Microbiological monitoring of marine recreational waters in southern California

An inventory was conducted to assess the number, type, spatial distribution , and costs of microbiological monitoring programs in southern California m arine waters from Point Conception to the US/Mexico International Border. T he location of each sampling site was determined using global positioning s ystem (GPS), and estimates of geographic coverage were determined using geo graphic information system (GIS) techniques. Twenty-one programs conducted 87,007 tests annually at 576 sites in the study area. The largest number of sites was sampled in Orange County, whereas the largest number of analyses was performed in Los Angeles County because monitoring programs in this ar ea focused on daily monitoring. Fifteen of the 21 programs were managed by National Pollutant Discharge Elimination System (NPDES) permitted sewage ef fluent dischargers who sampled both offshore and shoreline waters and typic ally tested for three indicator bacteria (total coliform, fecal coliform, a nd enterococcus). Their combined efforts comprised 82% of all of the microb iological indicator analyses conducted on an annual basis. Five of the rema ining monitoring organizations were public health agencies, which typically focus their efforts on testing only total coliforms. Laboratory methodolog y also varied considerably, with NPDES permittees predominantly utilizing m embrane filtration while public health agencies generally used multiple tub e fermentation or premanufactured test kits. Nearly three quarters of all t he effort expended in southern California occurred along the shoreline as o pposed to offshore locations. Two thirds of this shoreline effort was focus ed on high-use sandy beaches and in proximity to perennial fresh-water outl ets (storm drains and creeks). Most sampling occurred at a set of fixed sit es that were revisited frequently, but only represented about 7% of the tot al shoreline. We estimated that roughly $3 million is spent annually on mon itoring bathing water quality in southern California, exceeding that spent in any other part of the country.