In-soil organisms

According to the entry into force of the Regulation (EC) N. 1107/2009, a revision of SANCO/10329/ 2002 guidance document has been necessary. In this framework a split was made between Non-Target Arthropods, Non-Target Terrestrial Plants and in-soil organisms and an EFSA Scientific Opinion has just been published about the latest ones.

In-soil organisms are defined as the set of species inhabiting mostly the soil and the soil litter layer as earthworms, nematodes, enchytraeids, mycorrhiza and many others.

In-soil organisms provide a wide variety of ecosystem services such nutrient cycling, biodiversity, pest and diseases control, food web support, natural pollution attenuation.

Once defined the Specific Protection Goals (SPGs) for the different groups or species, one aim of the Scientific Opinion was to assess the suitability of the existing effect test methods to address these SPGs.

For the choice of the standard laboratory methods, in addition to the feasibility and reproducibility criteria, the representativeness of the ecosystem to protect and the responses criteria were taken into account.

For Non-arthropods invertebrates no sensitive species alternative to Eisenia faetida has been identified while, for in-soil arthropods, Folsomia candida is still representative of the other springtails in terms of sensitivity.

Due to the lack of data on other species it wasn’t possible to evaluate if Hypoaspis aculeifer is really representative but surely it’s still significant since is the only predatory species with a standardized test method.

For soil microorganisms activities/functions, nitrogen transformation test is confirmed but dose- effect test design is recommended also for the agrochemicals.

For in-soil organisms further research has to be done to make applicable the use of Species Sensitivity Distribution (SSD) since there’s little experience in combining toxicity data from different groups of in-soil organisms.

Additional test methods could be planned to address specific issues such as trans-generational effects, bioaccumulation, avoidance and biomarkers.

Some limits of the laboratory tests have been identified such as their experimental design that fits more for spray applications, poor consideration of the oral route of exposure and the widespread use of standard artificial soils rather than natural agriculture soils.These issues will certainly be improved in the near future.