Copper dichloride

Toxicity to terrestrial plants

Administrative data

Endpoint:

toxicity to terrestrial plants: long-term

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.

Data source

Reference

Reference Type:

publication

Title:

Copper toxicity and phosphorus concentration in Florida-502 oats

Author:

Rhoads, F.M. et al.

Year:

1992

Bibliographic source:

Soil and Crop Science Society of Florida Proceedings 51, 18-20

Materials and methods

Principles of method if other than guideline:

This study was designed to determine P concentration of oat plants as a function of soil-Cu at three lime rates.

GLP compliance:

not specified

Test material

Test material information

Constituent 1

Reference substance name:

Copper dihydroxide

EC Number:

243-815-9

EC Name:

Copper dihydroxide

Cas Number:

20427-59-2

Molecular formula:

CuH4O2

IUPAC Name:

copper(II) dihydroxide

Test organisms

Species:

Avena sativa

Study design

Study type:

laboratory study

Substrate type:

natural soil

Results and discussion

Effect concentrations

Species:

Avena sativa

Duration:

49 d

Dose descriptor:

NOEC

Effect conc.:

100 mg/kg soil dw

Conc. based on:

element

Basis for effect:

other: yield (No bioavailability correction possible as CEC is not given or can not be derived.)

Remarks on result:

other: No bioavailability correction possible as CEC is not given or can not be derived.

Any other information on results incl. tables

see Executive summary

Applicant's summary and conclusion

Conclusions:

Reliability: high quality NOEC values is 100 mg/kg (yield)
No bioavailability correction possible as CEC is not given or can not be derived.

Executive summary:

Severe foliage chlorosis has been observed for oats (Avena sativa L.), grown in rotation with tomatoes (Lycoperiscon esculentum Mill.) sprayed with copper hydroxide [Cu (OH₂)] to control bacterial diseases where soil Cu level was near 100 mg/kg. This research was conducted to determine P concentration of oat plants as a function of soil-Cu at three lime rates. Oat plants were grown 7 wk in pots containing 2 kg of soil each from the A horizon of Orangeburg loamy fine sand (fine-loamy, siliceous thermic Typic Kandiudult).Copper rates of 0, 100, 200, and 400 mg/kg of time to give a factorial arrangement of 12 treatments, with all treatments receiving 100 mg/kg P. A treatment containing 200 mg7kg P, 400 mg/kg Cu and 6 g/kg lime was also included. Dry-matter yield of oat shoots and roots; tissue content of Cu, P, and Ca; soil-test Cu, P and Ca; and soil pH were determined. Copper concentration in oat plants was positively correlated (P<0.001) with applied Cu, while P concentration, P  uptake, and plant dry weight were negatively correlated (P< 0.001) with applied Cu. Yield of oat plants was almost doubled by increasing P from 100 to 200 mg/kg with 400 mg/kg Cu and 6 g/kg lime. The data suggest that Cu toxicity of oats is due to Cu-induced P deficiency.