PRELIMINARY WATER QUALITY INVESTIGATION USING ENTEROCOCCUS CONCENTRATIONS IN TIDAL CHANNELS AT SILVER SANDS STATE PARK, MILFORD CT

The Enterococci species can be used as a fecal indicator bacterium (FIB) to indicate the presence of pathogenic micro-organisms associated with contamination from storm water runoff, sewage infrastructure, or human or animal fecal waste. From a human health perspective, detecting the presence and concentration of FIB is of particular interest in a public access area like Silver Sands State Park.

Prior land use at the current location of Silver Sands State Park has led to water quality concerns in the past. The Park was utilized as an unregulated landfill for over 25 years, until 1977 when the landfill was closed and partially capped with fly ash and sewage sludge. The 15-meter, topographic high created by the landfill altered the groundwater and surface water hydrology of the area. Monitoring wells were installed and water quality analysis of surface and groundwater revealed elevated levels of many contaminants including total coliforms at or above Federal and State levels. The DEP currently monitors seasonal water quality at a site in Great Creek, and also along the eastern beach.

In order to investigate water quality around the former landfill and its potential influence on water quality at the swimming areas, 20 surface water and sediment samples were collected from 3 tidal creeks within the park. The primary objectives of this pilot study were threefold: 1) to determine the presence and/or concentration of FIB in sediment and water within the tidal creeks; 2) to compare our results to previous water quality studies; and 3) to assess whether the sediment may be acting as a reservoir for the bacteria.

Preliminary results revealed 3 samples with levels of Enteroccocus bacteria that were above the detection limits of our laboratory methods. The bacterial concentration in an additional sample measured 3 times the limit put forth in federal water quality standards. Fieldwork in March of 2012 will employ a grid-sampling strategy based on these locations to ascertain potential sources of contamination.