Timeline: 2007
Collaborator: Southern California Coastal Water Research Project (SCCWRP)
Study Location: Laboratory of the Orange County Sanitation District Laboratory (OCSD)
Role: Lab Manager
Background:
The Southern California Coastal Water Research Project (SCCWRP), in partnership with the Cooperative Institute for Coastal and Estuarine Environmental Technology (CICEET), was planning to conduct an epidemiology study of swimming-related illness (see section 10) in summer 2007 at Doheny State Beach and other beaches. Part of the study involved measuring new indicators, most of which have been anticipated to be present at much lower density than historically measured fecal indicator bacteria (FIB). Moreover, the principal fecal sources at Doheny Beach were thought to be urban runoff and birds. Even though more than half of the samples previously taken at the site exceed enterococcus standards, it was thought possible that many of the samples collected during the epidemiology study will contain low counts of the alternative targets.
Interpreting outcomes from the epidemiology study required the ability to confidently differentiate non-detects of target organisms attributable to low density at the study site from a recovery issue associated with the new measurement method. To better understand method sensitivity for the new measurement methods and measurement targets, SCCWRP wanted to conduct a methods evaluation study prior to the epidemiology study. Results from the evaluation study will provide participants an opportunity to refine their methods before they begin processing irreplaceable field samples from the epidemiological study.
A secondary objective of the study was to train SCCWRP personnel in the sample processing and analysis techniques that will be performed during the epidemiological study. More than 20 water quality measurement methods have been included in the epidemiological study. For most of these, SCCWRP will be responsible for collecting, filtering, storing and shipping filters to our partners at external laboratories. While some methods share a common filtration or DNA extraction technique, most have been developed independently and require individual filtrations or unique sample manipulations. SCCWRP was committed to performing each sample preparation and/or analysis protocol in a manner that ensures quantification of a target if it is present in the sample. This study allowed SCCWRP personnel to interact with the method
developer to ensure familiarity with each method in advance of the epidemiological study.
Alexander Schriewer participated in this study in April 2007 as a representative of the Dr. Wuertz laboratory and its methods for the following epidemiological study.
Publication:
Griffith, J.F., Cao, Y., McGee, C.D., Weisberg, S.B., 2009. Evaluation of rapid methods and novel indicators for assessing microbiological beach water quality. Water Research 43, 4900-4907.