Copper di(acetate)

Toxicity to terrestrial plants

Administrative data

Endpoint:

toxicity to terrestrial plants

Type of information:

experimental study

Adequacy of study:

supporting study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Already evaluated by the Competent Authorities for Biocides and Existing Substance Regulations.

Cross-reference

Reason / purpose for cross-reference:

reference to same study

Data source

Reference

Reference Type:

publication

Title:

Soil factors controlling the expression of copper toxicity to plants in a wide range of European soils

Author:

Rooney, C.P. et al.

Year:

2006

Bibliographic source:

Environ Toxicol Chem., 25(3):726-32

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

other: ISO 11269-2 method for measuring the inhibition on emergence and growth of higher plants (Lycopersicon esculentum)

Test guideline 2

Qualifier:

according to guideline

Guideline:

other: ISO 11269-1 method for measuring the inhibition of root growth (Hordeum vulgare)

GLP compliance:

not specified

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

Test organisms

1

Species:

Hordeum vulgare

Plant group:

Monocotyledonae (monocots)

Details on test organisms:

Barley

2

Species:

Lycopersicon esculentum

Plant group:

Dicotyledonae (dicots)

Details on test organisms:

Tomato

Results and discussion

Effect concentrations

Dose descriptor:

other: see summary

Remarks on result:

other: see summary

Any other information on results incl. tables

see Executive summary

Applicant's summary and conclusion

Conclusions:

The paper provides regressions between Cu toxicity in plants and soil properties : CEC and pH. The data support the normalization of plant toxicity data

Executive summary:

The impact of soil properties on metal bioavailability is well recognized. However, the effect of soil bioavailability parameters on toxicity threshold values for Cu in plants needs quantification. Eighteen European soils varying widely in soil properties were amended with CuCl₂ to obtain a range of seven concentrations including an unamended control. Two plant toxicity assays, barely root elongation (4d) and tomato shoot growth (21d after emergence), were performed on each soil under controlled environment conditions. The effective concentration of added Cu causing 50 % inhibition (EC50) ranged from 36 to 536 mg/kg soil and from 22 to 851 mg/kg soil for barely root elongation and tomato shoot growth, respectively, representing variation in EC50 among soils of 15- and 39- fold. Single regressions carried out between Cu toxicity threshold values and various soil properties showed that exchangeable calcium and soil cation exchange capacity (CEC; measured at soil pH) were the best single predictors for toxicity values from both plant tests. The inclusion of other soil properties, such as iron oxide concentration, soil pH, clay, or organic carbon content, further improved predictions. For risk assessment, we suggest that Cu toxicity threshold values (EC50) be nomalized on the key soil property of CEC. If available, soil exchangeable calcium and iron oxide concentration would improve the normalization.