Targeting assessment data requirements

The Mitre Model and site ranking. EPA has developed a hazard assessment model (commonly called the Mitre Model) to help rank problem hazardous waste sites for potential Superfund response. The model is a relatively simple one, with minimal data requirements. The model is designed to provide scores for actual or potential impacts on health or the environment by three routes of exposure — groundwater, surface water, or air emissions — as well as by direct contact or fire and explosion. Parameters include toxicity, quantity, physical state and persistence of the waste at a site characteristics of a potential route (to groundwater, surface water, or air) of release of the wastes, e.g., soil permeability the mode of exposure or use of the natural resource, e.g., an aquifer or surface waters used for drinking water and the target of... 

To assess the risk of contamination of the environment or exposure of non-target organisms, the potential of the pesticide for movement through the environment must be addressed. For pesticides used in, on or over soils, a study of the pesticide s breakdown in soil is retpiired. Similarly, for pesticides intended for use in or near water, or whose entry into water cannot be mled out, information must be supplied on mobility in soil and on the fate in the aquatic environment, including natural water/sediment systems. Such requirements and any trigger values for performing different types of study are detailed in the data requirements guidance. 

The advantage of the basic targeting assessment lies in its simplicity it can be done quickly if the right data are available, it does not require exceptional analytic skills, and it produces results that are relatively easy to understand and interpret. However, this simplicity brings with it a number of limitations, some of which can be handled by more elaborated forms of targeting assessment (table 6.10). 

The transition from single- to multi-risk assessment represents a process in which both the complexity and the data requirements are significantly increased (Fig. la). This transition implies a shift from a hazard-centered perspective that characterizes the single-risk assessment, to a territorial-centered one. In fact, from a multirisk perspective, the first element to be defined is the target area of interest, which is in general terms the piece of territory composed of elements at risk that are vulnerable in different ways to various sources of hazard. 

Screening hundreds of compounds against 80-100 targets/year is an expensive research endeavor Ho vever, it is one of the crucial parts of predinical safety assessment and is also required by regulatory authorities [9]. Beside a better understanding of compound bioactivity profiles, which in some cases can be reliably linked to clinically observed side effects, there is also a particular aspect of the generated data which makes it worthwhile to be analyzed in more detail. 

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