Zinc, dross

Short-term toxicity to aquatic invertebrates

Administrative data

Endpoint:

short-term toxicity to aquatic invertebrates

Type of information:

other: read accross of critical study record from specific substance (Zn) driving classification

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: Tests done according to standard protocol. Good quality and considered useful for setting the reference value for acute aquatic ecotoxicity. Culture medium, test water conditions well described and relevant the purpose of classification.

Data source

Reference

Reference Type:

publication

Title:

Influence of water chemistry on the acute toxicity of copper and zinc to the cladoceran Ceriodaphnia dubia

Author:

Hyne R.V., Pablo F, Moreno J; , Markisch S.J.

Year:

2005

Bibliographic source:

Environm. Toxic. & Chemistry 24,1667-1675

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

other: US EPA EPA 821-R-02-012. Methods for measuring the acute toxicity of effluents and receiving waters to freshwater and marine organisms, 5th Ed. (2002)

Deviations:

yes

Remarks:

tests were done under varying conditions of pH, hardness, DOC

GLP compliance:

not specified

Test material

Test material information

Constituent 1

Reference substance name:

Zinc

EC Number:

231-175-3

EC Name:

Zinc

Cas Number:

7440-66-6

Molecular formula:

Zn

IUPAC Name:

zinc

Details on test material:

zinc compound used for testing is not mentioned, but results are expressed as measured dissolved Zn concentrations, so useful. Most probably a soluble zinc compound (ZnCl2 or ZnSO4) is used.

Sampling and analysis

Analytical monitoring:

yes

Details on sampling:

samples taken at beginning and end of test (48hrs).

Test solutions

Vehicle:

no

Details on test solutions:

US EPA synthetic soft water at pH 7.5-7.7 was used as control for tests at different pH; pH was modified with 2mM MES buffer or 1mM MOPS buffer.

Test organisms

Test organisms (species):

Ceriodaphnia dubia

Details on test organisms:

Ceridaphnia cultures were kept in the center for Ecotoxicology (NSW Australia) laboratories. Cladocerans were fed with Ankistrodesmus sp. and Pseudokircherniella subcapitata (50.000 cells/ml of each species).
tests done on neonates <24hrs old. organisms 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:

tests done at varying hardness; only the tests at low hardness (44 mg CaCO3/l) are considered relevant and reported (other hardness: 374 mg CaCO3/l)

Test temperature:

25+/-1°C

pH:

tests performed at pH 6.5 and 7.5 are relevant for the purpose of classification and reported;

Nominal and measured concentrations:

5 metal concentrations were used + control

Results and discussion

Effect concentrations

Effect concentrations 1

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

413 µg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

dissolved

Basis for effect:

mobility

Remarks on result:

other: 95% C.I. are 388-437 µg/l; test at pH 6.5, hardness 44mgCaCO3/l

Effect concentrations 2

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

200 µg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

dissolved

Basis for effect:

mobility

Remarks on result:

other: 95% C.I. are 186-214 µg/l; test at pH 7.5, hardness 44mg CaCO3/l

Effect concentrations 3

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

155 µg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

dissolved

Basis for effect:

mobility

Remarks on result:

other: 95% C.I. 130-185; test at pH 7.5, hardness 44mg CaCO3/l

Reported statistics and error estimates:

EC50 values calculated with the Trimmed-Spearman-Karber method. Differences between EC50 values determined with a procedure based on the F ratio of Litchfield and Wilcoxon.

Any other information on results incl. tables

tests not considered relevant when performed

-at pH 5.5

-at very high alkalinity/high hardness at pH 8.4

-in presence of DOC

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Conclusions:

Tests done according to standard protocol. Good quality and considered useful for setting the reference value for acute aquatic ecotoxicity.

Executive summary:

Study determined the influence of key water parameters on the acute toxicity of zinc to Ceriodaphnia dubia. Tests done according to standard protocol. Good quality and considered useful for setting the reference value for acute aquatic ecotoxicity. Culture medium, test water conditions well described and relevant the purpose of classification. LC50 values: see “results” section.LC50 of 413 µg Zn/l observed at pH 6.5 is the reference value for classification at this pH.