Simplified Linear Dose‐Response Models for Low‐Dose QMRAs

This study analyzes widely used dose‐response (DR) models from potable reuse quantitative microbial risk assessments (QMRAs) to identify the low‐dose ranges where the log 10 ‐transformed probability of infection and pathogen dose exhibit a linear relationship. Target pathogens include norovirus, adenovirus, enterovirus, Cryptosporidium , and Giardia . This study (i) defines the low‐dose linear range for each DR model, (ii) extracts slope and intercept parameters via regression, and (iii) shows that municipal drinking water risk thresholds fall within these ranges. This promotes low‐dose risk estimation transparency, reproducibility, and accessibility for utility decision making, regardless of the underlying complexity of the DR model. Also, this study shows that within the low‐dose ranges relevant to potable reuse, commonly used DR models exhibit linear relationships with a slope of ~1. Therefore, each 10‐fold reduction in pathogen concentration, equivalent to one log reduction value (LRV), reduces risk by a corresponding order of magnitude. Finally, the outputs from the various DR models are separated by relatively constant risk differentials, thereby reducing the need for complex DR‐based sensitivity analyses when conducting potable reuse QMRAs.