Anthropogenic Currents and Shoreline Water Quality in Avalon Bay, California

作者：Ho Lin C; Litton Rachel M; Grant Stanley B^*

来源：Environmental Science & Technology, 2011, 45(6): 2079-2085.

DOI：10.1021/es103904n

Shoreline concentrations of fecal indicator bacteria (FIB) and fecal indicator viruses (Fly) in Avalon Bay (Catalina Island, California) display a marked diurnal pattern (higher at night and lower during the day) previously attributed to the tidal flux of sewage-contaminated groundwater and the tidal washing of contaminated sediments, coupled with light and dark die off of FIB and FTV (Boehm, et al, Environ. Technol. 2009, 43, 8046-8052). In this paper we document the existence of strong (peak velocities between 20 to,40 cm/s)transient currents in the near-Shore Waters of Avalon Bay that occur between 07:00 and 20:00 each day. These currents, which have a significant onshore component, are generated by anthropogenic activities: in the Bay, including prop wash from local boat traffic and the docking practices of large passenger ferries. A budget analysis carried out on simultaneous Measurements of FIB at two cross-shore locations indicates that anthropogenic currents contribute to the diurnal cycling of FIB concentrations along the shoreline, by transporting relatively unpolluted water from offshore toward the beach. The data and analysis presented in this paper support the idea that anthropogenic currents represent a significant, and previously overlooked, source of variability in shoreline water quality.

• 出版日期2011-3-15