Evaluation of bacteriological and nutrient concerns in nearshore waters of a barrier island community in SW Florida

To determine if local onsite treatment systems affect nearshore water quality, seasonal and rain event monitoring of bacteria and nitrogen was conducted on the Gulf and estuary sides of Captiva Island. Monitoring wells were used to examine the relationship between surface water and groundwater quality. es were found to be significantly greater in ground water samples from the areas of Captiva using onsite treatment compared to areas with sewer. However, groundwater enterococci were no greater in areas with onsite treatment. Surface water nitrogen was significantly greater near onsite systems than areas with sewer, linking groundwater and surface water quality. e water enterococci increased significantly after rain events. Study results indicated stormwater runoff disperses indicator bacteria from diffuse terrestrial sources into nearshore waters, elevating the concentrations. tudy reveals local onsite treatment systems produce elevated surface water nitrogen levels but do not contribute to elevated indicator bacteria concentrations in this system.