In Chapter 2, the generic approach to steps 1 and 2 is described and we applied as such to the four case studies. Deviations to these two first steps were relatively few and are discussed in Chapter 7. In this section the third step in the EFSA framework is discussed for each case study, i.e. the ranking of potential impacts for each habitat x ES combination using chemical exposure and effects information.
In an attempt to describe and capture ecosystem services in relationship to chemical use and disposal in the environment, a series of scenarios have been developed as examples to better understand the potential risks to ecosystem services. Scenarios include: oil refinery emissions to an estuary, oil dispersant application at sea, down the drain chemicals, air dispersed persistent organic pollutants (POPs). Whilst the Task Force’s application of the EFSA framework follows a prospective approach to informing risk assessment (generic or site specific), we recognise that the framework can also be applied retrospectively (site specific). For example, identifying relevant ecosystem services can follow a site-specific exercise dependent upon temporal and spatial aspects of the material release or application. Elements of ecosystem services may overlap between similarly described habitats and may be an ecological entity or a physical aspect. When conducting an ecosystem services evaluation it is often necessary to utilise local experts in the fields of environment and socio-economic issues, who are familiar with the local complexities and priorities. Nevertheless the following chemical case studies are intended to cover a broad range of generic cases. Note that we have identified and considered only negative effects of the chemicals represented in the case studies. Positive, impacts may arise, e.g. indirect effects following application of oil dispersants is usually tied to oil spills. As such dispersants enhance the opportunities for water purification through material breakdown enabling micro-organisms to better feed upon contaminants.