Soil and Sediment – strategic planning

Soil and Sediment – strategic planning

Identifying baseline data needs

Expert interpretation of the baseline information appropriate to the Annex requirements is an important starting point for strategic planning of soil and sediment studies. This includes identifying data gaps and cases where additional requirements apply, for example from PBT assessment needs. In some cases, adaptation criteria may reveal instances where additional testing is not required. The chemistry context of each substance is central to test planning from the outset. Similarly, understanding specific requirements of ECHA and being aware of pre-existing test proposals with regard to the legalities and timings associated with conducting tests is necessary. Finally, a substance impurity profile, where hazardous properties of the impurities need further consideration, should be identified early.

What can be established from available data?

A chemistry-oriented understanding of the data set is an essential foundation when planning the direction and methods of further research and experimental work. Expert analysis of available ecotoxicology studies presenting known effects can help identify which terrestrial and sediment species are likely to be sensitive, and thereby affect testing strategy. It may be that data are available or required for closely related substances. In this case, read-across and establishing an integrated testing strategy can considerably reduce the amount of testing needed. Other important areas which require expert consideration include the relevance of physicochemical and adsorption properties, the duration of any prospective new study, suspected and established modes of toxicity of the substance, and how existing PNECs have been derived.

Exposure and risk as driving factors

It may not be necessary or useful to perform every soil and sediment test required under a particular Annex level. It is therefore practical to attempt to identify the most sensitive compartments early on via the exposure modelling process, before conducting further studies. We are able to provide a full review of the approach to exposure assessment to ensure that the exposure to soil and sediment has been estimated appropriately based on all available data.

Other important factors to consider in planning testing strategy include the stability properties of the substance and the exposure pathway dominating environmental concentration in soil. Outside the scientific data set, business development factors (such as expansion into new applications or a potential future tonnage increase into a higher tonnage band) would result in increased information requirements.

Technical planning of studies

Once the compartments and endpoints of most significance have been identified, it is necessary to approach the experimental work with care, in order to maximise the relevance and usefulness of studies conducted. Outcomes of new tests can still influence the planning. The use of appropriate techniques in the conducted studies is fundamental to a coherent testing strategy. Similarly, the choice of guideline in terms of study design and applicability in the global regulatory context is important. Finally, substance specific technical issues such as volatilisation or instability are best identified in the planning phase of the technical studies, in order to ensure the resulting experimental work is valid, relevant, and informative.