Copper hydroxide nitrate (Cu2(OH)3(NO3))

Long-term toxicity to fish

Administrative data

Endpoint:

fish, juvenile growth test

Type of information:

migrated information: read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Data source

Reference

Reference 1

Reference Type:

secondary source

Title:

Unnamed

Year:

2006

Reference 2

Reference Type:

publication

Title:

Effects of different ligands on the bioaccumulation and subsequen depuration of dietary Cu and Zn in juvenile rainbow trout (Oncorhynchus mykiss)

Author:

Kjoss, V.A., Wood C.M. and Mc Donald, D.G.

Year:

2006

Bibliographic source:

Canadian Journal of Fisheries and Aquatic Sciences , Vol. 63, 412-422 (2006)

Materials and methods

Test guideline

Qualifier:

no guideline followed

Principles of method if other than guideline:

Juvenile rainbow trout (Oncorhynchus mykiss) were exposed to control food or to food supplemented with different Cu (~400 µg·g–1 food) compounds. Tissue metal accumulation was compared among groups.

GLP compliance:

not specified

Test material

Test material information

Constituent 1

Reference substance name:

Copper oxide

EC Number:

215-269-1

EC Name:

Copper oxide

Cas Number:

1317-38-0

Molecular formula:

CuO

IUPAC Name:

copper (II) oxide

Constituent 2

Reference substance name:

CuO

IUPAC Name:

CuO

Details on test material:

CAS number: 1317-38-0
Formula: CuO

Test solutions

Details on test solutions:

Copper oxide was obtained from Aldrich Chemical Co., Milwaukee, Wisconsin, USA. Diet was processed as follows: 110 mL of deionized water with predissolved metal complex were added to 250 g of starter feed and mixed thoroughly with pasta maker. Food was then extruded in small pellets, dried at 60°C and allowed to cool to room temperature prior to being crushed into fine powder by hands.

Test organisms

Test organisms (species):

Oncorhynchus mykiss (previous name: Salmo gairdneri)

Details on test organisms:

Juvenile rainbow trout (mean weight around 200 mg) were obtained from a local trout farm.

Study design

Test type:

flow-through

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

15 d

Post exposure observation period:

15 days

Test conditions

Hardness:

140 mg/L as CaCO3

Test temperature:

12.5°C

Salinity:

Alkalinity = 95 mg/L as CaCO3

Results and discussion

Effect concentrations

Duration:

15 d

Dose descriptor:

NOEC

Effect conc.:

292 800 µg/L

Nominal / measured:

meas. (not specified)

Conc. based on:

element

Remarks:

Copper

Basis for effect:

other: residue

Details on results:

Free ionic copper is considered the active ingredient in inorganic copper salts, and is believed to be repsonsible for adverse effects. The bioavailablity of the copper ion at target sites determines the severity of effects. Both copper oxide and and copper hydroxide nitrate are considered sparingly soluble inorganic copper salts and would be expected to dissociate similarly within the organism.

Fish fed CuO showed no differences in tissue Cu concentrations relative to control fish, suggesting that Cu was not readily available for uptake in this form. In contrast, Cu in the form of CuSO4, Cu-proteinate, or Cu-lysine was much more available for uptake, resulting in substantial increases in liver, gut tissue, and whole-body Cu concentrations during the loading phase and decreases during depuration, although liver and whole-body levels remained elevated after 2 weeks. No differences in tissue Cu accumulation among these three complexes were found. There were no effects on growth.

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Conclusions:

Under the conditions of the test, the NOEL for Copper oxide, using a rainbow trout, was 292 800 µg Cu/L. Based on a content of 53% Copper in Basic Copper Nitrate, the fish NOEL for this substance is estimated to be 552 mg/L.