Tetracopper hexahydroxide sulphate

Short-term toxicity to aquatic invertebrates

Link to relevant study record(s)

Reference

Endpoint:

short-term toxicity to aquatic invertebrates

Type of information:

experimental study

Adequacy of study:

key study

Study period:

Experimental phase: 01 August 2018 to September 2018 Study completion date: 08 October 2018

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)

Deviations:

no

Qualifier:

according to guideline

Guideline:

EU Method C.2 (Acute Toxicity for Daphnia)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Analytical monitoring:

yes

Details on sampling:

- Sampling method: Duplicate samples from the freshly prepared test media of all test concentrations and the control were taken at the start of the test and at the test water renewal on day 1. For the determination of the stability of the test item under the test conditions and of the maintenance of the test item concentrations during the test period, duplicate samples from the aged test media of all test concentrations and the control were collected at day 1 (after 24 hours of exposure) and at the end of the test by pouring together the contents of the test beakers of each treatment. The pH value was adjusted to pH 2 with nitric acid directly after sampling.
Additional samples of the aged control were taken at day one without any sample treatment.

- Sample storage conditions before analysis: All samples were stored in a freezer (≤ - 20 °C), protected from light, until analysis was performed. Afterwards the samples were again stored deep frozen (≤ -20 °C).

Vehicle:

no

Details on test solutions:

Preparation of the control: In the control, test water was used without addition of the test item.
Peparation of the test solutions: The test medium of the highest test concentration of nominal 2 mg test item/L was prepared by dissolving 9.9 and 10.2 mg test item into 4950 and 5100 mL test water by intense stirring for 1 hour and 30 minutes and 1 hour and 15 minutes and ultrasonic treatment for 10 minutes. Adequate volumes of this test medium were diluted with test water to prepare the test media of the other desired test concentrations.

The test media were prepared just before introduction of the daphnids (= start of the test) and test medium renewal on Day 1.

Test organisms (species):

Daphnia magna

Details on test organisms:

TEST ORGANISM
- Common name: Daphnia magna (Straus)
- Strain/clone: clone 5
- Source: In house laboratory culture.
- Sex: Female
- Age: From 3.50 to 21.0 hours old

ACCLIMATION
- Acclimation period: Not necessary, since the test was performed in the same medium as the culturing

Test type:

semi-static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

48 h

Hardness:

Not stated

Test temperature:

20.2 to 21.0 °C in the freshly prepared media
20.3 to 21.0°C in the aged test media

pH:

7.6 to 7.8 in the freshly prepared media
7.7 to 7.8 in the aged test media; and thus the pH-value did not vary by more than 1.5 units

Dissolved oxygen:

8.7 to 9.1 mg/L in the freshly prepared media;
8.7 to 8.9 mg/L in the aged test media

Salinity:

Not stated

Conductivity:

Not stated

Nominal and measured concentrations:

2.0, 0.909, 0.413, 0.188 and 0.085 mg test item/L (spacing factor 2.2) and a control corresponding to following geometric mean measured concentrations of the test item: 1.49, 0.296, 0.142, 0.0836 and 0.0423 mg test item/L, and a control.

Details on test conditions:

TEST SYSTEM
- Test vessel: Glass beakers of 100 mL volume containing approximately 60 mL of test medium. The test vessels were covered with a lid to reduce the loss of water due to evaporation and to avoid the entry of dust into the solutions.
- No. of organisms per vessel: 20 daphnids per control and test concentration, divided into 4 groups of 5 animals, each group in 60 mL test medium
- Replicates: The test was performed with four replicates per treatment group.
- Exposure Time: 48 hours

OTHER TEST CONDITIONS
Light Regime: 16 h light : 8 h dark
Light Intensity: The light intensity was 490 to 960 lux (measured once during the test).

TEST WATER
Reconstituted water: In deionised water (conductivity < 5 µScm-1) analytical grade salts were added at the following nominal concentrations:
CaCl2 x 2H2O 2.0 mmol/L (= 294 mg/L)
MgSO4 x 7H2O 0.5 mmol/L (= 123 mg/L)
NaHCO3 0.75 mmol/L (= 65 mg/L)
KCl 0.075 mmol/L (= 5.8 mg/L)
Water Hardness: 2.5 mmol/L (= 250 mg/L) as CaCO3
Alkalinity: 0.8 mmol/L
Ratio of Ca : Mg = 4 : 1 (based on molarity)
Na : K = 10 : 1 (based on molarity)

Reference substance (positive control):

no

Remarks:

For the evaluation of the quality of the Daphnia clone and the consistency of the experimental conditions, the reference item potassium dichromate is tested at least twice a year to demonstrate satisfactory test conditions.

Key result

Duration:

48 h

Dose descriptor:

NOEC

Effect conc.:

0.084 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

mobility

Duration:

48 h

Dose descriptor:

LOEC

Effect conc.:

0.142 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

mobility

Key result

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

0.295 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Details on results:

After 48 hours of exposure, no immobilisation of the test animals was observed in the control. At concentrations of 0.0423 and 0.0836 mg test item/L, one animal was immobile. At a concentration of 0.142 mg test item/L, four animals were immobile. 13 and 18 animals were immobile at concentrations of 0.296 and 1.49 mg test item/L.

The validity criteria of the study were met. The control immobilisation rate was 0% and furthermore no daphnid showed signs of disease or stress. The dissolved oxygen concentration was >8.7 mg O2/L in the control and test vessels at the end of the test.

Results with reference substance (positive control):

Not applicable.

Table 1. Summary of Biological Results
Geometric MeanMeasured Concentration	% of immobilised daphnids after
[mg test item/L]	24 hours	48 hours
Control	0	0
0.0423	0	5
0.0836	5	5
0.142	0	20
0.296	0	65
1.49	0	90
EC50[mg test item/L]:	> 1.49	0.295
95 % CI [mg test item/L]:	n.d.	0.212 - 0.453
EC20[mg test item/L]:	> 1.49	0.122
95 % CI [mg test item/L]:	n.d.	0.077 - 0.170
EC10[mg test item/L]:	> 1.49	0.077
95 % CI [mg test item/L]:	n.d.	< 0.0423 -0.112
NOEC [mg test item/L]:	≥1.49	0.0836
LOEC [mg test item/L]:	>1.49	0.142
Values refer to geometric mean measured test concentrations CI: Confidence interval n.d.: not determinable NOEC and LOEC were determined directly from the raw data.

Validity criteria fulfilled:

yes

Conclusions:

The toxic effect of the test item, tribasic copper sulphate to Daphnia magna was assessed in a semi-static concentration-response test. The 48-hour NOEC was determined to be 0.0836 mg test item/L. The 48-hour LOEC was determined to be 0.142 mg test item/L and the 48-hour EC50 value was calculated to be 0.295 mg test item/L.

Executive summary:

The purpose of this study was to determine the influence of the test item, tribasic copper sulphate on the mobility of Daphnia magna. For this purpose, young daphnids (< 24 hours old) were exposed in a semi-static test to various concentrations under defined conditions for 48 hours in accordance with OECD Guidelines No. 202. The recorded effects were the mobility of the daphnids after 24 and 48 hours.

After 48 hours of exposure, no immobilisation of the test animals was observed in the control. At concentrations of 0.0423 and 0.0836 mg test item/L, one animal was immobile. At a concentration of 0.142 mg test item/L, four animals were immobile. 13 and 18 animals were immobile at concentrations of 0.296 and 1.49 mg test item/L.

The 48-hour NOEC was determined to be  0.0836 mg test item/L. The 48-hour LOEC was determined to be 0.142 mg test item/L and the 48-hour EC50 value was calculated to be 0.295 mg test item/L.

The initial concentrations and the maintenance of the exposure concentrations during the test were verified in the analytical part. All reported results refer to geometric mean concentrations, since the test item concentrations were not within ± 20 % of the nominal concentrations during the test.

Description of key information

The toxic effect of the test item Tribasic copper sulphate to Daphnia magna was assessed in a semi-static concentration-response test. The 48-hour NOEC was determined to be  0.0836 mg test item/L. The 48-hour LOEC was determined to be 0.142 mg test item/L and the 48-hour EC₅₀value was calculated to be 0.295 mg test item/L.

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates

Effect concentration:

0.295 mg/L