Copper dichromium tetraoxide

Toxicity to soil macroorganisms except arthropods

Administrative data

Endpoint:

toxicity to soil macroorganisms except arthropods

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:

Development of a Standardised Reproduction Toxicity Test with the Earthworm Species Eisenia fetida andrei Using Copper, Pentachlorophenol and 2,4-Dichloroaniline.

Author:

van Gestel, C.A.M., Van Dis, W.A., Breemen, E.M. & Sparenburg, P.M.

Year:

1989

Bibliographic source:

Ecotoxicol. Environ. Safety. 18: 305-312

Materials and methods

Principles of method if other than guideline:

The experimental design was set out to describe chronic earthworm toxicity using test systems designed to define acute toxicity.

Test material

Test material information

Constituent 1

Reference substance name:

soluble copper

IUPAC Name:

soluble copper

Test organisms

Test organisms (species):

Eisenia fetida

Study design

Study type:

laboratory study

Results and discussion

Effect concentrations

Dose descriptor:

other: see summary

Remarks on result:

other: see summary

Any other information on results incl. tables

RS-Freetext:
Copper analysis - All Soil tests
		
Initial concentrations of test substance
Nominal exposure concentrations in the soil are provided
table A7_5_2_1-4
	
Effects of soil characteristics
	
Concentration-response curves	
The results of the cocoon production test are shown in
Figure A7_5_2_1-1.
 	
Toxicity thresholds	
Cocoon Production
There was no difference between the number of cocoons
produced in jars with treated and untreated cow dung. In
Figure A7_5_2_1-1 the numbers of cocoons produced are
therefore averaged for all four jars per concentration.

EC50 values for the effect of Cu (phase B) on cocoon
production by E. fetida andrei are 191 (163-223) mg/kg dry
artificial soil. Using Student t tests the NOEL value for Cu
(phase B) was 120 mg/kg.

In phase A* of the test, the increase in worm weights was
affected in a dose-related manner: 19.9% increase in control
and 0.3% at 300 mg Cu per kg. During phase B, however, the
opposite occurred: control worms lost 4.4% of their weight,
while at 300 mg Cu per kg worm weights increased by 21.1 %.
There seemed to be a negative correlation between growth and
cocoon production during phase B, but not during phase A*.
In phase A* cocoon production was more affected than in
phase B. In phase C worms did recover cocoon production to a
level as high as or even exceeding control. 

Cocoon hatchability 
Cocoon hatchability was not affected by Cu (Table
A7_5_2_1-4).
	
APPLICANT'S SUMMARY AND CONCLUSION
	
Materials and methods	
This reference describes an extension to a standardised
acute (lethality) test method to enable determination of the
effect of chemical substances on the reproduction of the
earthworm Eisenia fetida andrei. It is based on the existing
guidelines for acute toxicity testing with earthworms.

After being preconditioned for one week in untreated soil,
earthworms are exposed to the chemical substances for 3
weeks. The number of cocoons produced is determined, and
cocoons are incubated in untreated artificial soil for 5
weeks to assess hatchability. 
	
Results and discussion

From Figure A7_5_2_1-1 it can be concluded that cocoon
production is always higher in phase B than in phase A. This
proves the necessity of a preincubation period to enlarge
the number of cocoons produced and with this the reliability
of the test.

From other data described in the reference relating to two
other test materials (not reported in this summary), it can
also be concluded that there is a large variation in the
amount of cocoons produced in the different tests. In phase
A of the Cu test, only 0.3-0.4 cocoons per worm per week
were produced, in the PCP test 1.0-1.3, and in the DCA test
1.4-2.2. In controls of phase B the difference between Cu
and PCP was reduced: 1.2 and 1.4 cocoons/worm/week,
respectively. In the DCA test more cocoons were produced:
2.0 cocoons/worm/week. Finally, in phase C cocoon production
was more or less similar for all three tests.
The number of juveniles per cocoon and the number of fertile
cocoons also varies greatly between the three tests
described. In the Cu test, 42% of the cocoons in the control
were infertile; in case of PCP this was 14.8%, and for DCA
5.7%. The number of juvenile worms per fertile cocoon were
1.7, 2.3, and 3.5 for the controls of the tests with Cu,
PCP, and DCA, respectively. The authors speculate that since
the tests were not performed at the same time, it is
possible that the reproductive performance of E. fetida
andrei is influenced by the season. 
Because of high infertile control values, the results are
less robust than would otherwise be expected, however the
NOEL for cocoon production has statistical strength.	

EC50 values for the effect of Cu (phase B) on cocoon
production by E. fetida andrei are 191 (163-223) mg/kg dry
artificial soil. Using Student t tests the NOEL value for Cu
(phase B) was 120 mg/kg.

Applicant's summary and conclusion

Conclusions:

The data warn against use of cocoon production as reliable endpoint for Eisena Feitida

Executive summary:

CL-Freetext:

The experimental design was set out to describe chronic

earthworm toxicity using test systems designed to define

acute toxicity. Therefore it is not considered appropriate

to assess these data in light of validity criteria designed

for the acute guidelines.

However, high infertile control values indicate the cocoon

fertility data are less robust than would otherwise be

expected, indicating these data are not useable in the risk

assessment. However the NOEL for cocoon production has

statistical strength and indicates a NOEL of 120 mg/kg dw

can be derived from the results.

Reliability

The report does not provide extensive information on the

test material, preparation of the spiking solutions, or

spiking protocol, neither was the work performed to the

principles of GLP. The work was performed to an adaptation

of existing guidelines, and the results indicate very high

control cocoon infertility.

Therefore it is appropriate to classify the reliability as

2.