Modeling the Health Risk of Stream E. coli with Qualitative Microbial Risk Assessment and Assessing its Relationship with Social Vulnerability Index

Abstract

Escherichia coli contamination poses a significant water quality challenge, especially in recreational water settings, with adverse health effects particularly pronounced in socially vulnerable communities. Despite regional studies, a comprehensive national understanding of spatial-temporal variations in E. coli health risks remains a challenge, and the association between social vulnerability and E. coli exposure in recreational waters is understudied. Utilizing a continuous E. coli time series from national stream data spanning 1987-2022, we conducted a quantitative microbial risk assessment (QMRA) to evaluate E. coli exposures during water-related recreational activities across the U.S. We employed the Mann-Kendall trend test to analyze monotonic trend patterns in E. coli infection probabilities. Our findings pinpoint E. coli risk exposure hotspots, predominantly in the Midwest and West regions, notably in Wisconsin, Minnesota, Iowa, Missouri, and Oregon. Regional disparities in social vulnerability are closely associated with elevated E. coli health risks across various dimensions. Of the 406 sampling sites assessed, 76 showed an increasing trend in E. coli infectious probability, while 107 exhibited a decreasing trend. Regions with increasing health burdens are predominantly vulnerable in the Southeast and Southwest, while decreasing health burdens are observed in the Northeast. This research offers novel insights into E. coli health risk dynamics in U.S. streams, informing the formulation of targeted public health interventions and environmental management strategies to enhance water safety during recreational activities.