The results reported here establish the relevance and propose a method for including biotic transport in the assess111ent and 1 icensing process for commercial low-level waste disposal sites. Earlier work identified the biotic transport mechanisms and process scenarios linking biotic transport with does to man, and developed models for assessment of impacts. !n this, the second phase of the project, we focused on a review of the sub-models of the B!OPORT computer code and scenarios that were developed in Fhase I. Also site specific assessments of the relevance of biotic transport were conducted for two commercial low-level waste disposal facilities. The resulting Case calculotions indicate that the current BIOPORT/f•1AXI1 models predict lower doses than the previous ordPr-of-magnitude estimates developed in Phase I. However, the resulting doses, depending on model and scenario assumptions, range from the same order-of-magnitude to an order-of-magnitude lower than the doses from the comparable intruder-agriculture scenaric. The efforts to review and enhance the BIOPORT model resulted in the following: • no change in the sub-model representing waste package form de campo~. it ion 4.4.1 Cover Cor1figuration 4.4.2 Erosion Rates. .. . 4.4.3 Plant Populations. . 4.4.4 Animal Populations o o 0 0 4o4o5 ~Jaste-Package Form Integrity \' 1 •i iii 1.1 1.1 2.1 2 .I 2.2 2.4 2.5 2.5 2.7

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