Assessment of historical emissions is outside the scope of this case study and the chemical is assumed not to be locally produced in Arctic regions. The chemical is expected to have low but ubiquitous concentrations in all Arctic habitats (see Figure 4.4). It is possible that larger dilution factors in the open ocean might result in lower concentrations than those found in coastal habitats. However, such differences are small and are not considered likely to affect the major concern associated with accumulation of POPs through food webs. Although lotic and lentic freshwater habitats have been considered separately in this case study, both habitat types could have been combined into a generic freshwater habitat since the potential for exposure and food chain accumulation is likely to apply to both. Differences in exposure concentrations would be addressed in any risk assessment of the POP chemical in prioritised SPUs.
The chemical would be expected to be detected in most habitats around the globe but notably in Arctic regions due to global fate and transport processes such as atmospheric advection and polar condensation. In this study the assessment of exposure is restricted to the Arctic environment. Local transport processes could also be important, e.g. terrestrial to aquatic systems.
Figure 4.4: Emissions of a POP-like chemical to Arctic regions
Table 4.4: Potential impact of Persistent Organic Pollutant (POP) on specific ecosystem services (green: no impact; yellow: moderate impact; red: severe impact) and potentially impacted service-providing units (SPU)