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Ecotoxicological information

Toxicity to soil macroorganisms except arthropods

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Administrative data

Endpoint:
toxicity to soil macroorganisms except arthropods: 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:
Analysis of separate and combined effects of heavy metals on the growth of Aporrectodea caliginosa (Oligochaeta; Annelida), using the toxic unit approach
Author:
Khalil M.A.et al.
Year:
1996
Bibliographic source:
Applied Soil Ecology 4, 213-219

Materials and methods

Principles of method if other than guideline:
The effects of mixtures of three heavy metals, cadmium, copper and zinc, on the growth of earthworms were assessed.

Test material

Reference
Name:
Unnamed
Type:
Constituent

Test organisms

Test organisms (species):
Aporrectodea caliginosa

Study design

Study type:
laboratory study
Substrate type:
natural soil

Results and discussion

Effect concentrations
Duration:
6 wk
Dose descriptor:
NOEC
Effect conc.:
25 mg/kg soil dw
Nominal / measured:
meas. (arithm. mean)
Conc. based on:
element
Basis for effect:
growth
Remarks:
(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 25 mg/kg (growth)
No bioavailability correction possible as CEC is not given or can not be derived.
Executive summary:

The assessment of polluted soils is often made difficult by the presence of a mixture of toxicants. In this study the authors try to analyse the effects of mixture of three heavy metals, cadmium, copper and zinc, on the growth of earthworms,Aporrectodea caliginosa. Laboratory toxicity tests were conducted in which worms were exposed, over a period of 6 weeks, to sulphate salts of metals mixed into a natural soil. EC50s and EC10s were estimated for each metal separately following a log-togistic curve fitting of growth versus exposure concentration. Cadmium was the most toxic metal followed by copper and zinc; relative toxicities on a molecular basis were approximately Cd:Cu:Zn = 1:2:10. Based on a single metal EC50s, a mixture of one-third of the concentrations of three metals was prepared to cover the whole effect range and effects of the mixture were evaluated against toxic units derived from the separate metal tests. The EC50of the mixture was not significantly different from unit (1.33 toxic units). It may be concluded that the effect of mixture of metals on the growth of earthworm can be described by relative addition of concentrations, although there was a tendency for antagonism.