Model regulatory, design

For the case where perturbations from a cyclic steady are moderate in magnitude, it is convenient to employ a linearized process model when designing a regulatory system. In particular, if the effluent profiles are linearized locally about the upstream and downstream cut points, and if the yield is maximized by enforcing the restriction Puic = P Equations 1-5 lead to the following result ... 

In general, the best models are designed to answer specific questions (Grimm and Railsback 2005 Chapter 9), and it seems that models are needed that are designed specifically to address the questions posed in regulatory risk assessments. 

Regulatory status In 1998, Lopez Canyon Sanitary Landfill received conditional approval for an ET cover, which required a minimum of 2 years of field performance data to validate the model used for the design. An analysis was conducted and provided the basis for final regulatory approval of the ET cover. The cover was fully approved in October 2002 by the California Regional Water Quality Control Board—Los Angeles Region. 

A spin-off of all of these task forces has been the open discussions that have led to improved design considerations and effective use of resources in the conduct of field exposure studies. These task forces have evaluated a variety of exposure measuring techniques, developed study designs for conducting studies, and performed field studies in a uniform and efficient manner. The task force protocols and designs have become models for the industry, having received valuable input and approval from the regulatory community. 

In addition to rodent studies, regulatory guidelines for pharmaceuticals require that repeated dose safety studies of up to nine months (in the United States, six months elsewhere) in duration be conducted in a nonrodent species. The most commonly used nonrodent species is the dog, followed by the monkey and pig. Another nonrodent model used to a limited extent in systemic safety evaluation is the ferret. The major objectives of this chapter are (1) to discuss differences in rodent and nonrodent experimental design, (2) to examine the feasibility of using the dog, monkey, pig, and ferret in safety assessment testing, and (3) to identify the advantages and limitations associated with each species. 

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