Copper thiocyanate

Toxicity to aquatic algae and cyanobacteria

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:

other: well performed and documented study

Data source

Reference

Reference Type:

publication

Title:

Unnamed

Year:

2006

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 201 (Alga, Growth Inhibition Test)

GLP compliance:

no

Test material

Test material information

Constituent 1

Reference substance name:

Copper chloride

EC Number:

231-842-9

EC Name:

Copper chloride

Cas Number:

7758-89-6

Molecular formula:

ClCu

IUPAC Name:

copper (I) chloride

Constituent 2

Reference substance name:

Copper dichloride

EC Number:

231-210-2

EC Name:

Copper dichloride

Cas Number:

7447-39-4

Molecular formula:

CuCl2

IUPAC Name:

copper(2+) dichloride

Details on test material:

not reported

Sampling and analysis

Analytical monitoring:

yes

Details on sampling:

Dissolved copper was determined at the beginning and end of the tests

Test solutions

Vehicle:

not specified

Test organisms

Test organisms (species):

Chlorella vulgaris

Details on test organisms:

TEST ORGANISM
- Source (laboratory, culture collection): the starter culture was obtained from the Culture Collection for Algae and Protozoa (CCAP 211/11B)
- Culture: the algae were grown in the laboratory at 20°C under continuous illumination and pH 8.3 in carbon filtered and 0.45 µm filtered tapwater to which modified Provasoli's ES enrichment at 50% strength and other nutrients were added. Culture media contained 1-1.5 µgCu/L
- Density: At the beginning of the tests the density of the algae was 1x10^4 cells/mL
- Only log-phase algae are used for the tests

Study design

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

72 h

Test conditions

Hardness:

between 25 and 250 mg/L CaCO3

Test temperature:

25+-1°C

pH:

between 5.5 and 8.75

Nominal and measured concentrations:

1 control + 5 different Cu concentrations

Details on test conditions:

TEST SYSTEM
- Test vessel: glass erlenmeyers
- Material, size, headspace, fill volume: 100 mL vessels containing 50 mL of test medium
- Aeration: none
- Initial cells density: 1x10^4
- No. of vessels per concentration (replicates): 3
- No. of vessels per control (replicates): 6

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: artificial ISO medium (1989) to which MOPS and DOC was added. Natural DOC replaced EDTA and were concentrated from the Ankeveense Plassen in The Netherlands using reverse osmosis techniques. The spiked samples were equilibrated fro 48 h before testing
- Total organic carbon: 1.5-19.1 mg/L

OTHER TEST CONDITIONS
- Adjustment of pH: the pH was adjusted through addition of HCl or KOH
- Light intensity and quality: continuous uniform illumination with a light intensity of 4000 lux measured at the surface of the light table
- Tests were performed at 25°C under continuous illumination

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) :
- Determination of cell concentrations: electronic particle counter

TEST CONCENTRATIONS
- Spacing factor for test concentrations: 1 order of magnitude difference between the highest and lowest concentrations

Results and discussion

Effect concentrations

Effect concentrations 1

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

333 µg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

dissolved

Basis for effect:

growth rate

Remarks on result:

other: confidence limits: 253-440 µg/L. hardness 100 mg/L CaCO3, pH 6.03, DOC 5.17 mg/L

Effect concentrations 2

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

773 µg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

dissolved

Basis for effect:

growth rate

Remarks on result:

other: confidence limits: 704-850 µg/L; pH 6.04, hardness 100 mg/L CaCO3, DOC 15.49 mg/L

Effect concentrations 3

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

99 µg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

dissolved

Basis for effect:

growth rate

Remarks on result:

other: confidence limits: 91-109 µg/L; pH 7.92, hardness 400 mg/L CaCO3, DOC 5.04 mg/L

Effect concentrations 4

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

506 µg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

dissolved

Basis for effect:

growth rate

Remarks on result:

other: confidence limits: 411-623 µg/L; pH 7.97, hardness 400 mg/L CaCO3, DOC 15.82 mg/L

Effect concentrations 5

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

296 µg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

dissolved

Basis for effect:

growth rate

Remarks on result:

other: confidence limits: 254-345 µg/L; pH 7.03, hardness 250 mg/L CaCO3, DOC 10.81 mg/L

Effect concentrations 6

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

254 µg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

dissolved

Basis for effect:

growth rate

Remarks on result:

other: confidence limits: 218-295 µg/L; pH 7.01, hardness 500 mg/L CaCO3, DOC 10.03 mg/L

Effect concentrations 7

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

60 µg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

dissolved

Basis for effect:

growth rate

Remarks on result:

other: confidence limits: 56-65 µg/L; pH 7.04, hardness 250 mg/L CaCO3, DOC 1.5 mg/L

Effect concentrations 8

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

200 µg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

dissolved

Basis for effect:

growth rate

Remarks on result:

other: confidence limits: 158-254 µg/L; pH 8.75, hardness 250 mg/L CaCO3, DOC 9.9 mg/L

Effect concentrations 9

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

446 µg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

dissolved

Basis for effect:

growth rate

Remarks on result:

other: confidence limits: 417-478 µg/L; pH 7.05, hardness 250 mg/L CaCO3, DOC 19.09 mg/L

Effect concentrations 10

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

440 µg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

dissolved

Basis for effect:

growth rate

Remarks on result:

other: confidence limits: 383-506 µg/L; pH 6.01, hardness 400 mg/L CaCO3, DOC 5.03 mg/L

Effect concentrations 11

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

987 µg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

dissolved

Basis for effect:

growth rate

Remarks on result:

other: confidence limits: 858-1135 µg/L; pH 6.05, hardness 400 mg/L CaCO3, DOC 15.24 mg/L

Effect concentrations 12

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

111 µg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

dissolved

Basis for effect:

growth rate

Remarks on result:

other: confidence limits: 90-137 µg/L; pH 7.88, hardness 100 mg/L CaCO4, DOC 5.31 mg/L

Effect concentrations 13

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

380 µg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

dissolved

Basis for effect:

growth rate

Remarks on result:

other: confidence limits: 347-415 µg/L; pH 7.88, hardness 100 mg/L CaCO3, DOC 15.66 mg/L

Effect concentrations 14

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

602 µg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

dissolved

Basis for effect:

growth rate

Remarks on result:

other: confidence limits: 540-672 µg/L; pH 5.5, hardness 250 mg/L CaCO3, DOC 10.27 mg/L

Effect concentrations 15

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

238 µg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

dissolved

Basis for effect:

growth rate

Remarks on result:

other: confidence limits: 222-254 µg/L; pH 7.07, hardness 25 mg/L CaCO3, DOC 10.26 mg/L

Effect concentrations 16

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

364 µg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

dissolved

Basis for effect:

growth rate

Remarks on result:

other: confidence limits: 257-514 µg/L; pH 7.03, hardness 250 mg/L CaCO3, DOC 10.81 mg/L

Effect concentrations 17

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

208 µg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

dissolved

Basis for effect:

growth rate

Remarks on result:

other: confidence limits: 196-220 µg/L; pH 7.04, hardness 250 mg/L CaCO3, DOC 10.23 mg/L

Details on results:

control growth rate was between 1.0 and 1.3 d-1

Reported statistics and error estimates:

Exponential growth rates for all species and all treatments were calculated as the slope of a linear regression between the natural logarithm of the cell
density and time. The concentrations associated with 10% (ErC10) or 50% (ErC50) inhibition of the growth rate after 72 h of exposure were calculated with Statistica 6.0 (Statsoft, Tulsa) using a logistic regression equation with the ErC10 and EC50 as the fitting parameters

Applicant's summary and conclusion

Conclusions:

This study was well performed and documented and is therefore considered reliable. EC50 values (72h) of Chlorella ranged between 60 µg/L (pH 7.04, hardness 250 mg/L CaCO3, DOC 1.5 mg/L) and 987 µg/L (pH 6.05, hardness 400 mg/L CaCO3, DOC 15.24 mg/L).