Evironmental project, 986 – Background report on pre-validation of an OECD springtail test guideline

Background Report on Pre-validation of an OECD Springtail Test Guideline

Summary and conclusions

The aim of the present project was to develop a draft proposal for an OECD test guideline for long-term toxicity-testing of Collembola (see Annex A). The draft guideline was based on two existing standardised test methods, one for Folsomia fimetaria (Wiles & Krogh, 1998) and one for Folsomia candida (ISO, 1999), which were combined and updated.

The test on F. candida employs an asexually reproducing species typically living in the organic matter of compost heaps or pot-plants, whereas the test on F. fimetaria employs a sexually reproducing species living in garden and agricultural soils. Accordingly for the test on F. fimetaria the effect on sexual reproduction is obtained. This latter may be seen as a more ecologically relevant endpoint than effects on asexual reproduction, as sexual reproduction is the most frequent reproductive strategy of soil dwelling organisms. In addition, effects on the sexual reproduction of F. fimetaria would include effects caused by chemicals that act via a disturbance of the sex-determination system in arthropods. In the present project the possibility of including a simple test for effects on the sex-determination was investigated, but this was not successful. Given distinct life strategies (and sizes) initial studies were performed investigating possible general sensitivity differences between the two species. The results indicate a difference in chemical sensitivity both according to species and to life-stage, but the differences could only partly be explained by size-differences.

To prepare for a ring-test of the draft test guideline three compounds were tested fipronil, 3,5-dichlorophenol and boric acid. Future test concentration ranges were identified for these compounds.