Lewis-Lynch-Nikiforov Approach

In 1990, Lewis et al. published a new approach introducing flexibility such that both new information and expert judgment could be readily incorporated. The Lewis-Lynch-Nikiforov (LLN) method, and its rehnements, are extensions of established principles and procedures, and 

Toxicological Risk Assessments of Chemicals A Practical Guide 

FIGURE 5.1 Subdivision of the 100-fold UF showing the relationship between the use of UFs (above the dashed line), and the proposed subdivisions (below the dashed line) based on toxicokinetics and toxicody-namics. (From Renwick, A.G., Food Addit. Contain., 10, 275, 1993 WHO/IPCS Assessing human health risks of chemicals Derivation of guidance values for health-based exposure limits. Environmental Health Criteria 170. Geneva, 1994. Available at http //www.inchem.org/documents/ehc/ehc/ehcl70.htm) 

An aggregate adjustment factor of about 250 is typical the theoretical maximum value is 

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Lewis, S.C., J.R. Lynch, and A.L. Nikiforov. 1990. A new approach to deriving community exposure guidelines from no-observed-adverse-effect levels. Regul. Toxicol. Pharmacol. 11 314—330. 

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