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Ecotoxicological information

Toxicity to aquatic algae and cyanobacteria

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Administrative data

Endpoint:
toxicity to aquatic algae and cyanobacteria
Type of information:
experimental study
Adequacy of study:
weight of evidence
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
study well documented, meets generally accepted scientific principles, acceptable for assessment

Data source

Reference
Reference Type:
publication
Title:
Bioavailability Models for Predicting Copper Toxicity to Freshwater Green Microalgae as a Function of Water Chemistry
Author:
De Schamphelaere, K.C. and Janssen, C.R.
Year:
2006
Bibliographic source:
Environ. Sci. Technol. 2006; 40:4514-4522

Materials and methods

Test guideline
Qualifier:
equivalent or similar to guideline
Guideline:
OECD Guideline 201 (Alga, Growth Inhibition Test)
Deviations:
yes
Remarks:
Tests conducted in a range of test waters, with varying physico-chemistry (DOC, pH, Hardness)
GLP compliance:
no

Test material

Constituent 1
Chemical structure
Reference substance name:
Copper sulphate
EC Number:
231-847-6
EC Name:
Copper sulphate
Cas Number:
7758-98-7
Molecular formula:
Cu.H2O4S
IUPAC Name:
copper(2+) sulfate
Specific details on test material used for the study:
Cu +2 delivered as Copper Sulphate

Sampling and analysis

Analytical monitoring:
yes
Details on sampling:
samples at T0 and Tend

Test solutions

Vehicle:
no
Details on test solutions:
test solutions pre-equilibrated for 48 hrs prior to the test

Test organisms

Test organisms (species):
other: Pseudokirchneriella subcapitata, Chlorella vulgaris, Chlamydomonas reinhardtii, Scenedesmus quadricauda
Details on test organisms:
It was investigated, if an earlier-developed bioavailability model for predicting toxicity to growth rate of Pseudokirchneriella subcapitata could be extrapolated to other species, such as Chlorella vulgaris, Chlamydomonas reinhardtii, Scenedesmus quadricauda. Experimental toxicity bioassays were performed with Chlorella vulgaris and Chlamydomonas reinhardtii.

Study design

Test type:
static
Water media type:
freshwater
Limit test:
no
Total exposure duration:
72 h

Test conditions

Hardness:
see attachement es0525051
Test temperature:
see attachement es0525051
pH:
see attachement es0525051
Nominal and measured concentrations:
Measured concentrations- 5 concentrations + 1 control
Details on test conditions:
Range of test waters : see attachement es0525051
Reference substance (positive control):
no

Results and discussion

Effect concentrationsopen allclose all
Key result
Duration:
72 h
Dose descriptor:
EC10
Effect conc.:
108 µg/L
Nominal / measured:
meas. (arithm. mean)
Conc. based on:
element (dissolved fraction)
Basis for effect:
growth rate
Remarks on result:
other: Chlorella vulgaris / Test water: Ankeveen 1
Key result
Duration:
72 h
Dose descriptor:
EC10
Effect conc.:
407 µg/L
Nominal / measured:
meas. (arithm. mean)
Conc. based on:
element (dissolved fraction)
Basis for effect:
growth rate
Remarks on result:
other: Chlorella vulgaris / Test water: Ankeveen 2
Key result
Duration:
72 h
Dose descriptor:
EC10
Effect conc.:
56 µg/L
Nominal / measured:
meas. (arithm. mean)
Conc. based on:
element (dissolved fraction)
Basis for effect:
growth rate
Remarks on result:
other: Chlorella vulgaris / Test water: Ankeveen 3
Key result
Duration:
72 h
Dose descriptor:
EC10
Effect conc.:
36 µg/L
Nominal / measured:
meas. (arithm. mean)
Conc. based on:
element (dissolved fraction)
Basis for effect:
growth rate
Remarks on result:
other: Chlorella vulgaris / Test water: Ankeveen 4
Key result
Duration:
72 h
Dose descriptor:
EC10
Effect conc.:
173 µg/L
Nominal / measured:
meas. (arithm. mean)
Conc. based on:
element (dissolved fraction)
Basis for effect:
growth rate
Remarks on result:
other: Chlorella vulgaris / Test water: Ankeveen 5
Key result
Duration:
72 h
Dose descriptor:
EC10
Effect conc.:
99 µg/L
Nominal / measured:
meas. (arithm. mean)
Conc. based on:
element (dissolved fraction)
Basis for effect:
growth rate
Remarks on result:
other: Chlorella vulgaris / Test water: Ankeveen 6
Key result
Duration:
72 h
Dose descriptor:
EC10
Effect conc.:
85 µg/L
Nominal / measured:
meas. (arithm. mean)
Conc. based on:
element (dissolved fraction)
Basis for effect:
growth rate
Remarks on result:
other: Chlorella vulgaris / Test water: Ankeveen 7
Key result
Duration:
72 h
Dose descriptor:
EC10
Effect conc.:
162 µg/L
Nominal / measured:
meas. (arithm. mean)
Conc. based on:
element (dissolved fraction)
Basis for effect:
growth rate
Remarks on result:
other: Chlorella vulgaris / Test water: Ankeveen 8
Key result
Duration:
72 h
Dose descriptor:
EC10
Effect conc.:
283 µg/L
Nominal / measured:
meas. (arithm. mean)
Conc. based on:
element (dissolved fraction)
Basis for effect:
growth rate
Remarks on result:
other: Chlorella vulgaris / Test water: Ankeveen 9
Key result
Duration:
72 h
Dose descriptor:
EC10
Effect conc.:
188 µg/L
Nominal / measured:
meas. (arithm. mean)
Conc. based on:
element (dissolved fraction)
Basis for effect:
growth rate
Remarks on result:
other: Chlorella vulgaris / Test water: Ankeveen 10
Key result
Duration:
72 h
Dose descriptor:
EC10
Effect conc.:
510 µg/L
Nominal / measured:
meas. (arithm. mean)
Conc. based on:
element (dissolved fraction)
Basis for effect:
growth rate
Remarks on result:
other: Chlorella vulgaris / Test water: Ankeveen 11
Key result
Duration:
72 h
Dose descriptor:
EC10
Effect conc.:
31 µg/L
Nominal / measured:
meas. (arithm. mean)
Conc. based on:
element (dissolved fraction)
Basis for effect:
growth rate
Remarks on result:
other: Chlorella vulgaris / Test water: Ankeveen 12
Key result
Duration:
72 h
Dose descriptor:
EC10
Effect conc.:
188 µg/L
Nominal / measured:
meas. (arithm. mean)
Conc. based on:
element (dissolved fraction)
Basis for effect:
growth rate
Remarks on result:
other: Chlorella vulgaris / Test water: Ankeveen 13
Key result
Duration:
72 h
Dose descriptor:
EC10
Effect conc.:
404 µg/L
Nominal / measured:
meas. (arithm. mean)
Conc. based on:
element (dissolved fraction)
Basis for effect:
growth rate
Remarks on result:
other: Chlorella vulgaris / Test water: Ankeveen 14
Key result
Duration:
72 h
Dose descriptor:
EC10
Effect conc.:
159 µg/L
Nominal / measured:
meas. (arithm. mean)
Conc. based on:
element (dissolved fraction)
Basis for effect:
growth rate
Remarks on result:
other: Chlorella vulgaris / Test water: Ankeveen 15
Key result
Duration:
72 h
Dose descriptor:
EC10
Effect conc.:
84 µg/L
Nominal / measured:
meas. (arithm. mean)
Conc. based on:
element (dissolved fraction)
Basis for effect:
growth rate
Remarks on result:
other: Chlorella vulgaris / Test water: Ankeveen 16
Key result
Duration:
72 h
Dose descriptor:
EC10
Effect conc.:
132 µg/L
Nominal / measured:
meas. (arithm. mean)
Conc. based on:
element (dissolved fraction)
Basis for effect:
growth rate
Remarks on result:
other: Chlorella vulgaris / Test water: Ankeveen 17
Key result
Duration:
72 h
Dose descriptor:
EC10
Effect conc.:
178 µg/L
Nominal / measured:
meas. (arithm. mean)
Conc. based on:
element (dissolved fraction)
Basis for effect:
growth rate
Remarks on result:
other: Chlamydomonas reinhardtii, pH 6
Key result
Duration:
72 h
Dose descriptor:
EC10
Effect conc.:
108 µg/L
Nominal / measured:
meas. (arithm. mean)
Conc. based on:
element (dissolved fraction)
Basis for effect:
growth rate
Remarks on result:
other: Chlamydomonas reinhardtii, pH 7
Key result
Duration:
72 h
Dose descriptor:
EC10
Effect conc.:
96 µg/L
Nominal / measured:
meas. (arithm. mean)
Conc. based on:
element (dissolved fraction)
Basis for effect:
growth rate
Remarks on result:
other: Chlamydomonas reinhardtii, pH 8
Reported statistics and error estimates:
See attachment es0525051

Applicant's summary and conclusion

Validity criteria fulfilled:
not applicable
Conclusions:
Several EC10 values were obtained for C. vulgaris, C. reinhardti and P. Sucapitata depending on the water used for the study.
Executive summary:

It was investigated whether an earlier-developed bioavailability model for predicting copper toxicity to growth rate of the freshwater alga Pseudokirchneriella subcapitata could be extrapolated to other species and toxicological effects (endpoints). Hardness and dissolved organic carbon did not significantly affect the toxicity of the free Cu2+ion to P.subcapitata (earlier study) andChlorella vulgaris (this study), but a higher pH resulted in an increased toxicity for both species. Regression analysis showed significant linear relationships between ECxpCu()“effect concentration” that produces x% adverse effect, expressed as pCu) -log of the Cu2+activity) and pH. By linking these regression models with a geochemical metal speciation model, dissolved copper concentrations that elicit a given adverse effect (ECxdissolved) can be predicted. Within the pH range investigated (5.5-8.7), slopes of the linear ECxpCuvs pH regression models varied between 1.301 and 1.472 depending on the species and the effect level (10% or 50%) considered.

In a statistical sense these slopes were all significantly different from one another (p<0.05), suggesting that this empirical regression model does not yet capture the full complexity of toxicological copper bioavailability to algae. However, we demonstrated that regression models with an “average” slope of 1.354 had predictive power very similar to those of regression models with species and effectspecific slopes. Additionally, the “average” regression model was further successfully validated for other species (Chlamydomonas reinhardtii andScenedesmus quadricauda) and for different toxicological effects/endpoints (growth rate, biomass yield, and phosphorus uptake rate). For all these toxicity datasets effect concentrations of copper could be predicted with this “average” model by errors of less than a factor of 2 in 94-100% of the cases. The success of this “average” model suggests the possibility that the pHbased linear regression model may form a sound conceptual basis for modeling the toxicological bioavailability of copper to green algae in regulatory assessments, although a full mechanistic understanding is lacking and should be the focus of future studies.