Research - Category III: Water Quality

Is Urban Runoff a Source of Human Pathogenic Viruses to Recreational Beach Waters
(Funded 2000-2001)

Principal Investigator: Sunny C. Jiang
Department of Environmental Analysis and Design
UC Irvine
(949) 824-5527
sjiang@uci.edu

Executive Summary:
Southern California beaches are unique recreational and economic resources to the state of California due to their temperate climate and long coastline. More than 100 million people worldwide visit Southern California beaches and coastal areas annually to sunbathe, surf, swim and scuba dive. The recent closure of Huntington Beach in Orange County, due to bacterial contamination, during the summer of 1999 has drawn both state and national attention. After months of intense investigation into the source of contamination, it was concluded that urban runoff from either the Santa Ana River or nearby wetlands were the possible sources of pollution. In addition, a systematic investigation of beach water quality along the coast of Southern California indicated the presence of human viruses at many sites, especially near the mouths of rivers, creeks and wetlands. Thus, this suggests that urban runoff may be an important source of viral pollution of beach waters. With the rapid urban development of Southern California, the volume of urban runoff will only increase in future years. Therefore, it is crucial to understand if urban runoff is a persistent source of beach contamination in order to develop proper strategies for the management of storm water. The objective of this study is to refine current methods for the detection of human viruses in urban runoff and to understand the prevalence, distribution and seasonal pattern of viruses in urban waterways. Since Southern California displays distinct dry and wet seasons, the runoff viral load is expected to be the highest during the first heavy rainstorm of the wet season. A sequential sampling of storm water after the first "storm flush" of the wet season will provide information on the supply, transport and fate of viruses in urban waterways. In this study, a molecular technique based method will be used for the sensitive detection of several types of human pathogenic viruses. This method has been successfully applied to the detection of viruses in seawater and sewage; therefore it is a feasible method to be adopted to detect viruses in urban waters. Water samples will be collected from 12 sites in rivers, creeks and lagoons of Southern California from Malibu to the Mexican border to understand the prevalence of human viruses in urban waterways. A more detailed study in the second year will focus on two major urban rivers, the Los Angeles and Santa Ana rivers, to investigate geographical and seasonal patterns of viral distribution in these systems. The viral abundance and distribution will be correlated with the temperature, level of precipitation and other biological parameters to create a model on the source, fate and transport of human viral pollutants in urban runoff. The results of this study will answer the question as to if urban runoff can be a major source of beach contamination and thereby assist with the development of proper strategies to manage urban runoff.