakers; all replicates per test concentration were held in a rack and the position of the racks was randomised in the incubator.
Approximately 50 mL of each test medium was added to each replicate test vessel followed by five D. magna less than 24 h old.
- Aeration: test vessels were not aerated during the test.
- Renewal of test media: no
- No. of organisms per vessel: 5 daphnids
- No. of vessels per concentration (replicates): 4
- No. of vessels per control (replicates): 4
- No. of vessels per vehicle control (replicates):
- Biomass loading rate:

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: dechlorinated local tap water was used in accordance with the OECD guideline 202 (2004). The tap water was sourced from the Schmallenberg district water production plants, mostly fed by small springs and percolation. The purification process occurs on site at the laboratory and included filtration with activated charcoal, passage through a lime-stone column, and aeration to the point of oxygen saturation. To avoid copper contamination, plastic water pipes were used in the test facilities.
All water quality measurements were considered to be within the specifications recommended in the OECD 202 guideline (2004).
Physical properties of the dilution and holding water used in the test:
- Conductivity: 238.6 µS/cm
- pH: 8.3
- dissolved oxygen: 104%
- nitrate: 1.3 mg/L
- nitrite: <0.005 mg/L*
- ammonium: <0.010 mg/L*
- phosphate: <0.100 mg/L*
- total hardness: 1.1 mmol/L
- alkalinity: 1.8 mmol/L
- calcium: 0.8 mmol/L
- magnesium: 0.3 mmol/L
- NPOC: 0.336 mg/L
- chromium: <0.309 µg/L
- cadmium: < 0.286 µg/L*
- copper: < 1.83 µg/L*
- iron: < 2.20 µg/L*
- manganese: < 0.567 µg/L*
- nickel: < 0.882 µg/L*
- lead: < 2.61 µg/L*
- zinc: < 2.80 µg/L*
- total residual chlorine: < 0.02 mg/L*
* < LOD: value below the respective limit of detection

OTHER TEST CONDITIONS
- Photoperiod: 16 hours light/8 hours dark
- Light intensity: 684 lux at test start and 655 lux at test end

EFFECT PARAMETERS MEASURED:
- number of immobile daphnids (did not swim 15 seconds after perturbation) in each treatment was visually determined daily and any immobile daphnids were removed.
- any abnormalities in appearance and behaviour were also recorded.

TEST CONCENTRATIONS
- Range finding study
A non-GLP range-finding test was performed prior to the definitive test with WAF loadings of reaction mass of willemite, white and zinc iron chromite brown spinel of 1, 10, and 100 mg/L, without chemical analysis. At the highest WAF loading of 100 mg/L, a 40 % immobilization was observed after 48 hours. No effects were observed during the test at loadings of 1 and 10 mg/L.

Reference substance (positive control):

yes

Remarks:

potassium dichromate

Results and discussion

Effect concentrations

Effect concentrations 1

Duration:

24 h

Dose descriptor:

EL10

Effect conc.:

105 mg/L

Nominal / measured:

estimated

Conc. based on:

test mat.

Remarks:

water accommodated fraction after 7 days

Basis for effect:

mobility

Effect concentrations 2

Duration:

24 h

Dose descriptor:

other: EL20

Effect conc.:

321 mg/L

Nominal / measured:

estimated

Conc. based on:

test mat.

Remarks:

water accommodated fraction after 7 days

Basis for effect:

mobility

Effect concentrations 3

Duration:

24 h

Dose descriptor:

other: NOEL

Effect conc.:

100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Remarks:

water accommodated fraction at 100 mg/L after 7 days

Basis for effect:

mobility

Effect concentrations 4

Duration:

48 h

Dose descriptor:

EL10

Effect conc.:

11.3 mg/L

Nominal / measured:

estimated

Conc. based on:

test mat.

Remarks:

water accommodated fraction after 7 days

Basis for effect:

mobility

Effect concentrations 5

Duration:

48 h

Dose descriptor:

other: EL20

Effect conc.:

28.1 mg/L

Nominal / measured:

estimated

Conc. based on:

test mat.

Remarks:

water accommodated fraction after 7 days

Basis for effect:

mobility

Effect concentrations 6

Duration:

48 h

Dose descriptor:

EL50

Effect conc.:

160 mg/L

Nominal / measured:

estimated

Conc. based on:

test mat.

Remarks:

water accommodated fraction after 7 days

Basis for effect:

mobility

Effect concentrations 7

Duration:

48 h

Dose descriptor:

other: NOEL

Effect conc.:

32 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Remarks:

water accommodated fraction at 32 mg/L after 7 days

Basis for effect:

mobility

Details on results:

- Behavioural abnormalities/Mortality/Clinical signs:
24 hours:
- immobolisation of daphnids at the WAF loading of 320 mg/L amounted to 25 % and was significantly different from control immobilsation.
- one daphnia was found to be immobile at WAF loadings of 10 and 100 mg/L, respectively, however this effect was not statistically significant.
48 hours:
- WAF loadings of 100 mg/L and at 320 mg/L of reaction mass of willemite, white and zinc iron chromite brown spindle resulted in an immobilisation of daphnids of 65 % and 60 %, respectively.

There were not any signs of disease or stress, e.g. discolouration or abnormal behaviour, observed in any replicate during the test. All surviving specimens appeared normal.

Results with reference substance (positive control):

The nominal 24-h EC50 is 1.19 mg/L (November 2013) and thus in the range of 0.6 - 2.1 mg/L as set in the ISO standard 6341.2012 (Anonymous, 2012)*.

* Reference:
Water quality - Determination of the inhibition of the mobility of Daphnia magna Straus (Cladocera, Crustacea) - Acute toxicity test (ISO 6341.2012).

Reported statistics and error estimates:

The endpoint of the test was immobilisation, evaluated quantitatively by ELx, NOEL, and LOEL determination. The NOEL and LOEL were calculated by ANOVA followed by parametric pairwise comparisons of the treatments to the control using a Fishers Exact test with Bonferroni correction (OECD, 2006)*. Probit analysis was performed for the estimate of the EL50 and dose-response curve, assuming log-normal distribution of the values, when 50% immobilisation for treatments compared to the control was observed. The size of the effect detectable is reported. The computer software ToxRat® Professional was used for statistical evaluations (ToxRat® Professional 2.10)*.

*References:
- OECD (2006). OECD current approaches in the statistical analysis of ecotoxicity data: a guidance to application. Organisation for Economic Co-operation and
Development, Paris.
- ToxRat® Professional 2.10. ToxRat® Solutions GmbH. Dr. Monika M. Ratte, Naheweg 15, 52477 Alsdorf, Germany.

Any other information on results incl. tables

Validity of the test:

All validity criteria according to the OECD Guideline 202 (2004) were met as the immobilisation of the control group was 0% and the dissolved oxygen concentration was >3 mg O2/L in control and test vessels during the test. Therefore, the test is valid.

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Conclusions:

For the water accommodated fractions of reaction mass of willemite, white and zinc iron chromite brown spindle a NOEL of 32 mg/L (WAF loading) and an EL50 of 160 mg/L (WAF loading) for the immobilisation of daphnids after 48 hours were determined. All concentrations are based on WAF loadings.