Conceptual Model Formation Sample Clauses

Conceptual Model Formation. Information gathered during the problem formulation provided a base for constructing the conceptual model. First, we divided the Port into eleven separate sub-areas (Table 2-1, Figure 2-1). Analysis of smaller areas within a region maximizes the chance of detecting effects from an anthropogenic input. We then selected categories for each of the regional risk components: sources, habitats, and impacts (Tables 2-2, 2-3, and 2-4). Source and habitat categories described anthropogenic and ecological components of the Port (Figure 2-2 and 2-3) whereas impact categories incorporated the assessment endpoints. Other categories can be nested into these primary categories. In this way all potential stressors, receptors, and receptor responses in the Port are included in the assessment. For instance, accidental spills are a source category that releases hydrocarbons and other stressors. Hydrocarbons include both alkanes and aromatic compounds. Aromatics can be further broken down into the monoaromatics and the polyaromatics, which in turn are made up of a numerous individual chemicals (e.g., benzo[a]pyrene, fluorene, and phenanthrene). Likewise, hydrocarbons represent a number of mixtures released into the environment. Crude oil, gasoline, diesel, kerosene, and jet fuel are all materials that contain an individual array of hydrocarbons, along with many other non- hydrocarbon constituents. Receptors in the environment are also numerous as demonstrated by the number of species found in the Port (Appendix B). For the model we placed receptors into general groups and identified the predominant habitat types in which they are found. Once these component categories were established, we explored links between the components. In traditional risk assessment, where one or only a few stressors, are involved the exposure pathway links the stressor to receptors. However, in a regional multiple stressor assessment the stressors can also be linked to sources, and the receptors to habitats (described in Section 1.2).