Copper Chelate Complex

Toxicity to aquatic algae and cyanobacteria

Link to relevant study record(s)

Reference

Endpoint:

effects on growth of green algae

Type of information:

experimental study

Adequacy of study:

key study

Study period:

September 2020 - June 2021

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 201 (Alga, Growth Inhibition Test)

Deviations:

no

Qualifier:

according to guideline

Guideline:

EU Method C.3 (Algal Inhibition test)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Specific details on test material used for the study:

- Storage conditions: Controlled room temperature (15-25°C, ≤70% relative humidity), protected from light and humidity (stored in a tightly closed container)

Analytical monitoring:

yes

Details on sampling:

The test item is a sparingly soluble substance which hydrolyses immediately after application to aqueous solutions leading to the release of an organic compound and formation of copper. As analytical determination of the organic compound was not feasible (due to the low applied concentrations of test item resulting in concentrations of the organic compound below the limit of detection of the analytical method), the biological results are expressed based on loading rates.

Vehicle:

no

Details on test solutions:

The preparation of the test media was based on the OECD Guidance Document No. 23 (Second Edition) on Aquatic Toxicity Testing of Difficult Substances and Mixtures, 2019. For preparation of the WAFs a dispersion of the test item with the loading rate of 3.2 mg/L was prepared. The dispersion was intensively stirred for 3 hours at room temperature in the dark to dissolve a maximum amount of the test item in the dispersion. After stirring the dispersion was filtered through a pre-conditioned membrane filter (0.45 μm). The resulting undiluted filtrate was tested as a WAF. Due to technical reasons (operational constraints on the precision of direct weighing of test item), the WAFs with the lower loading rates of 0.032, 0.10, 0.32 and 1.0 mg/L were prepared as dilutions of the filtrate of the WAF with the loading rate of 3.2 mg/L. Additionally, a control group (test water without test item) was tested in parallel.

Test organisms (species):

Raphidocelis subcapitata (previous names: Pseudokirchneriella subcapitata, Selenastrum capricornutum)

Details on test organisms:

TEST ORGANISM
The test organism used for the study was Pseudokirchneriella subcapitata (formerly Selenastrum capricornutum, occasionally also listed as Raphidocelis subcapitata), Strain No. 61.81 SAG, supplied by the Collection of Algal Cultures (SAG, Institute for Plant Physiology, University of Göttingen, 37073 Göttingen / Germany). The algae were cultivated at the test lab under standardized conditions according to the test guidelines.
An inoculum culture was set up three days before the start of the exposure. The algae were cultivated under the test conditions and were kept in the exponential growth phase until inoculation of the test solutions.

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

72 h

Post exposure observation period:

none

Hardness:

The water hardness (calculated) of the test water was 0.15 mmol/L (= 15 mg/L as CaCO3).

Test temperature:

The water temperature during the test was maintained at 22 °C.

pH:

The pH was 7.5.

Dissolved oxygen:

Not measured

Salinity:

Freshwater used

Conductivity:

no data

Nominal and measured concentrations:

LZ 60102 is a sparingly soluble substance, which hydrolyses in aqueous solutions resulting in the compound LZ399 and copper. Therefore, Water Accommodated Fractions (WAFs) with the loading rates of 0.032, 0.10, 0.32, 1.0 and 3.2 mg/L were tested to assess the toxicity of the test item to algae.

Details on test conditions:

As a precaution, the test was performed using glass Erlenmeyer flasks completely filled (without headspace) with test medium that were tightly sealed with glass stoppers to avoid potential losses of test item by evaporation (closed system).

Key result

Duration:

72 h

Dose descriptor:

EL10

Effect conc.:

0.72 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Remarks on result:

other: concentration based on loading rate

Details on results:

In conclusion, the 72-hour EL10 value was determined to be 0.72 mg/L for growth rate, based on the nominal loading rate.

Results with reference substance (positive control):

For evaluation of the algal quality and experimental conditions, potassium dichromate is tested as a positive control twice a year to demonstrate satisfactory test conditions. The 72-hour EC50 for growth rate in the reference test at the test lab (November 2020) was 0.9 mg/L and showed that the sensitivity of the test system was within the range recommended by the guideline (72-hour EC50 for the growth rate 0.9-1.5 mg/L).

Reported statistics and error estimates:

Statistical analysis was performed using ToxRat Professional.

Validity criteria fulfilled:

yes

Conclusions:

The biological results are expressed based on loading rates, since the test item is a sparingly soluble compound, which hydrolyses immediately after being applied to aqueous solutions. The EL10 (72h) on Green Algae (Pseudokirchneriella subcapitata) was found to be 0.72 mg/L based on loading rate.

Executive summary:

The impact of the test item on the growth of the freshwater green algal species Pseudokirchneriella subcapitata was investigated in a 72-hour static test according to the OECD Guideline 201 (2006, corrected 2011) and the Commission Regulation (EU) No 2016/266, C.3. The substance is a sparingly soluble substance, which hydrolyses in aqueous solutions resulting in an organic degradation product and copper. Therefore, Water Accommodated Fractions (WAFs) with the loading rates of 0.032, 0.10, 0.32, 1.0 and 3.2 mg/L were tested to assess the toxicity of the test item to algae. As a precaution, the test was performed using glass Erlenmeyer flasks completely filled (without headspace) with test medium that were tightly sealed with glass stoppers to avoid potential losses of test item by evaporation (closed system).

A static test was performed. For preparation of the WAFs a dispersion of the test item with the loading rate of 3.2 mg/L was prepared. The dispersion was intensively stirred for 3 hours at room temperature in the dark to dissolve a maximum amount of the test item in the dispersion. After stirring the dispersion was filtered through a pre-conditioned membrane filter (0.45 μm). The resulting undiluted filtrate was tested as a WAF. The preparation of the test media was based on the OECD Guidance Document No. 23 (Second Edition) on Aquatic Toxicity Testing of Difficult Substances and Mixtures, 2019.

The biological results are expressed based on loading rates, since the test item isa sparingly soluble compound, which hydrolyses immediately after being applied to aqueous solutions, forming an organic degradation product and copper.The EL10 (72h) on Green Algae was found to be 0.72 mg/L based on loading rate.

Description of key information

The impact of the test item on the growth of the freshwater green algal species Pseudokirchneriella subcapitata was investigated in a 72-hour static test according to the OECD Guideline 201 (2006, corrected 2011) and the Commission Regulation (EU) No 2016/266, C.3. The substance is a sparingly soluble substance, which hydrolyses in aqueous solutions resulting in an organic degradation product and copper. Therefore, Water Accommodated Fractions (WAFs) with the loading rates of 0.032, 0.10, 0.32, 1.0 and 3.2 mg/L were tested to assess the toxicity of the test item to algae. As a precaution, the test was performed using glass Erlenmeyer flasks completely filled (without headspace) with test medium that were tightly sealed with glass stoppers to avoid potential losses of test item by evaporation (closed system).

A static test was performed. For preparation of the WAFs a dispersion of the test item with the loading rate of 3.2 mg/L was prepared. The dispersion was intensively stirred for 3 hours at room temperature in the dark to dissolve a maximum amount of the test item in the dispersion. After stirring the dispersion was filtered through a pre-conditioned membrane filter (0.45 μm). The resulting undiluted filtrate was tested as a WAF. The preparation of the test media was based on the OECD Guidance Document No. 23 (Second Edition) on Aquatic Toxicity Testing of Difficult Substances and Mixtures, 2019.

The biological results are expressed based on loading rates, since the test item isa sparingly soluble compound, which hydrolyses immediately after being applied to aqueous solutions, forming an organic degradation product and copper.The EL10 (72h) on Green Algae was found to be 0.72 mg/L based on loading rate.

Key value for chemical safety assessment

EC10 or NOEC for freshwater algae:

0.72 mg/L