Dicopper hydroxide phosphate

Toxicity to aquatic plants other than algae

Link to relevant study record(s)

Reference

Endpoint:

toxicity to aquatic plants other than algae

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

study well documented, meets generally accepted scientific principles, acceptable for assessment

Qualifier:

no guideline followed

Principles of method if other than guideline:

The effect of copper on the growth rate of Lemna minor (doubled fronded colonies) following an exposure period of 7 days was determined.

GLP compliance:

no

Specific details on test material used for the study:

Cu2+ delivered as copper sulphate

Analytical monitoring:

yes

Details on sampling:

At T0 and Tend

Vehicle:

no

Details on test solutions:

Test solution: inorganic growth medium
Background Cu concentration: 0.078 µg/L

Test organisms (species):

Lemna minor

Details on test organisms:

- Source: Lemna minor was collected from an artificial pond on the University de Reims Champagne-Ardenne, France Campus.
- Pretreatment: The fronds were disinfected by immersion in NaOCl (0.01M) for 20 seconds and rinsing with distilled water
Initial cell concentration: Double fronded colonies, no further details given

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

7 d

Hardness:

26.8 mg/L CaCO3

Test temperature:

25 +/- 1 °C

pH:

6.5

Dissolved oxygen:

0.5 mg/L

Nominal and measured concentrations:

5 concentrations and 1 control
Nominal copper concentrations were 0.05, 0.2, 0.4, 0.6 and 1 mg/L.

Details on test conditions:

TEST SYSTEM
- Test vessel volume: 100 ml vessels containing 50 ml growth medium
- Number of vessels/concentration: Experiments were repeated at least twice and each sample was triplicated

TEST CONDITIONS
- Light intensity: 2000 +/- 100 lux
- Photoperiod: 24 hours light

Key result

Duration:

7 d

Dose descriptor:

NOEC

Effect conc.:

30 µg/L

Nominal / measured:

nominal

Conc. based on:

element (dissolved fraction)

Basis for effect:

growth rate

Details on results:

Plants exposed to copper were chlorotic and had smaller fronds compared to that of the controls. After 1 day of exposure to copper the two fronds associated in colonies separated and lost their roots. After 2 to 3 days of incubation and for copper concentrations of 0.2 and 0.4 mg/L, new fronds failed to separate from the mother plants and colonies of six or seven fronds in the 200 and 400 µg/L dose groups were formed. In the control groups the number of associated fronds per colony never exceeded four. The IC50 for copper was 0.16 +/- 0.05 mg/l inhibition of growth and 0.16 +/- 0.04 mg/L for inhibition of chlorophyll content.

Validity criteria fulfilled:

not applicable

Conclusions:

Reliable NOEC value for Lemna minor is 30 µg Cu/L (growth rate).

Executive summary:

The aim of this study was to determine the effect of copper on Lemna minor (doubled fronded colonies) following an exposure period of 7 days. Cu2+ (delivered as copper sulphate) was added to static test systems at dose concentrations of 50, 200, 400, 600 and 1000 µg/L.

The 7-day NOEC was calculated to be 30 µg/L.

Description of key information

One high quality NOEC is available for higher plants. Toxicity data from terrestrial plants (Barley root elongation) demonstrated that the algae model can be used for normalization of the Lemna NOEC values. Therefore a high quality chronic NOEC values for Lemna minor (growth) of 30 µg Cu/L was determined.

Additional information

Data are available on a number of substances containing inorganic copper and read-across is justified on the basis that for the purposes of assessing the ecotoxicology of dicopper hydroxide phosphate the chemical species of interest is copper. As such studies referring to soluble copper ions from any source are considered to be directly relevant to dicopper hydroxide phosphate. Dicopper hydroxide phosphate is considered to contribute to copper toxicity in the environment and as such the data assessment and risk assessment focusses on the copper ion as the phosphate ion is not considered to be toxic.

 

One high quality NOEC is available for higher plants. Toxicity data from terrestrial plants (Barley root elongation) demonstrated that the algae model can be used for normalization of the Lemna NOEC values. Therefore a high quality chronic NOEC values for Lemna minor (growth) of 30 µg Cu/L was determined.

 

Additional information:

A voluntary risk assessment report of copper and copper compounds has been submitted to the European Chemicals Agency by the European Copper Institute (June 2008). This report is based on the industry initiative to perform a voluntary risk assessment on a substance according to the mechanisms of the implementation of the Existing Substance Regulation (EEC) No 793/93 (ESR). The procedure was agreed by the 11^thJoint Meeting of the Competent Authorities for the Implementation of Directive 67/548/EEC and ESR Regulation. Italy has been acting as a reviewing Member State for the substance and the risk assessment report has been reviewed by the Technical Committee on New and Existing Substances (TC NES) according to standard operational procedures of the Committee.

 

In accordance with the above mentioned European copper risk assessment, the environmental hazard assessment is based on tests carried out with soluble copper species. Studies reporting quantitative dose responses of Cu(II) ions, delivered from soluble copper compounds to aquatic organisms are used for this assessment.

 

The data presented are considered to be adequate and reliable for the purpose of defining an appropriate classification for the ecotoxicity of dicopper hydroxide phosphate in accordance with Regulation (EC) No.1272/2008 (EU CLP).